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Sanding Polyurathane Before Applying Pour-On Epoxy?

2K views 7 replies 7 participants last post by  cjg225 
#1 · (Edited by Moderator)
Will epoxy hide the scratch marks/cloudiness left by sanding polyurathane?

I applied Minwax Polyshades to a tabletop to get the color I wanted, and I want to use a pour-on epoxy for a protective layer. The manufacturer of the epoxy recommends light sanding before applying over polyurathane. I'm a little bit hesitant to do this, because I applied Polyshades on a scrap board, and tried to use steel wool to remove the little bumps (from bubbles/dust?). The Polyshades became cloudy because of all the scratch marks left by the steel wool.
 
#3 ·
The Polyshades became cloudy because of all the scratch marks left by the steel wool.
That is what it does. Always. And it will disappear after the next coat if you were to put one down.

Epoxy bonds mechanically to whatever substrate you put it on. If there is nothing for it to bite into, it won't hold. That is why you need to sand or otherwise rough up the surface prior to application. If you don't give it something to bond to, it will fail.

Cheers,
Brad
 
#5 ·
If you are going to use epoxy over the poly let the poly dry for several more days, often referred to as "cured." I am sure this could be a topic of great debate but all too often people get upset that a finish does this or that. When you get the whole story you find they applied the night before and wanted to use the next morning. It may be dry to the touch but letting it sit for a few days to get completely cured makes a big difference.
 
#7 ·
A woodworking n00b here…

Why would you put epoxy over a polyurethane finish? I guess a more basic question is, is poly merely a "looks" finish instead of any form of "protective" finish?

- cjg225
Poly is definitely a very protective finish. Sounds like the OP used polyshades to color the wood, and the epoxy to get a bar top like finish. A more typical approach would be to use dye or stain to color the wood and epoxy over that.
 
#8 ·
Poly is definitely a very protective finish. Sounds like the OP used polyshades to color the wood, and the epoxy to get a bar top like finish. A more typical approach would be to use dye or stain to color the wood and epoxy over that.

- OSU55
Okay. Thanks. I just finished a project with poly and was wondering, "Did I just give it good looks rather than actually any protection?"
 
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