Replies

1. 
   mikegagne | May 28, 2005 09:59am | #1

   Woodcote makes a product with "A" and "B" components that you mix and pour on the wood. It takes about 20 minutes to an hour to work. Will turn even dark woods light to white. Quite caustic though so dont get on your hands. Aloha, Mike

2. 
   ring | May 28, 2005 04:31pm | #2

   Jimbo,

   Basically there are 2 common types of bleach, and you need to experiment (or learn from someone else) as to which is better for any given wood.  I have never tried alder so I do not know which is preferable.

   1.  Chlorine bleach, like the stuff that is commonly used in laundry

   2.  Two-part bleaches, commercially sold under all kinds of brands but really all the same.  One part is lye (NaOH in water) and the other part is Hydrogen Peroxide.  I make my own because I use it fairly often, but the off-the-shelf stuff is fine for small jobs.   If you need a large quantity it is worthwhile to buy the chemicals and make it up.  If you want to try this I can tell you how to prepare it.  Both these chemicals need caution. 

   DR

1. 
   KeithNewton | May 29, 2005 07:35am | #4

   Ring. I usually have lye, or caustic soda around, and peroxide in the medicine cabinet. Is that all the two part bleach is? I never have looked to see what the active ingredients were.
   I am sure it would be cheaper to buy and combine your own. Do you need special grade stuff?

1. 
   ring | May 29, 2005 05:27pm | #5

   Rootburl,

   That is absolutely all there is to it. 

   To mix the lye I use a tablespoon of NaOH crystals in a cup of water.  Dissolves a little quicker if the water is lukewarm.   The peroxide I buy from a chemical supply house is 33%.  Immediately before use I mix equal parts of each together in a shallow pan, not a deep container.  I usually use a plastic tray for this.   It allows heat to dissipate if necessary.  A deep can or bottle can easily overheat itself and start overflowing all over the place.  Do not mix up more than you are going to use in 10 minutes.  Brush the mixture on liberally but don't leave puddles.  Use a nylon brush.  If you use a natural bristle brush it will be the last time you use it.  It goes without saying to use gloves and eye protection.  The bleaching action goes on until it dries in half an hour or so.

   Very important - after using this bleach, you must neutralize any residue of the lye that may be left in the wood.  I use the cheapest household vinegar, diluted about 50% and brushed on liberally.  If you skip this step you risk getting some nasty reactions with the varnish or lacquer that is going on top, and it may not show up for a few days.  (I speak from experience).

   best,

   DR 

1. 
   KeithNewton | May 30, 2005 05:26am | #7

   Ring, Thanks for the tip. I will try that sometime soon.

3. 
   TINK | May 28, 2005 07:13pm | #3

   Jimbo: I have used swiming pool bleach,which is 15% strong as oposed to 3% for house hold bleach ... As all ways the safety factor  is very important when useing a caustic material.. gloves ,eye  &a good mask.. Always start at bottom of piece & work up  .to open up pores of wood spray with clear water  prior to bleaching. Arubber aporn is advised... Alder should come out snow white.... don't forget to wash down with clear water after bleach has dried... Walnut & cherry ,mahogany bleach out as well... DREW

4. 
   HowardAcheson | May 29, 2005 09:25pm | #6

   There are three bleaches used in woodworking.

   The first is clorine bleach used to remove dye stain from wood. A new bottle of laundry bleach can be used but swimming pool chlorine bleach is stronger and works faster.

   The second is oxalic acid used to remove dark or black stains caused by water on some woods. Oxalic acid can be purchase in most paint stores or get "Teak cleaner/brightener" at a marine store.

   Third, is A/B bleach which is used to remove the natural color from wood. Most paint stores carry this.

   Howie.........