Replies

1. 
   garyowen | Mar 17, 2010 02:29pm | #1

   Hi JBAces, it sounds as though the poly was not fully set up, before sanding. Can you sand an area that is not seen, back to the start point and then finish that area, letting the poly cure fully, after each coat?. You can also try poly shades, if you can find the color. garyowen

2. 
   Julmer | Mar 17, 2010 05:40pm | #2

   Finishing with Minwax Poly - mixed properly?

   I had a similar frustrating problem using Minwax semi-gloss on a table top. One of the hints I got was that the finish might not have been mixed. The flatener added to the finish to produce the semigloss or flat versions of the finish can settle out giving you a different sheen depending on if you are using from the top of the can or bottom. I have mixed everytime before using a can of finish (new or used) and have not had the problem again. (had to strip off the problem finish)

3. 
   hammer1 | Mar 18, 2010 11:32am | #3

   It always helps to read the can, JB. They recommend sanding with 220 between coats. This is because poly doesn't melt into previous coats. You need some scratches for the next coats to adhere to but that's not your problem, nor is stirring.

   Minwax oil based poly turns white when you sand it. If you use a cloth damped with mineral spirits to remove dust, you have to be sure all of it is evaporated before applying another coat of the poly. Make sure you vacuum and blow off the work before wiping with the mineral spirits or you'll just wet the dust and deposit it in the grain.

   Sometimes, the last coat doesn't need any additional attention. If it does and you have, you will need something to cover the inevitable white result. I will use #0000 steel wool after fine sanding. I like to use it dry so I can see exactly what each stroke is doing. Once the dust is cleaned, I apply a light coat of furniture paste wax, allow to haze, buff out. This will return the surface to a nice shine.

   Here are a couple of pictures of trim boards, Minwax stain and poly. In the first, I'm sanding between coats. The second one is ready for steel wool, you can see where some dust nibs, goobers have been flattened. The steel wool will blend those in. Forgot my camera when finished and installed but the appearance is like an unsanded coat only glass smooth with a nice shine.