Large ceramic shell burnout kiln for lost wax - Zapins

Solid ideas. I'll see how the flame burns before mig tipping it. My main furnace burner is just a hole it a cap and it works well.

I can use the battery charger for sure.

I would burn out today but.... torrential rain. Of course. I'll probably just get it all spruced up today and do some of the stuff I was going to do later on after burning out now. Painting, door springs, grinding, etc. It is 55 f outside now.

 

Due to recent furnace upgrades to my blower assembly the car battery charger I previously used is now free for the soldenoid.

The furnace is very nearly done. Just a few more mostly cosmetic things and it will be totally done. I'll probably paint it tomorrow just before use.

I put a coat of satanite on it. One water thin coat used up 2.5 lbs. Very surprised at that. How thick exactly does the stuff need to be applied?? Is one coat enough or should I add a second coat? I bake each coat individually right?

I also added another row of spikes to the rack to support shells.

I'll weld on the wall supports when I'm done boating with satanite. Much easier to paint walls without bars in the way.

 

Damn that took me forever. Its finally finished. I edited a short video of the kiln during its maiden voyage.

 

Nicely done!

Pete

 

3rd use now. It burns molds out well but the panels are developing large cracks. It is concerning for long term usability. I am worried the panels will crack all the way through and fall out, especially the main side door.

 

Hmm that's interesting and unfortunate. The board was 2600F rated.

That looks exactly like what happened to me including the same curve direction bowing towards the flame.

Hopefully it doesn't move much more. But as it is the door won't close now because of the bowed panel. I might have to cut the board down the center to relieve the stress and then seal it with more satanite once it is on the wall again.

The good news is after 3 hours of run time I don't see any bowing of the 3/4" or 1/2" stainless steel grating or a huge amount of scaling for that matter. So that seems to have worked out so far.

 

Interesting observation about the shrinkage of Satanite. This must be a very frustrating occurrence. Not an appropriate reward for your diligent efforts!

It might be interesting/useful to accept that shrinkage and allow for it by incising the wide flat surface of the panel at intervals perhaps in a checkerboard pattern by cutting 1/4th of its thickness with an old skill saw blade or masonry blade. That would allow the shrinking surface to behave more like a bellows and not a like flat asymmetricly shrinking sheet. To do this cutting would require removing the panels from the frame. I assume doing so would not be too onerous.

How would a person figure what interval to use? It looks like a single crack occurred near the middle the wide panel. So, intuition would suggest to me that reducing the expanse from the crack to the edge to 1/3 the distance might be enough to allow the inevitable shrinkage but not overstress the board so that it cracked. So, if that panel is say 30 inches, I'd try a grid of cuts every 5 inches. Perhaps the cracking as it is occurring will, as Kelly suggested, provide adequate stress relief by itself.

These refractory materials are trying to teach us all lessons!

Added a few moments after posting: I would expect to coat the cuts with Satanite.

Denis

 

Yep I think I'll try one cut down the center along the fracture line to start with. Hopefully that fixes it. I want to stay away from multiple cuts because I've noticed that fiber blanket/panels seem to get more brittle the more flame time they see. And they would be more likely to crumble if in smaller bits.

I'm shocked at how much wax I got back. I must have salvaged 20 lbs of wax from the burnouts I did today. That's a buck a pound I can reuse. Cha-ching!

Here are some pics of the cracks. And a few pics of the burned out shells and the furnace again.

 

Sorry to see that... Now take your savings and cast some panels out of proper refractory cement about 1/2" and throw your panels in the trash. You tried, but they are shit man.
You would have been better off with monkey crap spread on some kaowool for the walls.

Kell, I'm pretty sure zap has this rig running on proPAINintheass.

 

Haha. I think I'll wait for them to totally crumble and fall out first. The panels weren't cheap. Might has well get some kind of use from them!

On the bright side of things I got the solenoid setup ready. I will connect it up to the PID soon and make a box for it.

And what's wrong with propane other than the expense?

 

Hauling the stuff. I'm forever out when I need it the most. When I moved to Texas, I tossed my propane grill in the trash. It's charcoal and mesquite for me only. The best steak I can find comes off my $30 walmart grill! Not easy getting it to go Chernobyl, but when it does, it seers the meat to a crisp and leaves the inside nice and juicy.

 

The closest thing we've seen around here is that 4 piece furnace made out of castable sections. How is that thing holding up? When I saw that one, I had the same nagging thought about thermal expansion. hmmm. Now Glen in Taiwan uses some kind of inch thick board for his little forge. (gstongs on yt) He has no mechanical fasteners, just gravity doing the dirty work. Again, a loose fit is critical. Heat does some strange things that's for sure.

 

The panels are secured by being stacked in place. There are some metal L shaped tabs to prevent the boards falling out and there is some caulking on the inside of the furnace to seal the gaps between boards but it doesn't really glue them together in any way. The steel panels are welded along all edges to the L shaped frame on the outside of the panels.

I'd love natural gas, but the other thread was at my friend's house not mine up in CT. Unfortunately I don't have a gas line, although I have seen a natural gas line in the woods while hiking not too far from my house so it seems to be in the area.

The lost PLA shell actually seems to have burned out very well. I'm really surprised. I don't hear any rattling around inside the shell at all so I assume the 1/2" to 3/4" core somehow held up to burnout. The PLA actually melted out like wax, it dripped out of the mold. It contaminated the catch pan full of wax in lumps and lots of drips of hard black plastic. I don't know if I can separate out the PLA from the salvaged wax but I am hopeful since its mixed in with about 10 lbs of wax.

I'm hoping to get most of these things cast today so with any luck I'll post photos later tonight with results.

 

Looking like in 2 to 3 hrs from now I'll be doing the first pour. Starting up the furnace now but I need to slowly burn out the refectory that I recently added before taking it up to full power. That should take about an hour then I'll crank it up for the second hour and pour.

Maybe I'll do another YouTube live casting?