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Josh Bernbaum 09-22-2020 09:48 AM

Castable additive?
I think I've heard it mentioned here before, but can't find in the search tab, about an additive to mix with castable to help ensure the chemical reaction takes place so it sets up properly. Is there such a product out there? I was just ordering some mortar from Harbison Walker and the guy with whom I spoke hadn't heard of such a thing as that 'additive'. And of course he reminded me that these castables have a limited shelf life. I'm hoping to use some Mizzou that's a little over a year old.

Pete VanderLaan 09-22-2020 01:18 PM

calcium aluminate is the binder that makes castables set. The only source I've seen for it is Missouri Refractory Company (MORCO). Hi Temp in Fenton Missouri can get it for you. I think it comes in 25 lb bags. Wisest to immediately put such materials in absolutely airtight containers. I don't know if you remember all those cat food containers we had for delicat. They keep castable, plaster and such very fresh forever.

Eric Trulson 09-22-2020 02:50 PM

FWIW, I expect your Mizzou will cast just fine as it is. I've used castable 2-3 years old that has sat through a couple New England winters with no issues. Can't hurt to have some of that calcium aluminate around just in case you do need to perk up some casting in the future though.

Philip Yamron 09-25-2020 11:07 AM

What kinda of ratio would you suggest for a 50# bag of castable?

Pete VanderLaan 09-25-2020 07:21 PM

About two pounds. It will slightly lower the max temp on performance on the rated temp for the bag.

Philip Yamron 09-25-2020 08:37 PM


Originally Posted by Pete VanderLaan (Post 148930)
About two pounds. It will slightly lower the max temp on performance on the rated temp for the bag.

Thanks. Good to know

Pete VanderLaan 09-26-2020 07:45 AM

Keep it fresh. I put it in totally sealed cat food containers on arrival. I do that with potters plaster and high alumina castables as well. If the plaster still works after two years in a new Hampshire summer, , I know the containers are doing their job. We must have a few hundred of those Delicat opal white containers with lids. I am amazed at how many of them that cats one and two went through. It was a sad moment when they quit using those things. You can buy the empty containers new on Amazon but it's ridiculously expensive.

I could lash ours together and make a raft like they did in Kon Tiki.

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