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Don't want to get this post too far off course -- but re: GB deck google using a GB deck for use even gluing a sound board and I think you'll find disturbing pictures where that practice has resulted in a rod inadvertently being shot right through the top -- can't image the balancing act required to glue on the bridge, and the weight of a child on sitting on a guitar top is a good visual as well.

Secondly -- as for squeeze out, before gluing the bridge I always coat the finish of the bridge out-line on sound board with soap or wax, its easy to fashion a pointed applicator out of a chunk of either material.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Wow lots of replies to this! Thanks for the info about hhg - I'll have to give it a go sometime.
We have a vacuum veneering setup at work, so I'll be able to use the pump to glue the bridge on.
No there isn't going to be a side port either. The plan is to use oversized tentellones and leave gaps between the top/sides and back/sides so the edges become the soundhole! It could well be a complete disaster, but I just had the idea and want to try it Following on from the Matsuda thread, I've also had what I think is a really cool idea for an externally adjustable neck that requires no metal fastenings, so I'm going to try that our too.

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"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

An access port is a great idea too.

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"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Wow that is interesting I would love to see pics as you progress.

I'll do a build thread on it when I get around to starting. I still have a violin, ukulele, electric guitar and 1 more acoustic guitar on the go!

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"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Wacky idea here: add a hole for an end pin jack, insert a balloon through the hole, inflate it to support from the inside, then deflate and extract it the same way after gluing?

OK. I have a couple of wacky ideas that I can't let go of so I have to get them off my chest. Feel free to ignore.

Stupid Luthier Trick #1: Drill a hole, as for an end pin jack. Insert a balloon, inflate to support top from inside, clamp as you like, deflate balloon and remove through end-pin hole. Don't know where you'd find a suitable ballon for this but maybe it could work.

Stupid Luthier Trick #2: Same end pin hole, fill guitar with clean sand, glue bridge, set 75 lb. child on bridge (ala Hesh's comments), drain sand when done, and apply vacuum to end-pin hole to clean out the dregs.

OK here's another idea that I actually dreamt about last night..... Yep that makes me a pretty sick puppy.....

Although not ideal..... there are lots of examples through time of bridges having either pins for locating and retention or......................b*lts and n*ts.....

Now before you get all upset about all the added mass of hardware right smack over the sweet spot of the top mass reduction is possible too.

On the underside of the top install two T-n*ts and be sure to perfectly locate them or all bets are off. Source nylon bolts in the appropriate thread that will be installed through two corresponding holes in your bridge.

Glue the bridge on, tighten the bolts to snug it down everywhere and......

1) Either remove the bolts when the glue is dry and cover the holes in the bridge with pearl, wood, whatever dots or:

2) If using nylon b*lts they could be left in place and covered with pearl, wood, or whatever dots.

You could also use steel b*lts not worrying about the mass and then when the glue is dry remove the steel bolts and cover the holes.

If the b*lts are removed the only added mass with this method is the T-n*ts. If the b*lts are left in place and you use nylon b*lts the added mass is pretty minimal.

No inside access is required provided that you locate the T-n*ts accurately and no access port is required either. The bridge can be reglued in time if it lifts, and they usually do eventually.... making this method serviceable into the future.

There are examples of this being done but not for the same reasons in the past with G*bson and the infamous pl*stic bridges used on the L series guitars in the 50's though the 70's. G*bson used all metal hardware and left it all in place......

What do you think?

Hey Bob I was thinking along these lines too and was thinking of filling up the thing with cat litter, clean cat litter....

Leave some of it in there and you now have a rhythm instrument to shake, rattle and roll....

I build a lot of classicals fitted with a tornavoz and also of course lutes, neither of which allow access through the sounhole for gluing on the bridge. With HHG or fish glue no great clamping pressure is needed as long as the fit of the bridge to the top is perfect, as has been said a rubbed joint would probably work perfectly well. I do however add clamping just for insurance, like this:



The bar on top is clamped to the neck exerting downward pressure on the bridge, the two cam clamps are only lightly applied just to stop the wings moving, they bear underneath on the cradle, not the guitar. I've probably done something like 20 doing this and all still fine. Just make sure the bridge is a perfect fit to the top.

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Hey Bob I was thinking along these lines too and was thinking of filling up the thing with cat litter, clean cat litter....

Leave some of it in there and you now have a rhythm instrument to shake, rattle and roll.... [/quote]

Well, I've always heard that two great minds can sometimes run along the same track.

Now we know that two minds like ours can do it too.

I did a "rubbed" HHG bridge with 315gm hide glue on my last steel string build. No clamping of any kind. It is still rock solid today. Maybe I got lucky.... Just my $.02. If it is a prototype guitar, what do you have to lose? --Jay

Generally speaking, the faster an epoxy cures, the more rubbery it will be when cured. So, what you say about consumer-grade epoxies you buy from your local hardware or department store is true. Once you move up the epoxy ladder, things change.

Hysol 9462 works very well for gluing bridges. It is an aerospace-grade epoxy. While it is thixotropic, it is quite slick, so it squeezes out when clamped, or even weighted, to form a very thin film.

9462 requires 72 hours to reach full strength and it is very hard when cured. This hardness transmits vibration from the bridge to the sound board as well, if not better than HHG. I used 9462 on the last two bridges I glued and both guitars sound great with plenty of volume and sustain.

Also, while consumer-grade epoxies have a TG of about 170 degrees or so, 9462 is good to 350 degrees, so cold creep is non-existent.

Dan we live in the land of West Systems here in Michigan and are no stranger to higher-end ep*xies.

I'm not here to argue with you but you will not find me using the word "better" when describing any ep*xy out there vs. HHG in respect to most Lutherie applications. I appreciate the attention that you have given in your post to the idea of thick glue lines as well because I would have surely gone there and no I am not calling you Shirley....

