Proguard was our clear topcoat prior to the introduction of Advance™. The last batch of Proguard was made in June, 2003. Proguard was a very good and effective topcoat, but one of its features was that it contained a fair amount of wax. The wax contributed to the water repellency of the system, but trying to apply a coat of stain on top of Proguard can occasionally present a bit of a challenge. You would think that after ten or more years the wax in a Proguard finish would be gone, and that’s true for those areas of a home that are exposed to direct sunlight. But in areas that are shaded like under the eaves or porch roofs, the Proguard may still be in good shape even though the underlying stain may need some maintenance.
The best solution to a Proguard problem is to remove the finish and get back down to bare wood. Our S-100™ works well removing both Proguard and the stains we manufactured at the time. But there is no way to just remove the Proguard without removing most of the stain. So the question is - how can you apply a fresh coat of stain or topcoat over Proguard that still contains enough wax to repel the finish?
There are three things you can try:
1. If the Proguard is a bit weathered, wiping the surface with denatured, isopropyl or rubbing alcohol may remove enough of the wax to make the surface stainable. This requires a lot of clean rags since they have to be changed often in order to remove the wax, rather than just moving it from one place to another. This may not be a sure fix, but it’s always worth a try.
2. Try a light scuffing or sanding using 80 grit sandpaper or sanding pad equivalent over the entire area. That should score the surface enough to allow the new coat of finish to adhere without creating fish eyes.
3. Most paint stores and home centers carry a product called Liquid Sandpaper made by Valspar, although equivalent products are also available. Wiping the Proguard surface with Liquid Sandpaper usually scores the surface enough to allow a coat of finish to be applied on top of it. Again, rags have to be changed often.
One thing about all of these solutions is that the stain must be applied as quickly as possible after using any of these procedures. If you wait too long, the wax will come back to the surface and you may have to start all over again. So what’s too long? When trying alcohol or Liquid Sandpaper it may be a matter of only a few hours. It’s best to get the finish applied while the surface is still a bit tacky. After sanding we usually recommend that the first coat of stain be applied within 24 hours, but the sooner that it’s applied, the better.