Auto-cycling vacuum pump for vaccum bagging veneers and vacuum clamping.

[TimberNut]

I've finally finished construction of my new auto-cycling vacuum system, so I thought I'd share the journey.
The original goal - to build a vacuum system to be used for vacuum pressing veneers, vacuum clamping stuff to the bench for sanding and routing, and also to connect to a vacuum clamp setup on the lathe.

When I starting researching how to go about it, these were the options I found I had:
- just buy a cheap refrigeration vacuum pump, to connect directly to a vacuum bag (bought or made), that would have to run continuously whilst clamping, till the glue dried (usually overnight).
- Buy a more expensive vacuum pump, that didn't disperse oil to the atmosphere (the problem with the refrigeration pump option). Use this pump, as above, to run continuously till the glue dried.
- Buy a ready made solution (vacupress)
- Build my own from parts sourced wherever.


When considering what path to take, each has pluses and minuses:
- Refrigeration pump
- PLUS - cheap
- PLUS - one purchase, and you're up and running
- MINUS - the pump atomises oil into the atmosphere, which means you either use it outside to protect your lungs, or you risk health issues if using indoors
- MINUS - the atomised oil will settle on everything in your shed, which is bad for many reasons.


- Oilless rocking piston pump (standalone)
- PLUS - no atomised oil
- PLUS - continuous rated - you can leave it running without it breaking, or voiding any warranty.
- MINUS - cost - a good one (continuous rated, with flow rate of ~5CFM) will cost you in the range of $800 - $1000
- MINUS - if used standalone it will run continuously, and whilst not excessively noisy, I don't really want any machinery noise all night that could upset neighbours
- MINUS - difficult to control vacuum pressure, and keep within a specified range.
- MINUS - if it doesn't auto-cycle on/off, you are limiting the life of the pump. The more it runs, the quicker it wears out.


- ready made solution
- PLUS - one purchase, and you're up and running
- MINUS - limited choice. There really is only 1 suitable solution out there that I could find - vacupress.
- MINUS - cost. I got a quote for a 5CFM model, and including postage was approximately $1500 AUD.
- MINUS - all internals are NPT thread as it is made in USA, so when sourcing spares, parts etc, you need to factor in that this is not a standard thread gauge readily available in Australia

- self-built solution
- PLUS - I could make it suit my requirements, without compromise
- MINUS - sourcing parts would take time, and total cost might creep up as I went along, depending on how elaborate I decided to be.
- MINUS - I didn't know much about vacuum pumps, regulators, relays, thread variations, brass fittings, filter options, etc etc etc.
- PLUS - There is good information available on joewoodworker.com about similar setups.

I quickly ruled out option 1 (refrigeration pump standalone). I value my health too much, and given what I ultimately hope to use my setup for, this just wouldn't cut it.

I ruled out option 2 (oilless rocking pump standalone). I can't risk upsetting my neighbours having machinery run all night whilst glue dries, and I just don't like the idea of it running all the time, wearing out quicker, even if it is continuously rated. Sooner or later it'll wear out. Also, not being able to easily keep vaccum pressure in a specified range, whilst not a massive issue when vacuum bagging veneers (as the more pressure the better), but would be a big issue when vacuum clamping on the lathe. This needs carefully controlled vaccum so you don't collapse the walls of thin pieces.

I ruled out option 3 (vacupress) for 2 reasons. Firstly, cost. I nearly died when I got the quote. Secondly, the issue of everything being NPT thread didn't appeal to me. I'd begun investigating a self-build solution, and was having lots of difficulty finding suppliers of brass fittings in BSP thread (which is the Australian standard), let alone trying to find NPT, which is standard in US, but not AUS.

I settled on option 4 - and set about researching everything I'd need to know to build my own solution. At that time I had no idea just how big an undertaking this would turn out to be. It's taken me 2 months to source everything I ended up needing, and many, many nights struggling to get my head around everything I didn't know. Silly little things like 'can I use a 40micron filter designed for air compressors and rated for 150PSI positive pressue, in a vaccum setup?'. The questions were many, and varied, and it's taken me 2 months to answer every question, and source every part. I'm not going to call myself an expert on vacuum pump setups now (that would be egotistical) but I will say I know so much more than I ever thought I'd need to when I started down this path. To quote a famous TV personality - "How hard can it be?" The answer - a hell of a lot harder than you think.


Am I sorry I chose this option - No. It's been a good learning experience (and you're never to old to learn something new, right?). But I do wish there were more options available here in Aus, because a self-build isn't for everyone, but the scope of what I'll be able to use this for I'm only just beginning to understand.

[BobL]

Given the flow rates are low, for those still interested in option one, it's very easy to filter most of the oil out of air using a crankcase oil vapour filter.
These can be purchased for about $20 on eBay.
If you wanted to be extra careful just vent the air exiting the filter outside the shed or even locate the whole pump outside the shed.

[Lappa]

Even with option 4) you must have purchased a vacuum source. You ruled out oiless rocking pump standalone and you ruled out a refrigeration standalone pump, so what did you purchase for your vacuum source?

[TimberNut]

Hey guys, yes, I ruled out using the oilless rocking piston pump standalone (ie 'just turn it on and leave it on'). I ended up buying an oilless rocking piston pump, then integrating that into an auto-cycling solution. (more details and pics to come, on that one).

