I wanna have kaowool under my kastolite floor, will rigidizer keep it from going flat?

[Alex W. 0]

8k of copper, a crucible, a floor and walls of a castable refractory, are all gonna rest on a circle of kaowool about 8 or 9" in diameter, so I'm a bit worried I'll flatten it under all that weight, and render it un-insulative.   Any idea?  Answering isn't a necessity anymore, they opted out for a copper casting instead.  Thanks!

[James Higson 84]

Cast some blocks to put under the cast floor and put the wool around these 'feet'? Using them as supports.

[Wayne Coe 74]

Once the casting has cured and it is cast to the walls it should not be a problem. 

[Garry Keown 1,398]

I used a fire brick in the center of the floor of my forge with refractory cement over it and the ridgidised kao wool at the sides of the brick and it has held up with no degradation in the years I have been using it although I mostly use the forge for HT rather than forging duties but over 300 knives has seen it used quite a bit.

Edited January 9, 2020 by Garry Keown

[Alex W. 0]

Idk if anything changes because of this, but I opted out for a couple ceramic fiber boards as a way to spread what I have found to be 10.7kg max for full crucible and whatever is added by the ceramic fiber board.  I will be aiming for a 10" interior, but a 13" interior is a possibility.  In other words, I'll have a 10 to 13" kaowool circle on which about 11.7 kg I hope will be spread over.  I will be operating at about exactly what the kaowool is rated for ,2300F, but there will be a fairly insulative layer in between the hotface and the kaowool layer.  

[Doug Lester 400]

Like Wayne said, let the castable refractory cure on top of the ceramic matting and you're good to go.  I have castable refractory over my ceramic matting in my large forge (built out of a large mailbox) and I haven't had any problems.

 

One other thing, the ridgidizer will compact the ceramic matting and decrease the insulating capacity.

 

Doug

Edited February 18, 2020 by Doug Lester

[TerryWay 0]

A question on the subject of using a rigidizer. I'm building my 1st forge using 2 layers of 1"  Kaowool should I apply home made Sodium Silicate between the layers of Kaowool as a fixitive (Binding agent) or for go the binding between the layers and just use Satanite for top coat? 

 

[Doug Lester 400]

Ridgedizer decreases the insular quality of the ceramic matting.  I don't recommend Satanite for a top coat; flux will eat it up and it's easy for the point of a blade to poke through it.  I recommend a castable refractory like Mizzou or Kast-O-Lite.

 

Doug

[Alan Longmire 3,673]

Choice of topcoat is up to you, but the vast majority of people don't use rigidizer anywhere or for anything.  And nobody puts anything between the layers of wool.

[TerryWay 0]

good to know thanks, do ither of you gentlemen  have experience with Ribbon Burners and is the satanite a good choice for casting the burner?

[Alan Longmire 3,673]

I have not made one, but I've used one, and no, Satanite is not a castable.  It takes way too long to cure at the thickness needed for a ribbon burner block, and so will tend to crack and crumble in use.  It's really good stuff for making hamon clay when mixed with charcoal fines, it's fine for forge linings as long as you realize it will need patching every so often, and it really shines at what it was designed to do, which is be the mortar between firebricks.  Wayne Coe has some good instructions on his site, and he sells small quantities of castable refractories.  He'll probably be along soon to tell you.  

 

In my opinion, and my opinion only, a ribbon burner doesn't have any real advantages over a standard blown burner provided said blown burner enters at a tangent to the interior walls of the forge.  They can be slightly quieter, but not always.  Very long ribbon burners are great for HT forges.  

[Chris Christenberry 363]

51 minutes ago, Alan Longmire said:

ribbon burner doesn't have any real advantages over a standard blown burner

 

No cold spots in my forge with a ribbon burner............period.  Top, bottom and sidewalls.  I've seen a lot of other forges with cold spots.  I like my ribbon burner.

[Alan Longmire 3,673]

I never said they weren't good!   I just meant that a properly done blown burner is just as good.  It's that "properly done" thing that escapes many. 

[Chris Christenberry 363]