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A week or so ago, I asked for input from others in stabilizing spalted woods. After doing some research, I purchased Minwax's Wood Hardener and soaked my glued up panels thoroughly on each side. As the Hardener is acetone based, I didn't think I would have much issue with the wood swelling. However, my top turned into a potato chip and developed several 3 to 4 inch cracks in from each end!

Needless to say, I was not a happy luthier! I let the hardener cure, then ripped the panels in half on the table saw, soaked them with veneer softener and sandwiched them in paper towels. I added a small amount of weight on top of the veneers and gently coaxed the cracks closed with some clamps. Over a period of several days, I increased the weight and clamping pressure. I finally got the panels flat again and used CA to glue the cracks closed.

The wood still wasn't as stabilized as I was looking for, so I took the panels outside and soaked both sides completely with CA, which provided the firmness I was looking for. I then cleaned up the edges and glued the panels back together. I thickness the back to .105", which is a little thicker than I normally go, but the panel doesn't seem that heavy, so I decided to leave it on the thicker side.

I wasn't initially going to post this, but after reading an email thread in one of the other OLF forums about the post count being down and folks not sharing their experiences, I decided to share mine.

Below is picture of the back ready for bracing. I'll likely use epoxy to glue on the backstrip and bracing. It will certainly make an interesting guitar. Plan is to use canarywood for bindings with padauk for purflings.

Ken

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http://www.casperguitar.com

Wow, Ken, that will be an interesting back!
Lovely stuff there.
I'm using some spalted maple on two instruments right now.
My approach has been to glue it in place before stabilizing.
For instance, one application is peghead overlay/rosette, the other is a drop top for a Tele. It seemed prudent to stabilize the spalt after glue up, but before attempting the routing (pickup cavities, peghead binding, etc.).
So far, so good....

Steve

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From Nacogdoches...the oldest town in Texas.

http://www.stephenkinnaird.com

I have used a number of spalted tops on electrics and it is always a bit of a challenge to work with but it is beautiful stuff.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Thanks for sharing! I have this set, probably from the same tree. I hadn't planned on doing anything special to it though, since it doesn't have any squishy spots except for at the edge of one side, which will hopefully be outside the pattern anyway. What are the dangers of using it as-is? Do the mold lines split, or does it warp over time, or something else?

I purchased several of these sets from Allied as well. In my opinion, you need to be very careful about how you use them. I would never use these unless they were laminated - meaning double sides (which I do anyway) and a double back -- as they just aren't very stable.

My plan is to first laminate them using epoxy and then also fully cover the mango with epoxy as well. Spalted woods have a tendency to shrink back severely during the finish application. You could also use CA glue but I find that it sometimes will darken spalted woods unnaturally. Epoxy doesn't seem to do that.

Kind Regards,
Simon

Very pretty mango Ken. I'm sure the finished product will be worth the hassle

Oh, never mind my question. Upon more thorough poking at it with fingernails, there are a few little squishy spots on the back, and a large soft area on each side. Yikes! Definitely will need to laminate them with something. The back will probably be ok with some asterisk or lattice bracing though. But since it's for a jumbo, maybe it would sound better hardened up with a lamination anyway, rather than being left fairly soft and thuddy.

Assuming you all got this stuff from Allied (where I got mine) -- then you know that, tonally speaking, these sets are far from exceptional . The whole appeal is how incredible they look!!!

I would definitely recommend laminating for that reason alone -- I think you can greatly improve the tone of the sets by laminating it to a stable and resonant tonewood. Also, I am going to do the back laminations separately and then join the back after they have been laminated. As I mentioned before, I highly recommend flooding these sets with low viscosity epoxy to stabilize the wood but also to "pre-shrink" the heavily spalted areas. You don't want that process to happen after you have already thicknessed your sets!!!

Please post some photos of the completed guitar -- I am really looking forward to seeing what these things will look like under a finish.

Thanks for all the comments folks. A couple of more observations. My panels did darken some on the outer edges after I hit them with the wood hardener. I don't know if the CA darkened them any further or not. I don't think the wood hardener did much for me at all other than, as Simon notes, cause the wood to shrink! After thoroughly soaking with CA, I am hoping the shrinking is done. I soaked before I rejoined and thickness the panels. As noted above, the joined back does seem fairly stable now. But given the comments, I may brush a thinned coat of EM6000 on the outside prior to gluing on braces just to make sure I get all the shrinkage out. I haven't done anything to the sides yet. Starting out, they have a firmer structure than the back panels. Regardless, I will definately hit them with something prior to final thicknessing and bending. I don't know if I want to go through another bottle of CA or whether I'll just thin epoxy as noted by Simon.

I have heard mango makes a decent tonewood, but what spalting does, I don't know. I can understand how it may be less resonant, but I wonder how much that changes after the wood has soaked up a pint of wood hardener and another bottle of thin CA? I had toyed with laminating using mahogany veneer, but sort of dropped the idea after the back stabilized. Perhaps I should rethink that option. I don't have the best setup for doing complicated laminations like the rims. I guess I could always laminate using my bending mold, but I don't have a good inverse mold to clamp the pre-bent laminates. How are you guys going about that?

Don't be holding your breath guys for pictures of a finished guitar anytime soon! Guitar building is a very part-time venture. I have my EIR OM and a Les Paul to spray and setup, and I will be building this spalted mango and a claro walnut at the same time. My goal is to be done before Christmas

BTW, my set came from Allied as well.

Ken

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http://www.casperguitar.com

I realise I have probably the least experience of anyone posting on this forum, but I would never use spalted anything. From what I understand, it's a form of rot. Even if it's not, it's obviously unstable, and I would wonder about longevity, even with all the measures taken to stabilize it. Just doesn't sound like a good idea to me.
I know that it's look is popular( and beautiful), and that there is a demand for it, but, again, not for me.
Please understand, this is not a flame or a knock at anyone's work. Ken, that is a beautiful looking back, and I'll bet it'll be a striking guitar. I admire you and others who can build with it and make it work. Thanks for sharing, and good luck on your build.

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Mike

The only thing nescessary for evil to thrive is for good men to do nothing.

Every time I use spalted maple I flood with CA before using, I do this with rosettes but I'm sure it would work with backs and sides.
Flood at about 20-30 thou oversize on either side and then level sand both sides. Make sure the CA is allowed to cure naturally without the use of accelerators in order for the glue to penetrate the soft wood.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com