[homey]

Hi TimberNut,

Thanks for sharing this with us. It’s very helpful for people like me who are just at the start of this jourmey.

I’ve looked at pumps from Yareus (Vacupress) - these seem very expensive in Australia. I’ve also looked at pumps from Airpress and Bagpress in the UK. All three seem to use the same type and make of pump, the Becker VT series (VT 4 Series - Becker Pumps - mdi (http://www.beckerpumpsales.com/vacuum-pumps-rotary-vane-oil-less-vt-4.html)) which are rotary vane pumps rated for continuous use against a vacuum and if I remember correctly Becker give a 4 year warranty. Noise level for the rotary vane pumps (8 m3) is 58db, about the same as a quiet conversation.

At Airpress in the UK their standard 4m3/hr pump is GBP480 plus postage (the pump is around 7kg)
Oil-less rotary vane Becker vacuum pump 4.4 AirPress (http://www.airpress.co.uk/279-standard-4m3hr-vacuum-pump-pump-only.html)

At Bagpress in the UK their website shows only a price for a kit including bag, hose, foot switch etc. it is GBP599 4m3 per hour Vacuum Press Kit - Professional Electric Presses - Bagpress (http://secure.instant-shop.com/bagpress/product30374catno40374.html)

In Victoria, Rob at Bettervac (Carbon Vane Becker Side Channel Blowers DVP Vacuum Pumps Australia (http://www.bettervac.com.au)) supplies all sorts of vacuum pumps (including Becker) but I haven’t asked for a quote yet.

Like you I’d prefer something that did not run all night so I’m looking forward to hearing more!

Thanks again,

Brian

[Bohdan]

Hi TimberNut,

Like you I’d prefer something that did not run all night so I’m looking forward to hearing more!



When I used to do a lot of vacuum laminating the glue tends to grab very quickly.

I think because the water in the glue evaporates in a vacuum environment the pump can be switched off after a few minutes.

The time is much shorter than the glue's open time and I had a timer on it that would switch the pump off, if I remember correctly, after about 15 mins.

[Newboy]

A rotary vane pump is designed to run continuously. The problem you will encounter with those, is, once you have reached a maximum vacuum, there is very little gas flow. Consequently, oil vapors will migrate out of the inlet, and onto whatever you are pumping on. This will not be wet, but you will be able to smell it on the wood. This is known in vacuum as backstreaming.

I would suspect that the ideal pump you need is a diaphragm pump. Typically they are cheaper ($150 USD). They are dry (no oil). They do not pull as much vacuum, but that is not important for what you are doing.
A good $2000 rotary vane will run for 10 Year’s continuously, and pull to 1 mTorr (1 millionth of atmosphere). A $200 diaphragm will pull to a thousandth of atmosphere. For veneering, either one would work. The diaphragm pumps also run continuously. At least, I have never seen any vacuum pump of any type that wasn’t.


Sent from my iPhone using Tapatalk Pro

[Chris Parks]

Would an Air Conditioning vacuum pump used to evacuate systems be used? There are heaps of old Automotive AC units laying around not used as the industry changes to more modern stuff.

[woodPixel]

I'm using an AirCon vacuum pump and its a ripper: https://hvacdirect.com.au/70-l-pm-2-stage-split-system-vacuum-pump/ (recommended by another forumite, but I cannot readily recall whom) .... (edit day after: I just had an email exchange from HVACdirect, Mike, "For your application you would need a single stage pump rather than a double. We do have single stage Value pumps which are pretty much made for that application.")

I've added a one-way valve to stop the fog getting in as well: Off The Edge Sailplanes :: Vacuum Bagging (http://www.offtheedge.com.au/page.php?id=18)

The idea of BobL to use a cylinder head oil filter on the outlet is excellent. When doing the initial air extraction it releases a light fog. This stops once the vacuum is beginning to form. The pump is quiet and not at all annoying when running.

edit: I bought this pump as its main purpose in life is to evacuate AC systems to a good hard vacuum for a long period of time to eliminate moisture in the systems. I felt this was an excellent predicator for doing stabilising of knife scales and pen blanks with cactus juice.

It seems I should also run an inline filter to stop accidental ingestion of goop (this has been discussed on another thread).

Any suggestions on hosing would be appreciated.

[bryn23]

Yeah the Vacupress aren't cheap, still can't get the head around the pricing here vs the states.

Did you consider, just getting a Festool VAC SYS Vac pump.

only does 2.2 cfm, but that should be plenty, if you aren't doing huge sheets.

From what i understand it cycles and is $999, plus the hose connection, and also a pre filter

[TimberNut]

Build info: Part 2:
Following on from my first post.

I'd decided on Option 4, and spoke to Rob @ Bettervac. I purchased the 140RVD. It's continuous rated, ~5CFM flow rate, and quiet. With no oil atomisation to worry about.

