Marinuer Posted July 11, 2023 Report Share Posted July 11, 2023 I am finishing new wood handrails. ... I first stained with natural color stain. Let dry for three days. Then varnished with natural color varnish. (Both products new cans of Min-Wax from Home Depot.) Waited three days and went back to put on a second coat of varnish. I had multiple small white spots scattered across the handrails. ... Depressing! ... Fine sanded the rails and hard sanded the white spots Am ready to try again. How do I keep from getting these white spots again? ... Also, a friend suggested I wipe down the rails with Mineral Spirits to remove any sanding dust from my fine sanding. Is this a recommended procedure and if so, how long should I wait to re-varnish after the wipe-down with the Mineral Spirits? ... Thanks for any help here. . Quote Link to comment Share on other sites More sharing options...
Jronman Posted July 12, 2023 Report Share Posted July 12, 2023 On 7/11/2023 at 8:31 AM, Marinuer said: I am finishing new wood handrails. ... I first stained with natural color stain. Let dry for three days. Then varnished with natural color varnish. (Both products new cans of Min-Wax from Home Depot.) Waited three days and went back to put on a second coat of varnish. I had multiple small white spots scattered across the handrails. ... Depressing! ... Fine sanded the rails and hard sanded the white spots Am ready to try again. How do I keep from getting these white spots again? ... Also, a friend suggested I wipe down the rails with Mineral Spirits to remove any sanding dust from my fine sanding. Is this a recommended procedure and if so, how long should I wait to re-varnish after the wipe-down with the Mineral Spirits? ... Thanks for any help here. . Are you using a water based finish like Minwax Polycrylic? Polycrylic is white and can leave spots if you have runs or other excess finish. I don't remember the spots being small and many. usually it would be a larger spot here and there more commonly along inside or outside edges if you didn't brush it out well enough. Minwax Polyurethane is a more yellow color. Making sure the finish is brushed out evenly is important in preventing uneven finish. Less is almost more. You can alway apply more thin coats to get the desired protection you want. In terms of cleaning, I normally use a tack cloth. I don't recall how mineral spirits work. I have also taken a cloth and rubbed in a very small amount of the finish into it and cleaned that way if a tack cloth is not an option. Just enough to make the cloth tacky but not too much as to be applying the finish to the workpiece. Quote Link to comment Share on other sites More sharing options...
leticia peter Posted July 17, 2023 Report Share Posted July 17, 2023 Difficult to say without seeing it. If it looks like tiny clumps of baby powder in the finish and the finish was satin I would say it's un-dissolved flattening agent. Sometimes if a can of satin finish has sat on the store shelf for a long time you have to thoroughly stir it, put the lid back on and let it sit for several hours and then thoroughly stir it again. If you open a new can and run a stir stick to the bottom of the can and bring up the goo on the bottom of the can, that goo is the flattening agent. If it's a haze on a larger area and you applied the varnish when it was very humid then it probably got moisture from the air into finish. https://paintsgeek.com/white-spots-after-sanding-polyurethane/ Quote Link to comment Share on other sites More sharing options...
RT29 Posted July 17, 2023 Report Share Posted July 17, 2023 Could possibly be that the first coat was not 100% dry before the second coat went on or some other moisture got trapped. Quote Link to comment Share on other sites More sharing options...
Eric - TIA Posted July 18, 2023 Report Share Posted July 18, 2023 I wonder if it's air that was trapped. I am pretty sure you are not supposed to shake that before you apply a coat. Just a possible reason. I found out the hard way. Quote Link to comment Share on other sites More sharing options...
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