Yellowish White Gunk on wood stove and liner in fireplace

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JAR

Member
Jul 22, 2018
3
Indianapolis, IN
Hello to all and some knowledge please!

I completed a self install for my stove in November 2018. I had the chimney professional cleaned and inspected with a camera before I installed my stove. I was extremely pleased with the finished look and heat this setup put out. This is not a primary source of heat and I only burned about a half of a cord seasoned Oak, Locust and Maple last winter.

Took a 10 day family vacation in the middle of July and came back to find think YELLOWISH WHITE GUNK on my stove top and liner within the fireplace. My first thought was I had some type of water leak. However, this has been a very dry summer for us. I know it did not rain while we were gone. It rained all but two days in May with no sign of leaking rain water down the liner. Also, before I painted my fireplace, I did some repointing on a few spots. You can see in one picture that those spots are turning white also.

I grabbed a plastic putty knife, a stiff brush and a respirator and clean it all up. Put a HEPA filter on my shop vac fearing it might be ceramic insulation dust. Climbed up the chimney to inspect the top plate for holes, a cracked weld or something like that, but found nothing. I’ll be damn if it didn’t show up again last week. Not as bad as the first time, but it is there. We have had no rain in 10 to 15 days, but it has been in the 90’s. The AC has been running constant most of the last two months. Could this be some type of internal moisture getting trapped in my fireplace. The only thing I noticed was I did not completely seal the tiny space around the liner and my block off plate. I didn’t think that would be a big deal since the top plate was sealed with silicone. I searched the forum hoping for an answer to my dilemma, but only found two discussions with anything even slightly close to this.

Has anyone experienced anything like this before?

My Setup
External wall fireplace
Summer’s Heat 50-SNC13
HomerSaver Ultra Pro Flexible Stainless Steel Liner (14 ft), top plate, and stove adapter
Simwool heat shield wrap insulation (.5 inch thick , 8lbs density)
22ga steal block off plate with 6 inches of ROXUL above
 

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I would guess it is water washing salts out of the masonry. But that is a complete guess.
 
Not a metal expert but could it be galvanic corosion from incompatible metals?