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So now I had the pump, it was time to figure the rest out.
A call to Rob confirmed the fitting on the pump was 1/4 BSP. This meant nothing much to me, so after a lot of investigation I concluded that BSP thread is standard in Aus, and if I'd bought a similar pump from the US,it would have come threaded with 1/4NPT instead. Given that BSP is our standard I decided I didn't want to mess around with adaptors and different thread gauges etc, so everything I had to find would need to be 1/4BSP. I figured, it's the Aus standard, so fittings should be easy to find, right? Well, maybe if you know the right suppliers to ask, yeah, but I didn't, and this decision would cost me 2 solid weeks of searching. I could have ordered them from ebay and waited a month for them to arrive, but as this was a bespoke solution I didn't really know what fittings I'd need, and would have to get them in several steps as things took shape, so I needed a local supplier I could run to, to get the odd fitting or 2. I decided to shelve that problem for now, and sort other stuff first.


For the pressure vessel, I'd read that you need to be using 'Class 12 Water Pressure Pipe', and the plans on joewoodworker.com call for 2x lengths of 4" pipe @ 15in long (x2 tanks). According to my calculations, each tank is ~3L volume. I scoured the net trying to locate suppliers of 100mm Class 12 pressure pipe, and they are only readily available at irrigation suppliers. That wasn't an option for me, so I decided that 50mm would do, as I could pick it up at Bunnings.


So, having decided on 50mm pipe, I needed to cram as much as I could into a toolbox to house everything. So at my local Bunnings, it was back and forth between the plumbing section to get PVC elbows, and T joints, and the tools section where all the toolboxes were, to try to figure out what I could realistically get into a toolbox, along with the pump, plus all the brass fittings to make the manifolds I'd need. The staff couldn't work out why I was pulling out every toolbox, and inserting PVC elbows and T's into them, this way and that, with a confused look on my face. :C


In the end I settled on this toolbox.

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Then I set about trying to come up with an arrangement of pipework that would give me the largest volume possible, leaving just enough room for other stuff to be purchased later. I was aiming for 6L capacity.


This is where I got to. It works out to be ~5.25L or thereabouts. It was the maximum I could cram in, so it would have to do. As it turns out, the is ample volume. It doesn't take too long to evacuate, but gives a good initial supply when connecting to a bag to be evacuated for initial pull down.

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[homey]

A rotary vane pump is designed to run continuously. The problem you will encounter with those, is, once you have reached a maximum vacuum, there is very little gas flow. Consequently, oil vapors will migrate out of the inlet, and onto whatever you are pumping on. This will not be wet, but you will be able to smell it on the wood.

Sent from my iPhone using Tapatalk Pro

Not with these pumps, Newboy. They are oil-less.

[BobL]

I know you wanted to have yours all self contained.
Otherwise what about using a 4kg LPG cylinder as a reservoir?
There's plenty of the available for free.
I know it takes a long time to get rid of the mercaptan smell out of them but new ones only cost $30 and that includes a tap so it will hold any vacuum that it has already attained.
Just thinking it would be safer than plastic?

[TimberNut]

Hi Bob, yes, I actually considered a 4kg LPG cylinder. I looked at the price of one new from SupaCheap Autos, and was surprised that it wasn't that expensive. I decided against it because of the size, and the weight. I was testing mine over the weekend, and took it down to 25in/hg and it will retain the vacuum in excess of 21in/hg for over 12 hours, without any issue. So I'm confident that there's no danger of it collapsing. The Class 12 PVC Pressure Pipe is a must though. I don't think I'd be so lucky if using regular thin walled PVC.

[Bohdan]

I use a discarded copper fire extinguisher. The correct model even has a standard pipe thread on top.

It is also used as a pressure vessel when I am on the end of a long air hose with a nail gun.

[TimberNut]

Build info: Part 3:
Now I had my pressure vessel sorted, it was time to glue it up.

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And then paint it (not that painting makes it work any better, but it sure looks nicer).

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Next I set about sourcing all the other parts I needed. The biggest hassle for me was sourcing 1/4BSP brass fittings. I tried everywhere I could think of and came up short, until one plumbing supplier suggested I try Pirtek. As it turns out they were the supplier I was looking for - local, with a good range of brass fittings. It's taken me 3 visits to my local Pirtek, to get all the fittings I actually ended up needing, mainly due to the compact nature of the manifold and that it had to fit in around the pressure vessel.


Other parts came from ebay (China mostly).

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I had some trouble sourcing the solenoid, as I didn't know much about them, and trying to understand what specs I needed was a challenge. In the end I sourced one from China, on spec, hoping it'd work. It didn't. It was a pilot-operated solenoid, and relies on positive pressure on the inlet port greater than atmospheric pressure, to assist the solenoid valve mechanism to move. After a lot of trial, and web trawling I determined I'd need a direct-acting solenoid, and the only real option was a 100 series Mac valve. They are ~$30-$40USD, but by the time you get them posted here it's $100+. And then you've got the issue of them not being 1/4BSP. I ended up sourcing mine from a pneumatics supplier in Aus. I was not real impressed with the cost, but was out of options. It works a treat and it was the final piece of the puzzle.
This is the original one I got, that didn't work, and the mac valve I ended up using.

