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Filling Spalted Maple and Burl
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Author:  jfmckenna [ Thu Feb 17, 2011 8:22 am ]
Post subject:  Filling Spalted Maple and Burl
Hey all,

Building an electric guitar for someone now who supplied me with the materials. Spalted wood for the body and Redwood burl top. It's beautiful but the spalted maple is so soft along the spalted lines that it indented quite a bit particularly along the sides. Just wondering what you all think would be a good filler. I tried epoxy and stick shellac on an experimental piece and am not too happy about the look. The epoxy I used was some sort of fiberglass boat epoxy so maybe that's why I don't like it. Would Z-Poxy be a good choice? The stick shellac fills pretty well but stains a bit.

Thanks.

Here is a pic:
Author:  alan stassforth [ Thu Feb 17, 2011 12:25 pm ]
Post subject:  Re: Filling Spalted Maple and Burl
I don't know for sure, but I think the way one works with spalted is to stabilize with epoxy or ca,
then carve or shape.
I think you have to keep doing that over and over.
Don't know how you could fill those.
Good luck.
Author:  Barry Daniels [ Thu Feb 17, 2011 12:35 pm ]
Post subject:  Re: Filling Spalted Maple and Burl
I would not be happy with trying to fill these, as it would still be visible under the finish. If it were mine, I would soak thin CA into the wood until it didn't penetrate any more. This will stabilize the punky areas to a depth of 1/4" or so. Then I would reshape the body on a spindle sander and re-shape the radius with hand sanding to remove the existing chip-outs. If you do all the wood removal with a sander then there will be less chance for additional chip-out.
Author:  Nick Oliver [ Thu Feb 17, 2011 7:20 pm ]
Post subject:  Re: Filling Spalted Maple and Burl
Personally I would be going at it with either ZPoxy or (as I use in my pore filling) Wests system. You won't fill it all in one go but build it up in layers & just sanding back to bare wood between coats, plus it will have the added benefit of enhancing the grain. Don't know about ZPoxy but Wests has a slight yellowy tinge to it but will match in well with spalted Maple & give it a nice golden hue. I have even used Araldite Crystal Clear in the past with some success on 'holes' such as the one you show, it has the advantage of being slightly thicker than the other two so you can apply it a bit thicker into the hole, just make sure you have the face you are filling 'horizontal' whilst the Araldite hardens off otherwise it runs out and away from the hole. Don't ask me how I know :oops: gaah ;) .
Any fill will look kinda 'punky' as Barry pointed out but it is Spalted Maple to begin with so is meant to look 'punky' with various voids e.t.c. After all the customer supplied the wood so was giving it to you because it was interesting to look at!
Author:  forgottenwoods [ Thu Feb 17, 2011 7:29 pm ]
Post subject:  Re: Filling Spalted Maple and Burl
You can fill those and make them all but disappear.
Use sawdust and CA.
Before you apply CA fill the voids with fine sawdust from the same wood. Pack it into the voids so that it is level or higher than the surface. Then apply thin CA to the entire surface. The CA will bond and stabilize the sawdust and it will match the color to the wood.
Author:  AlexanderLou3 [ Thu Feb 17, 2011 8:14 pm ]
Post subject:  Re: Filling Spalted Maple and Burl
I'd like to see more pics of the Redwood burl top.
you can always accent the pits and whatnot with crushed stone
Image
Author:  Jim Watts [ Fri Feb 18, 2011 12:13 am ]
Post subject:  Re: Filling Spalted Maple and Burl
forgottenwoods wrote:
You can fill those and make them all but disappear.
Use sawdust and CA.
Before you apply CA fill the voids with fine sawdust from the same wood. Pack it into the voids so that it is level or higher than the surface. Then apply thin CA to the entire surface. The CA will bond and stabilize the sawdust and it will match the color to the wood.


This does not work very well on light colored woods such as maple or spruce, it will be darker. also on large areas it won't have any grain lines in it so even if it were to match color wise it'll look like a patch.
Alexander's advice may be the best, make it like an accent or something, maybe a completly different color of epoxy. Epoxy can be dyed most any color.
Good luck.
Author:  forgottenwoods [ Fri Feb 18, 2011 1:53 pm ]
Post subject:  Re: Filling Spalted Maple and Burl
Quote:
This does not work very well on light colored woods such as maple or spruce, it will be darker. also on large areas it won't have any grain lines in it so even if it were to match color wise it'll look like a patch.


I think he said the wood was spalted and the indents were along the spalted lines? If that is the case then the patch should not be noticeable. To get the patched spots to not look darker the entire maple surface needs to be stabilized with the CA, that will even out the contrast.

Quote:
Alexander's advice may be the best, make it like an accent or something, maybe a completly different color of epoxy. Epoxy can be dyed most any color.
Good luck


With the surrounding wood being soft it might be difficult to use epoxy to fill as a patch and then maintain and even surface after sanding. You can add an accent also with the CA method. Just use something other than sawdust as the fill, even metal filings like copper to complement with the redwood top. The entire spalted maple surface needs to be hardened anyway and using CA rather than epoxy will better bind the fibers together and avoid future shrinkage issues.
Author:  jfmckenna [ Sat Feb 19, 2011 9:02 am ]
Post subject:  Re: Filling Spalted Maple and Burl
Thanks for all the advice. I went ahead and used the stick shellac after all. I like it because it's clear and acts as sort of a lens plus as soon as you pack it in there it's dry and hard. I've been using the stuff for years but never on deep voids like that so I hope it holds.

I LOVE the look of that crushed stone in the redwood burl that's a nice touch. I can see copper there too. But the burl top is actually quite tight on this guitar and only requires a little fill with shellac.

Now as far as CA goes, I've never used it for a sizer or in this case I suppose a hardener. Should I use a medium or thick CA and squeegee it across the grain? Or how do you all do that? I assume I would do that after sanding up to 320 or so, let it dry, hit it with 320 again and then start finishing?

Regards.
Author:  forgottenwoods [ Sat Feb 19, 2011 3:30 pm ]
Post subject:  Re: Filling Spalted Maple and Burl
jfmckenna wrote:

Now as far as CA goes, I've never used it for a sizer or in this case I suppose a hardener. Should I use a medium or thick CA and squeegee it across the grain? Or how do you all do that? I assume I would do that after sanding up to 320 or so, let it dry, hit it with 320 again and then start finishing?

Regards.


To use CA as a hardener use the Thin. Flow it onto the surface to be hardned and it soaks into all the soft spots and hairline cracks. It bonds almost instantly and you can start sanding right away. Sometimes I sand when the CA is still liquid and the result is a slurry of CA/sawdust that fills all the tiny voids. Just must be careful not to glue your self or the sandpaper to the wood! gaah

If you wind up sanding past where the CA soaked into then you can apply more to those areas. In the case of hardening an entire guitar back of soft spalted wood it is best to get the rough shape close (but still not at the finish level) and apply the CA. Then shape or sand down to finish level applying CA as needed. Once you are at your finish level all the wood will be stabilized and sealed. Works great and no time lost waiting for traditional hardener to dry between coats.

Try it on some scrap wood.
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