Have been trying to stain new Weathershield wood windows, but stain doesn't penetrate well, particularly at bottom. Just beads up, mostly wipes off after the waiting period, and adding second or third coat doesn't help much. The beading also makes for blotchy areas. The grilles that come with windows take the stain pretty well. Have tried 5 brands of oil-based stain and 2 of water based. Also would like to match existing trim and windows in room that were not replaced, but the only custom blended stain I could get (Benjamin Moore) is not one of the better ones for penetrating. I have presanded and applied the conditioner. Manufacturer has not been helpful about how to do this. They did finally, after a year!, replace the windows--but they have the same problems!! I am about going to have to just replace all windows with prestained windows from another company, but surely there must be something that will work. 3 painting contractors haven't been sure they could get this to work and estimates varied hugely. Thanks for any suggestions!
There is some type of sealer that is not allowing the stain to penetrate on these windows and I can't imagine the window company not being able to help you. But in light that they don't seemm inclined to help, you should sand a window very well and skip the wood conditioner and then stain and see if that helps. You may even have to try a gel stain as that should work as they are designed to go over a sealed surface.