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Below is the final, finished product. It uses a vacuum controller that I can set high/low thresholds on. The max current on the internal relay in the vacuum controller is 5A, so, to be safe I ran the pump and solenoid via a separate 20A relay, but I haven't measured the startup current on the pump to see if that was essential.
I've also set it up with dual switching so I can bypass the vacuum controller, to have the pump run continuously (necessary for vacuum chucking on the lathe).
At startup it will reach 25in/hg in about 30 seconds. It takes over 12 hours to get down to 21in/hg before the pump kicks back in to get it back up to 25in/hg (which takes about 15 seconds). So when gluing it may not even need to cycle back on once vacuum is reached (depending on how air-tight my vacuum bag fitting ends up). For me, having a pump run for ~15 seconds, once every 12+ hours is WAY better than having to leave the pump running continuously for 8+ hours (and a vindication of all the effort I've gone to in building it).


Hopefully this might inspire others to give it a go setting up an auto-cycling setup, rather than running the pumps continuously.

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[BobL]

Looks good - that purple paint looks like a winner !

[TimberNut]

Thanks Bob.

I'm not sure exactly why I chose purple. It just seemed like a nice colour when I saw the spray can, so I thought 'why not have a purple pressure vessel?' I couldn't come up with any answer to that one, hence I now have snazzy purple pipework!

The next item to tackle is making a large vacuum bag. I've got to figure out where to source the vinyl for the bag, the best way to glue it together, and what sort of valve to use, so I don't get any leaks.
I'm running a 3/8 reinforced hose from the pump, so ideally any fitting I attach at the other end wouldn't restrict the airflow (ie not a 1/4" fitting).

Does anyone have any suggestions on that front (making the bag etc)?

[Deverell]

I've been planning on putting a system together for a little while.

I was going to use an old air compressor tank and was thinking about one of those ac pumps but now you've got me thinking about this type...

In regards to the vinyl and the adhesive forum member thumbsucker made his out of .75mm vinyl sheeting from bunnings. He says it's worked out well. I think I will go this route too. For the glue he said use hh-66 vinyl cement which is the same stuff the Joe woodworker page suggests.

Here's a link to a local victorian seller.
HH66 Vinyl Cement - PCM Distributors Pty Ltd

I bought way more than I'll ever need for $50. Good price I thought and I'll have heaps left over to make lots of different sized bags.

[woodPixel]

HH66 Vinyl Cement - PCM Distributors Pty Ltd (http://pcmdistributors.com.au/hh66-vinyl-cement/)

[TimberNut]

whereabouts in Bunnings do you locate the vinyl? Is it with the rolls of flooring? Presumably its a roll of clear plastic I'm looking for (but I can't recall seeing anything like that at my local Bunnings).

I notice Clark Rubber list
GENERAL PURPOSE CLEAR PLASTIC 1.0MM X 1370MM @ $33.95 /m

https://www.clarkrubber.com.au/general-purpose-clear-plastic

How does that price compare with Bunnings price? and also I think 1370mm is a bit narrow. If I bought 2m and folded in half, that'd only get me 1m x 1.3m bag. Ok for the small stuff but not for bigger items. The pump I've made will cater for large items (ie table tops, should I have the desire to do that) and on the occasion I reckon a bigger bag would be called for. I reckon I'd be after a finished bag size somewhere around ~2m wide by ~3m long.

What dimensions is the Bunnings vinyl in?

Also, any recommendations on the valve connection?

[woodPixel]

TimberNut, I enquired about the pump you acquired, its quite an expensive little thing! Did you consider a cheaper refrigeration vacuum pump at less than 1/5th the cost?

[TimberNut]

yes, I looked at all options. I saw on another post here that someone scored it for $700 cash price from memory, but as I'm out of state I think my first quote from them was $900+ GST plus postage. 6months later he gave it to me for $800+GST but I still think that's a bit steep. Not that I could do anything about it as I couldn't offer COD. I looked into getting it out of the US, and can get same/cheaper price, but didn't want threaded in NPT thread, so bought here. I couldn't find anyone locally that was cheaper.

But to answer your other question - re refrigeration pump - the atomisation of the oil was a dealbreaker for me. I value my health way too much to be breathing atomised oil, and didn't fancy having that floating around my shed. Hence I thought I'd outline all options when I started this post, as everyone has different ideas and different price points. I'm sure there are yet more options I don't know about, but they were all I could discover in 6 months worth of looking/planning.

I'm not sorry that I went down the path I did, and got the pump I did (and I'd make the same choice again for the sake of my health, and longevity of the pump) but I do wish I could have sourced it cheaper.

[Deverell]

Bunnings has the same dimension unfortunately.

I'd hope that when you have a bag glued up you'd be able to easily fit a 1220 width sheet in, with say 50mm overlap both sides.. Might be tight though.

Here's a link to the .75mm stuff https://www.bunnings.com.au/vinyl-tablecloth-crystal-clear-0-75mm-137cm-wide_p6640034 for $21.45 / m

As well as the 1mm https://www.bunnings.com.au/vinyl-tablecloth-crystal-clear-1-0mm-137cm-wide_p6640301 for $29.90 / m

As for the connection I think it was somewhere on here that I saw a link for this item. https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F121837985444

As a side note, even $700 seems very expensive! I have been looking at the refrigeration pumps but I plan to run either outdoors undercover or just have all my shed doors open allowing a good cross breeze.

[TimberNut]

Hey Deverell,

thanks for those links. Any thoughts on .75mm vs 1.0mm thick? I reckon the thinner one would be more flexible but 1.0mm would be more durable??? I've no experience here, so if you have some I'd be glad for the feedback before I get some.

