Don Noon Posted October 23, 2015 Report Posted October 23, 2015 I'm experimenting with lightening the color of dark wood, and the common way to do that is with a 2-part application of sodium hydroxide and hydrogen peroxide. Those materials are easy to get, but I'm not sure what's the best concentrations to use or methods. I know such kits are available, although I haven't seen them, and buying the basic chemicals is certainly going to be much cheaper. Anyone know the details?
Michael Richwine Posted October 23, 2015 Report Posted October 23, 2015 www.fpl.fs.fed.us/documnts/fplrn/fplrn165.pdf The only place where I'd argue with this is that you'd probably want to apply the peroxide immediately after the lye solution. it's pretty caustic and will degrade the wood surface.
catnip Posted October 23, 2015 Report Posted October 23, 2015 Don, I have had success using industrial hydrogen peroxide (at 30%) as compared to 3% available from the drugstore for homeuse. I use it straight and also place the wood in the sun to dry. This H3O will destroy your brushes so use old brushes. I primarily use it on maple defects and it seems to work but several applications maybe necessary. I have not found any ill effects (wood softening etc) on the small areas I have done. I have never done a whole plate.
jezzupe Posted October 23, 2015 Report Posted October 23, 2015 A/B commercial wood bleach is available at hardwood floor supply houses, generally come's in 2 gal kit. Very destructive material, extreme caution should be used. It is also very caustic and will degrade surface wood fibers.
Matthew Noykos Posted October 23, 2015 Report Posted October 23, 2015 For restorations it is pretty common to use oxalic acid for bleaching cracks. Might work for your aplication.
Michael Richwine Posted October 23, 2015 Report Posted October 23, 2015 Probably should have asked what the application is, first. Overall plate color, streaks or spots, cracks, mineral stains? Sometimes bleach isn't the answer.
Don Noon Posted October 23, 2015 Author Report Posted October 23, 2015 www.fpl.fs.fed.us/documnts/fplrn/fplrn165.pdf The only place where I'd argue with this is that you'd probably want to apply the peroxide immediately after the lye solution. it's pretty caustic and will degrade the wood surface. Thanks for the link... that's exactly the information I was looking for. I did a search, but that document didn't show up anywhere near the top. I guess I need to shop for the killer hydrogen peroxide; I was just diddling around with the 3% stuff from WalMart. Probably should have asked what the application is, first. Overall plate color, streaks or spots, cracks, mineral stains? Sometimes bleach isn't the answer. This is for overall plate lightening, as I have a few plates that are too dark from processing. There also might be some interesting optical/aesthetic effects to having a light surface with darker wood underneath, as opposed to what you usually get on new fiddles, where the wood underneath is blazing white.
Michael Richwine Posted October 23, 2015 Report Posted October 23, 2015 Beauty supply shops will sell you 30 and 40% hydrogen peroxide. Watch it though - it'll burn you just as badly as lye. Sally Beauty sells it here, but who knows what's allowed in California. They do have locations in Carlsbad, though. I have had that information for years, but I always found it more economical just to buy the A/B kits when I needed to bleach a piece of wood. A quick look gives the impression that they aren't available to consumers any more, so maybe a can of drain cleaner and a bottle of peroxide makes some sense.
Don Noon Posted October 24, 2015 Author Report Posted October 24, 2015 The sodium hydroxide is available really cheap. Ebay has tons of it. The high concentration peroxide is more of a problem; apparently if it's over 17.5% concentration, there's a shipping Hazmat fee tacked on that's pretty steep. I'll try the beauty supply places. edit: I called the local beauty supply places, and they basically had no idea what I was talking about. So I ordered some from the internet... just a small quantity for testing.
Evan Smith Posted October 24, 2015 Report Posted October 24, 2015 food grade peroxide is 35% and is about $20.00 a quart at some health food stores. That's enough for a lot of fiddles. The two parts can be mixed prior to application, or the lye applied first, but if you wait too long before applying the peroxide, it won't bleach as well. The reaction between them will really take out the natural color. Use synthetic brushes, and don't get the lye on the aluminum ferrules. Sometimes just for matching wood tones weak lye and 3% hydrogen will lighten things up. Don, tomorrow I'll bleach some of your terrified wood and post the pics. , I'm fairly certain it will work..,, snow white if you like.
