Patching Kast O Lite 30

[Justin Keller]

I'm hoping to get some advice from the knowledgable folks here.  I lined my new forge with two layers of number eight Kaowool and rigidized then fired it.  I have mixed and applied Kast O Lite 30 to the forge, but I had a somewhat difficult time getting it to "stick".  I kept it in a gabage bag with a sopping wet towel for four days before slowly heating it up and driving out the moisture.

It turned out pretty well I think, but there are a couple of spots that the Kast O Lite just fell off of after I dried the forge out.  Can I just wet the area again and patch the spots it fell off of?  Does it look okay otherwise?  How big of a deal are the cracks?

Thanks in advance!

[Frosty]

Yes, mix up enough to fill the missing spots with a little extra to extend over what's still there and this time pat it in till it smooths out some. It looks like you had about the same luck I did trying to trowel Kast O lite on, it kept just coming up behind the trowel so I put on a pair of Playtex rubber glove and spanked it into submission. 

What that does is drive the aggregate down and packs the particles together while pumping the water and calcite binders to the surface and down into the kaowool a little. That leaves a smoother surface and a stronger flame face liner.

It's too late to do that on yours so I suggest you mix up a thickish batch of Plistex and paint over the liner. That will effectively cement everything together while providing an effective kiln wash. Don't try to cover it in one thick coat, several thin coats is stronger and will last longer.

That may not solve the problem but it's what I'd try. Better than ripping it all out and relining the forge completely.

Frosty The Lucky.

 

[Justin Keller]

Thank you, Frosty.  I will follow your advice and patch the spots that need it. I have not painted it with ITC yet, so I will do a few layers and just get to using it.

By the way, I am using your burner design and they sure work like a charm!

[mutant]

Hey Justin, can you take a picture of your cast-o-lite powder before it’s mixed with water? I’m planning on building a propane forge and I have a few boxes of mystery substances that are from my aluminum foundry hobby that I purchased a few years ago but never labeled. I’m pretty sure some of what I have is cast able refractory cement. I have a YouTube video showing my dilemma. 
 

Thanks!

 

[Frosty]

Justin: If you haven't spent the money yet do NOT use itc-100! It won't do any of the things I suggested would be helpful for your forge. Itc is formulated as a release agent to prevent glassy melt from sticking to kiln or furnace furniture, the zirconia content makes it pretty chemically inert. It doesn't form a hard surface and can't cement anything together.

Plistex on the other hand has NO zirconium content but fires hard like a coffee mug is high alumina so contact with strong caustics like molten borax based fluxes don't effect it and it's a strong binding cement. I do not mean cement as in Portland cement, I mean cement as in adhesive.

Frosty The Lucky.

[Justin Keller]

Hi Frosty,

I did already purchase the ITC-100, it was the only one of the recommended kiln finishes my local supplier had.  However, I will look into getting some Plistix instead.  It doesn't seem to be very readily available in Canada, so I'm hoping shipping from the US won't be too bad.

Justin

[Frosty]

Check the Iforge store, button at the top of the screen. Glenn ships smaller quantities at a reasonable price, Can't say about shipping to Canada though. There are other similar kiln washes and maybe available in Canada under a different name. Check with a ceramic supply, what you want is a 3,000f. water setting, high alumina, kiln wash. The important things are it's max temperature and high alumina so it can take the temps we make in a propane forge and won't be dissolved by molten borax based welding fluxes.

Frosty The Lucky.

[Justin Keller]

Hi Frosty,

I am not able to find Plistix 900f in Canada, looks like it will cost me about $55 for 2 lbs of it with shipping from the US.  I did find a couple of products that seem to be used the same way, do they look like they would work? [commercial link removed] or possibly this one  [commercial link removed]?

I have been researching kiln washes and I can get one locally for a pretty reasonable price.  It is called "Hi-Alumina kiln wash" and is made up of 60% Alumina Oxide and 40% Kaolin clay, does that sound like it would be a good replacement for the ITC?

Thanks again,

Justin

Edited May 3, 2022 by Mod34
Commercial link removed per TOS

[ThomasPowers]

So what did the refractory dealers in Canada suggest as a replacement for those products when you called and talked with them?

[Buzzkill]

Justin,

Those are high temperature mortars, They are designed to stick things like refractory bricks together.  They usually do not function well when exposed to direct flame for long periods of time like we see in a forge.  You may want to search for "kiln wash" at a ceramics/pottery supply store.

[Frosty]

A web search using, "Morgan Thermal Ceramics distributors" for search terms hits the company main page top of the list. I selected Canada and location on the site's locator. There is a distributor in Ontario. I didn't read through the rest of the several pages of hits and believe this is a company location rather than a retail site but I'm sure you can find a retailer without too much trouble.

Frosty The Lucky.

[Justin Keller]

On 5/3/2022 at 10:34 AM, ThomasPowers said:

So what did the refractory dealers in Canada suggest as a replacement for those products when you called and talked with them?

One suggested a product called "Heat Stop" or "Sairset", which seem to be much more available in Canada.  The Heat Stop website says "Good for applications well over 2,000°F.", which makes me wonder how much over 2000F it is good for.

[ThomasPowers]

Usually you have to talk to people to get the details; does the website have a phone number on it?

[Frosty]

"Good for applications well over 2,000°F" Doesn't mean much where a propane forge is concerned. Virtually any refractory mortar is good to 3,000f and doesn't last very long as the flame face in a propane forge. 

Have you contacted "Morgan Thermal Ceramics"? The name in quotes in a search WILL hit on their web page, from there you can locate a distributor close to you. I'd just link you but that's not allowed on Iforge. 

Frosty The Lucky.

[Justin Keller]

Hi Frosty,

I will be contacting them tomorrow and I'll see what I can discover.

Justin