How To Cabosil for rigidizing ceramic blanket?

[Burn Ointment]

I am a noob at this and am going to build a forge. I have most of the stuff already or on order. My question is can I use Cabosil for rigidizing the ceramic blanket for safely locking in the dangerous particles? I will being using Kastolite and Plistex over that.
Thanks,
B.O.

 

[Stacy E. Apelt - Bladesmith]

If covering with refractory, rigidizing isn't necessary. It doesn't hurt, though. I don't see why Cabosil would not work.

 

[Ken H>]

I would never think about cabosil, but I see the melting point is around 3100F, darn that's hot. As Stacy just posted if following up with Kastolite and Plistex I don't see the need. I've got around 5 gal of Cabosil on hand that's left over from boat building days. I still use it for thickening agent in epoxy.

 

[Burn Ointment]

If covering with refractory, rigidizing isn't necessary. It doesn't hurt, though. I don't see why Cabosil would not work.

I watched too many videos I guess and it was mentioned as a safety concern too. I gathered the rigidizing was done to make it easier to apply the refractory. I am guessing the Kastolite can be spread with a putty knife? Or is it just for pouring?
Thanks

 

[Burn Ointment]

I would never think about cabosil, but I see the melting point is around 3100F, darn that's hot. As Stacy just posted if following up with Kastolite and Plistex I don't see the need. I've got around 5 gal of Cabosil on hand that's left over from boat building days. I still use it for thickening agent in epoxy.

I have been researching a lot and trying to avoid paying too much for high dollar things when there is a viable lower cost substitute. Being new at this, I will likely be making more than a few forges as I progress. When I watched videos with people smearing whatever refractory they were using (Satanite etc), directly to the soft ceramic mat, I figured the rigidizing was to make a firmer surface to make it easier to apply.
Thanks

 

[Stacy E. Apelt - Bladesmith]

Yes, that is what rigidized does.
In most smaller forges, the wool blanket can just be covered with the refractory.

I usually put a waterier coat of satanite on first and let it dry, then the regular thickness refractory coating is applied. I use rubber gloved hands to apply the refractory. Long paint stir sticks can be used to smooth areas that need a touch-up.

Pouring a liner works very well if you can make the mold from something like PVC pipe. You want to cast a liner about 1" thick.
Cut the inner core into three sections and place them around something to keep in place (a fat pool noodle works great). Use electrical tape on the ends to hold together.
The outer shell of the mold can be two pieces of PVC pipe and taped together with duck tape. Place the two shells over each other with the bottom on some clay or putty, and pour about an inch of refractory down the void. This will keep the two mold pieces properly spaces. Adjust the two pieces to be evenly spaced.(temporary wooden spacers help) and let that bottom seal cure a while, then pour the mold full to the top.
After the refractory has cured, remove the inner core and three pieces of mold, then remove the outer shell. Let cure for a week, then wrap with the wool and enclose in the forge shell. Sheet metal makes a fine shell for a cast liner forge. Firing a cast liner with the burner to finish curing it is a long slow process, but once fired it will be very robust.
Once heat soaked in use for forging, the chamber will stay evenly heated quite well. Cast liners take a lot longer to fully soak. About 15-30 minutes is normal, depending on the thickness and chamber size.

 

[Burn Ointment]

Yes, that is what rigidized does.
In most smaller forges, the wool blanket can just be covered with the refractory.

I usually put a waterier coat of satanite on first and let it dry, then the regular thickness refractory coating is applied. I use rubber gloved hands to apply the refractory. Long paint stir sticks can be used to smooth areas that need a touch-up.

Pouring a liner works very well if you can make the mold from something like PVC pipe. You want to cast a liner about 1" thick.
Cut the inner core into three sections and place them around something to keep in place (a fat pool noodle works great). Use electrical tape on the ends to hold together.
The outer shell of the mold can be two pieces of PVC pipe and taped together with duck tape. Place the two shells over each other with the bottom on some clay or putty, and pour about an inch of refractory down the void. This will keep the two mold pieces properly spaces. Adjust the two pieces to be evenly spaced.(temporary wooden spacers help) and let that bottom seal cure a while, then pour the mold full to the top.
After the refractory has cured, remove the inner core and three pieces of mold, then remove the outer shell. Let cure for a week, then wrap with the wool and enclose in the forge shell. Sheet metal makes a fine shell for a cast liner forge. Firing a cast liner with the burner to finish curing it is a long slow process, but once fired it will be very robust.
Once heat soaked in use for forging, the chamber will stay evenly heated quite well. Cast liners take a lot longer to fully soak. About 15-30 minutes is normal, depending on the thickness and chamber size.

Good info. I guess it will make more sense if I see this in a video or pics. I am referring to the pvc pipe shells and pool noodles. I was just going to use a freon tank and am still wondering if I should cut holes in both ends or just one? And the burner angle and where to place it will be my next question. Through the top at 12 o'clock or 9, 10, or 11 o'clock? And straight in to the center or have the flame hit the curved portion?
Thanks

 

[Stacy E. Apelt - Bladesmith]

Both ends - You can block it off with firebricks if you need to.

 

[Burn Ointment]

Ok great. I am going to use "D" shaped holes and on the flat part will be the bottom of the opening. I have a freon and a helium tank and will go with the helium tank so I don't have to worry about sparks and hot freon. When I get around to build #2 I will drill a hole in the fron tank and fill it with water first.
Thanks