Cleaning Wood

[Aexion]

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Was just contemplating using an Oxalic Acid to prep wood before using sanding sealer as advised by Pete, a furniture restorer down the road.

Pete tells me that when you are not using any stain in a two or three piece solid body guitar, in order to obtain the woods natural colour evenly an exterior Cleaner/Brightner is best used, to remove any stains that may be present, and help the pieces balance their colour evenly after lacquer is sprayed on.

Whats your opinion on this? If this is true then what should i rinse off the Oxalic Cleaner with, Shelite or is water ok (water on guitars scares the hell out of me)


Tim Mason

[woodrat]

Water on guitars scares the hell out of me too! I wouldn't do it like that. If the pieces are from different bits of wood and the colour difference is fairly noticeable then doing this is not going to change things ie its not going to blend to evenness of colour.

[DarwinStrings]

Is the wood you are using old and stained? I have never use oxalic acid on wood but thought it was for cleaning up old stains. Best to check with your mate who recommended the use of it to see how he cleans it off. and what he feels is compatible over the top of it if you are going to use it.

I don't see water on wood as a problem and have saturated a few instruments with water based stains without problems, it will raise the grain though but that can be dealt with.

Jim

[Aexion]

The wood looks good to me but Pete seems to think once i spray it, a few stains are prob. going to show up... on ALL the wood i use as a natural colour wood colour, no staining/tinting.

He gave me a litre of the stuff he uses on furniture and he washes it off with water?

I dont know, im still a little shakey about using this method of preparation. A piece of furniture doesn't need good resonance, and if no one else seems to be doing it Confused i most likely should leave it unless its needed

[Puff]

http://www.realmilkpaint.com/oxalic-acid-bleach.html

[Adrian Cooper]

Good link Puff.
I've used it a fair bit & when I've wiped it with water afterwoods I've added a little metho ,to speed up the evaporation & used a hair drier to speed it up a bit . It dries pretty quickly that way.- not to scary

[Nick]

Aexion wrote:
I dont know, im still a little shakey about using this method of preparation. A piece of furniture doesn't need good resonance, and if no one else seems to be doing it Confused i most likely should leave it unless its needed

Tim, treating with acid or rinsing with water won't change a timber's resonant properties, that's 'built in' to the wood. As Jim has, I've wet bodies applying stains & washout coats (to lessen the amount of stain on the surface), once I've let it dry (Usually overnight) there's been no problem, it's only surface water, you aren't soaking the wood right through (Unless you are dropping it in the bath and leaving it for a few days! Shocked ) So what you are considering shouldn't be a problem for the wood. As to the acid use, I've never had anything to do with it so cannot comment but will say that I've never used or had to use any treatment on woods I've joined in guitars (both electric & acoustic), as long as the wood hasn't been stained by external sources (Such as Puff's link, pot rings, water stains e.t.c) there's never been a problem. I'm not sure what they do in the furniture industry but I've certainly never heard of it done in luthiery unless there's a definite 'mismatch' in the wood's colours to begin with.

[Aexion]

Ok Nicko, thanks. i cant wait to start building from scratch, collecting all the tools needed is a pain in the neck and taking alot longer than anticipated, but as soon as i get these prefab jobs finished and sold off...

Game on Twisted Evil

[matthew]

nappy san didn't work, i tried it.

[Kim]

Oxalic acid has been used for many many years in the furniture trade to even out grain discoulorations and can even remove iron stains to some extent. It does have a tendency to lighten the over all colour of the wood once treated but as long as it is rinsed off well, it will not react with any finish. Also agree with Matthew that a nutralising wash with bi-carb is a good idea.

Cheers

Kim

[matthew]

oh and it is very POISONOUS

[Kim]

Indeed it is. In fact oxalic acid is the very same compound that makes the 'leaves' of rhubarb so very deadly.

Cheers

Kim

[matthew]

but you need to eat around 7Kg of them to achieve that outcome.

from the bottle, it's a lot quicker.

Oxalic acid poisoning can lead to very painful conditions because the oxalate crystals formed when the acid reacts with calcium etc in the body are not easily soluble. The crystals are tiny and very sharp and cause burning sensations internally and kidney stones.

Once I bought a bunch of "elephants ear" from a fijiian supermarket - the stuff they cook up like spinach and use for wrapping food. unknown to me, this also contains large amounts of oxalic acif crystals in the leaves which are dissolved when cooked in boiling water. There I was driving along King street with my shopping next to me, tore off a small piece of leaf and munched on it to see what it was like. Holy shit, my mouth and throat was on fire for hours!! It was ahairy drive home ... i thought I was dying!

[Kim]

Better you than me mate......nibbling an elephant ear! Serves yourself right!

[Aexion]

I'll be sure to be careful and wear a mask if/when i use it, thanks. And be careful what plants i eat too

[kiwigeo]

There I was driving along King street with my shopping next to me, tore off a small piece of leaf and munched on it to see what it was like. Holy shit, my mouth and throat was on fire for hours!! It was ahairy drive home ... i thought I was dying!

I thought only 2 year olds did things like that.

[Nick]

There I was driving along King street with my shopping next to me, tore off a small piece of leaf and munched on it to see what it was like. Holy shit, my mouth and throat was on fire for hours!! It was ahairy drive home ... i thought I was dying!

I thought only 2 year olds did things like that.

Matthew maybe "old School" but never claimed to be old.