Official Luthiers Forum!

Instead of using a Vacuum frame, is there any drawback/ problem with
just putting your dish with braces etc in a vacuum veneering bag???
Andy

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Andy Z.
http://www.lazydogguitars.com

Can't see any reason not to, except the convenience of the frame VS the clumsiness of the bag.

But I'm brand new to vacuum bagging, so I offer up the above only because I've contemplated each one this past week, and weighed the plusses and minusses... I have not yet tried it either way.

The only issue I can think of would be the relative flexibility of the bag material VS a rubber membrane and the possibility of knocking over braces during setup.

The rubber membranes conform better to most shapes so there'd be less chance of side-loading the braces or knocking them over while pulling a vacuum.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Andy, a bag would work but getting the dish in the bag with the braces on would be a pain.

This is an easy solution if you don't want to go with a frame. I glued a sheet of 1/8" acrylic with contact cement to my dish, cut some air channels, glued in a barbed hose fitting. I seal the vinyl sheet down with butyl tape. The tape lasts for several gluings but needs to be replaced after a day or two as it wants to become permanent.

As Bob said, the vinyl is not as flexible as the rubber but the thinner stuff works fin...and you can see!

I made this set-up when I was using a venturi and wanted a totally airtight system so the compressor wouldn't run all the time.

 

 

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http://www.chassonguitars.com

That is a nice setup, Kent. Cheap and effective.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I was thinking along the lines of already having the dish in the bag, then simply slipping-in the braced plate, sealing(with dowel and a 'V' channel) and applying vacuum.

I have not used a vacuum frame but I have used a vacuum bag for other woodworking layups (not guitars). It is an effective way to do things BUT it can be a real pain in the butt to get everything into the bag. I just can't imagine getting a dish, top, and braces into the bag without something getting goofed up.

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Brad
Avon, OH

Guess I'll show my ignorance here, but I've been dieing to ask you what you're using vacuum clamping for, Mario. Are you actually doing braced plates? Is that doable with HHG? I always thought vacuum clamping would be out of the picture due to the short working time.

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Wes McMillian
Santo, TX
http://www.wesmcmillian.com

I haven't yet. I made up a system a month ago when I had to laminate up a soundport reinforcement plate of various veneers. But I've since had more and more ideas...

Others have used vacuum with HHG. It's been done.