Official Luthiers Forum!

The first one I have is from your common house refrigerator. I have others that are a step above that were given to me so I am using them but my first was MORE than adequate. All I can say is if it is free, try it!

Shane

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Canada

Hello to all,
A belated follow up on the vacuum generator discussed earlier. I finally made a decent vac fixture out of aluminium, and gave it a try. It holds down a fingerboard like a champ. The noise of the vac is not loud, however my compressor does run alot, and that heats up the shop pretty quick (1 car garage). I am thinking up finding a decent used pump, as the put put of a vac pump seems less annoying, and will generate less heat. The vac generator will make a great back up, and is great option if you have a large compressor, or if your compressor is more isolated than mine.
Evan

I've been using a 1-1/2" Becker blower style pump. It's been fine for bodies but a little lacking for pickguards and necks. Would I notice much difference with a larger let's say 5hp pump? Or am I just seeing the limitations of vacuum for this type of work?

Hi Sheldon, with good jigs and adequate vacuum, you should be able to fixture and machine pretty much any part in a guitar (including necks). I apologize as the flow rates and vacuum levels used escape me...but it is certainly all possible!

EDIT" One quick note - vacuum is most effective when used in conjunction with locating pins, or other similar features

Trev

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http://www.PeakeGuitars.com

Do you have a vacuum gauge on your work? If you're getting 15mmHg then that's enough to hold any part of a guitar in a good fixture, though I'd argue that any good fixture should have you at 20-25mmHg. My Venturi pulls 4 CFM, and it's overkill.

Vacuum doesn't take shear well, so it can be important to account for that using pins or some other method.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I built one of the Joe Woodworker venturi systems for vacuum bagging, and it really works great. For clamping though, I use a Gast piston pump that I picked up cheap on Ebay. It works great too. The main reasons I went with the Gast pump for clamping are that the Gast is quieter than the venturi and I only have one 220 circuit in my shop. My compressor runs on that circuit, but so does my dust collector and my CNC spindle. I can run any two of the three easy enough, but all at the same time is pushing it. The Gast runs 110 and off of another circuit....

It doesn't take much of a pump to handle the kinds of fixtures I use. Mine is a fractional HP unit, and will easily pull and hold 25 inches or better on my jigs.

Dave

We've gone through two gauges and they've both died so I'm not sure what we're pulling now. When we do sheet work there end up being lots of holes and slots letting air through. This is why I'm thinking of a larger volume pump. Proly on pickguards we should use a 2-stage fixture. One stage for drilling the holes and a second stage with pins that holds the part for routing. That leaves circuitboards...

Depends on the size how practical this idea might be for you but I'm in the habit of laying down a thin tape barrier on the vacuum side of the wood. This solves the problem of porosity in a lot of tough situations. In fact, I always do it when using vacuum jigs.

Use a really thin, wide, colored packaging tape. The color helps you see the edges when placing the tape. You want to overlap the edges when you lay it down. This may seem like a hassle but the vacuum seal becomes 100% and there's no way to throw the part off the tape.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Outstanding tip. Thanks Z.

Bob