Wood Refinishing: Bleaching
As a follow-up to my Wood Refinishing: Stripping post, I’ll now detail the steps we took to get the wood stain ready.
Our douglas fir built-ins were very dark and blotchy after chemical stripping was complete. The doors and trim that we had Houck’s Process Stripping Centerdip were already bleached during the dipping process, saving us a step for the majority of our woodwork. Another reason I highly recommend dipping everything that you can. You can bypass all these steps and get straight to sanding.
Since we couldn’t dip our built-ins, to get a consistent match to the dipped trim, we needed to hand bleach ourselves. 1912 Bungalow talked about bleaching their woodwork, which gave us some confidence to try it out. Also, this article about using wood bleach on AntiqueRestorers.com was a great starting place to learn about types of wood bleach. Yet, another good reference is this PDF on Bleaching Wood.
We decided against A/B type peroxide bleaches because they can remove the wood’s natural color as well as the stain. However, if this may be your desired result, you can read more about how to use two-part bleach on Wood.com.
The next type we read about, oxalic acid, was available at our neighborhood Miller Paint. Directions state to mix 1 oz. powder to 1 cup hot water, apply to the wood surface evenly and let sit for 3-5 minutes for softwoods like douglas fir. You then rinse off with warm water and neutralize with ammonia. E-how.com has a good run down of how to use oxalic acid.
I tested the solution on a fully stripped drawer of our built-in. I would recommend doing a test patch in an inconspicuous area to make sure there isn’t an adverse reaction on your wood. The solution did work, but took a few applications to get most of the blotchiness out. I could see on a larger scale, that oxalic acid was going to be expensive to do all our built-ins based on the 1 oz. to 1 cup ratio.
I decided to try the chlorine bleach route. Chlorine bleach won’t remove the natural wood color, which was a big plus as well. A very strong bleach called 30 Seconds Outdoor Cleaner was the product of choice. It’s sold at our local Lowe’s.
We were skeptical because its supposedly for outdoor use to clean decks and driveways. However, It’s a lot stronger than laundry bleach, and in our test, it worked fast, as we didn’t dilute it at all. It is very cheap (about $10 a bottle) and I think it only took 1-2 bottles to bleach our 3 large built-ins including the full wall buffet.
The steps below will be similar if you use peroxide or oxalic acid, but depending on your type of wood and desired end result, durations and neutralizing solutions may be different than listed below.
- Plastic drop cloths
- Protective clothes (these will get bleached)
- Old towels (these will get bleached).
- Chlorine bleach like 30 Seconds Outdoor Cleaner or alternately, swimming pool chlorine.
- Large paint brush to apply bleach
- There is a motorized spray bottle version of the 30 Seconds product, but I would recommend using the paint brush application method. The spray bottle is best for outdoor use.
- Small bowl to dip paint brush in
- 2 buckets for rinsing, filled with hot water and Borax or baking soda solution
- 2 spray bottles for rinsing, filled with hot water and Borax or baking soda solution
- Boxes of Borax and/or baking soda for neutralization
- Optional: Canvas drop cloths for extra floor protection and runoff collection
Steps to Bleach Wood:
- Strip wood and do a quick pass with a sander in case any finish, chemical residue, or high spots remain.
- Note: You will also need to properly sand after bleaching as the grain may rise during the bleaching process, so don’t spend too much time sanding at this point.
- Also, any chemical stripping residue may react with the bleach, so make sure at the very least that you have fully neutralized and cleaned off any chemical stripper. We learned this the hard way in some spots. The bleach didn’t take well in those areas.
- Protect floors and walls with plastic. Also use old towels and/or canvas drop cloths to catch any runoff that might seep under the plastic edges on the floor.
- Wear gloves and protective clothing that you don’t mind getting bleached.
- Keep kids and pets out of the area. Follow other manufacturer’s recommended safety precautions.
- Apply bleach to dry wood with the large paint brush.
- Don’t forget to first do a test patch in an inconspicuous area.
- Monitor and let set until stain disappears. At a point, it will stop bleaching any further. Usually around 5 minutes. Don’t allow to dry.
- Spray with water/Borax solution bottle and let set for a few minutes.
- Use wet rag and/or sponge to begin rinsing. Do a few passes. Use the second bucket of clean water as the last pass. You will need to change out the bucket water frequently.
- Use towels to dry area and soak up any remaining solution.
- Repeat process after wood dries. We did 3 passes.
- I would recommend allowing several days, possibly 2-3 weeks to let the wood fully dry. I wouldn’t chance trying to stain bleached wood immediately. You may see adverse results if any bleach residue remains in the wood. We weren’t willing to chance it.
As you can see, the blotchiness is minimized and the overall color is much more uniform and true to nature. This really minimizes the need for heavy sanding, which was our main goal from bleaching. Trying to sand down to this level manually is very time intensive, so bleaching was worth it for us.