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Thanks for sharing Ken, very nice simple design!

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Pat

Braces do not move or skate in our vacuum press -- the tape is simply used to hold place while layout the braces. And this of course is the point of using a vacuum press in the first place. Now I have been told, actually by a tech from the Taylor factory, that the vacuum press has the added benefit of drawing off water quickly and speeding drying time as well. Seems logical to me.

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Ken Cierp

http://www.kennethmichaelguitars.com/

I have only had one or two go-bars get away from me. Rubber tips may be one thing that keeps them in place. Someone here once suggested putting a piece of carpet on the upper deck to keep them from sliding on that end.

I constructed a simple (crude) vacuum system that I use only for bracing. I constructed a wood frame, got some clear plastic from the fabric store (Jo-Ann's as I recall), and glued the plastic around the frame. I placed weather stripping around the frame (on top of the plastic) so that it would seal around the edge of a radius disk. I had sealed the radius disks with Z-poxy so the weather stripping seals against it well. I bought a valve from joe woodworker that fits into the plastic sheeting to attach the vacuum pump to. The vacuum pump was purchased from ebay used for about $50. I clamp the frame to the radius dish after placing the top or back inside and turn on the pump. I run the pump continuously during glue up. It may be crude but it works quite well... and saves space in my small shop. I don't have a picture to share right now...

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Steve Sollod (pronounced sorta like "Solid")
www.swiftcreekguitars.com

Before you give up on go bars consider tacking a piece of carpet to the slick gobar deck ceiling. Use a piece of old door mat to give a little friction to the bars and they won't be prone to go slipping.

Thanks for all the great input folks!

Kenneth,

Yours looks like a very simple, economical set up. I'm a bit confused though. Do you just drop it over a radius dish? What does the top rest on?

For those of you rocking the joe woodworker pump, is it noisy?

You guys used vacuum with hide glue?

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Ed,

Yes you could construct it in such a way to do that, but I prefer individual contoured cauls under each brace. The ones (braces) that are flat on the glue surface do lay flat and therefore do not get distorted or cause distortion.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Interesting I use all radiused braces, so I should have any even easier time.

Hmm, now y'all got me thinkins...

I have the Excel 1 and while not completely silent , I hardly notice it when I'm working.

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"I've been had again"
Tim Benware
Creedmoor, NC

Not me I can't glue it up that fast. When using hide glue I go to my Go-bar deck.

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"I've been had again"
Tim Benware
Creedmoor, NC

I have experience with vacuum systems (they have their points), and various go-bars. I've settled on a system like Waddy's. I won't go back.

Go bar.2 eh?

Well I've picked up some great tips on go bars. Stops - why didn't I ever think of that! One thing I have noticed on some pics of go bars in use is that some folks put way too much bend in them. IMO there is plenty of pressure without bending them much. I've never had a problem with them springing out or slipping.


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I did not read everything, so maybe this is redundant. I have seen go bars that are spring loaded, telescoping. Do those have any advantage?

You need to read everything!

Regarding how much pressure go-bars produce based on the degree of deflection here is a bit of a study that I did years ago. The results are not what some might expect.

Note the amount of deflection below:



And the resulting clamping force:



A bit more deflection:



And the resulting clamping force:



The most deflection:



And what it gets us in clamping force:



Ain't physics great.....

And ya know if you bend em more it takes more force so where does that go? Sideways! I think that's the biggest mistake I've seen other luthiers make.

I set my deck for a deflection of about 1" for my 24" bars. I've had em slip off of a brace top but they don't go shooting out anywhere.

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Steve Smith
"Music is what feelings sound like"

Yeah, just a little flex is all you need. Easier to place and less risk of drama.

I do as Michael Colbert and temporarily key braces in place and use scrap to span them. I find this to be an effective method of keeping them in place while I quickly and safely apply even pressure.

I'm with Terence regarding the hot hide glue. I like to use it on braces and really can't see how I would do so if I were to employ a vacuum system. I'm not saying it can't be done, or that not using HHG makes an inferior instrument. It's just not how I do it.

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George :-)

HHG's very short open time is what stopped me from going the vacuum clamping route as well that along with the noise of the pump reminding me of.... well I won't go there.

You can extend the open time of HHG by using a "hot room" which is something that the violin folks are very familiar with. It could be a small room or closet that you bring up to say 110F or so.

No issues here with positioning or placement of the bars causing skating because of HHG's quality to tack stuff in place quickly.

Not having read the entire thread so forgive me please if this has been mentioned but back in the day on the OLF Howard Klepper used to remind folks to wear eye protection when using go-bars - always a good idea too!

Rusty's post about lining the top of your go-bar deck with something abrasive to help keep the bars in place - another great idea that I have yet to get around to.

Vacuum systems are a popular way of getting it done, but, when I do the math and see they can only generate up to maybe 14 psi I shy away. I'm a titebond user and am always looking for 100-150 psi.

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Joe Beaver
Maker of Sawdust

But not for guitar bracing, right?

Friederich shows an interesting jig for gluing braces in the Courtnall book. More compact than a go bar deck and less complex than a vacuum system.