Building with Epoxy

[fatt-dad]

Dear NG,

I played several hand made mandolins yesterday. Not much on the little details, but great volume, tone, etc. Sitting with the builder, he tells me he assembles the mandolins with epoxy. That said, there is not one joint on the instrument that will be unglued. I see this as a good thing (i.e., no seam separation in the decades to come) and a bad thing (how could you ever perform surgery).

Comments?

Thanks in advance.

Fatt-dad

[Luthier]

IMHO....I'm not a big fan on the use of epoxy in a musical instrument. #I use a powdered resin glue for my banjo rim laminations and the resonator plys but I like Titebond for almost all other construction applications.

Don

[sunburst]

Heat will melt epoxy at lower temperatures than hide glue. You can take the joints apart.(Possibly in the trunk of the car)
I've seen epoxy joints fail, I've seen glue joints of many kinds fail. There's no perfect adhesive or glue.

Epoxy is generally considered a "tone sink". I don't know how much science there is behind that designation, but I know it's sometimes used in speaker cabinets to dampen resonances. I have my doubts if I could hear any real tone differences in an instrument assembled with epoxy as opposed to hide glue tho.

I can't think of any good reason to use epoxy as a general adhesive for assembly, but I do use it for certain repairs, especially when there is no good way to achieve a good joint due to deterioration of old wood or from misguided past repair attempts, or if I need an extreemly long open time.

My opinion is: A good joint is more important than the type of glue or adhesive, and I think hot hide glue has the best set of characteristics for musical instrument use.

[Dave Cohen]

Frank Ford and Don MacRostie had an article on hide glue in American Lutherie a while back. They reported that hide glue withstands much higher temperatures than most thermosetting glues (such as Aliphatic resins and epoxies). That said, I use a variety of glues - different glues for different joins. For joints which you want to be able to take apart with the least damage, aliphatic resin glues (e.g., Titebond) are easier than hide glue. For joints in which you want absolutely no possibility of "cold creep", hide glue is the hands-down winner. For the greatest strength at room temperature, some varieties of epoxy have a slight edge. Polyurethane glues are good for joints w/ large surface area, when you know that you can squeeze the holy ____ out of them w/ your clamps. Otherwise, the stuff can foam and expand, resulting in a very weak joint.

[Chris Baird]

Although hide glue joints can be difficult to get apart they clean up and reglue MUCH easier than anything else.

[fatt-dad]

Dear All,

Thanks, I may continue to ponder this guys work. Big sound!

f-d

[jim simpson]

Does anyone use Elmer's white or carpenter's glue?

[sunburst]

Yellow Elmers and Titebond are the same basic adhesive, aliphatic resin. The white elmers might be something else I can't remember right now. I like the working characteristics of Titebond a little better.

[jim simpson]

Thanks sunburst,
I was worried because I have used both in the past and they seemed to hold okay.
Jim

[Dave Cohen]

With extremely oily or resinous woods such as cocobolo or ziricote, all of the glue types except epoxies lose a lot of strength. Fine Woodworking had an article on that a few issues back. Neither spruce nor maple are in the same category as cocobolo or ziricote, though, so hide glue and AR glues (e.g., Titibond) are more than sufficiently strong for mandolins and violins.

As I use all rosewood and maple binding, I once tried gluing the binding on w/ epoxy. notice that I said "once". It was an awful mess, and I couldn't make it work. Gaps showed up and I eventually had to rout the binding off and start over. So I never repeated that experiment.

[BigJoe]

I've used cocobola for woodworking projects over the years and have had no problem using titebond or cyanoacrylate. If the wood is sanded and glued pretty quickly before the oils can resurface it seems to work fine. I cannot imagine a need for epoxy in manufacturing of anything one may wish to repair at some point in the future. I have seem repairs done with epoxy and if you have to repair the repair it is almost impossible. I have seen a couple of pieces built with epoxy and repairs are near impossible.

[Rob Grant]

I generally use epoxy for mandolin and mandola neck joints. I have used epoxy to glue fretboards and have successfully removed said boards with the standard hot, flat spatula.

One problem with epoxy is the fact that the stuff does have a toxic component which can cause health problems.

