Official Luthiers Forum!

Hello All,
This is my first topic on this forum, been a longtime lurker, and hoping some of you can help me with this. I've been attempting to sand/scrape my sides clean and can't seem to get this stain out. My sides are laminated (1/16" sapele inside, 1/16" cherry outside). I first bent them on a hot pipe then used West Systems 206 with some silica harder to glue them together in a mold.

When scraping/sanding, the stain does not appear to change at all. The dust doesn't look to have any epoxy in it and is just the light color of the cherry. Any solutions or ideas to what may have caused this? Could it be bleeding from the sapele that somehow pushed through the pores? I wish I hadn't closed the box yet and could deal with the sides alone, but I thought it was just going to be some routine cleanup.





Thanks for your help!
- Michael

I have no personal experience with this but I spoke with a builder who doesn't post here & he stopped using West Systems for laminating double sides because it would bleed through.

If you're going to do an epoxy pore fill, the color may even out?

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

I'm with Kevin. Stop trying to sand it out... it won't come out. You'll want to try to epoxy pore fill to even it out.

_________________
"I want to know what kind of pickups Vince Gill uses in his Tele, because if I had those, as good of a player as I am, I'm sure I could make it sound like that.
Only badly."

Ok. I will try the epoxy fill and see if that fixes it.

I hate to say it - but this has actually happened before on a piece of maple (pic below). I thought it was mineral streaking or something, but now I know better! No more West Systems for me!

On that note, any recommendations for gluing the double sides? system three? Z-Poxy? fish glue? Titebond?

Thank you for the advice, I'll post some more pics when I get to the pore filling stage.

The builder I spoke with switched to Urea Resin glue, I think Unibond 800.

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

I have done lots of double sides with Unibond 800. Works great. The resin has a shelf life, probably 6 months if warm. I have had some in the fridge for almost a year and it is still good.

I have done similar woods with Maple, Mahogany, and IRW, and dissimilar woods with Maple outer-Rosewood inner with no issues.

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

This would be my thoughts also...!!
Tom

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A person who has never made a mistake has never made anything!!!

I've only laminated one set using vacuum and Unibond 800, but the results were outstanding.

It doesn't look like bleed through to me. Both cherry and maple are susceptible to scorch marks which can sometimes be sanded out. Looking at where the discoloration on the maple is and the pattern and dark color on the cherry, that would be my guess. I could be wrong. Sanding scorch marks usually makes them lighter, sanding epoxy bleed through usually makes it more prominent.
If it is scorch marks, and you can't sand them out, then a nice dark "cherry" stain might help disguise them.

With laminated sides (with a vacuum bag)I have used the unibond with success & also the titebond original extend which also works fine.

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Mike McNerney

Thanks for all the responses! I have ordered some unibond and will be using that from now on. I tried putting some more West Systems on, but to no avail - the stains remain darker. Mixing sapele dust into the epoxy to darken it didn't work either. I'll take it as a lesson learned and will be sure to fully clean my sides before closing the box from now on! Looks like a black/dark finish on the B&S is the solution for this one.

Clay - I don't believe they are scorch marks I've had to deal with those before, so am extra careful when bending to avoid them; and I certainly would've noticed burning the lower bout that badly!

Doesn't look like epoxy bleed through to me, either. I'm thinking possibly iron/tannin staining caused by tannins in the wood reacting with iron on your bender or laminating form. If that sounds plausible, try treating it with a solution of oxalic acid in water. Test on an offcut first, of course, so you don't end up bleaching the wood to a completely different colour.

If it turns out to be a combination of both staining as above locked in by bleed-through, its there to stay.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I did a lot of laminated sides testing with West Systems epoxy and UniBond 800. They both would bleed through to a certain extent depending on wood thickness and species. There really is little difference between them. Adding thickener to epoxy does help.

I've used West Systems, fish glue and Titebond for laminating sides. The only glue "bleed through" I'v ever experienced was through the pores of the woods like padauk and EIR, which is inevitable. However, I've always given the outer surface of the outer laminate a thin coat of either shellac or lacquer, to eliminate any possible staining of its surface.

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michael propsom
www.propsomguitars.com