Official Luthiers Forum!

I'm bringing in a venturi style vacuum system from Joe Woodworker for use with my CNC router and other jigs. I think I brought this up once before but I can't seem to find it. How do we all feel about clamping glue ups with vacuum? What are we comfortable vacuum clamping and what not? For example, it seems pretty well agreed on that braces can be glued with vacuum. What about gluing an electric guitar top to the body...for example, a 5/8" maple top to a 1" mahogany body.

Inquiring minds want to know

All I can say about Vacuum is, how deep is your wallet?

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

I have less than $50 invested in my bridge clamping setup. I have plans to expand my use of vacuum so this thread will be a good read.

So are you using a venturi as a vacuum source or you just use the inlet of an air compressor? I can't find a vacuum pump or venturi system for less than 100 dollars.

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

That's a pretty thin veneer, right? wonder how it would work on a thick top glued to a thick back. I'm assuming a good fit, straight off the drum sander, for example.

Also, you you have any experience with manifolds, check valves, etc? I'd like to be able to use this for multiple things at a time. So for example, I'd like to have a glue up going somewhere but still be able to use vacuum for my fixtures once I've gotten all the air out of the vacuum bag. I don't think it would be practical to actually have several things drawing down all at once but I think it would be reasonable to having one thing going while something else is just in "maintenance" mode.

I glued the Maple top to my Les Paul with a vacuum bag, worked great.

I like it because it delivers even clamping force as opposed to traditional clamps that deliver a lot of force in their immediate vicinity.

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

What I ended up doing is making a monstrosity of a clamping press, with about 10 press screws, clamping cauls, etc. It's just a PITA, and it's monstrous to store. I'm glad to hear you had success doing this. I think I'll place my order for the venturi kit today and we'll see where I end up.

I think I know the answer to this one..., but has anyone tried using a "Spacebag" vacuum storage back hooked up to your vacuum? It seems like if it had enough pressure to compress bed comforters etc.., it would have plenty of clamping pressure for most glue scenarios. Just a thought.

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Brad

Vacuum cleaners are good for higher CFM, but they aren't all that good at pulling a very high vacuum... I do not know if they are adequate for glue ups. I think a vacuum bridge thing would be good for me, eliminate the clumsy clamps and bad joint just because I forgot one part didn't get clamped...

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Cat-gut strings are made from kitten guts, stretched out to near breaking point and then hardened with grue saliva. As a result these give a feeling of Pain and anguish whenever played, and often end up playing themselves backwards as part of satanic rituals.

Typhoon Guitars
http://www.typhoon-guitars.com

Thanks for noticing Todd. These nails are homegrown, and I've put quite a bit of work into them. I'm left handed, but no problem with right hand reaches as of yet!

I've just recently ordered a vac system for vacuum clamping and a vacuum press I'm building, but seriously, has anyone ever tried a vacuum bag that you hook up to a vacuum cleaner for anything guitar related? It seems in theory that it would work fine, assuming the bag holds a proper seal. Just putting it out there.

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Brad

It's not easy for me to get online & do any research now but go look at the vacuum of an industrial vac like a Fein or a Festool or a Nilfisk Alto Wap - they'll list it in inches of H20 then compare that to a vacuum pump in inches of Hg - there is no comparison.

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

You can use the -bag- but you must use an actual vacuum pump. I've used garbage bags for vacuum claming/pressing and they work fine so long as your seal is good. You don't even need to use thick bags. Vinyl shower curtains, edge welded, make good vacuum bags.

A shop vac, at least the one I tested, will pull ~2-3 PSI tops where a vacuum pump will get you in the 12-15 PSI range. You need that extra force to get good results.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Has anyone here tried this?:

http://www.leevalley.com/en/Wood/page.a ... 43314&ap=1

That's a wine cork.

http://www.acemart.com/bar-supplies/bar ... d7313.html

I thought that looked familiar. I used to have one, but never used it - always drank the wine too quickly!

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

Years ago, I used an old refrigerator pump to vacuum laminate fiberglass and carbon fiber over foam cores to make RC sailplane wings. You can build a setup for cheap, and it won't tie up your air compressor. Don't even think of using a vacuum cleaner or shop vac. The motor needs the airflow for cooling, so not only will it not produce enough vacuum, but it will burn up the motor.

Al

I do my solidbody laminations with vacuum, typical .7" maple + 1.75" mahogany stuff, using a JWW 5cfm pump + PVC tanks and large bag. It's a sandwich going into the bag: 3/4" MDF with a 2" sawcut grid (like graph paper) on the outsides with the delrin dowelled body/top lamination in the middle that has wax paper on the sides to keep the squeeze-out from bonding to the MDF. Much more pressure than what I can do with clamps even though at about 6000ft elevation I can only pull about 21". Gotta be quick using HHG. With HHG I need to cover the top of the wiring channel in the body with a strip of scotch tape or it will foam and harden blocking the channel. I leave it in the bag for at least an hour. The pump etc gets used for vacuum fixtures for the cnc.