2 part Wood Bleach?

Re: 2 part Wood Bleach?

Keith Newton

Ah ha, good idea Jim, thanks I had not thought of that.

Google is your friend

Ellis Walentine

Keith, if you search for "Klean Strip Wood Bleach" you'll find other brands of the same combo, sodium hydroxide and hydrogen peroxide.

Ellis

Thanks Ellis

Keith Newton

Yes I have done some searching, and those are the two chemicals I was trying. I already had/have some of both, I just wasn't sure the 3% hydrogen peroxide was strong enough to do the trick. I did give it a try yesterday afternoon late, but didn't see much change yet with just one application. I'll give it a couple more tries today though, and will see if Sunshine helps it along.

I found two empty bottles of the Kleen Strip back in my finishing storage area, but so far haven't been able to find it locally. There is plenty of time to order it if I get the job, but my friend wanting the sample will be driving about 200 miles too soon to wait for it to come in then wait for it to work.

Curious

Ellis Walentine

I was wondering about your method of using the stuff. I always brushed on the NaOH first and let it soak for a little while before applying the peroxide. But, I've seen other sources that recommend mixing the two ingredients and then applying. That always seemed to me to be inherently bonkers; why would you neutralize your alkali before you apply it? Zinsser apparently agrees with me, according to a PDF I downladed today. I guess what I've never understood is the exact action of the two ingredients on whatever it is in the wood that colors it. The chemistry was never clearly explained to me. I just know that my method works.

Ellis

Re: 2 part Wood Bleach?

kkruizen

I purchased a box of this 2 weeks ago at my local Menards. If you them in you part of the country I would check there. It is only available in stores because of the shipping issues associated with part 1.

I can explain it ....again.

Bill Tindall, E.Tn.

This bleaching chemistry works best at high pH. The role of the sodium hydroxide is to make the environment where the bleaching occurs highly basic.

Lots of stuff decomposes hydrogen peroxide to form oxygen and water. No good will come of this reaction. With that in mind, while it may not matter I would think it could be best to make the wood basic and then add the peroxide. Doing it the other order, the peroxide might begin to uselessly decompose before it got in a basic environment to do the desired chemistry.

There seems to be some risk of leaving behind sodium hydroxide. I can imagine it being harmful to some finishes and a disaster for an acid catalyzed finish like conversion varnish.

Thanks Ellis and Bill

Keith Newton

That is the method I recalled as well, and what I've been trying to limited results after 4 applications. It is getting lighter, but still a long way from what I was wanting. I think I'll just go get some white pigmented stain mixed up and see if that will finish it up.

Since I'm only doing a small sample, I'm wondering how long to wait to add the peroxide. Maybe I should have waited longer than a minute. I'm pretty sure my lye mix it plenty strong. It generates some heat as it dissolves.

mixing

Bill Tindall, E.Tn.

Acid base reactions are instantaneous. No need, and likely not desirable, to wait any time. Lignin is going to begin to neutralize the lye at some rate unknown to me, if you are bleaching wood.

Peroxide decomposes to oxygen and water and this reaction is sped up (catalyzed by all sorts of stuff and light). Drop some manganese dioxide in it and instantly you get oxygen. Great way to make oxygen to catch stuff a fire and impress children.

A store bought 3% solution may, or may not, be depending on how much it has decomposed sitting around. If you are not using new stuff, suggest new stuff from a source that turns it over quickly.

What are you bleaching? Some of the Tide detergents have a dandy bleach for some chemicals- blood, body oil stain, grass.

As a reasonable guess for lye concentration, I think 5% is plenty. 1% might do.

Nothing happens to the lye over the short term. Keep pouring the peroxide to it.

warming may help, or may not

Chemistry

Bill Tindall, E.Tn.

I could not find the details of the chemistry of bleaching wood colors. Peroxide is a stronger bleaching agent in an acidic solution. What I think is going on is that the lye (base) is reacting with the wood colors (probably phenols) to change them into something that is more easily bleached even though the bleach itself is weaker.

Bill have you ever experimented wit lye on wood?

Keith Newton

I did quite a bit back in late seventies early eighties. It makes some interesting changes. Some woods like the really orange Padauk turn a nice deep purple like E I Rosewood. This Sassafras which is about the color of Ash, turned a nice teal color with the first wetting.

Weren’t you going for a lighter look on a recent Ask project. What did you end up using? I just went over to the nearest Ace hardware store hoping to find a really white stain but they didn’t have anything, and now their paint pigments are in a computer controlled measuring system so they couldn’t just give me a squirt of white. Then it dawned on me to just come back to the shop and dig the pigments out of the bottom of a Kilz primer can to mix into some wipe on poly. Not what I wanted but.

caution

Bill Tindall, E.Tn.

Kilz is formulated different from typical "oil" based products. Do some experiments to see that this "whitening" will be compatible.

I have experimented with lye on wood. The colors are not especially light fast, at with on mahogany.