Postby rsaldivar » Fri Sep 15, 2017 12:48 am
so Im so behind in my work it wont be a while till I get around to test casting but because I see so many fail casting I had to try one test cast , but this is brass ( dont think it matters for surface testing )
Yes I used way many spruse because this was a wire setting and I thought every wire needed a feed , would rather wrestle with cutting off sprus than have non fills , another thing is I was too tired to cast at midnight so I turned off the oven and turned it back on in the AM , which is why I think the Flash exists , I totally believe like it was said that every resin has to be cured extremely well to produce the best castings , that said , I will share what I did and what I suspect .
(weeks ago) So after curing I wash in acetone , swish about 8 times or so , then with compressed air blow it off , I immediately UV cure for 1 or 2 hours , then in my oven at 120 f over night , I haven't had a chance to cast in a while with my mishap with the water heater and the model stayed out for a couple of weeks , ( this is worth noting because of what I suspect ) then this mourning I casted and this was my results .
so in another forum someone suggested that aging was the key factor in all resins for perfect results ( still after whatever you do for curring ) ( obviosly the best cure , the better ) annealing was one form of ageing because ageing took to long ( 2 weeks or so and not practical for customers ) and heat may have something to do with ageing which is why microwing was working for some people and that guy who wrote that paper on vacuum curing , he did it with heat too , however I am convinced that aging after curing makes for a successful cast almost every time , in other words fully cured with time all the way to the core of the piece , maybe by a window for the 2 weeks ?
I used plasticast R&R 39 /100 because of all the wire work , ( usually I use 38/100) , I did it with 1.5% boric water ,
bench sit for 3 hours total, after 1 hour removed the base and with a fan hitting the crusible for the other 2 hours
in at 300 f for 3 hours
up to 700 f for 1.5 hours
up to 1350 - 1450 for 3.5 hours
then thats when I turnned it off for the night
but would have waited for an hour or so ( maybe 2 ) down to 850 f to cast , I use a necraft centrifugal , I melt the metal first , then when its almost all liquid I put the crucible in and melt to complete liquid , then let it go
I think the surface is good , the flash because I turned the oven off and on again
hope this helps
oh and I belive that it should be 2 hours curing and overnight in heat , not the other way around , but thats just my guess