[BobL]

- the atomisation of the oil was a dealbreaker for me. I value my health way too much to be breathing atomised oil, and didn't fancy having that floating around my shed. Hence I thought I'd outline all options when I started this post, as everyone has different ideas and different price points. I'm sure there are yet more options I don't know about, but they were all I could discover in 6 months worth of looking/planning.

I don't see a problem here, just run a hose from the pump exhaust to the outside of the shed.

In various labs I worked in all over the world where we often used dozens of vacuum pumps in the one lab all used a variation of this approach.
In small labs, vinyl hoses across the floor to holes in the wall were used but this was not OHS compliant in larger labs where these hoses had to cross walkways.
In larger labs we had ducted vacuum exhaust systems to cope with up to a dozen pumps.
One lab used forced exhaust ducting made with 25mm copper pipe ducting that ran around the walls of the lab, and was powered a small fan,.
The fanciest ducting setup used under floor ducting so we just had to run any pump exhaust hose to the nearest floor duct.

[TimberNut]

Hi Bob,

For some people, in some scenarios venting externally could solve the problem of atomised oil, and I note in an earlier post you mentioned filters that could be fitted to the exhaust to capture that oil.
The old adage applies here I guess - there's more than 1 way to skin a cat.

At the time I settled on, and started building, my setup I wasn't aware of the filters available for the exhaust. That may possibly have given me more options when choosing a pump.

Venting externally isn't an option for me given that the pump will be multi-purpose (ie located near the bench for vacuum clamping, near the glue up area of the shed if vacuum bagging, or right at the other end of my shed when vacuum clamping on the lathe). Particularly when using the lathe I have no option to vent externally, and a hose attached would need to run 20+ meters to get to the outside of the shed. I wouldn't bother doing that as it would be a trip hazard and major pain in the backside.

The intention when I built mine was to be as multi-functional as possible so as not to limit anything I wanted to use it for. Given I can run it anywhere in my shed, without having to worry about exhausting externally, or any issues with loud vacuum pumps bothering the neighbours at night, I'm happy that in the long run, my setup will allow me freedom to vacuum clamp anything, anywhere, for as long as I want.

For some, a $100 refrigeration pump plugged straight into a plastic bag is the right answer (and all power to them - it'd save them bulk $$$$) but it isn't for me.

Hopefully others reading this (and other posts on this topic) will gather enough information to choose the right solution to meet their needs, whatever they may be.

[BobL]

Hopefully others reading this (and other posts on this topic) will gather enough information to choose the right solution to meet their needs, whatever they may be.
Sure.

For anyone thinking of a fridge pump, I guess it depends how much use it will get, but an over head 25mm PVC duct network with inlets at your most likely places of operation is worth considering and will get away from that 20m+ hose running across the floor. If you do intend using it in another place in the shed then it only takes 30s to install another T piece inlet. OTOH a simple oil filter will pretty much do the same thing.

[Deverell]

Timbernut,

I actually don't have any experience using either, I'm still in the planning stages of my setup. I did use a proper set up with some kind of flexible non see through sheet when i was at uni but i didnt pay too much attention to the specific details.

Everything else I have said is just as a result of my research and from other forum members. Thumbsucker told me about the bunnings vinyl sheet, beforehands I was looking at importing a very expensive pre made pot sheet from the US. However they wanted almost just as much for shipping which just blows this exercise way out of budget.

I like the idea Bob of the pvc exhaust network.

[woodPixel]

If you do solve the big bag acquisition I'd be keen to know.

My bag, clip and nozzle were supplied by offtheedge.com.au

The bag is long and the nozzles fit well.

[shanesmith80]

Timbernut,

In response to your pm.

The vinyl linked above looks like what i used but I'm sure I paid no where near that. Think was somewhere between $5 - $10 a meter. My bag was meant to be able to hold a half sheet of ply, but I stuffed it up and was a bit short. But with bunnings vinyl width you can get 1200mm wide. Yes in the flooring section.

I am led to believe that a poly bag is better/more durable, although more expensive. I did find some somewhere but can't remember where.

I used VHB tape to seal it on the sides and made a caul for the open end.

As for the valve I done the John Samuel trick with the bunnings irrigation valve. http://www.woodworkforums.com/f11/vacuum-press-179215?highlight=veneer

Where in NSW are you?I dont know when or if i'll use my bag again, your more than welcome to have it to try out.

cheers
Shane

[TimberNut]

The hose I'm running from the pump is 3/8" reinforced, and one of the issues I was struggling to solve, was some sort of connection to the bag, that didn't restrict airflow. I had bought some tyre valves from ebay (only cost me $1), but when they arrived, I realised that the connection to them would be 1/4" maximum. I know some will say "what does it matter? It'll only take a bit longer to evacuate the bag" but having gone to all the trouble of building this setup, I didn't want to restrict it in the final stages. So I tossed the tyre valve idea out the window and set about trying to find some sort of bag connection that was 3/8" minimum.

A big thanks to Shane for pointing me in the right direction here (and John Samuel for the original idea, or whoever he got the idea from :-).

