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