Our shop has a huge walnut job ($95,000), which requires all of the walnut to be bleached (Part A and part B wood bleach). We do not usually offer this service, but the customer was willing to pay an up charge, so, here we are. Whenever I have bleached wood in the past, it has always been on a small scale. Usually I wipe it on with a sponge or rag. Our lab tech wants to spray the bleach through a one quart cup gun. I am concerned about the safety of the spraying process. (for the person spraying and also for those in the surrounding area, even though the work will be done in a spray booth.). Also, concerned about how well the bleaching process will work applying with a cup gun. Does anyone have any advice on the application process of the bleach, and if in fact it is safe to apply by spray?
From contributor Ke
Bleach doesnt have much affect on walnut. Very slight color difference will take several applications of bleach. If the customer wants a very dramatic difference, i would suggest Butternut. It is like a white walnut
From contributor Ni
Be forewarned most wood bleaches warn against contact with metal, I'd contact your wood bleach supplier too see if this is necessary for the product you'll be using. I use Daly's and they recommend no metal contact but I've sprayed a number of times with-out issue by using a plastic garden sprayer...just spray-on then brush-in...quick and easy.
From contributor CW
No real need to spray it. Soak a large rag, apply very wet and wipe off. I have done a large car showroom with bleached walnut and it came out great. I did have to bleach twice to get the end look. I also neutralized after the last bleach dried with white vinegar and water. if you don't you may have lifting problems. also had to lightly resand because of the grain raise.
From contributor sh
yes you can spray, done it many times. Adjust technique for vertical surfaces to horizontal surfaces; in a nut shell, do not flood horizontal, do not starve vertical. A/B can be mixed or sprayed separately - use 2 cups - one each - wait a bit after A coating or apply B immediately after A. But be consistent. Flush/wash guns immediately. I have also used ss pressure pots with liner. No worries. Good idea to wear mask, disposable suit cap or tied rag on head, gloves, etc. One way to deal with grain raise is to scuff between coatings with 220 - 320 your choice. You may need 2 cycles or one with a second cycle of B. neutralize with white vinegar in any case even if you are successful with one cycle. And if you will notice better results if you can apply heat during the bleaching cycle. It dries faster, of course, and it also impacts the chemical reaction during the bleaching process.
Back in the day 'white wood' was a reference to goods that had been bleached white. Typically, this was in the Grand Rapids area depression era heyday and again, typically, these goods were processed from a booth into a heated drying room .
Not a big deal if you do practical practice sessions
From contributor Al
Thanks everyone, Very good information. Heat is an option, so we will give that a try also.