Heat Resistant Wood Finish

[Steve Benson]

Ok so i recently made a large solid wood mantel, a 16/4, 12" wide, 6ft long piece of Walnut. I filled pores with about 6-8 coats of shellac sanding it down between coats. After that i threw 3 coats or Arm-R-Seal satin. Ok so the issue is i put the coat on a week ago and lit a fire for the first time tonight and the finish bubbled up/blistered on the bottom. Im looking for a more heat resistant finish, i assume it was the Arm-R-Seal that bubbled up due to it being more of a film than shellac. Will more coats of shellac with just a little rub down in between be better or should i find a good 2 part laquer or something. Any suggestions will be appreciated.

Thanks
Steve

[Bob Vavricka]

Steve, I can't answer you question about heat resistant finish, but I would encourage you to make sure you are meeting fire codes for the location of the mantel. If the mantel is getting hot enough to bubble the finish, I would be worried about it catching on fire. The more the mantel projects out from the wall, the further it needs to be from the fireplace opening (19 inches for a 12 inch mantel in one place I looked). When I installed mine, I put a decorative diverter (not sure what the correct term is) that allowed me to decrease the distance some. It serves to divert the heat rising from the fireplace out away from the wall. You may know all of this, but it would worry me that the mantel is getting that hot.
Bob V.

[Steve Benson]

My mantle is well over code and 20" above the blower vent at the top for the fireplace. I place a Thermometer at the mantle and it never exceeded 100F. I personally just thing the finish had not cured yet.

Thanks though.

[Bob Vavricka]

Steve,
It's good to know that you have the mantel a safe distance from the fireplace. I was just concerned about it after reading about the bubbles on your finish.
You are right it might just be a curing time issue. I have noticed that there doesn't seem to be a lot of traffic in this forum and your problem got me to doing a little more research. Here is a site that I thought did a good job of listing benefits and drawbacks of different types of finishes. Granted it at Lowes, but the information seems good even though it lacks a lot of detail.
http://www.lowes.com/lowes/lkn?actio...nishingBG.html

I am using Waterlox for the first time on some small turnings and I noticed on their website this quote concerning using it for wood countertops.
"Waterlox Original Tung oil finishes have good heat resistance, can be used around stoves and are unaffected by boiling water and liquids." Of course they still recommend using a hot pad for pans. The only thing that concerns me with Waterlox is the curing time feedback that I am getting. However, their website indicates that it is 90-95% cured after 96 hours and it can take up to 30-90 days for the final 5-10% cure.
Good luck on your search for a solution and let us know the final outcome.
Bob V.

[J. Scott Holmes]

Waterlox is indeed a very durable finish. Arm & Seal is a poly varnish and poly tends not to stick very well so that coupled with the incompletely curing of the finish spells disaster.

Let it cure to see if it wil last or strip it and start over.

VERY thin coats will dry and cure better.

[Jim Becker]

Interestingly, Fuhr International had a specific heat resistant water borne finish a few years ago. I don't know if they still produce it, however. That said, as long as your fireplace woodworking is away from the heat source an appropriate distance, most finishes will be just fine.