Ok everybody, lets put this one to bed. The steel floor in my kiln has always caused issues. I had straightened it and braced it several times but with all of its downfalls it worked. We often have guests (read potential customers) at our pours. It made a good show to stick the molds into a hot oven and watch the wax flow. I got into the habit of not dewaxing until pour day so guests could better see the process. It was not necessarily a good habit. It is best to preform the burn out, let the molds cool, and rinse out the interiors with water and look for cracks. Then the molds can be reheated at pour time. But I had done it the "wrong" way so many times my mind was stuck on making the burnout preheat one continuous activity.
This wrong way was blinding me to several solutions to the steel floor problem. I have seen the light! My new steel grating should withstand dewaxing temperatures. After dewaxing and cooldown the molds will be removed, the steel floor insulated, the molds reinstalled and the steel floor will be protected from the high temperatures. I think it sounds good anyway. Time will tell.
Way to keep swinging Barry. Especially a 20lb sledge! Too bad ya couldnt have worked out a 1 step process. I like the new setup. Shielding that steel grate you made with that insulation stuff is a good idea. PM me some contact info, I'd like to stop in soon and say hello.
Here it is ladies. Dimensional wax burnout at 2am. Enjoy the show! lol
Mr WHOOWANG would be proud. Or not! I wonder how much of the slurry is washing off with the dip in the drink? It will be interesting to see what happens to the strength of the shell after vitrification. If it even vitrifies? lol I'll hit the thing with a weedburner tomorrow and see what happens.
I thought flying in clapped old single engine airplanes in the weather was frightening.....
Thanks for the WARNING gang! WOW WAS THIS HOT! I used the surround off an old clothes dryer to help contain the heat and hit this sucker hard and fast. I'm glad I put on my chrome gear. Recover wax? HA, that was a joke.
Whats the secret to keeping the HF weedburner running? I used the valve to put out a foot long flame, then the trigger for blast mode...
Here's the carnage. My brain must have been in my shorts, wtf was I thinking a plastic container filled with water to catch the wax? lmao.
My 25buck Kiln hits 947 Celsius on just 3 elements. I'll hold off installing the new ones until a 2nd one pukes out.
Took it to orange heat, left it there for about an hr. Hope that was long enough. I have no idea...?? I'm going by what machinemaker above said.
Here the kiln has been off for 10minutes. I'll let it cool down with the lid closed....
Boys, I think there is something to this water dewax method. I can't see any difference between the part of the cup that went for a swim and the rest that spent 2 mins in a fiery hell!
Last edited by jagboy69; 02-20-2017 at 02:26 AM.
Wow, you have been busy Jason!
Im liking the "mould in water" experiment. I used to put small shells in a pressure cooker to dewax if i only had one to do and this worked fine but was always restricted by the size of the small pressure cooker. Ive never tried the "drop it it a pan o boiling water" trick cos i was worried the shells would break down. Looks like you may be on to something. Your "hit it with a torch hard" looked exciting, ive been there and its amazing how hot a bit of wax can burn isnt it?
Your kiln burn out looks to have vitrified your mould, totally clean inside and out with no carbon.
One thing i would check if you are thinking of slinging some metal in it, i noticed on your weed burner video that there was a bit of flame coming off the top corner (left side) when the mould got hot. This sometimes means there is a crack around there and the wax is seeping out and ignighting. It could just be burning shell but definitely worth a check. Cracks tend to appear around sharp edges and corners, the usual weak spots.
Im interested in the results of this water bath thing. It would be so easy to sling several shells in a large tin of hot water to reclaim the wax.
Keep up the good work!
Thanks john. This morning there was a nice layer of hard wax on top of the water in that pot. Thanks for the heads up on the potential crack. I'll water check it and revisit the exciting video footage. I'll probably pour this test piece with aluminum tomorrow for shits and giggles. A practice run for me and the kiln would not be a bad thing at all. If I do find a crack, I suppose it's a quick dip in the slurry, dry and then revitrify in the kiln prior to pour time.
I do see an annoying flame that keeps happening in the top left corner.. Uhhh oh...
Yep, a quick dip in the slurry (or dip a small paint brush in the slurry and slap it on the crack with a half inch overlap) should be fine for hairline cracks on this test piece. If i was reinforcing something important i would mix a bit of slurry with a bit of stucco flour to mak a paste and put that on, this way the slurry isnt so thin that in can flow into your shell. If i was really worried i would let it dry and put another coat on top.
Dont need to bother with the kiln tho to vitrify, just hit it with the burner for 2 minutes till the fill turns white. I usually apply the slurry to cracks straight after burnout so when i paint it on it hardens instantly. If its still not white after a minute i blast it with a torch for a minute. Usually i dont need to as i will be preheating them anyways for the pour and this does the trick.
Quick edit, just reread your post. If you are reheating to do the pour you dont really need to wait for the filled crack to dry. It wont make much difference if its dry or not before reheating to pour as long as it gets up to pour temp.
Good stuff John. I gotta say with this test piece, it was a pretty VIOLENT affair. And this didn't have a 1/3rd the wax of my little jewelry box. (Might want to warn my buddies at the fire department...lol)
The dip in the hot water was such a nice and calm affair. I saw on youtube some of the jewelry guys steam their waxes out. My family in the jewelry business doesnt bother and proceeds straight to burnout. You said you steamed your smaller stuff out. I'm not opposed to building a large rig to accomplish the same task. Are we just talking about a large pot filled with a few inches of water and the shells parked on a grate a few inches above the boiling water? Sounds pretty benign to me and a safe way to pull this off and actually collect the wax. My method today was total BS trying to collect any wax. Maybe it was the way I concentrated the heat on the opening instead of the body of the shell. What do I know, I'm a pilot. That stands for Poor Intelligence Lots Of Training.... lol
Yep, i have done both the "full pressure" experience with the sealed lid with an inch of water in the bottom and the mould standing on a wire shelf, and the slightly more haphazard "mould too big to get the lid on so fabricobbled some extra height with a wicker basket wrapped in aluminium foil precariously balanced on top to keep the steam in" set up. While they both worked the sealed one was done in about 10 minutes and the second took over an hour probably, im guessing cos it felt like forever.
Originally Posted by jagboy69
Quick tip- wicker baskets get soft when they get soaked in steam! Obvious now, but back then i was young, needed the money and at that experimenting stage....cough... i mean rushing to get the job done!
The reason i steamed the wax out was i was using someone elses electric kiln to burn out at the time and didnt want to kill their elements with the smoke from the wax.
I actually started my casting thing through jewellery making, its just got out of hand. I thought i could handle it but it creeps up on you. You start making rings, pendants and jewellery boxes and before you know it youre looking at a life size figure commission and going "yeah, its only the once and i wont inhale!" Jewellery making was my "gateway" drug! Let that be a lesson to any of you out there that think "it wont happen to me!"
You were right to initially concentrate the heat at the base, you need to get that running to clear the cup n sprue to get the rest out. Then you work upwards. Your torch seemed quite aggressive, blasting the burning wax about quite a bit and blowing the flame out. Is it self aspirating? If so maybe back off on the gas a bit. If it uses additional air maybe back off the air to keep the flame going on its own without needing the wax as a pilot light. And keep the collection pan (an old large frying pan works for something this size for me) a fair distance from the bottom of the mould to give the falling wax a chance to cool a bit. Once that thing catches there will be exciting times ahead!
And when you pour your metal have the mould standing in a bucket of sand just in case.
When do you think youll be pouring the box Jason?