|Forum topic by Durnik150||posted 07-19-2009 05:48 AM||11654 views||1 time favorited||10 replies|
07-19-2009 05:48 AM
I’m working on some Black Walnut and have been running into a little problem.
I sanded up through the grits to 220, usually pretty decent for this hard of a wood. I then applied a natural tone stain (nothing fancy-Minwax-Natural). After that dried I put on a layer of semi-gloss polyurethane thinned 50/50 with thinner. I let it dry and went back to rub the first coat down with 0000 steel wool when I noticed a problem.
On various spots of the walnut there is a white discoloration. It is under the first coat of poly and looks like either trapped air or wax. But I haven’t even had wax near the pieces! The discolored areas tend to be on corners or edges but on one piece it looks like there are white dots in the grain, scattered over a flat surface.
I resanded one piece down to the wood and was able to make it go away but matching the finish after getting that far is not all that easy. And it doesn’t tell me what the problem was.
My initial thought was trapped dust and that may be what it is, but I brushed and rubbed the heck out of these pieces before going to the poly. It has been running in the low 90’s with about 25% humidity (super dry) here in Colorado over the last week and the poly has been drying very fast. I don’t know if that has anything to do with this problem.
Any thoughts or suggestions? If we don’t get a quick answer I’ll post some pictures to further illustrate the issue. Thanks ahead for helping out!
-- Behind the Bark is a lot of Heartwood----Charles, Centennial, CO