Vacuum bag veneering question

[noddy67]

I'd welcome some advice here please. Totally new to the practice of using a vacuum bag for some veneering and looking to try and put a setup together on a pretty tight budget. Had been looking on ebay for a second hand pump without much luck. Could anyone tell me whether this one might be sufficient:

http://www.ebay.co.uk/itm/Double-Stage- ... SS:GB:3160

Largest size I can imagine I'd ever do would be a full sheet of 4 by 8.

Many thanks

 

[swb58]

Not answering your question but just thinking, how much suck is there on the intake side of a compressor? Or is it a completely different animal.

 

[Steve Maskery]

I'm sure that would be fine but note that it is not maintenance free, you have to oil it. I had one that was oil-free. It would easily evacuate a single 8x4 bag.
I'm looking to build something similar myself one day, it is a very useful tool. I hope that whoever has mine dies a long slow lingering painful death.
S

 

[condeesteso]

Keep us posted on this, it's interesting. Where will you get bags from and how durable are they? Same for connection from pump to bag etc. I'd be keen to see how you get on with this.

 

[RogerM]

The East Coast Fibreglass Supplies package strikes me as good value, and nice people to deal with as well. I was starting from scratch so bought their vacuum pump as well which is a 2 stage jobbie which accounted for £217 of the overall cost of £275 for the complete package. You may be able to find a cheaper single stage pump on ebay, one of these perhaps, which look very similar. But overall I'm very happy with what I bought.

In particular, rather than invest in an expensive bag, a poly tube sealed at each end works really well, and is dirt cheap. Seal one end permanently and then use tape across the open end. It's like dung to a blanket so you have to cut the end off each time so your bag gets progressively shorter, but for occasional use it will take ages to reduce it's length to below that which you'll commonly need - and it's cheap.

I used it on this project and described its use in the thread.

The Joe Woodworker site is a treasure trove of information for Vacuum pressing and I'm tempted to build one of his presses before I do any more major veneering projects.

 

[marcros]

any recommendations on the tape to use roger?

 

[RogerM]

any recommendations on the tape to use roger?

I used the tape sold by the East Coast FG supplies. It's a bit like chewing gum and is as sticky as really sticky stuff. They are worth phoning - I found them to be really helpful and no hard sell.

 

[Yetty]

Not answering your question but just thinking, how much suck is there on the intake side of a compressor? Or is it a completely different animal.

A while back, I plumbed a vacuum gauge to the inlet on my 3HP compressor to test the idea, and wow, it sucked right down to near zero bar.

But, then I read this, ref A9 http://www.joewoodworker.com/veneering/faq.htm#A9 , so instead I got a used vacuum pump from an auction site. Much smaller and quieter!

 

[noddy67]

Thanks for the comments chaps. Steve the maintenance you're referring to...is it literally just putting a little oil in occasionally? Does the oil come out anywhere and cause other problems?

There was a great thread on UKW about a self build for a vacuum bag build that I was planning on following but wanted to source the pump first. Would welcome any other input if anyone has any further knowledge they would like to share.

Thanks again and merry Christmas to you all.

 

[marcros]

i have followed the same build, having got the pump first too. once you have the bits it is pretty easy to do.

I havent yet made the bags- I got some of the tubing mentioned before but no tape. I rather like the idea of just using the tape and trimming a couple of inches off each time.

I used the same source of bag connection as in the WIP, and some speedfit pneumatic fittings. I think I paid a lot for the latter, but it is a pain to try and find everything from one shop on ebay

 

[RogerS]

Couple of thoughts.

1) Thumbs up to East Coast Supplies

2) Remember that your pump needs rating for constant running unless you have some mechanism for totally sealing the bag after you have evacuated it and/or some system that kicks the pump into action when the vacuum starts to drop

3) Square electrical trunking and 1/2" dowel work just as well for sealing up the ends.

I posted a complete How To on the old a different place but sadly that's gone and we've not been able to resurrect those posts for woodhaven2.

 

[Steve Maskery]

Steve the maintenance you're referring to...is it literally just putting a little oil in occasionally? Does the oil come out anywhere and cause other problems?

Sorry, I don't know. Mine was oil-free. The vanes were carbon, IIRC, and as such were self-lubricating.

 

[noddy67]

Hello all. About to pull the trigger on a vacuum pump but before I do I just wanted to repost this in case anyone else had any further thoughts on what kind of pump to buy.

This is about the cheapest I've found online as nothing second hand has come up:

http://www.ebay.co.uk/itm/Double-Stage- ... 418be1c62f


Any further input would be most welcome

 

[Mr T]

Occasionally I have had jobs too big for my 8x4 bag and made up an over size bag using visqueen and double sided tape. Used some square ducting and plastic tube for sealing, took a bit to find the right size combination. Bagpress sell the connecting tubing and the seals for connecting pump to bag.

Chris

 

[mouppe]

Having used two different pumps over the last 8 years or so, I would suggest that the most important factor when choosing a pump is its ability to continuously cycle and hold a vacuum pressure level over several hours.

My first pump was a converted air compressor which was basically either on or off. So more than once I left the workshop with a veneer job in the bag and the pump on, only to come back the next day and find the breaker had tripped or the pump had cut out etc. Ruinous and very depressing!

My second pump is a completely different affair. It reaches the set pressure level, and then switches itself off, as the vacuum pressure slowly drops it then comes back on for a few seconds to bring the pressure level back. It can do this for as long as you like. (You can also override the cycle mode in case you want to use it as a vacuum clamp.)

The other important item is the bag. The thicker the plastic the better as it won't tear around sharp edges. Mine is an 8'x4' bag and I have found this to be big enough for what I need.

I paid $500 for the whole set (about 300 pounds) - used but in first-rate condition. New I think it costs $1300. I'm posting the link so you can see what is behind a good pump and compare it to any you are considering.

Hope this helps.

https://www.vacupress.com/products.htm

 

[worn thumbs]

For several years I have used damp proof membrane for bag material.I don't use the plastic clamping strip as I often find it useful to add a tuck to the seal to compensate for bulges or other shapes and the sticky mastic is totally flexible in every respect.I think anybody buying anything other than a purpose made pump should give it a trial run for the period they believe the glue will need holding for.There are few things more exasperating than having a substitute system break down before the bond is secure.

 

[koemanrob]

Coincidentally, I'm looking to get rid of an airpress with bags and connectors that i used to use for work. It's pretty heavy duty and can connect 4 bags to it and should run for hours. Only problem is i haven't used it for a while and doesn't want to run now, going to have a tinker to see if i can get it running properly. Got to get up to 20 posts before I can offer it on the sales board here!

 

[RogerM]

This thread is an elegant solution to the continuous running issue.