Evan Smith Posted October 26, 2015 Report Posted October 26, 2015 Here’s what I use for bleaching or matching woods of different colors. Lye(sodium hydroxide) and 35% hydrogen peroxide. Here is the final result on a piece of Don’s terrified wood.(Don,, you recognize the batch#,44sg red spruce) 1. weak lye and 3% h2o2, 2. weak lye and 35% h2o2 3. strong lye and 35%h2o2 4. 35%h2o2 only, no depth to the bleaching. 5. Strong lye and 35% h2o2 premixed then applied, left wet for about 3 min. then towel dried then fan dried. 6. Strong lye, 30 sec. then 35%h2o2 on top of the lye. Dried after a few minutes then re applied. 7. Lye, h2o2 applied then dried 3x then a taste test revealed excess alkalinity, so more h2o2 was applied. If more h2o2 is applied after the wood is dry but still alkaline the h2o2 will foam. With varnish. The wood was planed flat, so after all of this,,, I scraped it to raise the grain. There was enough thickness to the bleached part to not cut through to the dark color. The wood scraped well, it felt tough like red spruce and quite normal. If there is resin of some sort in the wood the lye will cause it to expand and it will squeeze it out of the wood. It can un burrn wood that has been burned or overly darkened with stains or resins..for this reason I will vary the length of time that I leave it before adding the h2o2 according to the situation. I have left the lye,,,h2o2 on whole fiddles for hours keeping it wet expecting them to fall apart,,, never to have a center seam open up Or a plate come off of the ribs. Go figure. After all is dried h2o2 can be added one more time for addional whitening. Then I dry it with a fan and wash it in 5% vinegar to neutralize the lye. Want to make sure the acid is neutralized?. Calcium in water or baking soda. Striped ebony anyone? I have been a bit shocked at the little amount of damage this actually does to the wood. I was expecting the damage to be obvious but as of yet been unable to prove it any more than a small amount of surface fiber that brushes off easily after repeated bleaching's and drying cycles. Lye eats protein easily, so natural bristle brushes are toast after a few minutes, and hide glue is destroyed.(gets rid of glue ghosts) So I was surprised that I have not had any joints open back up. But then the joints are tight and the lye cannot get to the glue to harm it. I suppose that a loose joint with a gap filled with glue might be in trouble. And for the record I have only done this on my own expieri"mental" fiddles.
Don Noon Posted October 26, 2015 Author Report Posted October 26, 2015 So, are you going to make a striped fiddle with that processed wood, or what? Thanks for the test results. I have seen some lightening using the 3% peroxide, so I expect more with the stronger stuff. On test stripe #7, was the application similar to #6, i.e. H2O2 applied onto wet lye? Between Lye/H2O2 cycles, was the wood allowed to dry first, or was it just one after the other?
Evan Smith Posted October 26, 2015 Report Posted October 26, 2015 Absolutely! The striped Fiddle Fad started Here! Drying between applications seems to work the best, and keeps the fiddle from becoming too saturated. After drying if it still tastes alkali a coat of H2O2 will bleach a little more. It seems that if reapplied wet not only is the chemical diluted before reaching any depth but the wood can become overly saturated, and even I sometimes err on the side of caution. There are times that the wood will bleach white as you apply the H2O2 over the wet lye, right before your beady little eyes. Other times there won't be much change until it has thoroughly dried. It seems to depend on how translucent the fibers are, some times you see right through the fibers to the dark wood underneath, only to see the bleached wood after drying. The varnish makes the fibers translucent so If there is not enough depth to the bleach, it will appear light,, but will be too dark after the varnish is applied. My MO is to apply lye, then just as soon as I've rinsed the brush, start applying the H2O2, it seems the the real bleaching occurs with the reaction between the two. I rinse the brush every time before putting it in the H2O2 because I have picked up lye and don't want to weaken the H2O2 prematurely. I might do a little scrubbing with a soft tooth brush when I'm done applying depending upon the situation.(i.e. resin oozing out of the wood) It seems that drying between applications gives better results with less damage. Some maple is extremely absorbent, and it will soak up liquid like a sponge. It is low SG and can be any species, on this I might use a weaker lye solution, and do it quickly and put less on, give the H2O2 a few minutes,, then dry it off and get it in front of a fan. It can swell up and do damage if not handled properly. Denser maple can be left wet for quite a while, or even allowed to dry naturally. Actually I have allowed it to dry naturally many times even on the ribs with no ill effect, be careful with low SG maple. I've heard you talk about having to make your fiddles as light as the darkest wood involved. I know exactly what you mean. I am notorious for using unbelievably flamed ribs that are a bit dark, with a light colored back or vise versa, then trying to match, or red maple ribs with fantastic flame that don't quite match a euro back in color. I have lots of expiermental stuff to mess with,,, I have a real bad case of the what ifs. My parents were fearful that I would dissemble all the cars and house to figure out how it all worked. I now have a 6 and a 13 year old clone of me, kind of fun, maybe not so fun.( tools I've had for 40 yrs. are disappearing.) I do have some fantastic Norway maple ribs that have been ammoniated, I threw the chunk in just to see what it would do. It is now green and it doesn't want to bleach so well. Whatever causes the darker color in ammoniated wood is more difficult to remove. But the natural color of most wood or wood that has been darkened by heat can be lightened back up,, clear up to the point of being turned black. Once it's black,,, there's no turning back. So as a disclaimer,,, I'm not saying this is safe or necessarily easy,,, For someone like Don it will be a breeze,,, So unless you are willing to do the homework and experimenting don't do this at home. Carelessness with this can cost you your eyesight, I have a big stainless steel counter with sink, and lots of water at hands reach. And safety glasses. I know where to rinse my arms off,,, it burns. 35% H2O2 can cause instant blindness. Used cautiously and judiciously this stuff works great. And I got the Idea from Jezzupe,,thank you very much! looked it up on a flooring fourm and some guy gave the ingredients for the 2 part bleach,,, BINGO!
yancypup Posted October 26, 2015 Report Posted October 26, 2015 Oxalic acid is pretty safe to use so long as you don't ingest it or use it in very hot water. If you get 30% hydrogen peroxide on any platinum (like a wedding ring) it will explode into steam. The Budwiser car that broke the sound barrier was basically an engine that sprayed hydrogen peroxide through a platinum nozzle. The explosive steam reaction turned it into a rocket with wheels!