As such I'm happy for you that ep*xy works well for you but you won't see me ever using it for a bridge unless.... it's a basket-case beater and the top is all torn up AND it's appropriate for the instrument.

If you like beating your head against the wall for decades that's what would likely result from trying to convince career Luthiers that any ep*xy is superior to HHG for what we do.

Personally I appreciate your comments but we will just have to agree to disagree.

One last thing. Serviceability also includes the notion that what ever it is that we do it's not so far from the norm that in time when you and I are worm food and someone else has to deal with what we have done that they won't have to do any unnatural acts to service the beast. You already addressed the release temp and that's WAY higher than HHG. Often it's the case that heating a bridge to soften the glue puts the neighboring finish in peril of bubbling and being visually damaged.... not a good thing. Any glue that releases at a temp higher than HHG increases the risk of finish damage in the removal process.

Additionally if the bridge ever does have to be removed and lifting is not the only reason bridges are removed, they split, they break, pin holes get worn and making a replacement bridge a good option. A glue that will not release until 350 degrees stands a pretty good fire risk as well if that future repair person uses standard bridge removal protocol, gets no where, and keeps applying more heat.

PS: Cold creep is nonexistent with HHG too and there is debate still ongoing about Titebond original.

PSS: We have one OLF member who was made deathly ill by ep*xy exposure so much so that it's changed my tune around the stuff too. HHG to my knowledge has never harmed anyone and you can eat it all day too but likely will be sorry the next day unless you have a body temp of around 140F....

Well 2 people beat me to the access port idea I know I've seen it other places, but here is one link I found with a quick google plus a second one I remembered from another forum:

http://www.classicalguitars.ca/features.htm

http://luthiercom.org/phpBB3/viewtopic. ... ort#p72770

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Bobby Masten

I appreciate your thoughtful reply, which does raise valid points against the use of epoxy in luthery. I'm not arguing with you, or anyone else, either.

Serviceability is a valid reason not to use epoxy. As you note, there will be times where the bridge will need to be replaced.

Sensitivity is another valid point against epoxy.

Thanks Dan, much appreciated.

I spent my first years on this forum as a builder only. When I did an apprenticeship in repair for three years.... it opened my eyes to what happens to our creations after they leave our care. It's a good perspective to have and I thought that I would be a better builder as well if I understood much more about the idea of serviceability.

It also puts me at odds with folks frequently, not a welcome thing but when you greatly value the idea of giving very sound advice a balance of sorts has to be struck.

I worked in Aerospace for nearly 30 years including a stint with the YF-22 program. Aerospace grade ep*xies are indeed amazing in many respects and so is composite material science. This is stuff that I greatly appreciate and as such I greatly appreciated your post where you provide specific data, not something we see around here very often but certainly welcomed by me.

My hat's off to ya for trying different things too and I should have said that in my original post(s).

A funny thing happened to me on the way to thinking that I could engineer a superior guitar using what I know about CF, Aerospace manufacturing, etc. I discovered that there are very good reasons for tradition in terms of guitar design and that a lot of very bright guys (men and woman) really broke trail and then some for us long ago.

Thanks for your reply but most of all keep on thinking as you do of new ways to do things. That's how we make progress, always!

Right back at you, Hesh.

The first time I used 9462 on a bridge was because the HHG joint failed. In retrospect this due, in a large part, to my failure to properly prepare the top prior to gluing. When I pulled the masking tape off, the wood grain had developed ridges in the along soft part of the grain. I should have scraped it smooth prior to applying the glue. A few weeks after stringing up the guitar, the bridge popped off in the middle of the night with a very loud bang, scaring the bejeepers out of my sleeping wife and pet birds. Knowing that 9462 was very strong and very hard led me to try that for the re-glue.

I used 9462 a second time because of my positive experience with the first.

But, upon reconsideration, I think I'll give HHG another try on the guitar I'm rebuilding, a 1978 Ovation Legend that is receiving a torrefied Sitka spruce top and torrefied braces.

Like you, I come from an aviation background, albeit model aviation. Aviation and luthery share a lot of things in common and I've found the transition from building model airplanes to building guitars pretty easy.

And I'm jumping off a cliff with melting wax wings????? OK I get it, I'm old but do you have to keep bringing it up????

Kidding of course! Long ago on the OLF another poster posted about hearing a loud crack in the middle of the night that woke him and his wife up. He had built his first guitar without any RH control.... and had 9 coats of lacquer on it when it decided to split down the top. When one is a Luthier that old expression about things going bump in the night has new meaning...

Have a great day Dan!

A picture posted by John Ray on his blog a while back. Basically the same thing Colin said.

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Jim Kirby
kirby@udel.edu

Go-bar deck clamping?

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Another day, another dollar.

What I've done a few times is
fit the bridge perfectly to the top,
locate bridge and drill and install bridge pins,
drill for 2 abalone dot markers, on bridge wings,
glue and screw bridge to top, where ab markers are,
with 2 end bridge pins installed,
clean up glue and remove 2 pins,
remove screws,
inlay ab dots later.

I think pinless bridge is the issue?

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Ken Cierp

http://www.kennethmichaelguitars.com/

Oh, right!
Well, he could substitute the pins with the spikes?
Plus, he might not want inlays on his bridge.

I'm in the epoxy camp. I would wet out both surfaces with west systems, thicken the mixture to approx honey thickness, with microfibers, place it on with locating pins, and put a little weight on it to settle it down.

mask off the area around the bridge, to collect the squeeze out, q tip it away until its done squeezing out, then remove the masking. use low tack masking.

yes, if the bridge needs to come off later, it will need to be routed off.