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Dark Stains on Mahogany after sanding

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Forum topic by Airwreck posted 903 days ago 2164 views 0 times favorited 5 replies Add to Favorites Watch
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Airwreck

2 posts in 904 days


903 days ago

Hope someone has a solution or answer to what is going on with this mahogany table..

My wife started to refinish the table she stripped the old finish off and started to sand the surface..At the end of the day it was looking grand ..
The next day was the shocker.. these weird brown stain (spots) appeared …
so she decided to sand again the brown spots disappeared with minimal sanding… she was a happy camper..
till the next day…they were back..
This is tropical mahogany.. the table is about 100 yrs old..
here are some images of the irritating spots.
any ideas on how to deal with them would be greatly appreciated


5 replies so far

View RogerM's profile

RogerM

445 posts in 1031 days


#1 posted 903 days ago

I have never seen this situation in mahogany. It appears to be an oil that is bleeding out of the pores after sanding. One possible way to deal with it is to work with it by putting a coat of boiled linseed oil on it then finish from there. Wish I could be of more help.

-- Roger M, Aiken, SC

View bondogaposis's profile

bondogaposis

2490 posts in 983 days


#2 posted 903 days ago

I think what is going on is that the original finish was an oil finish and some of it is still there. I may not be possible to remove all of it w/o sanding all of the wood away. What did you have in mind for the new finish? I would let it sit for a few days and see what happens. I think that you probably can’t fight it and I would look at using an oil finish or an oil modified urethane. I would really do some experimentation on the under side of the table before making a final decision. Why did the table need refinishing, what type finish was it? Let’s hope those spots aren’t from some type of silicone.

-- Bondo Gaposis

View tenontim's profile

tenontim

2131 posts in 2376 days


#3 posted 903 days ago

I’ve gotten rid of these by wiping down the wood with M.E.K. Lacquer thinner may work in a pinch. Let it set for a day to make sure nothing else bleeds out.

View Airwreck's profile

Airwreck

2 posts in 904 days


#4 posted 903 days ago

I thought it was something oil based. the way it appears is that kind of behavior.. Just needed the conformation.. Yeah I have never seen this before.

Because of the age of the table it is very unlikely that there is anything silicone base involved.

HA :-) the reason the table is being refinished is you have to see the way that Bajan Joiners have been finishing wood here for centuries.. They had this idea that you need to HIDE the grain of the wood and slathered on, for a better word, this brown shoe polish.. and they did it to all their wood projects.. This disease has not appeared on any other wood products that had this same shoe polish

after she my wife recently refinished these pair of small three leg tables that were nothing really special… but after she was done they looked wonderful.

Not sure if we can get M.E.K. here but will look into it..

If all else fails break out the linseed oil…

Thanks a million guys

View tom427cid's profile

tom427cid

294 posts in 1102 days


#5 posted 903 days ago

When I strip and after the final rinse,I let it dry and then wash two or three times with DA. Generally does the trick. It appears what is happening is stripper is bleeding back. As was said earlier if the DA doesn’t work MEK should do the trick. Be patient and give the piece a day or two to dry between steps.
Hope this helps.
tom

-- "certified sawdust maker"

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