I've just ordered some Metrikote to wash the inside of my gasser, and I had a question about application. There are a couple of little cracks in the Cast-O-Lite (at the junctions between the separately cast sections) that seem to be catching the swirl from the ribbon burner. Does the Metrikote have any significant gap-filling properties? Should I coat the cracks first to build up a little thickness and then do a wash over the entire interior? Or am I just overthinking (again)?

I've filled cracks in Kastolite with Matrikote.  I don't think it will do anything structurally at all, but it can plug small gaps.  However, if the Matrikote is too thick it will tend to crack with heat cycles anyway.  As a side note, it does seem to be a bit more flux resistant than Kastolite, so if you're going to be welding there will be a benefit to covering any place that flux can reach the Kastolite layer.

One of the two things refractory cement (which is cheap and easy to buy) is actually good for is filling cracks in refractory and firebricks.

Does Metrikote stick to refractory cement?

No clue on that.

My guess is that it will, and if I remember, I'll mix up a little and check it tonight. I cemented my IFB test NARB burner block into the plenum, so I can check it there.  I can't think of any good reason it wouldn't stick similarly to how it sticks to Kastolite.

Are we talking the stuff that comes dry in a tub that you mix yourself, or the stuff that comes in a tube (like caulk)?

Most refractory cement offered on the Web comes in plastic pails, ready to go.

The stuff I used is as Mikey describes.  It didn't work as well as I'd hoped for cementing IFB's together for a project I was working on, but it seemed to do quite well cementing an IFB chunk into a steel plenum.  I may not have been using enough between the bricks.

There are many different refractory cements on the market; which was yours?

I just got a mini-tub of Meeco's from my local hardware store, which has the advantage -- unlike the big-box retailers -- of actually carrying pretty much everything all year round.  I'll let folks know how it works.

Meeco's was the brand I used.  Unfortunately I didn't get a chance to coat it last night.  I forgot one of the kids had a school function.  Maybe tonight.

Well, I went to fill those cracks, and a couple of little chunks of Kastolite flaked off and crumbled. I’ve stuck everything back together with the Meeco’s and crossed my fingers.

The Metrikote is expected in a couple of days. I’ll fire things up before I put it on, to see if the Meeco’s holds up to forging temperatures (it’s rated to 2000F).

Looks like you may have gotten the Furnace Cement and Fireplace Mortar version.  I got the Refractory Cement which claims to be good up to 3000 degrees F.

Well, if it doesn’t hold up, we can tear it down to the wall and start over.

Quick test fire. Looks okay; we’ll see how it does at full heat. 

On 4/8/2019 at 12:58 PM, Buzzkill said:

It didn't work as well as I'd hoped for cementing IFB's together 

Did you butter your IFBs first?

That's just a thought, I'm following this one I have to experience so no real opinion. 

Frosty The Lucky.