vacuum press

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nkforster
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vacuum press

Post by nkforster » Mon Jan 10, 2022 8:17 pm

Happy new year all.

I use a vacuum bag for a few jobs but I'd really rather like one of those press frames that open and shut like a suitcase.

Anyone got one or made one?

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Allen
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Re: vacuum press

Post by Allen » Tue Jan 11, 2022 6:51 am

I just have a frame that is made from timber with silicone rubber membrane. Rubber gasket on the sealing surface. Very much just like a bridge clamp. Just super sized. Use it on a smooth countertop. Works like the hinged ones but far less expensive, and I can store it out of the way when not in use.
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Spring
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Re: vacuum press

Post by Spring » Tue Jan 11, 2022 6:59 am

Would you mind posting a photo of this when you have the time, it quite interests me.
Thanks.

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nkforster
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Re: vacuum press

Post by nkforster » Tue Jan 11, 2022 9:30 am

Allen wrote:
Tue Jan 11, 2022 6:51 am
I just have a frame that is made from timber with silicone rubber membrane. Rubber gasket on the sealing surface. Very much just like a bridge clamp. Just super sized. Use it on a smooth countertop. Works like the hinged ones but far less expensive, and I can store it out of the way when not in use.
Ta. Did you use a 1.5mm thick sheet Allen?

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Allen
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Re: vacuum press

Post by Allen » Tue Jan 11, 2022 10:34 am

It's just over 1.0 mm when I measure it. I bought a roll of it years ago out of China that was targeted at industry that used vacuum and heat to cure.

My original press just used PVC material from the local rubber place that is usually sliced up to make fly screen doors. The silcone works heaps better.
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Jim watts
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Re: vacuum press

Post by Jim watts » Tue Jan 11, 2022 2:59 pm

Here's one I made some time back. I used a closed cell rubber foam for the seal.
vacuum frame.JPG
vacuum frame.JPG (51.29 KiB) Viewed 2133 times

TomBeltran
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Re: vacuum press

Post by TomBeltran » Fri Jan 14, 2022 4:24 am

VacuumClampingFixture.pdf
(345.93 KiB) Downloaded 89 times
nkforster wrote:
Mon Jan 10, 2022 8:17 pm
Happy new year all.

I use a vacuum bag for a few jobs but I'd really rather like one of those press frames that open and shut like a suitcase.

Anyone got one or made one?
I have built one, the plans are attached. Also, here is a little background, some tips on building the jig, a little about my own experiences, and also contrasting the vacuum clamp with a go-bar deck.

I first encountered the concept of vacuum clamping when I studied with Richard Schneider in 1983. Richard got the idea from Gibson Guitars, where they made extensive use of vacuum jigs at that time. After I finished studying with Richard and was back home, I made the clamp from the plans that are attached. For the lid assembly and bottom surface plate, I used plywood, but worked epoxy into both the inside and outside pores and gaps so it would hold vacuum better. If you have a good vacuum pump, it can suck through mdf, and certainly through the plywood sides. Also, I varnished the surface plate with several coats, wet sanded and buffed like a guitar finish.

The hinge is a piano hinge that goes the full length of the lid. I did not use the two struts shown in the plan to hold the lid up, the piano hinge was quite strong, and the lid went back just far enough so it did not close. A limitation, at least with the design in the attached pdf, is that the height or thickness of the wood to be glued is limited. So vacuum bag clamping gets around that limitation.

The surgical tubing works very well as a gasket, and I use it for my bridge clamps as well. I use a 3/8" Radius Round Nose Bit to cut the groove, and glue the tubing in with clear silicone glue/sealant. The gap where the two ends meet is joined with a smaller size tubing and silicone sealant. To me, it seems that the surgical tubing is more durable than the foam that is being used now days. For example, the LMI vacuum jig for holding a guitar body, uses foam and it gets damaged very easily. By the way, Richard also had a version of that clamp that Gibson was using at the time.

I used to laminate my sides in a vacuum bag jig I made. It worked fine, but it was a mess to deal with if something slipped. This year, I made a laminating mold after Bogdanovich. It was much easier than I thought it would be. I made the master template, and then used a half-inch follower bearing router bit on a router table to make all the pieces, that were indexed with drill bushings. The caul was made of laminated maple veneer. I came out very nice, and the laminated sides were very good. There are youtube videos showing how well vacuum clamped laminated sides work, so it is simply a thing of personal preference.

At the Estes Park convention, I met David Russell Young, who drew me plans of his go-bar deck with spring-loaded bars, also something I had not heard about before, which I went on to use to glue the back braces on. By the early 1990's, I was using hide glue for everything, including the top braces, so I abandoned the vacuum clamp for the go-bar deck. In comparing my experience of vacuum gluing with go-bar gluing braces, I think go-bars are more predictable and easier to clean the glue and make sure things don't slip then the vacuum jig. For one thing, you can glue each brace and clamp it before moving on to the next one. With the vacuum jig, you glue all your braces at one time, close the lid, turn on the vacuum pump, and it takes a bit (depending on the size of your pump) before the clamping starts. Even for Richard, this was an issue. On the Kasha model, he started gluing every other brace, clamped, and when dry, he put in the rest of the braces. So having used both, I find the go-bar deck much more convenient. But for holding things, clampless holding is much more convenient for me. I hope this helps.
VacuumClampingFixture.pdf
(345.93 KiB) Downloaded 89 times

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kiwigeo
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Re: vacuum press

Post by kiwigeo » Fri Jan 14, 2022 10:13 am

Thanks for some very useful information Tom.
Martin

Spring
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Re: vacuum press

Post by Spring » Sun Jan 16, 2022 1:50 am

Yes thank you so much.

joolstacho
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Re: vacuum press

Post by joolstacho » Tue Jan 25, 2022 4:20 pm

Nigel, I'm currently selling one. See my Closing Down Sale.
It consists of a steel lid lined with rubber which has lots of holes drilled through.
The outer face of the lid has two knobs which control the 'sucking area'.
It was originally used in the printing industry for film-making.
It easily hinges up. Comes with a powerful vacuum pump.
PM me if you want more info.

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nkforster
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Re: vacuum press

Post by nkforster » Thu Jan 27, 2022 4:45 pm

Thanks for your help chaps. I made a simple jig re Allens' instructions - like a big bridge clamp. The frame is made from knot free softwood, painted with rubber paint on the inside (I had a tin left over from doing some roof repairs) The membrane is 1mm thick silicone rubber. The pvc tape around it is just belt and braces. The gasket material I bought some time ago from veneersupplies.com over in the USA. The pump is a Thomas pump I've used for years, vacuum bagging. It's a little underpowered for frame veneering but as everything fits together well, its fine.

I\ve posted a video of it over in Instagram:

https://www.instagram.com/p/CZOJoPhlaLw/

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