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I'm building a Gypsy Jazz Selmer style and have been researching this and will try to do "double sides" in a vacuum bag but haven't decided which adhesive to use. It's down to West Systems epoxy, maybe with a chopped fiber additive or a formaldehyde urea resin 2 part mix. I'm trying to find out if there will be a bad smell afterwards using the formaldehyde urea mix. From what I've read, there is less chance of "bleed through" using it.

I’ve had extremely good results with Unibond. Absolutely no bleed through like you mentioned.


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+1 I have been using unibond based on James recommendation for a few years. I use it to laminate full width lining sides when I then slice up to use for solid linings. It works great and lasts a long time.


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Which Unibond are you using!?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

You can get a bit of bleed through with either glue. But it sands off and doesn't really cause any problems.

Bleeding through with epoxy is not a problem if you were intending to pore fill with epoxy anyway.

Ok, there's Unibond One (1 part ,PVA resin) and Unibond 800 (formaldehyde urea) . which would I need? Also, I usually pore fill with Z-Poxy finishing resin. The outside layer will be spalted Sycamore.

The 800 - https://www.vacupress.com/product-categ ... ibond-800/


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If you pore fill with epoxy then using it to laminate the layers would keep everything compatible. Any splotchy bleed through would be incorporated into the pore fill.

So, I might as well use the Z-Poxy I already have instead of buying a gallon of Unibond 800?

Also, about how much Z-Poxy will I need to do one guitar? I have about 5oz. on hand (resin and hardner). This is one thing I want to have more than enough to do the job once I get started mixing.

Make sure that you’re using the zpoxy finishing resin for porefill. There is more than one version labeled as zpoxy.


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It's the "Z-Poxy finishing resin and on the box "Laminates Wood & foam"

I would suggest a structural epoxy for the laminating instead of a finishing resin. I prefer a formulation designed for strength instead of surface quality. I like West Systems.

Agree with Barry, that’s why I was asking about the zpoxy you had. I would be hesitant to laminate sides with it. It could work, but would be a problem if they decided to delam.


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Ok, Thanks guys, I'll look into the West Systems products.

Sorry guys, I’ve been traveling!

I’m not trying to sell anyone on products, but I’m a Z-Poxy guy, too. I haven’t had any issue with the combo bc the Unibond doesn’t bleed through.

If Unibond has a downside, it’s that the resin has a somewhat short shelf-life once you open it. My West epoxy just lasts.


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For those using West Systems epoxies, check the shelf life after opening, it's not infinite, but it may also not matter much for guitars as compared to structural assembly in boats and airplanes. Test first.

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Peter Havriluk

I've done laminated sides, mostly three layers, on dozens of ukuleles, all with Titebond red and clamped mechanically with a closely fitting caul. I have a vacuum system and tried using it for sides early on but found that it was an unnecessary complication. Laminated backs are the opposite. It's easier to use a radius dish in a vacuum bag and the back will potato chip unless epoxy is used.

Satisfied Unibond 800 user, have laminated lots of sides with it. Clamped over an inside caul. The resin is available in quarts or pints and refrigerating it seems to prolong shelf life. I like that it dries like glass, really hard.

https://nelsonpaint.com/search.php?sear ... on=product

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

Thanks for that link Terry! The cost for a quart from them is the same as the 1/2 gallon from vacupress ($26), but at least I wouldn’t be tossing so much in the trash. The pint stored in the fridge might be the perfect compromise!


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I already ordered some "West Systems" epoxy , enough to do one guitar. I'm getting there, piece by piece. Got the pump (Gast brand) , ordered a gauge and check valve, made the inside "mold"/caul, outside mold and now all I have to do is figure out how to put that bend/pilage in the top. I've been reading the discussions in "Django books", seems like everyone doing these models have their own take on what is needed as far as that goes. Most of the time you want to get rid of a "belly", not make one, ha.