Replies

1. 
   Steve_Conroy | Feb 20, 2002 06:07pm | #1

   *
   John,
   I'm not sure how the reactions would differ, having never applied nitric acid to Yellow pine. Of course you can always experiment on a scrap. I've also had success with lye (about 1 tsp for 8 oz) on soft woods.
   Just as a reminder, before applying any finish over nitric acid or lye, its best to wash the surface of the wood or neutralizing in some way, as the acids may undermine the quality of the finish.
   Happy experimenting,
   Steve

1. 
   John_Krist | Feb 21, 2002 05:52am | #2

   *Steve,Thanks for the kind reply. My bio-lab friends asked what was the concentration of the nitric acid before dilution (if it matters)before they would mix me some. I like the lye idea as this is Drano, and H20 would presumably neutralize it, as baking soda would to nitric acid, I assume. For the lye, would this need the heat treatment as well?I am excited about trying this because I have never seen a stain that really makes wood look old, and oxidization is really the aging process anyway, so why not start with that?JK

1. 
   keith_newton | Feb 21, 2002 09:50am | #3

   *Hey John, I happen to have both nitric acid, and caustic soda in the shop, and managed to find a SYP board to slosh some on.The lye was the only one to have any reaction, but it didn't impress me. You could do better with dye,and stain. I even tried some vinegar which is acid also.I used lye on some projects back in the early eighties with some interesting results, but I backed away, because I was never felt very comfortable with it, just because I don't like to add water to the finishing stage.You can put lye or caustic soda on padauk and turn it purple like EI rosewood, then put vinegar on it and turn it back to orange. I found it hard to control. Since you can't neutralize either, I felt that I need to rinse, and that adds more water, and lets see. Is there a reason why we buy kiln dried lumber?Let me see if I remember. If you add water to wood, things start to move. Whiskers raise. You sand those off and there is no color once you sand the oxidized surface off, so you need to add more acid, which contains more water which needs to be rinsed off.How long does a piece of wood need to dry after you wet it down with acid, then sand then wet down, and then rinse off before you can finish it?I think I did use some mahogany without rinsing, and no ill effects, but it was still hard to control. It was fun to play with, but it seemed risky.Have fun, Keith

1. 
   Steve_Conroy | Feb 21, 2002 07:40pm | #4

   *John, The stuff I purchase is labelled "65% Technical." I'm not sure what that means. The lye I've used is just Red Devil; how that differs from Drano I don't know, but I would hesitate using something that isn't specifically labelled "Lye." Lye doesn't require heat treating, where the nitric definitely does. YOu can use a heat gun to speed up the reaction with the lye. Another product that I've have tried with no real success is called "Old Growth." (I'm not even sure they are in business anymore.) It is a two step aging process. I'm not sold on it as it is expensive and the results yield a weak color as compared to other chemicals. If anybody has had success with it I'd love to hear from them. Good luck, Steve

1. 
   Steve_Conroy | Feb 21, 2002 08:08pm | #5

   *Keith, I love that you ran out to the shop and experimented on some SYP. Another reason why this forum is so good. I share your concern with how much water can we add to the finishing process. But I think it is a matter of degree. Water based finishing products are common place these days, as we have Transtint and powder dyes which can be used with water, other water based stains and products like Polycrylic. All of which add water to the finishing stage, and raise whiskers thus needing to be sanded. This is one of the weaknesses of water based products. But it seems there is a difference between water that briefly applied to the surface layers and moisture that exists deep within the wood. Yes they are related, but water can be applied and evaporate before it soaks to the core. The kiln dried wood is still dry where it matters most. The surface layers dry rather quickly, so, as with water based stains, you can be back to finishing in a couple hours. After rinsing I usually leave it for 24 hours, just to be sure. No problems so far. You voiced a concern about sanding through the color. I've have not found that to be a problem. The color is a deep as any liquid based stain I've applied. I do admit that when I am concerned about sanding I add alcohol instead of water to my dyes or use gel stains. Thanks Steve

2. 
   John_Krist | Feb 22, 2002 02:41am | #6

   *Steve, Keith,Thanks a bunch for the classy replies and the experimentation. I am going to take a shot and report back. Steve, is there a brand/source on the nitric that you buy?On the general water based issue, I have been using water poly on a table of poplar and SYP (high gloss), a table of SYP and birch plywood (HG), and a bench of SYP and oak (HG), and a puppet theater of birch plywood and oak (satin). The raised grain surely needs sanding, but 600 grit was fine. Real issue was the murky/muddiness of the HG on everything. There was really no highlighting of any translucence of the wood, which is makes the grain and patterns visible. I tried the satin on the theater and the effect was better. I used the water based because the shop was too cold to paint in, and all the above had to be done in January. I'm going to stick to the oils and oil bases, but jee whiz, gotta love that lightning fast drying time of the water base.Thanks again for the comments. Oh yes, not to let it rest, has anyone tried bleaching? I really like light woods but not the effect of ambering from oil finishes. My ideal would be a clear oil, like mineral oil, that will take a tung-like polish eventually. My thought is that bleaching might lighten the wood before the oil darkens it. Maybe I'll through some poly and mineral oil together. MO is a non-volitile mineral spirit, right? Maybe desolve some parafin in the mix?Thanks very much again,JK

3. 
   Steve_Conroy | Feb 22, 2002 05:14am | #7

   *John, As far as the brand of nitric acid, I'm not sure. I get it from a local chemical supply house, which supplies high schools, universities, and local businesses. They carry large quantities and pour it into smaller containers when you purchase it. I buy 4 or 6 ounces at a time, which costs about $7. If you have trouble finding it, I would look up "chemical supply" in the phone book. AS far as bleaching goes, I haven't had the oppurtunity to learn about it. I look forward to reading what people write in.Steve