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  1. #16
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    Build info: Part 3:
    Now I had my pressure vessel sorted, it was time to glue it up.

    20180223_181627.jpg


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

    20180223_182303.jpg


    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).

    20180216_100354.jpg
    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.

    20180222_160353.jpg


    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.

    20180225_091110.jpg

    20180225_093737.jpg

    20180225_095845.jpg

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  3. #17
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    Looks good - that purple paint looks like a winner !

  4. #18
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    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)?

  5. #19
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    Melbourne
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    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.

  6. #20
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  7. #21
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    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/gener...-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?
    Last edited by TimberNut; 8th March 2018 at 10:14 AM. Reason: adding stuff

  8. #22
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    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?

  9. #23
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    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.

  10. #24
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    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-ta...-wide_p6640034 for $21.45 / m

    As well as the 1mm https://www.bunnings.com.au/vinyl-ta...-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?m...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.

  11. #25
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    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.

  12. #26
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    Quote Originally Posted by TimberNut View Post
    - 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.

  13. #27
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    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.

  14. #28
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    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.

  15. #29
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    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.

  16. #30
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    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.

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