How much refractory do I need

I just bought a cheap ceramic fiber lined furnace and plan on using rigidizer and RESCOCAST 8, 2800° hot facing with stainless steel reinforcing needles, how much of the refractory do I need, it comes in 2.2 and 8.8 pound packages, plus larger, which size will be sufficient? Is it worth while going to a 3000° refractory instead as I only expect to be casting nonferrous, aluminum and brass/bronze? The inside of the furnace is about 11" ID x 12" deep. How thick should the coating be? The lid is flat, what is the normal way of holding the refractory coating so it doesn't fall off the lid or is it to be thin enough that it's not a problem?

 

Two trains leave from Chicago, one going East and the other going West...

11" D x 12" H x .25" thick to inside minus (3" dia vent and 2" dia tuyere)
Bodies (1)
Volume 144.17 in^3 or 0.08343 ft^3 or 0.002362 m^3




I could not find the dry pounds per cubic foot 'as-mixed' for RESCOCAST 8.
Once this is known, that could be applied to the above volume and then adjusted for the desired thickness.
I coated my smaller furnace using the wrong stuff and ended up leaving it on the sides but taking it off the lid for fear of it falling in the crucible.

 

Thanks for the reply.
I've sent a request for information to the seller, Canadian Forge in Alberta, to see if they can provide more information and generally how much they suggest for that furnace, I can't imagine they've not had anyone ask before. From what I've seen on the forum, it looks like none of the coatings last forever so keeping extra is probably a good idea anyway. Also, is a 1/4" coating 'normal' or just what whoever prefers, I assume it's a tradeoff between strength and mass of refractory that has to be heated?
BTW, someone was commenting on rigidizer and suggested 40% sodium silicate, is that worth trying or better to just spend the $30 and not worry about whether the sodium silicate will work?

 

The 1/4" was just a starting point for the CAD to get a number.
In my case I just wanted a coating, not to build a thick hot face.

 

I found the manufacturers spec sheet, it's 89 pf^3 or 1.43 g/cm^3 so it doesn't sound like I'll need a lot, even with ¼" coating all I'd need would be 7½ pounds. Now, on to getting safety equipment and building a crucible lifter and the rest of the tools. FWIW, I worked in a nickel smelter many years ago and everyone wore boots with a splash guard over the tongue and laces, having the laces not done up to the top and pantlegs not over the boots was a safety violation.

 

This is from Canadaforge.com's page on Rescocast 8

 

That's kind of where I was going, follow their suggestions instead of beating a new path

 

TO (Topic Opener):
Using ceramic fiber does barely require refractory. I use a 2" layer of Kaowool in my smaller furnace, painted with a thin layer of 1650 C (3000 F) rated Fermit refractory I apply this with a bit too much water so I can just use a brush.
That insulates very good. In your case make a 3" thick ceramic fiber wall and paint it with a kind of porridge made of refractory with a bit too much water. Some users here use Satanite which is similar to the Fermit I use. This lasts very long but it is vulnerable to breakage, feels like 'papier maché', so don't poke tongs to it and be careful when returning a crucible, regardless when cold or hot.
The problem I had with a concrete or castable refractory inner wall is that is SOAKS heat, so it takes much longer to heat up.

 

I was waiting for you to reply.
I know there's no buying small quantities of Satanite for the Canuk's but maybe they can get the tub of Fermit.
Probably better than trying to paint refractory on.

 

Canadian Forge & Farrier has Satanite in Pint Jars, 10 and 20lb Pails, and 45lb bags
https://canadianforge.com/
I’ve dealt with them a few times for stuff that’s hard to find in Canada, good people. I don’t know about shipping costs there only a 30 minute drive for me.

 

"Canadian Forge & Farrier has Satanite in Pint Jars, 10 and 20lb Pails, and 45lb bags"
Well there you go Pontiac.
Forget the rigidizer, forget cooking your wool, forget the needles.
Get a 10lb tub, a 1" chip brush and paint the wool. three coats on the floor, two coats on the walls and lid.
Easy peasy, done in an afternoon. Cure each layer before adding another. If you have a weed burner it goes faster than using the furnace burner.

 

Thanks for the lead on Foundry Supply, many years ago I dealt with Smelko Foundry that are also in Milton, it might be worth a visit, sometimes the people actually know what they are selling and can give advice. As for the others suggesting the needles aren't needed, they were only $10 so I figured it was cheaper getting them now than later as freight costs would kill any savings. I did end up getting more refractory than I needed, but figured it wouldn't go bad in a sealed container so I'm set for the duration.

Along the lines of advice, the regulator won't fit the QCC1 fitting on the tank, any suggestions on the appropriate adapter?

 

L, Are you saying that the outlet on the valve on your propane tank does not have internal left-handed POL threads (mating fitting will have notches on the flats like the one you show above) concentric with the right-hand QCC1 ?

 

The Smelco's retired, Foundry Supply bought their business.

You shouldn't need an adapter. Have a closer look at the valve on your propane tank. It should look something like this with both male threads to fit the QCC1 style regulator and female left hand threads that will fit the POL style regulator that you show in your picture.

 

Agreed, I shouldn't need a different fitting but I do, when the regulator fitting is inserted into the tank fitting, it doesn't go in far enough for the threads to engage, except for the o-ring, it's more like an acetylene tank fitting. worst case, and with a threaded coupling and a nipple, I might be able to use a QCC1 to ¼ NPT that I can buy online.

 

Odd. With my furnace, I use an acetylene regulator on a normal 20lb propane tank without any problem.

 

Still trying to find the right fitting. Princess Auto sells a POL fitting, it's a Fairview #2018-LP, it looks similar but has a 9/16-18 LH thread to fit a propane hose. Even then the 'nose' below the thread in nut looks too long, I have no idea what it is. I've asked Vevor what it is, but typically, no reply. I could modify it to make it work, but being on a propane tank, I'm not sure it's a good idea, I'd rather be able to buy what I need.