I ended up going with 0.75mm thick PVC for the bag. I looked at the 1.0mm, and whilst it might be more durable, it's not as flexible.
It was 1370mm wide, so I started with 1m length. This will make a small bag, and allow me to validate the valve fitting before stepping up to a larger bag. And see how flexible it is and whether a bigger bag should be made out of 0.75mm or 1.0mm.

The fitting to go through the bag is this one: https://www.bunnings.com.au/philmac-3-4-tank-outlet_p4814051. Cost $11.28
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I was trying to find a way to connect a 3/8 reinforced hose to it, when I thought of garden hose fittings. They are either 3/4" or 1" BSP threads. For a total cost of $1.97 I got one suitable for 12mm garden hose.
I knew I wouldn't be able to fit the 3/8" reinforced hose over it but being plastic, and fairly thick, it was nothing I couldn't solve with 5 mins on the lathe :-)
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For the tank outlet, I cut the nut section off with the hacksaw, and smoothed it out on the lathe. Then I used the router to cut some channels in it to allow air flow out if it sits flush on anything in the bag.
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Here's the final fitting. All that is needed now is some thread tape on the threads, and to be attached to the vinyl.
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I've got to glue/tape the vinyl edge to make the bag. From what I read most are using HH-66 vinyl cement, or VHB tape.
Does anyone have any info on either, and whether one would be better than the other? Is gluing more likely to reduce chances of leaks, or be more durable? It seems like the process of gluing isn't easy (without assistance), to ensure a good seal. I've got to source either the glue or the tape now, so any info re one or the other would be appreciated.

[woodPixel]

Many posts I've seen talk positively of the VHB tape. Its is in my Amazon cart.

As far as ensuring a seal, I've seen pictures of where people have made two cauls that are clamped together. The same method is also used for the "open" end.

With the plastic, did you end up using the Bunnings flooring PVC?

[TimberNut]

yes I just got the Bunnings vinyl. https://www.bunnings.com.au/vinyl-tablecloth-crystal-clear-0-75mm-137cm-wide_p6640034 $21.45 per meter.

I've already made the cauls for the ends of the bag, from 20mm and 25mm pvc that I had lying around. They should do the trick for closing both ends of the bag. Now it's just rolling the vinyl into a cylinder and then gluing/taping it in place. Hence the question re the glue & tape ;-)

[TimberNut]

I sent a request to Blue Nautilus Marine for a price for some HH66 (237 ml can).
They came back with "The price is $35.00 and around $20.00 freight depending on how far out of Sydney you are."

$20 postage for a single can, really?? I got stuff posted from China for less than half of that (admittedly non-flammable though). I don't know if this is what is being reflected in the high postage cost.
Does anyone know of any suppliers in Sydney that might be cheaper than that?

[BobL]

$20 postage for a single can, really?? I got stuff posted from China for less than half of that (admittedly non-flammable though). I don't know if this is what is being reflected in the high postage cost.

Most folks don't realise the reason local charges are so high is because of free or cheap shipping from China.
Because of the international postal agreements, shipping items from China that are delivered in Australia by Australia Post costs AP millions of $ a year so they make up the difference by raising charges on internal postage.

[damian]

I've only just noticed this thread. Many of the issues you are trying to solve are the same as those in resin infusion/vacuum bagging for boatbuilding.

You might consider searching resin infusion and reading some threads.

There is "tacky tape" specifically for sealing vacuum bags and around the standard fittings for getting the vacuum and resin lines into the bags. The fittings are cheap, some just a few $ some fancier ones about $35ish. Tacky tape is somewhat expensive but works well. Talk to good fiberglass consumable suppliers and they will know what you need. Unfortunately not all fiberglass retailers are good, some are pretty hopeless.

You can buy bagging film that comes as a tube, so you only need seal the ends. Newer bagging film is often multi layered to avoid pin hole leaks. Infusion often means keeping the vacuum on the part for 24 hours and striving for the best vacuum you can pull and testing it, all of which takes time. Unless you are doing many large panels the cost of good quality consumables should not be prohibitive.

Good luck whichever way you decide to go.

[shanesmith80]

I did find a place in Western Sydney that sold HH-66. Can't remember the exact place but think it was a place that dealt with pools.

[TimberNut]

After much searching, I've been unable to source a Sydney-based supplier of HH-66, so ended up ordering it from these guys - PCM Distributors - Marine Distributors, Boat Paint, Antifouling (http://pcmdistributors.com.au/)

I got the 2nd smallest tin (around 500mL ?? I think it was).
It cost me $45 + $20 courier to Sydney. I'm guessing due to it being flammable, they couldn't use Aus Post. The suppliers couldn't give me expected shelf-life of the stuff, but googling indicates it should last a while. I expect to have a fair bit left over after I make a couple of bags, so if any forumite is in Sydney, looking to source this stuff, they might want to go halves with me or something (assuming I haven't used it already). Hopefully it'll arrive before Easter and I can get a bag glued up over the long weekend.

[shanesmith80]

It’s been a while and was wondering how the system is going?

Especially the garden hose fittings in the pipe connections.

Starting to gather the ingredients to put my system together.

