Shop Made Vacuum Setup

[Russell Shelly]

Have any of you guys made your own vacuum clamping/bag systems? I was wondering if it would be possible to use a secondhand scientific vacuum pump, or a new one from harbor freight (automotive most likely). I have some knowledge of vacuum in industrial applications, but have never used a vacuum bag or vacuum clamping in the woodshop. Im assuming, a vacuum pump, regardless of the cfm, will be capable of pulling a sufficient vacuum or this type of service, but just will take longer to get there.

I have a homemade Venturi that’s good for draining small engine oil and syphoning liquids, but I don’t have a large air compressor anymore and I assume I’d need a bigger compressor to evacuate a large vacuum bag. Plus I’d prefer the quieter vacuum pump to the loud intermediate size compressor that i have.

Let me know what you guys do and how often you’re using vacuum bags, clamps and presses. If it’s cost effective, I wouldn’t be opposed to spending the time making a setup. I just need some ideas for inspiration. I would like to use more veneering and shop made plywood in my work, so a bag would most likely be the most practical use for vacuum in my shop.

also I’m curious about veneer presses (acme screw style). Who uses those and what do you see as the benefit/drawbacks compared to vacuum bags? I usually make furniture and not really small projects. In my mind, I see veneer presses as more useful for smaller applications, but please correct me if I’m wrong.

Any response is greatly appreciated. Thanks!

[John TenEyck]

Making your own vacuum bag system is pretty easy. I'm cheap, so I made the bags I use, too, from 30 mil sheet vinyl that I first bought from McMaster Carr and later from my local boat cover place. Sheet vinyl glues really well with regular PVC pipe cement (no cleaner needed or wanted). I didn't know about Joe Woodworker at the time, maybe he wasn't even in business yet, so I made my own bag penetration for the vacuum hose, too, using 1/2" PVC, glued to the bag, that I threaded for a hose nipple. I've been using the first bag I made for over 25 years now and had to patch two small leaks after hundreds of uses. Vinyl is a lot more durable than many give it credit for.

I have a Gast vacuum pump that has about 3 cfm capacity I think, and it pulls maybe 21" Hg. Not a lot, but plenty good enough even for bent laminations. I use a simple on/off timer to cycle the vacuum based on observation on what will maintain the vacuum above about 16" Hg. When it cycles on the vacuum goes up to 21" and then drifts down slowly until the timer turns it on again. Again, not elegant, but it works fine and was really low cost.

I make a lot of large parts, often using shop sawn veneer on MDF or plywood. A vacuum bag makes it easy.

https://lh3.googleusercontent.com/pw/AL9nZEU_9ZwZINsFWBiQ_10wrlL2MPqnfWFK9rvizCqiqjDJy8 11DMRyUFexLhbgSV6AFFwoVOEDTRA40jkF47ZlSceYm1hDp6nH CFf97-AuJ_rNXWxBeyd2HrbXA06FHcFCGG923I1Y1MRJt0JCJFqaTbPr Pg=w1190-h893-no?authuser=1

This is my original bag. It will do parts at least 40" wide by over 5 ft long. Underneath it is a heating blanket to increase the curing speed of the Plastic Resin Glue I was using. Today, I use Unibond 800 which only needs 3 hours in the bag, or Titebond II, or epoxy, depending upon what I'm doing.

I've done lots of curved work in this bag, too, using simple forms. This is a small one, but I've done some curved parts 5 ft long and at least 18" wide.

https://lh3.googleusercontent.com/pw/AL9nZEUbwkPP6ISj1tNkd1epLYW2796kXVsF4p2bJrTf83fXlp EEF5fjOW3u0sCvpEf1YNPV9hObID95y7CmcOSNN79uK2T_nipH mcrglAwPHOr4HK63fG9BU48TFGx1_YKYTkJtlSuVXPF73huEZz 1Za0Jaww=w1190-h893-no?authuser=1


I built a long, narrow bag to use making curved door headers. In this case, you put the parts into the bag, pull a light vacuum, then pull the bag and parts against the bending form, and then pull the final vacuum, much easier than trying to use the bag to pull the laminations down against a form. On this bag I used a bag penetration from Joe Woodworker.

https://lh3.googleusercontent.com/pw/AL9nZEUFQglRUopJS8NLzpd42zslJJn8E3PTbdZN5ygsuD7QgO APHX9DodI_vM0vEXmLOWt3sJk5U94LCuXogT7ADFpm4O7AVY7B e2-TsckbKvGrEgvDM4ZZHb7dQYziAvWtdCXNvYwf8I8hR6dYRWq69 Mtixw=w1190-h893-no?authuser=1

https://lh3.googleusercontent.com/pw/AL9nZEWsQCWG5tEvPTIhQBkOJbdU6sH0bzMeYWIyV4gYAgwigx QJFwUypNdMJle_F82Ek_kbHRuxzE8H1Dgt3mWgZFlYeDa9HAtf 7vL60c9zwjM3pkBgfVxp_g2GKzEBDXWvAh2ZPohv3py0WMPDSq n9OCD-Mw=w1190-h893-no?authuser=1

You can buy everything you need, or you can make most of it. The only thing you pretty have to buy is a vacuum pump. However you go about it, having a vacuum bag system can really open up a new range of capabilities for your woodworking.

John

[Russell Shelly]

Thank you John! That was exactly the kind of information I was looking for. I quickly browsed Joe woodworker’s site a while back but completely forgot about it. I will be checking out his parts offerings again. I’m also glad to know McMaster carries vinyl sheets for bags. I live forty minutes from them and their will call option never takes more than an hour.

is the Gast vac pump you’re using the only one you’ve had these 25 years? Id like to know if there are other vac pump models/brands I should avoid and skip right to one that will not disappoint.

[Jim Becker]

My vacuum pump was a surplus Gast pump I bought off "that auction site" many years ago. It was essentially "new in the box", but surplus. It worked well for the purpose. Bags are easy to come by from JoeWoodworker, etc., as are the required hoses, valves, etc. Cauls/plattens are all shop made things using inexpensive MDF and/or melamine.

[John TenEyck]

If you want to build Joe Woodworker's constant vacuum rig you should avoid Gast pumps as I think I remember him saying they are not compatible. To answer your question though, yes, it's the same pump I've had all these years, with hundreds of hours on it and zero maintenance. Very reliable, very durable, but quite loud. If you are thinking about how quiet those lab or air conditioning vacuum pumps are, the Gast rotary vane pumps aren't it. Honestly, you can probably use nearly any vacuum pump successfully. I'd look for a surplus pump on Ebay, etc. Even the HF vacuum pump you talked about in your first post will probably work just fine.

John

[Mike Henderson]

Joe Woodworker used to sell refurbished vacuum pumps. I have one of his and have been using it for a good many years. I think the amount we use vacuum pumps, they will last a long time.

I have a second one that I bought off eBay that is a bit larger than the Joe Woodworker but that was just by chance. The Joe Woodworker vac is adequate.

Mike

[Bruce Wrenn]

I use either HVAC vacuum pumps, or a block (AVR039H) from Air-Vac Engineering. The HVAC pumps came from scrap yard. They no longer pulled in the micron range, so they were trashed. My first vacuum pump / air compressor was an automobile AC compressor. Still have such a unit. Now it's vacuum only.