Re: Any ideas as to what is causing this 14kW
Posted: Sun Feb 11, 2018 11:27 pm
printcast wrote:I reached out to a very experienced B9 resin caster who informed me that he thinks this issue is remaining resin ash. He said he sees this sort of thing fairly regular but with a laser welder is able to repair these things. He also said that he sometimes makes a wax sprue vent from the highest points to a spot on the rubber base away from the button so that he can vacuum residue through and out.
In your first photo that look like ash to me. If you have no problems casting other metals with B9 resins...then as others have said probably ignore this....you have a basic casting issue not related to resin burnout.
The furthest points burn out the hardest as they get the least circulation inside the flask. It is also sometimes the end point to where your metal pushes the ash. You need to get more air into your flask to assist in burnout. Try opening the oven door every now and then and flapping some air into the oven. Crude but I still do this.
JewelleryExpress on the Asiga forums was one of the first to use that loop vent method. He prints with B9 resins. AFAIK he did not vacuum it he sprayed compressed air in one side of the loop so that it forced the ash out the other side. When you do this you should notice that the inside of the flask reduces in redness. It is important to make sure that you give the flask time back in the oven from there to regain its temperature and also be hot enough to burn any remaining ash with the assistance of that fresh air.
edit: Forgot to add .......that one thing I do not like about spraying compressed air into that loop method is that I feel it can sometimes push the ash further into hard to burn areas of your flask like the under rails of your ring or the claw ends.
I find trying to vacuum a sealed flask akin to jamming the vacuum with a cloth. It does very little. I think this is indicated by very little colour change to the inside of the flask after doing it. If the vacuum was indeed sucking the inside of the flask it would cool to a degree IMO.