Cheers
shane

[TimberNut]

Hi Shane,
yes it's been a while, so it's probably time to provide a detailed update for all interested, and anyone researching their own vacuum solutions. I'll try to keep the comments brief, but just let me know if you want more detail on any of the below:


I absolutely love the vacuum setup I made. 2 years on I've gotten over the high $$ to purchase the pump. I've been able to use my setup anywhere in the shed at any time I want, and the auto-cycling works an absolute treat. Bugger all noise so I can leave going at night and it happily auto-cycles away, and given how long it can be between cycles, this thing will outlast my grandkids.


I've read all my original comments and they are all still valid.


Things I'd change if I did it over again:
- The PVC from Bunnings - in summer it's fine, but as it cools in winter time, the bag can be a little stiff in a cold shed. That's not a problem once the pump gets going and evacuates the bag, but clamping the ends to seal them is a bit more of a pain as the bag isn't as flexible when cold so it takes a bit of wrangling to get it clamped. It probably only adds another 15-20 seconds so not a deal breaker at all (more of a first world problem), but if I were sourcing more PVC I'd look for something thinner. The HH-66 cement makes it so simple to make bags I'm no longer worried about durability of the bag - if I need to make another one, it'd take me about 20 minutes. So bag durability is far less of an issue than I originally thought. Bag flexibility is quite important, so I'd aim for a thinner bag where possible.


As part of a business we run from home, I use this setup every second day, so it gets a regular workout.
I haven't had to change anything from the original build, with 1 exception - how I seal the bag ends.
On one end I've glued the bag closed so it's permanently sealed.
The open end - I originally used 2 lengths of 1 inch PVC pipe snapping one over the other with the bag sandwiched between - whilst this worked, it lead to leakage and the bag would lose vacuum. The pump cycling was easily able to keep up with it, but having invested so much time into this solution, I didn't like a half-solved solution for sealing the open end of the bag, so I changed it. Now I use this method:


472501 472502 472503 472504

It only takes about 30-40 seconds to clamp the bag between the 2 bits of timber. I've still got a very minor leak somewhere so the pump cycles now about once every 5-10 minutes. If I had nothing better to do I'd track down that source of the leak. I know it's in 1 of 3 spots:
- the clamping of the open end
- a pinhole in the bag itself somewhere (can be fixed with a dab of HH-66 cement if I find it)
- the hose fittings from the manifold to the bag.


I'm sure it's not in the pump/pressure vessel part, so I'm not worried about it. Having the pump cycling every 10 minutes vs once per hour is really nothing to stress about, so for now I've put up with it, but one day I'll track it down and sort it, just because I'm like that :-)


I've added one item - a TP-link smart switch - that is linked to my phone. You can see it in the photo. I use google home and say 'Hey Google, turn on vacuum pump" and voila! it kicks in. I can also turn off with voice commands, but most jobs I do with it I need it running for about 2 hours, so I just go into the Kasa app on my phone, and set the timer for 2 hours, and walk away. 2 hours later my phone shuts down the switch and turns off the whole setup.
I have also linked it into my Samsung Smartthings hub so I can write rules to sms/email/notify me based on any criteria I want. For example I can have a rule that says 'if pump is running for more than 3 hours for ANY reason, shut it off, and send me a message'. Flexibility like that means I'll get the maximum longevity of my setup, so my grandkids can use it one day (or perhaps say their granddad always over-engineered solutions :-)

472505
Anyone in Sydney investigating building their own that would like to see mine in action before they get underway is more than happy to come and check it out.

[shanesmith80]

Thanks for the update.
I might have to revisit my plan. I was going to just take the simple Fridge vacuum pump plan but you've got me thinking now.

[TimberNut]

Hi Shane,
there are pros and cons to both approaches. By the time I completed my vacuum build the price ended up over $1k, which I know will be a roadblock for a lot of woodworkers. I hadn't set out to spend that much but after investigating all the options, the idea of atomised oil in the environment didn't appeal to me so this is the path I chose.

The intent of this post was to provide everyone with all the options that I was aware of, and my reasons for either choosing, or avoiding, at each step. It took me months and months to do all the investigation, and sourcing of materials required so I figured I'd give others the benefit of my hard-earned experience.

I know there are a lot out there for whom a < $100 refrigeration pump is more than suitable, and I'm certainly not going to try to dissuade them from choosing that path, but rather I'm just outlining the reasons why I built what I did, so others can make their own informed decisions as to what works best for them.

Regardless of which solution you choose, I can say that having the flexibility to use vacuum pressure as a clamping method has made so many clamping jobs much more easily managed, with more consistent results. I'd recommend anyone to add it to their 'toolbox' of options to make woodwork that much more fun.

Good luck with your build. Keep us posted on what option you choose, and how well it works for you.

[Neil T]

Great video here from NSW maker Darren Oates on how he set up his vacuum system for veneering. Very detailed video including bag construction.

Make A Two Stage Vacuum Press For Woodworking - YouTube (https://www.youtube.com/watch?v=nvXxynIKgaM&ab_channel=DarrenOatesFineFurniture)

[acejas]

@timbernut Ive got a lot of information from this topic - thank you.

I'm building a vacuum clamp only with a venturi with an air compressor. It wont be the same as yours but your information of titbits has made it easier.

