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Tear out Kast-O-Lite, or add another layer?


JHCC

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The Kast-O-Lite layer on the inside of my forge is getting rather battered, and I am thinking of relining. My question is this: can I trowel a layer over the existing refractory (well buttered, of course), or do I need to strip the forge down the ceramic wool and redo the hard refractory entirely? 

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Personally I would remove it just so I could check the condition of the insulation as well.  You won’t have to worry about weather it will spall off the old kol and you’ll have the choice of replacing the first layer of insulation if it needs it and not loose any volume in the forge.  Jmo as I haven’t needed to do this just yet.  

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I'm gettin' close to doing the KOL on my forge.  My thought was to coat everything and then after it's cured put a layer of aluminum foil on the bottom and up the sides about an inch and put a coat of KOL on that.  Pull out the aluminum foil after curing and I've got an easily replaceable "liner" for  the floor.  When it gets messed up I'll just toss it and make another.

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One of the things KOL is designed to do is stick to damaged furnace walls so you CAN just patch it if you like. However Jason has a good point, the Kaowool behind it may be wearing out. 

I started to shake my head when I started reading your post Chris. I'm glad I finished before replying. KOL will stick to aluminum or heck any metal like Elmer's to your Mom's good furniture. Heck it sticks to just about everything but wax paper can be removed and Saran Wrap just goes away when it gets hot. The idea is a good one but you'll need to make clearance or the "liner" will form fit and be a mother bear to get out. A sheet of typing paper should make enough relief to get it out. Could be wrong, it's my trademark.

Frosty The Lucky.

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Thanks, Frosty, good suggestion.  Got the ceiling done just now.  Will do one of the walls tomorrow and the other the next day............then the floor.  Hope that's the way to do it.  For some reason I'm thinking I can't do all four surfaces at once...............correct?

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When I made the forge, I mixed up a couple of cups of KOL in a ziploc bag, put that in the bottom, tamped it into shape, let it cure, took it out, and removed the bag. It was a cool idea, but it ended up being somewhat fragile and the edges would catch the swirl of the flame and mess up the even heating in the forge. 

I'm pretty confident in the state of the kaowool; it's just that the floor is getting pretty battered, especially around the opening.

 

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I did my whole forge in an hour.  I’ve done a ton of concrete work so I do have experience playing with similar stuff.   I did mine in 1/3’s and it worked well for me.  Started with the floor as that was the thickest part.  One reason is I only just enough water to shape it as needed.  More like mortar for stone work than concrete 

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Yup, I know to mix it like mortar.   I think that's why it stabilizes so quickly.   Never messed with KOL30 before, so am kind of surprised how easily it has gone.   I'll go out and see if I can turn it to the next wall in a little while.  I want to do the floor last.

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I'm starting to think that the Inswool Moldable refractory would be a good option. It's rated up to 2300F and can be troweled on like joint compound. A bit pricey ($86/gallon retail), though. I know it comes in tubes to fit a caulking gun, though, so maybe I'll get one of those to touch up the existing refractory and fix its cracks.

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After a text message exchange with Lou L, I'm strongly leaning towards getting a tube of the Inswool Pumpable, which is basically the same as the Moldable but in a tube that fits into a caulking gun. I'll vacuum out the forge, lightly wire brush the spots that are looking iffy, vacuum again, wet down ("butter") those spots, and apply. 

I'm headed out of town on a business trip tomorrow, and there's a Harbison Walker outlet right near where I'm getting my rental car. I have a feeling that I'll need to keep myself on a strict budget....

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John,

I've used that caulking tube stuff in the past to seal up gaps in my glass furnace.  Just be aware that it is not flux resistant and most likley does not have the same thermal expansion characteristics as the surrounding castable refractory.  If you can live with a smaller forge I would consider just putting in an inside lining of maybe 1/2" of Kastolite.  Soon as it warms up here again I'll be doing the same to my gas forges, which originally had a satanite over blanket linings.

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Stopped by my local Harbison Walker distributor today and got a couple of tubes of the Inswool Pumpable. Had a really good chat with the manager, who suggested Greenpatch 421 for eventual relining: it's rated up to 3200F and goes on like drywall compound. It only comes in 15 lb tubs, though, so I'd have to find other uses and/or someone interested in sharing.

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I’m sure you’ve used yours way more then I haves used mine, but my liner is holding up ok after a year. If I remember right your coating was a little tougher, maybe if it was smoother it wouldn’t break up as easy? I was pretty careful with keeping mine as smooth as I could and the only cracking I have is between the floor and the wall. I think I’ve ran 250ish pound of propane through it?

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