Large ceramic shell burnout kiln for lost wax - Zapins

Started a new large burnout kiln to dewax my ceramic shell molds. The old one was too small for my new larger sculptures. So I figured I need a bigger one.

I am using fiber board 2600F rating, 1" thick sourced from a local kiln making shop. I'll coat the inside with 5 layers of satanite to protect the surface.

I welded up a box for the boards made from L angle iron.

I'm drawing inspiration from out back foundries for the design. I think I'll end up making a 316 stainless grating for the bottom where the sculptures will sit.

More pics as it comes along.

 

The external dimensions are 26 wide x 24 deep x 26 high. The internal ones are 24 by 22 by 24.

I'm at the a local steel supply place. Buying a lot of 316 stainless steel 1/2" and 1/8" to make a grate for the ceramic shell molds to sit on. I hope it doesn't burn up like mild steel would. Rather expensive material.

I'll be tig welding it all later tonight. Pics soon!

 

It will not burn up. It also tigs very easily. I used SS filer but you do not have to. I have some in the base of my kiln that I trun up to 2000 and it has tarnished but not burned.

Denis

 

Does it warp or keep its shape? Approximately how thick is your SS?

I'm going to use 316L tig rod for welding it. I tried welding 316 a few days back. It does weld easily!

 

Mine is in the form of 3/4": diameter rod. It has not warped noticeably. I also used it on a grate for my chimney in 1/2 rod and it did not warp or degrade there.

Denis

 

Perfect. I hope my rods will work. They are thinner so I'll cross my fingers.

 

Zap, stainless will burn up just like mild steel. You will get a little more use out of it, but not really enough to justify the cost. It's the temps you will go to and the length of time.... Don't you watch Barry Luke on Youtube?
The best defense for this system is cheap and easily made grates replaced regularly. Couldn't you get 304? The ONLY reason to run 316 is for chemical resistance and that's not you.

 

Well too late lol. Already dropped big bucks. Hopefully it lasts at least 20 melts. It says good up to 1500f. Gonna tig it up soon.

 

In my experience SS is much much more resistant to scaling than plain carbon steels. I found this to be true on my burner tube, on the original carbon steel floor vs the SS floor of my kiln and similar comparative uses.

I think my observations are not out of line with industry recommendations concerning resistance to scaling and hot strength:https://www.google.com/amp/s/www.azom.com/amp/article.aspx?ArticleID=1175

I’ll be interested to hear Zaps results. The error Outback made was he did not fab his grates and mesh from SS.

Denis

Edit: For the sake of "science" place a rod of equal diameter of carbon steel in the furnace just to see how it behaves.

Also it is noteworthy that heat treat foil (for heat treating tool steel in a kiln) is made from SS. It would be much cheaper to make it from plain carbon steel, but it would not withstand a single cycle. I have used it countless times to heat treat steel where the SS pouch emerges slightly discolored and no longer as pliable but otherwise no worse for wear. The whole reason for wrapping the tool steel in foil is to prevent the tool steel from scaling which happens pretty fast at heat treat temps but does not affect the foil. When you wrap the tool steel in SS and include a little source of carbon (commonly a scrap of brown bag paper) to occupy the oxygen trapped in the foil pouch, scaling of the tool steel is prevented.

 

Zap, did you get a fat ass tig cup yet? I currently have a #17 air cooled and run stubby gas lens on it. I've had some gas coverage issues with the biggest cup I have which is a #8. I bought some of these, but haven't gotten to try them yet. I JUST ordered them 2 days ago and paid 40bucks... Now they are 30! WTF? https://www.amazon.com/gp/product/B075ZHJ3RD/ref=ppx_od_dt_b_detailpages00?ie=UTF8&psc=1 Anyhow, ya might want to watch this if you are going to be doing any stainless work.

 

I use #6 lenses for most of my work. I get them from ebay they are like 13 bucks shipped for 10.

I did more work on the kiln. Got the doors hinging nicely and the start of the legs done. I need to add supports all over the place and then tig up the ss platform. I think I'll do a strut design with triangles so it doesn't want to warp. Will work on that tomorrow.

 

Them some cold looking welds man! You running flux core mig?

 

Nah its 25/75. Not sure what's up with the welder. Its sputtering a lot and not giving good gas coverage or good welds. I think it is a bit underpowered. I tried out a better welder at svseeker. I think the welder is an intro level welder with intro level issues.

Its turned up to max. Maybe it can't draw enough power due to the long 90 ft run of wire in the wall to reach the garage?

 

How many amps you at on that thicker stuff? I know doug has a bad ass suitcase miller.

 

It doesn't display amps on the welder. Just 1 to 4 on the power setting. I've got it maxed at 4. It's a hobart 140.

 

Yeah, I highly doubt you are getting 140amps at 90feet unless that cord is really fat. Try dialing down the wire speed so you can get the parent metal to melt. If the speed it too high, your wire cools the puddle and the welds get tall. Globbed on metal birdshit isn't what you're after. Welding is just melting 3 pieces of metal at the same time. Part A, Part B and the filler. Ya gotta just get it to happen at roughly the same time. lol. See now why I want a bad ass mig machine? I love tig, but ya need something bigger than that toy for this heavy rod. Don't get me wrong, I've welded 1/2" stuff with my 200amp htp using just a #17 torch. Many passes and plenty of cool down time. I haven't hit the overtemp yet, for an inverter, it's got plenty of balls.

 

Here's a little woopsie from today while working on the kiln. Lucky I had on so many layers and the angle grinder has a deadman switch to turn it off when let go.