furnace cement keeps poping when the stove gets hot.

[lotust]

Hey guys, I have this old lange stove that I have rebuilt. I used some furnace cement in a tube from home depot. It was in a caulking tube formula. I did as the directions said. I pre wet the area then applyed the cement, I let it air dry on a COOL stove for 3-4 hours. I burned a "green" type Duraflame log that did not over heat the cement to cure it. This was like 3 days ago. Now Im burning seasoned wood (much hotter fire) and the furnace cement is pop off in small sections :-( This stuff says it is Perminate and will not come off glass ect..


What am doing wrong?

 

[fraxinus]

The joint where you apply the furnace cement needs to be thoroughly cleaned. Steel wool followed by wiping with a rag is what I do. The cement also needs to be compressed into the joint with your finger or a tool just as you would do with caulking. High temperatures too soon can also cause it to fail. You may, however, have done absolutely nothing wrong. Sometimes the cement quickly fails even when everything has been done just right. I'm not sure why this happens, but it does.

 

[elmoleaf]

Not sure how much/where you're using it, but if the cement is deep/thick, it probably needs to air dry much more than 3-4 hours.
It could be that your small fire simply drove off moisture from the cement exterior. When you then had a hotter fire, it may have boiled off the moisture inside, and caused the cement to bubble/pop off the harder exterior.
Try air drying for for a couple of days if possible before firing up.

 

[lotust]

The joint where you apply the furnace cement needs to be thoroughly cleaned. Steel wool followed by wiping with a rag is what I do. The cement also needs to be compressed into the joint with your finger or a tool just as you would do with caulking. High temperatures too soon can also cause it to fail. You may, however, have done absolutely nothing wrong. Sometimes the cement quickly fails even when everything has been done just right. I'm not sure why this happens, but it does.

I was really clean. I think I put to much on Like elmoleaf said. I had the hole in the tube cut pretty large from when I reassembeld the stove a few months back. I let that air dry for a few weeks.

Not sure how much/where you’re using it, but if the cement is deep/thick, it probably needs to air dry much more than 3-4 hours.
It could be that your small fire simply drove off moisture from the cement exterior. When you then had a hotter fire, it may have boiled off the moisture inside, and caused the cement to bubble/pop off the harder exterior.
Try air drying for for a couple of days if possible before firing up.

I think you hit the nail on the head. On some spots I see blistering. Thanks for the reply! I guess I will touch it up when it warms up next week. Its supposed to be in the 40's


Thanks,
Shawn