Lol, Yea... Im suffering right now from a cold that is really kicking my ass. Otherwise Id be doing the burn out right now...
Been an hour on a very low heat just to soften up the plastic. All ready see one crack in the pouring cup. Not that big of a deal, but hoping no more form...
Dave, will this flow like wax, or does it have to be burned out like block investments of plants or insects (bumble bee)?
Surprisingly there is a point / temperature where the plastic does flow out. But you still need to run through a burn out cycle the same as you would if using block investment casting but up to a wee bit higher temperature. I just completed the burn out at 6pm. Maximum temp was 930 C and held for 1 hour. Now I'm in cool down mode and will inspect the shell, clean it out, and refire it tomorrow before the pour.
Does it stink like shit? Hope you film the pour. Do it in flip flops and a jock-strap. I hear that's the best PPE these days.
There is a smell to it, but it's less than what wax is. I've burned out abs as well, now that shit will stink up a city block. Was planning on wearing my pink bedazzled tutu and nothing else for this pour ...
remember polyester is flame retardant at cast iron temps...... You should be safe! Just make sure the camera is rolling and your wife knows how to upload your stuff to YouTube ahead of time just to be sure.
Cool down complete, there is a couple of cracks in the pouring basin, i probably should have wire wrapped it (hind sight is 20/20) but everything else looks good. No rattling or debris falling out so i think the investment held up ok. Thats another good reason for a top down pour, if there is material in the shell you can get it to shake/ rinse out... Now as long as the investment holds up to the iron... I'm thinking it will because it seems to be the same binder, just different sand and viscosity... Sorry for keeping you all in suspense, I could have rammed this in sand in a day and been done with it, but that would have not been much fun for me....
Will you burry and vibe the shell in sand and preheat the whole shebang before pour? Extra support! Best, Kelly
I thought about that. and thought about wrapping the shell with ceramic blanket as well. But it was mostly to hold the heat and not for support... This time around im just going to go for it !!
No reason to vibe it... But standing it in a bucket of sand is cheap insurance for your feet when that sucker springs a leak like Zaps bird did! Hurry up and pour the thing!
Now that would be interesting, but not in a good way. You could get a lot of views on y-tube with that. .
Ever try it? You might be surprised. If you did so, you'd never again loose a casting to a ruptured shell. Burying in sand will take much longer to heat and also much longer too cool, which gives you plenty of time pour but also a long time for the casting to remain in liquid state.....could be helpful thing for iron. Best, Kelly
Nope. I haven't lost a shell yet. Ceramic shell is tough stuff once it's been fired to 1700. David should have wrapped in ss wire between layers because of the pla. Thinking about this, I bet hitting a layer of wet slurry with some chopped fiberglass mat would accomplish the same task. It's the thin edges you have to watch out for with shell when you have a large side wall that could blow out due to the weight of the metal. The art foundries that bury shell in sand do that to preserve temperature when they have 20 shells to pour at once. No time to vibe.
Better check the melting point of the fiberglass first.... I dont even think S glass will take those temps....
