Airflow in burnout

[SWDesign]

Hi everyone. I'm just starting with the Solus printer and finally have good models to cast. I've been having models printed for me for a few years and have used a few tricks to get better castings. I have found even better ones on this forum. Thanks so much for that.
I have a question about improving airflow in the kiln. I have been reluctant to drill holes in it as I may damage the elements. One article I read a couple of years ago, suggested letting the resin and wax flow out and then flip the flask at 800 degrees. That's what I have been doing but still don't have the best results. Thanks so much for mentioning vacuuming the ash, that may take care of it. I'll be switching to the emerald and I'm wondering if it will need as much special care and if the holes and air pump will be necessary.
Thanks for any and all input, Sherry

[Archerm]

Sherry what investment are you using? I don't pump air in and haven't had any problems . I do flip my flasks like you do. Mark

[SWDesign]

I'm using plasticast and I do a pretty long cycle. I'm going to up my top temperature to 1400 to see if I will get rid of the dark stain around the spru. I hold at the top for 3 hours and I use small flasks. Thanks so much, I'm glad I won't have to mod the kiln. Sherry

[Jewelermdt]

My oven gets air flow from a vent on top and with a small chip in the front of door panel. I have put my flasks down and when casting the cherry I did vacuum the flask. The green burns out much cleaner. No ash to worry about. I do regular wax and green resin burn out at the same time with same burn out settings as I did for wax only. Using regular Satincast investment.

[SWDesign]

That sounds great. I guess this will be my only cherry casting. Although, it doesn't sound too difficult to cope with anyway. I love the surface on these models. Yeah, Solus!

[Jewelermdt]

With the cherry I still had the stain. Use a shop vac to suck out the ash. Doesn't take much time, just a few seconds.

[SWDesign]

Well, my casting went better than I have come to expect. I think vacuuming is the answer. Yeah!
Something is up with my kiln though. It stopped before it was at casting temp and it kept shutting off instead of holding. I'll read up and see what is wrong. It was a windy day and may have been electric fluctuations. Sherry

[wawatobi]

I've been getting very good results in my casting with both B9 cherry and emerald. I have a 30 year old kiln and an analog controller. I have a small vent in the door of the kiln and a larger one in the top which is vented with a pipe into a chimney. I don't bother to turn the flask up. I don't vacuum. I generally use a 8 hour burn out. BUT!!! I start burn out with a hold at 250 F for two hours before the 8 hour cycle. I got this info from Stuller and it has worked very well for me. I don't know the theory but I think it may be as simple as the lower temp hardens the investment before the plastic begins to burn. Also, I use plasticast for everything now. I keep the phosphate bonded investment on hand for special jobs. Oh, even more important, i leave my models in ultraviolet light for up to
seven hours. Models have to be very very well cured for good casting results.

[M-Williams]

Curing is an important step in a successful casting. I can't stress this enough. William.

[Wdshea]

cherry is not a very good castable resin, i've had pretty good results, but the B9 yellow is so much better.

crisper lines, and burnout is almost idiot proof. with a good burnout you shouldn't need to get to 1400F.

also, if you have an accurate, calibrated pyrometer that will help you significantly. after using a high temp thermocouple i found that our kiln was overshooting by 60*F!