[fatt-dad]

Again, thanks for the great feedback. While I have no immediate plans to build a mandolin, I sure do like to pick up interesting information on this forum. Re-reading through this post, makes me now feel somewhat cool on getting a mandolin assembled with epoxy, but then again, I likley have more to learn.

f-d

[Jim Rowland]

Back in the l950s (the stone age for you youngins)I was a fabricator on the first missle nose cones to go into space.
This was the big ice cream cone that Alan Shepard and a few monkeys rode in. The metal substructure was sheathed in fitted segments pressed from asbestos flocking,resin,and ground glass and glued on using...guess what..epoxy. We got the capsules back after flight and the only real damage was to the paint job,which had vaporized, and a plastic called Duroid which filled the telemetering slots and which had lost about 20% of its volume. The segments were tight except for some slight damage caused by the charges used to blast the bulkhead loose after landing. I can't imagine a car trunk in the sun generating more heat than a re-entry through the atmosphere,but evidently subsequent tests have shown that the E isn't as strong as we thought.

[Chris Baird]

Not all epoxies are equal.

[pickinpox]

Yellow Elmers and Titebond are the same basic adhesive, aliphatic resin. The white elmers might be something else I can't remember right now.

I believe Elmers (white glue) is polyvinyl acetate resin. The aliphatic resin glues (yellow) are the better choice in my opinion.

[labraid]

Curious, epoxies are not all thermosetting? Someone mentioned them coming apart in the heat, but thermosets are supposed to only become more permanently hard, and therefore brittle, with heat. In any case, epoxies tend not to seep into the cellular structure of wood as well as aliphatic resin glues thus preventing good molecular bonds. The better it can seep in, the better the hold. I wouldn't imagine (and haven't ever experienced), therefore, epoxies being better than Titebond in, for example, any wood joint at all.. Just keep that mando out of the trunk on a hot day, it's your friend don't ya know? http://www.mandolincafe.net/iB_html/non-cgi/emoticons/cool.gif
Another thought.. hide glue is not supposed to be so succeptible to heat by itself, but combined heat and humidity will probably do it worse than any aliphatic resin. Any comments from the hide glue adepts to back up or argue that?

[albrandan]

How about using Fish Glue? Will it stand the test of time?

It doesnt need to be applied warm, can be used right out of the bottle.
I met a fellow that builds violins, who used to build with Hide Glue, but has now switched to Fish Glue with great results.
Im not sure of the differences in top loading between a violin and a mando, but it sure would be nice to use a product straight out of the bottle.
Has anyone tried the Fish Glue?

Ted

[HoGo]

Fish glue that violinmakers use is made by cooking sturgeon bladders. It is applied hot just like a hide glue. Maybe you have something similar to Franklin's Liquid Hide Glue which is not recommended by anyone for instrument making.
The top load of a violin is roughly half of the mandolin load (4 strings vs. 8 on mandolin).

[albrandan]

Thanks for the reply HoGo
I was buying some wood (for my first mandolin)from this fellow, and talking about glue, he showed me bottle he was using. Here is a link to the product that he had.
http://www.leevalley.com/wood....0,42965 (http://www.leevalley.com/wood/page.asp?SID=&ccurrency=1&page=20019&category=1,110,42965)

He has been using it for a few years now with great success on violins.
Sounds like the mando has a higher loading, so probably not a good choice. Looks like its back to Hide Glue.
Now I hope we didnt throw out that old baby bottle warmer!


Thanks

[twombo]

As glues go, #I am not very adventurous. #For a beginner, I would (and do) stick with #good old yellow Titebond because it has good strength and pretty good open time. #

As you become more experienced, then you may consider going to hot hide glue. #Remember, hot hide glue has a very short open time (maybe 30 seconds or so to apply the glue, #position the parts, and clamp it). hot hide has great strength but demands near flawless joinery. I'm not there yet!!!!

Epoxy, remember someone is going to have to make repairs down the road. #If you want to be cussed throughout the ages by luthiers trying to repair your creation... go for it! #Not me... I have enough eternal damnation to worry about as it is!!!!!

[Mario Proulx]

Most hardware store type epoxy will release at about the same temperatures as Titebond will, making for easy repairs.

It is only the high end, structural epoxy that are near impossible to take apart.