Carpentry and Woodworking - Refinishing my piece of oak furniture, WHAT WENT WRONG!?

Well this last week I have been working on refinishing an aquarium stand/canopy. Im 98% sure it is all solid oak. The old finish was a very light honey oak color and I wanted to change it to a red/dark mohagony.

To begin with I began sandying the old finish/varnish off of the oak with a 60 grit powersander sander followed by me hand sanding everything with 160 grit sand paper.

With the sanding complete I decided I would bleach the would to help with some of the dark spots (water stains) on the stand. To do this I applied a past made from 3 parts oxalic acid to 1 part hot water. I placed the past on the dark spots and removed the paste one hour later. The water stains came out perfectly!

After that I scrubbed the whole stand/canopy/doors/oak light fixture with an oxalic acid mixture (1 oz of acid per 1 cup of hot water). I applied this to the tank, let sit for a few minutes, then washed the wood with warm water. I then washed everything with an ammonia solution (1:1 with water) to neutralize the bleach. Everything looked like it was doing great.

The next day I moved everything out into the sun. When I returned from work the stand/canopy/light fixture looked "nearly" perfect BUT the doors were destroyed! All 4 doors looks as though they were caught in a house fire with black streaks and spots on the entire door!!

WHAT WENT WRONG???! I would post pics but not sure how

I can help with the pics, but will leave the basic question to a pro.

To post pictures first you must upload them to a host site. Photobucket is often used; it's free as are several others. Once your pics are uploaded at the host site click on the icon at the top of the post dialogue box here for "Insert Image" and put the url for the location at the host site. Voila!

Welcome to the forums! Why would you use such harsh chemicals on a tight grained wood like oak? And certainly you didn't expect perfection after putting all the chemicals, water and wood in the sun. Oak stains black when exposed to water. You can post pictures on a site such as photobucket.com and copy/paste the HTML code to your reply post and let us look at what happened.

Congratulations... you just learned how to "fume" wood using ammonia. I would be willing to bet that it was the ammonia that turned the wood dark once it was set in the sun and the moisture began to evaporate out of the wood. Maybe the doors absorbed more of the ammonia... or for some other reason they took a hit worse than the rest.

I agree that all the chemicals used contributed to the problem. Oak and water don't mix. Minerals in the water can also lead to problems.

First off im definately no pro at staining wood furniture. Not even an amateur. The reason for me using these chemicals on the oak was because I had some bad waterstained areas on my wood and was told the bleaching the wood would lighten and remove these stains. I followed step by step instuctions provided by easy2diy.com on how to strip the finish and to bleach the wood with oxalic acid.

I added the bleach and washed off the bleach the amonia at night (6-9 in the evening). After applying the ammonia to neutralize the bleach I washed it off well with warm water. After this I dried my wood with a towl and placed in the garage for over night. The next morning I had someone at my house wheel the stand/canopy/ and doors out into the sun/breeze to help dry the wood (even though by this time it should have been quite dry). I planned on staining the wood this weekend (48 hours after the bleach). I wil try to add some pics later :(

It seems your problem now is where to go from here? (Btw, there is a product called "bleach stop" that you can buy online to stop any bleaching action, but it does have to be mixed with water, so you would still raise the grain. The problem with water and wood is 1. it raises the grain, requiring sanding, 2. it makes the wood swell, 3. it can damage the joints because of 2. and depending on the type of glue used. If none of these are a problem for you, then using water was not an issue.)

As to where you go -- your choices are pretty simple -- go through the whole process again including sanding but without ammonia; live with the dark color - and stain the rest to match; or paint a red/brown mahogany color. Sorry no better options.

Also, fyi, I don't think oak would have taken a mahogany stain very well -- the grain is so pronounced - I doubt you would have been pleased with the result. And if you had used a sealer before staining to even the color, you would never have gotten a good dark mahogany color.

You might want to simulate mahogany without going through a whole faux-painting process: paint a dark red/brown and then dry-brushing black over it (just a very small amount of black on a dry brush until you get the look you want).