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Okay a friend picked up a damaged mini martin off of ebay made from HPL. High pressure laminate I believe thats what it stands for. He wanted to fix it for his kid but he's a mechanic and not a guitar builder. So he asked me to do it. The instrument from what I believe happened was that it was dropped on it's end pin causing the top and sides to separate somewhat about ten inches or so. No damage at all to the side and top. This stuff seems very flexible so it didn't crack at all like solid wood may have if you dropped it on the end pin. The kerfing is wood and it sheered off at the wood leaving a very thin layer on the top. If this was real wood I would know what glue to use for the repair but since this isn't anyone have a clue what Martin uses? In other trades they use a contact cement for this stuff. Would CA be a good choice? Mike

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Another day, another dollar.

Titebond will work fine for this type of repair. Contact cement is for counter tops, not guitars. CA would also work but clean up would be a no go as you will scrape through the color on the HPL before you even know it.

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Roo Glue is made for this purpose.

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Wisdom is justified by her children

I did some test samples with some laminate that I had around the shop. I sanded the back slightly and glued some wood to it with a few different glues including Titebond regular and it seems to hold well so thats what I'll use. I heard that they used a certain brand of medium viscosity CA at the factory for this type of stuff so I was concerned with Titebond not adhering well to this stuff...Thanks

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I aways wanted to give this stuff a try so I may just order some of it for the hell of it. But which one Roo clear or roo wood? Or maybe both..Mike

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Another day, another dollar.

Okay I went and glue this up successfully using Titebond Melamine glue.This glue is used for gluing wood to various laminate materials including HPL. It's basically the same glue as the roo glue clear that Mark recomended. It dries hard like regular titebond but seems to have less working time then regular and has a lot more tack then regular. It worked fine. Previous to starting this job I emailed Martin and asked what they use. I finally got an answer today a little to late. They told me they use 3M Scotchweld epoxy...Mike

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Another day, another dollar.

Thanks for the feedback - two glues I did not know about that I'll write down for possible future repairs.

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Steve Smith
"Music is what feelings sound like"

I've been using medium viscosity cyanoacrylate to paste these things back together since they first appeared on the scene, and it seems to work just fine. Cleanup with acetone, sand the bevel back in the edge, and Robert's your mother's brother. . .

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Cheers,

Frank Ford

FRETS.COM
HomeShopTech
FRETS.NET

Thanks for the tip Frank. Just checked out your new machining site and like it. I do some hobby machining myself.

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Another day, another dollar.

Thanks for the good word, Shaw.

Forgot to mention that HPL is regular countertop material, i.e. Formica, Micarta, or whatever, so it's pretty much solvent resistant.

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Cheers,

Frank Ford

FRETS.COM
HomeShopTech
FRETS.NET

I was going to guess epoxy, I've used that before on Richlite and Paperstone countertops which are basically HPL or sometimes called "dimensional laminate"

Frank I wasn't really sure about the outer skin of these guitars. It looked thin and I wasn't sure about if it would hold up to solvents. I Originally thought of using an epoxy but was concerned with squeeze out and cleanups. I didn't have an outer mold for this size guitar so I needed to improvise. I didn't think I could glue it up with CA fast enough without a mold to help me keep it in the proper shape. The sides on these guitars don't hold their shape like bent wood side do. There is a lot if resistance. I believe the only thing holding them to shape is the top and back. I think they are simply straight pieces of material that are flexed and not bent to shape. I used a lot of Irwin trigger clamps and kept loosening and re tightening them till I had the the top and sides lined up proper ...Mike

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Another day, another dollar.