40belowwoodworking Posted February 7, 2015 Report Share Posted February 7, 2015 Finishing a bookcase. Applied Minwax stain, after sanding, 3 coats and wiped off thoroughly and allowed to dry completely. After the 2nd coat of Minwax Poly Satin finish these small white stains appeared. 1st coat of poly was dry (24H) and clean, no stains.. I lightly sanded the areas with 600 grit and fine steel wool, wiped areas down and applied the 3rd coat of poly. Within 30 min's the stain came right through. Original wood surface was clean, oil free, glue free.. Stain's did not appear until after the 1st coat of poly. So....What is it, how can I prevent it in the future and...how can I fix it?? Quote Link to comment Share on other sites More sharing options...
davewyo Posted February 7, 2015 Report Share Posted February 7, 2015 I don't have anything for you right off, but I bet folks will want to know what wood. And welcome aboard. D Quote Link to comment Share on other sites More sharing options...
Tpt life Posted February 7, 2015 Report Share Posted February 7, 2015 Any chance of posting a picture? White spots can be contaminates, trapped humidity, or even the part of the finish that is a solid that obscures the gloss carrier to satin sheen. Quote Link to comment Share on other sites More sharing options...
40belowwoodworking Posted February 7, 2015 Author Report Share Posted February 7, 2015 I posted a photo on my original post....Thanks for input. I did stir the can well but maybe not well enough. Also case is baltic birch plywood. RW Quote Link to comment Share on other sites More sharing options...
T-astragal Posted February 7, 2015 Report Share Posted February 7, 2015 I remember something about the color "red mahogany" in minwax that needed special consideration. Other than that idk. 600 and steel wool is too fine. 240 or 320 then recoat. 3 coats outta level out darn near perfect. Especially with satin. 600 would polish satin to the next sheen level or at least close to it. It looks like inter coat adhesion problems. Good luck. Steve 1 Quote Link to comment Share on other sites More sharing options...
40belowwoodworking Posted February 7, 2015 Author Report Share Posted February 7, 2015 Oil based poly. The stain is "Gunstock" Thanks for the input! I'll review the Minwax link. RW Quote Link to comment Share on other sites More sharing options...
Jfitz Posted February 7, 2015 Report Share Posted February 7, 2015 Was it a new can of poly? Partially empty when you used it? Were you taking it right from the can or did you pour some into a secondary container? Satin poly has silica or other flattening agents to provide the satin sheen. What you're seeing could be where you picked up blobs or heavier parts of flattener. You need to keep it well stirred while using it so the silica stayed mixed in. 1 Quote Link to comment Share on other sites More sharing options...
T-astragal Posted February 7, 2015 Report Share Posted February 7, 2015 Was it a new can of poly? Partially empty when you used it? Were you taking it right from the can or did you pour some into a secondary container? Satin poly has silica or other flattening agents to provide the satin sheen. What you're seeing could be where you picked up blobs or heavier parts of flattener. You need to keep it well stirred while using it so the silica stayed mixed in. I think this is it. I was shocked at how long it took to stir the lumps out. Steve 1 Quote Link to comment Share on other sites More sharing options...
40belowwoodworking Posted February 7, 2015 Author Report Share Posted February 7, 2015 Thanks everyone! RW Quote Link to comment Share on other sites More sharing options...
40belowwoodworking Posted February 9, 2015 Author Report Share Posted February 9, 2015 To close this post...The advice I received I believe was correct. I don't think I stirred/mixed the satin poly correctly. To remove the stains, I used a cabinet scraper to carefully remove the poly on stained areas. I did notice an abrasivness as I scraped the poly which confirms the advice I received here. I used a scotch-brite pad and 600 grit to soften the surrounding area, touched up with a dab of stain and re-poly'd the spots. It really came out OK. So...stir better, and while staining and finishing is not my favorite part of a project...beer and Bob Seger make it bearable. Thanks for all the advice and suggestions. -50F here this AM RW Quote Link to comment Share on other sites More sharing options...
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