Discussion in 'Lost wax casting' started by Mantrid, Nov 13, 2021.
Sprues and pouring cup attached and ready for ceramic shell
Some images of shell application. I used an air gun to dry the core. A tube was also used for the main core
Thought Id do my first Youtube video. Gotta move with the times I suppose
Just two very small hair line cracks, easily patched. No rattling bits inside so looks like everything is intact. Now I need to order a larger crucible before I proceed. My current one might be able to do it full to the brim but Ive put too many hours in to risk it
Cheap A8 crucible purchased.
Unfortunately working away from home until next begining of next month so long wait before i can do any casting with it. I saw a video of them making crucibles in india or somewhere like that, and they used straw between the crucibles as protection. This one had straw in it. Do they use straw in better quality western produced crucibles?
This is how morgan makes them.
Casting my shark and coral sculpture.
Excuse the heavy breathing, the camera was right next to my face.
First pour in 9 years. What can go wrong?
Wow, very eventful! (trying not to spoil it)
Looking forward to seeing the next installment.
Did you ever figure out the issue with the one burner?
No. Its a mystery.
I used it in exactly the same way to fire the shell and burn out the wax and it worked fine. The only difference was that I had the burner enter on the left side rather than the right.
The kiln really made you work for it! Looking forward to pictures with the shell off...
Yes. Panic was setting in.
Pretty good scramble with kiln burner. Made me pucker a little when the weed burner fell out and the flame was momentarily on the LP bottle. Glad you were there to quickly remedy that. Hopefully the rest of the casting is there and you can cast and graft a shark onto the casting. Seems odd since it didn't fill since it was the bottom of the casting. Air locked?
Been sand blasting it today. Apart from the shark and a couple of minor issues it cast really well as far as the detail is concerned.
Yes I think you are correct blockage of the vent is the probable cause trapping air in the back half of the shark. The only vent was a very narrow space where the tail made contact with one of the corals. The whole of the main part of the shell must have filled up with metal before all the air could escape throught this narrow passage.
Some pics of the casting. Not cleaned up fully as I dont have any proper blasting media at the moment. Just used normal sand that couldnt quite get into the smaller crevices.
The defects close up
The shark didnt fill. The vent for the air was too narrow and probably got blocked
The stub in the centre should have had a branched coral on the end
The outer leaf of this coral is incomplete and the blob on the next leaf in shouldnt be there.
The lip of this sponge is incomplete and the holes shouldnt be there.
On the other side of this flower like coral the leaf is also incomplete
Tops of these tube like sponges are incomplete
Not too bad considering the complexity of it and its my first casting for nine years.
Things to do different.
Wider sprue entering the shark
Pour at higher temp to aid filling out the areas closer to the pouring cup.
More metal so pouring cup is filled to create higher pressure.
I wont try to repair this as welding will be tricky and Im out of practice. I will use this to practice the many patinas I intend to use on this piece.
I have another wax ready for sprueing soon.
New wax prepared and sprued up and ceramic shell applied. Waiting to get back home now so I can cast it for the second time. Ive taken a few percautions tht I hope will prevent the problems of thelast pour.
Video of sprueing below
Hey wow this is a beautiful piece...geez you don't like to make things easier for yourself do you! Nice varieties of coral there, I see brain, fire, dead mans fingers and sea fans - are you a diver at all?
Nice work on the shelling though I have a theory of why you got a blockage, you've probably already figured it out but I think (and bearing in mind I've not sprued anything myself for ages so could be talking complete bollocks) that main feed into the back of the shark (connected to the fin) was maybe not pointing down enough and then an air off the edge of the fin to the cup edge might have backed up the release inside the shell at that point? Ignore me if that doesn't make sense, like I said it's been a while!
You're brave to do it all in one, I'd be too chicken for that and would just do it separately, find some way to join it together again afterwards.
Can't wait to see the next one, on tenterhooks here!!
Ah or maybe that feed was an air? Or a back fill feed?
There were two feeds into the shark (red arrows) and just one vent where the tail contacted another coral further up (green arrow). I suspect that that connection got blocked and didnt allow the air out.
I have corrected this in the new shell. You can see the whole process on my youtube videos
This video is sprueing the new wax. as is the shell video. The wax burnout and casting videos were of the first wax that failed
Yes I do dive, or rather did dive. I havent done any for many years now. but now that travel restrictions are over I hope to get away to do a bit soon. Also my degree was marine biology, again many years ago.
Hey how did the re-cast go?
I've dug out one of my patina books - there is something called 'cherokee red' that may interest you
medium ferric nitrate mix plus 1 teaspoon of red ferric oxide
hot application dabbed on, layer up.
could try that?
Maybe red ferric oxide on it's own could be worth a shot.
And for blue - bismuth nitrate mix, medium strength and windsor blue pigment dry mix. hot application, load your brush with the bismuth then dip it in the blue powder before applying to the bronze- indoors only, not stable for outdoors.
couldn't find purple sorry but maybe the pigment method could work with something like this
Disclaimer: I know nothing about the safety aspects of these chemicals, use at your own risk!
thanks for the recipies. Ivecome across the first one.
Havent done the casting yet as Im away from home until start on aug.
But should be able to give it a go then.
i will post the results
good day today. Made about 8kg of silicone bronze was very heavy (just on the limit of my single man tongs) and cast the coral reef for the second time. Its early days but I think I have a perfect casting
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