Michael_Molnar Posted October 26, 2015 Report Posted October 26, 2015 Hi Don, Sounds like you are trying to make your own "Klean-Strip". I used it and it works well. I have had luck with oxalic acid too.
Evan Smith Posted October 26, 2015 Report Posted October 26, 2015 Oxalic acid is pretty safe to use so long as you don't ingest it or use it in very hot water. If you get 30% hydrogen peroxide on any platinum (like a wedding ring) it will explode into steam. The Budwiser car that broke the sound barrier was basically an engine that sprayed hydrogen peroxide through a platinum nozzle. The explosive steam reaction turned it into a rocket with wheels! What is being dealt with here is bleaching the natural color out of the wood and making it white, or so. Wood that has been cooked or torrified = toasted= brown= dark colored fiddle. Here is oxalic acid full saturation in hot water. It did absolutely nothing, I have tried every bleaching method I could find with no results. here is the instructions on the bottle of oxalic acid, notice that oxalic acid is not a full method,, you must use the A-B two part bleach, if you want to truly bleach the wood. It also sayes,,,, dissolve in hot water. And I can't speak of my disappointment when my dreams of a rocket car were dashed upon the rocks of reality,,, 35% H2O2 SLOWLY bubbles on a 90% silver dollar. (10% copper) (1921) Silver has the same catalyst properties as platinum. I had all ways thought that it took 80 to 95% to make a rocket. Clean strip is to remove varnish,,,, this is to take the natural color out of the wood itself. This method of bleaching will not satisfactorily remove varnish.
Michael Richwine Posted October 26, 2015 Report Posted October 26, 2015 Klean Strip Two Part Wood Bleach It's lye and H2O2. Klean Strip also makes 95% ethyl alcohol that's sold in big box stores, and a whole lot of other products.
yancypup Posted October 27, 2015 Report Posted October 27, 2015 Evan, please don't try that with platinum! In High School, I poured part of a beaker of 30% hydrogen peroxide down a lab sink that had a bit of platinum from a test rod in the trap. The explosion blew the trap to pieces.
Michael Richwine Posted October 27, 2015 Report Posted October 27, 2015 Some interesting info about cosmetic grade H2O2: http://www.using-hydrogen-peroxide.com/hairdressing-peroxide.html I use it for bleaching cracks. Kinda wondered why it wasn't more caustic. For cracks, it works pretty well.
Don Noon Posted November 1, 2015 Author Report Posted November 1, 2015 Some interesting info about cosmetic grade H2O2: http://www.using-hydrogen-peroxide.com/hairdressing-peroxide.html No wonder the cosmetic supply places had no idea what I was talking about when I asked about high percentage of hydrogen peroxide. They only know it as a volume of developer, even though it's exactly the same thing. In any case, the strongest they had was 40 Volume (12%), and the really strong (35%) H2O2 is apparently impossible to come by locally, and even internet is not readily available except in very small quantities... or very large quantities for industrial use. I had done a few tests with 5% NaOH and 3% H2O2, and got reasonable bleaching effect. The NaOH at 5% is about right, but I found that the stronger H2O2 worked far better than the weak stuff. It took multiple soakings of the weaker solution to get the reasonable results, but just one wetting of the strong. Here is a hodgepodge of tests on a processed piece of spruce from my earlier experimentation that came out much darker than I would want. Most of the light patches are multiple weak solutions of H2O2, and the lightest spots in the center are from the stronger solution. I then used a gouge and plane to go through the bleached areas, both to check the depth of the bleaching and see if the shavings had any strength left. I had soaked the wood with the bleaching materials, and the depth of bleaching came out between 0.1 and0 .2 mm. I expect it would be much thinner with controlled wiping vs. soaking. The shavings didn't seem to be unusually weak or brittle or otherwise much different from the already brittle processed (but unbleached) wood. I tried following up the NaOH treatment with a solution of Oxalic Acid, and it had some bleaching effect... but not as much as with the H2O2. It might be a reasonable option for neutralizing any residual alkalinity from the NaOH. So, this has been a very useful thread for me, allowing me to use some of my over-processed wood that is too dark, but has otherwise fine acoustic properties.
Evan Smith Posted November 1, 2015 Report Posted November 1, 2015 Don, those are the same results that I have had. It takes a lot of bleaching to see any obvious degradation of the wood. The 35% is sold in health food stores as food grade.(search health food) Maybe not in Ca. They keep you guys safe from all harm out there in the land of no rain. I have purchased it several times. If you get it shipped to you there is now a hasmat charge on it. I can buy it locally.
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