What adhesives to use on a body

[kbrmiller]

I've heard that the main problem with the Titebond liquid hide glue is its short shelf life, but I've had enough bad experiences with it not to trust it for anything other than gluing labels in place. I used to work with an old violin "repairman" who didn't know how to use hot hide glue (unpardonable in the violin world) and used the liquid stuff for everything. I was the guy who had to redo all his work when things like neck resets would come loose after two weeks. It makes sense that this would happen, since the additives that keep it liquid in the bottle would also tend to keep it from hardening.

You don't actually have to buy a glue pot if you want to try hot hide glue-- I use a Rival electric HotPot I got at Wal-Mart for about $10. I cut a hole in the top to drop a Mason jelly jar into and stuck a cheap instant-read thermometer through another small hole. Frank Ford's site has a good way of preparing it using a microwave to heat the water. If you only use it occasionally, this works quite well.

[soapbarstrat]

Go ahead and do it that way, but some long-time luthiers noticed that glued wood pieces that were not made a little "porous" before gluing tend to be the ones that come apart. So, when repairing these failed bonds, they rough-up the surface before re-gluing, and noticed that those glue bonds never fail.

It's not about creating "fuzz fibers", it's about getting the pieces of wood together as close as possible, for better sound transmission between the two. On a guitar, I'd rather 50% of the wood piece glued area to have small grooves to hold more glue, while the other 50% has a layer so thin, it would be hard to measure, so those areas are mated together as closely as possible. Instead of a very flat surface that requires a thicker layer of glue, which is holding the 2 pieces farther apart from each-other.

With guitars, we're usually talking about hardwoods, which are not as porous as soft-woods. The soft woods will allow a little more glue to soak into the wood, even if there's no roughing-up.

[Setch]

Soap, if it's about getting the pieces of wood close together then they need to be flat and smooth.

If you sand or otherwise rough up your surface you introduce upstanding wood fibres which prevent the two surfaces touching. I am aware that a number of experienced builders and repairers score glueing surfaces to improve strength, and get good results, but I am convinced they get these in spite of their scoring, not because of it. Aliphatic resin, and hide glue, works best in tiny amounts, not when it's required to fill a space between 2 surfaces.

I am also pretty sure that the idea behind smooth surfaces being bad for gluing is based on failed glue joints due to surface contamination/oxidisation or burnishing by a planer or tablesaw. Removing burnished surfaces, and exposing fresh wood before gluing is important, but this is a different thing from roughing the surface, and is best accomplished with a scraper.

The only advantage I can see to a roughened surface is to prevent you squeezing all the glue out by overtightening your clamps, something which can be a equally well addressed with a little self control when clamping!

[frank falbo]

Its always a toss up as to who to believe. The "scientists" who do the experiments are usually right. But sometimes they work for the companies, so they can exaggerate claims, or only do studies that support the companies' marketing claims. Luthiers sometimes can say "Sure that's what it says on paper, but in the real world...." But most of the time luthiers are not also highly schooled in things like chemistry, physics, etc. They are artists. So I'll take both conclusions with a grain of salt. In this case I'd believe the study that supports the smooth, flat surface. Guitar work does involve a lot of joint stress, but not so much that the joints have to be perfect. I mean think of how many botched factory guitars there are out there that are still holding together! In other words, you could go through life scuffing up joints and never have one fail, because it's still strong enough. But the scientists tell us that when they do the tests (and they do them until it breaks, right?) the flat join is stronger, so I believe them. I use the idea of "relief channels" like from scuffing or scoring only with epoxy.

[Dugz Ink]

The only advantage I can see to a roughened surface is to prevent you squeezing all the glue out by overtightening your clamps, something which can be a equally well addressed with a little self control when clamping!

And that is something to consider; some people clamp down two pieces of wood with enough force to pin a rhino to the workbench. There has to be some glue left between the pieces of wood if you expect them to stick together.

When I'm using epoxy, I don't even use clamps. Instead, I set up the pieces of wood so that the joint is parallel to the floor, and drape a couple cords/ropes over the project. Then I add weight to the ropes, directly under the project, until I get the amount of epoxy-thickness that I want. (If you try that, put pieces of wax paper between the ropes and the epoxy joint, so the rope doesn't become a permanent part of the project.)

And I've always used a fine file on the joint surfaces, instead of sand paper. That gives me a clean flat surface, and a sharp straight edge. If I'm working with wood that has poor absorption properties, I might make some very shallow grooves in the two pieces (with the grooves on each piece offset 90° to each other)... but they have to wide and shallow, otherwise they'll just turn into air pockets.

D~s

[SawDust_Junkie]

I've noticed that several posters here have stated that they prefer the Tite-Bond original to the Tie-Bond II. I believe it was stated that the Tite-Bond II was design for marine uses.

Well, yesterday I was at a local big box home improvement store and I saw Tite-Bond III. I picked up a bottle of it. I was just curious if anyone here has seen it or used it and what are their recommendations about whether it is suitable for instrument construction.

Edited September 13, 2004 by Fender4me

[Nicksguitar]

A new glue that I tried with my last build was Gorrilla Glue. You wet one or both surfaces and then eavenly spread this on the other. It foams as it expands and fills and small voids that may occur while still bonding the surfaces together. My uncle runs a hardware store and swears by the stuff. I haven't used it on a book match but it has done a great job gluing a cap on to a mahogany back and the finish took the same as it did with titebond.

PS I didn't realize Titebond II bit the big one that much. I'll be throwing out my bottle!

[westhemann]

gorrilla glue is messy

i use it for some things...but usually only on poor fits....because of the gap filling you mention...but it is much tougher to clean up than wood glue

i always regret when i use it

[Dugz Ink]

gorrilla glue is messy ... i always regret when i use it

Ditto for epoxy... especially if it has dye in it. I have one pair of jeans that always wear when I'm working with epoxy, because they're already ruined. And I always end up with a spot of epoxy someplace like the back of my elbow. "How the ---- did that get there?"

D~s

[Dugz Ink]

Okay... I just used the Titebond Original for the first time.

I glued two pieces together, then started the process of gluing and clamping two other pieces. After the second set, I checked on the first set of pieces. Hmmm... I realised that the first two pieces weren't exactly like I wanted them. (They must have moved 1/4" while I was trying to set up the clamps.) So I tried to pull the first two pieces apart.

-- BZZZZZZZ -- Wrong answer!

This stuff REALLY holds fast and strong! Thanks for the advice.

As for the wood, well, I had about 3/8 of an inch of excess at either end, so now I only have 1/8 of an inch of excess at one end (and a bunch at the other end)... but that will still work. And that's why I always leave some excess on the pieces that I cut; because I'm accident prone.

D~s