Thread: veneersupplies.com - Vacuum Bag System

So from the pdf what would be the best one for vacuum bagging?

I am guessing the double head serial connection Model 70RND?

Originally Posted by Bohdan

The double heads are available in series or parallel. The series gives higher pressure and the parallel higher flow rate.

Originally Posted by thumbsucker

I like the look of the screw fitted types, where would I get those?

2 x Car Motocycle Tyre Tire Valve Tubeless Metal Valve Stems With Dust Caps AU | eBay

The parallel 140RND gives you 93% of the pressure of the serial 70RND but at twice the speed. For veneering use I think that the pressure is more than adequate and the double speed enables you to use a smaller unit to save money.

Only if you are doing really large jobs, that is very thick ones, where you can't press out most of the air manually would this become a potential problem and you would need to go large.

It is interesting that they all use the same motor power so the difference must be in the speed but I don't see how as they are usually direct drive.

I would go for the biggest that I could afford.

As an aside the parallel ones can also be used as a compressor but the max pressure drops off as the size increases so if you were to consider getting a tool like a stapler or nailer the 100RND is the largest that you should consider.

Originally Posted by Lappa

2 x Car Motocycle Tyre Tire Valve Tubeless Metal Valve Stems With Dust Caps AU | eBay

The tubeless valve stems are designed to seal against the curved hole in the wheel. Very hard to get them to work properly against something like a washer each side of a bag.

Guy at work vacuum forms and uses similar Units with steel washers and rubber sealing rings.

Bohdan thanks for the explanation.

I checked and my version is the 140RVD so it looks like a I got the right one. since I work small scale.

I had a look at the tubeless valve stems and while they look good I do share Bohdan concern about the rubber seal and the washer on a flat surface.

Pete those Vacuum Bag Connector - Aluminum | eBay seems perfect but with the exchange rate and postage coming in at almost $90 its pricy.

These are available in OZ
Off The Edge Sailplanes :: Vacuum Bagging

Bloody perfect

Purchased two, so I can have a spare, also purchased the Check Valve.

Originally Posted by Lappa

These are available in OZ
Off The Edge Sailplanes :: Vacuum Bagging

You know - all this makes me think that this is so much harder then it needs to be, why there is not a local Australian supplier who provides an end to end solution is a little perplexing.

I think you could have a nice little business providing a vacuum pump kit with all the valves, pipes, fittings, filters and bag at a moderate & reasonable price.

IF
serial = higher vacuum
and parallel = faster air extraction

For most veneering, the difference in applied pressure between higher vacuum and faster extraction will be inconsequential.

I would think you would want faster air extraction so that the atmospheric pressure acts as a clamp more speedily. i.e. before the glue starts to gel.

Originally Posted by thumbsucker

You know - all this makes me think that this is so much harder then it needs to be, why there is not a local Australian supplier who provides an end to end solution is a little perplexing.

I think you could have a nice little business providing a vacuum pump kit with all the valves, pipes, fittings, filters and bag at a moderate & reasonable price.

Im surprised as well that there isn't, i started looking at the start of the year, but i've just put it on the back burner until i have time.

Ian that seems to be the prevailing opinion.

However in my limited experience of vacuum bagging having only done it a few times at Uni and having seen people do it. It takes very little time <1minute to suck the air out of a bag even on larger 1 x 1meter pieces. Because people tend to flatten bags and push air out manually before sealing the bag and applying vacuum. Also when veneering I prefer to use epoxy or polyurethane, instead of PVA. Mostly due to the longer open time, more rigid glue line and the lack of water not swelling verniers.

bryn23 well I hope this thread has been helpful, you should give Rob a call.

Originally Posted by Chrism3

I bought the roarrocket kit Thin Air Press
from an Australian supplier. Has a 20" x 70" bag and I have veneered quite large pieces with it. It uses a wine bottle pump instead of an electric pump. It cost me $125 in 2015 and is still the same price. There is a smaller bag kit for $99.

Here's a demo:
https://www.youtube.com/watch?v=IjQe9p1LBCk

Yes, I agree Chrism3, I have the Roarrocket kit too and have been using it successfully for about 4 years - but I'm only a hobbyist so that wouldn't be more than 20 times to make my own laminated bases for boxes etc. using choice figured veneers (so fairly small pieces no more than 600mm x 400mm). It works just as well as the vacuum pump system I used at a professional workshop I 'studied' in here in Brisbane. I can't justify spending upwards of $700 on a pump for a vacuum press when the Roarrocket does that task just fine for me. Remember, for vacuum bagging the pressure applied to the press comes from the atmospheric pressure, not the negative pressure applied by the pump (as I understand it).

However, I have been reading this thread with interest because I'm interested in vacuum chucking on my lathe and vacuum clamping for working on difficult shaped pieces of wood carving. The Vicmarc vacuum chuck cups require a minimum flow of 1.9 cfm (3.2 cubic meters of air in an hour) which many of the less expensive eBay aircon vacuum pumps will deliver. For vacuum clamping there is leakage past the object so the requirements will be different - probably the higher airflow options as mentioned above. However, the inexpensive pumps give no data on noise levels so that may be the killer.

Does anyone have any recent experience with setting-up vacuum chucking or clamping? (I have seen some older threads)

If this is too much of a hijack just PM me and I will post separately.

David