A few questions I have:
The yellow gauge - what model is it? - is this the vacuum controller (or just gauge)? (part of next question)
The grey box with 71.1 - 84.6 - whats in there?
In one of your photos you show to controllers...not sure which one is which

Some close up photos of the components showing models etc would be great (or just writing them)

Cheers

[TimberNut]

Hi Acejas,

answers to your questions are:

The yellow gauge - what model is it? - is this the vacuum controller (or just gauge)?
The yellow gauge is a vacuum controller. I've set high/low points on it, and it is wired into the control box (answer to next question), and it controls the auto-cycling of the system. It sends a voltage to a relay when the vacuum drops below the 'low' value, and cuts the voltage when it reaches the 'high' value, and yes it displays the current vacuum at all times.
I bought it off eBay for $36.00 USD. The ad described it as
"Digital Pressure Switch, 0 to -0.1Mpa Air Negative Vacuum, 240VAC G1/4 0.5%FS (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180987591897&ppid=PPX000608&cnac=AU&rsta=en_AU(en_AU)&cust=739005509Y836223C&unptid=f978ae02-002a-11e8-a3a9-441ea14e0854&t=&cal=6e4c75609fa75&calc=6e4c75609fa75&calf=6e4c75609fa75&unp_tpcid=email-receipt-auction-payment&page=main:email&pgrp=main:email&e=op&mchn=em&s=ci&mail=sys)"

The grey box with 71.1 - 84.6 - whats in there?
A 3-way 240V rotary switch, terminal blocks for all the wiring, and a 240V relay

In one of your photos you show to controllers...not sure which one is which
If you are referring to the photo with the black/blue solenoid on the left, and the fawn coloured "Airtac" solenoid on the right, then they are as follows:
The right one is a cheap Chinese Airtac 3/2 solenoid that didn't end up working as it is pilot operated and relies on positive air pressure for initial actuation. Given you are running a venturi setup, that would work for you as you can bleed your compressed air line onto that to give the pilot enough pressure for actuation.

In an all-vacuum setup like mine it wouldn't work, so I needed to go with a MAC valve (the blue/black one on the left). The mac valve doesn't require positive air pressure for actuation, so is suitable for a vacuum setup (but costs $$$ compared to the Airtac one).

I forgot to metion: The purpose of the 3-way rotary switch is so that I can bypass the vacuum controller if I want. It is wired so the rotary switch has 3 positions -
'0' = off (cuts power from the power point to the system)
'1' = 'auto-cycling' (power goes via vacuum controller and the system cycles on/off between high/low as described above)
'2' = bypass vacuum controller - constant power sent to relay so vacuum pump runs constantly.

For 99% of usage it is on '1' and cycles as it needs to, but if using for vacuum clamping on the lathe, you don't want the system to cycle, lest the vacuum pressure drop too low and you end up with the rotating timber leaving the lathe and entering your face at a decent speed. In that setup it is safer to have continual vacuum pressure, and control it via a bleed valve on the air line. If you don't plan on needing the pump running constantly then a 2-way switch ON/OFF would be sufficient (and significantly cheaper).

[acejas]

Hey Timbernut
Thanks heaps for all the info. The vacuum controller you shown has confirmed what I was after - thank you. Now I know how you feel regarding at looking at so much info from knowing nothing lol.
I could be wrong but I thought I would need the MAC one - need to do more research - I was following Joes workshop.

Im going the 24v DC route but may change my mind to 240v. Reason being is again I followed joes instructions and I have a few high amp 24v PSU's as well as relays.
Ill defintely put a post up when completed (or started lol) My post may help others like your post did.

The other reason I'm going the vebturi /compressed air is Ive bought a JLC10 ( I know its small but all I need IF I order correct parts) and with under $200 not much will be lost if it fails - keep tuned (in the next 6 months lol)

[TimberNut]

I'm glad the info helps. It sure is a lot to process, but if it helps you iron out your idea before committing $$ then that was my aim putting as much detail as I have. There are so many ways to go about it, all at different cost points. I still marvel at just how well my system works, and don't for one second begrudge the money I spent. I'd recommend every woodworker has some form of vacuum clamping setup.
Post a link on this thread, to your build when you get it underway, as I know a lot of interested people have been reviewing all the detail here, and if you go about it a different way, a link from here to your build will give them more info (to drown in :-) I mean, to read and make their own minds up which way to go about their builds.

Re the mac valve - if you're just going to switch a negative pressure line, then yes, you will need to go with the mac valve, as any pilot actuated solenoid relies on positive pressure for the initial movement of the gates. Given you have access to a positive pressure line from the compressor you could do it with a combination of pneumatic solenoids, but you'll find it a lot easier to just get a mac valve and move on. BUT they are quite expensive, so make sure you settle on your switched voltage first (24v or 240v) so you know which mac valve to buy. I went the 240v route, and used a relay on the compressor as I wasn't sure what startup current there would be and if it would flow back through the vacuum controller and fry it, but looking at it now, I'm 99% sure the relay adds unnecessary complexity. But it didn't cost much, so I'm happy to have used it for extra peace of mind.

BTW my standing offer remains to any Sydney-based woodworker investigating these builds - I'm more than happy for woodworkers to come over and check my build out (and bore them to death with endless chatter about vacuum pump builds.......). Sometimes seeing these things in the flesh can help people determine if they are the right solution for them.