Hardening Spalted

[brewu22]

When should I harden the wood, before I cut and route, or after?

Thanks

[Mattia]

From my limited experience: before. The hardening makes it more consistent in its properties, meaning you can machine/cut it as if the entire piece had more or less the same properties...

[SwedishLuthier]

PM Drak.He has a lot of experience with spalted maple.

[George Brown]

right n00b question comming up,

what do you mean by hardening wood? do you mean like stabilizing it by drying it out?

[brewu22]

Spalted maple is maple that has started to rot. Some parts of the wood are very soft, to the point of falling apart. To harden it means, to make it return to it's original hardness, or close to it.

[George Brown]

yeh i know to figue is caused by rot but how is it then hardened?

[Mattia]

There's spalted, and there's spalted. Some spalt maple (some of the nicest spalt maple, even) is solid, sound wood throughout. The fungus invasion has cause coloration, but not degradation of the wood's structure. I've even seen acoustics made of the stuff. Once it's far gone, really going rotten, you have to be careful about using it at all, and/or avoid bits and pieces that are too far gone if at all possible (ie, don't try anchoring bridge studs in a piece that's rotted through and through).

As for hardening, basically it gets soaked with CA (superglue) or epoxy, and I believe (but I've never seen) that products exist specifically designed to harden wood, generally 2-part stuff. This glue-soaked wood is quite a bit harder/tougher, as the 'rotty' bits tend to be very good at absorbing/soaking the stuff up.

[George Brown]

thanks for the info, you learn something new everyday

[Drak]

Where can I get the large amount of the red CA needed to do a spalted top. Should I harden the top before I cut the body shape out, or do the routing? Sorry for all the questions, I am new to guitar building, and don't want to screw up my first one at the start of the process..

Mattia pretty much spelled it out, or you could do a search for spalt and read a lot, most of it's been posted before.

As Mattia stated, it's all about how far gone your wood is, so I would ask you, how far gone is it? It makes a huge difference.

A few notes: Sorry, but I would -never- recommend spalt for a first time project, your chances of ruining it are quite high, leading to dissapointment, leading to depression, leading to pot-smoking and heavy drinking, leading to heroin usage, leading to crack addiction, leading to home being a cold, dank, street corner on a Sunday morning some fine day.

Not a pretty picture, you think spalt is worth that kind of risk?

Anyway, if you must, you must. The more rotten it is, the thinner I make it. Hard spalt, as thick as you want it.

Rotton spalt? 1/8" to 3/16" maximum thickness. I consider rotton spalt, although very beautiful, to be a tone sucker, so I keep it's thickness to a minimum.

There are so many things you can do wrong with a rotton piece of spalt I don't have the time to list them all here really, there are dangers at -every single turn-, I'm not kidding.

Just be prepared to chalk the whole thing up to a valuable learning experience if it goes south on you at any time, and it very well could.

I'm not trying to rain on your parade, but the reality of working with spalt may very well come home to roost with you.

I would consider rotton spalted wood as an 'advanced' wood to try, certainly not a first-time wood.

I know, I suck.

[Mattia]

Let's add one more health warning: Spalted wood can and does contain fungal spores which no amount of kilning is likely to kill. Sanding and cutting should really be done outdoors, with adequate respiratory protection!

Mind, this applies to all wood dust (the respiratory protection), but doubly so if we're talking about wood infused with essence of fungus.

[brewu22]

I didn't know spalted maple was a pain to work with. No worries . It is a 3/16 top, and I only paid 10 bucks for it on ebay. I would post a pic but having trouble remembering how to do that. Only a small portion of the spalt seems soft. It is vary light in color. Is that advanced rot, or the beginning of rot?

Thanks for the help

[Mattia]

If you can dent it with a fingernail, that's pretty advanced rot in my book. Super-advanced rot is when it literally crumbles away at the slightest of touches. The fun bit: all this can happen within one board.

[Drak]

It's not so much the color, but the weight really.

Really rotton spalt will be as light as balsa wood, superlight, ...does it feel like you're holding balsa wood in your hands?

[doug]

I actually carve the spalt in it's raw state. However, it goes way better if special sanding tools are made for the job. Sanding by hand using your fingers only on the sandpaper will trash it.

System 3 water clear epoxy works very well for hardening as well as the CA trick. However, CA can cause some clear coats to lift after a spell. Epoxy is not without pitfalls either. Improper mixing ratio will prevent it from hardening. You can also mix up a real thin mixture of lacquer, and retarder, then flood the surface several times. It soaks in really good then hardens the fibers. This can shrink after a while so it would have to cure for some time.

Like the others have said, spalt is really a pain to work with so be careful....

-Doug

[brewu22]

It's not so much the color, but the weight really.

Really rotton spalt will be as light as balsa wood, superlight, ...does it feel like you're holding balsa wood in your hands?

It was was slightly heavier than another set of figured maple that I have. Just the light areas are kinda soft (like pine), The rest is nice and hard.

[Drak]

If it's as heavy as regular Maple, then you should be able to treat it like regular wood pretty much.

As already said, it all depends on the state of the spalting as to how to treat it. Some spalted pieces are as hard and dense as regular Maple, and you can then work it like regular Maple, even to the point of not having to flood it with any glues or epoxies or anything special. This is one reason why working with spalted is not recommended for beginners, because the rules change so much from one piece to the next, spalted wood is full of extremes, from extreme care to no special care involved at all, from wood that will fall apart if you look at it wrong to wood that is as tough and hard as any Maple out there, you have to be somewhat familiar with wood to start off with to be able to judge what kind of spalt you'll be working with, and the appropriate measures to take hencewith.

Pics might help.

[j. pierce]

System 3 water clear epoxy works very well for hardening as well as the CA trick. However, CA can cause some clear coats to lift after a spell. Epoxy is not without pitfalls either. Improper mixing ratio will prevent it from hardening.

The System 3 stuff is great, but like Doug mentioned, improper mixing ratio will mess it up. For the quantities used in guitar-making, it's really easy to mess up the ratios since you're dealing with such small amounts. Mix the stuff by weight using a small, accurate scale, rather than by volume or half the time you end up with epoxy that won't cure properly or at all. The stuff goes real far, I've coated whole guitars in a just a couple of tablespoons worth, and mixing that little at a time is difficult by volume.