udog
Well-Known Member
Hi
I´m into molding and casting a pair of babies (reborn kind, 8-12cm). I´ve already molded them with PlatSil 73-15.
And am casting both with Smooth On´s Colormatch 325 Slow and a FormX resin called Rhino (slow version).
Silicone was degassed prior to pouring, but not pressured potted. Resins are pressure potted when casted.
I´m running into several problems. 50% of the castings have to be discarded due to different reasons And it´s starting to drive me nuts.
For what I´ve read here in the forum molds that will be used in a pressure pot should have been put in a pressure pot too or you can get distortion when pressure pot casting. Well yes, I´m experiencing these distortions.
Although I degassed the silicone (molds of 1 and 2kg each, powerful pump), most probably there are still bubbles left and therefore the distortion when casting in the pressure pot. I mixed the silicone with a mechanical mixer, which introduces much air in the mix, I have to try mixing by hand I guess. Would that help?.
Is it a must to put the silicone in a pressure pot then?. It´s a narrow one, I could have problems fitting the big mold in.
The other thing is that Platsil 73/15 is shore D15 hardness, might be too soft for the pressure. Anyone uses it?. Should I go for a D20 shore?. The problem there is that it´s viscosity is higher and I need it to be as low as possible. Any suggestions?.
And also, the figures have lots of details that in the negative end in zero, peaks in the mold etc. which tear off after little castings. I´m in the dilema of using a harder silicone, but not sure it would stop happening or if it would be worse...and the viscosity issue remains.
What silicones could you recommend for this kind of small detailed castings?. I can get my hands on most Smooth On and Polytek products here in Spain. But can´t find anything better than what I´m using.
Thanks in advance.
I´m into molding and casting a pair of babies (reborn kind, 8-12cm). I´ve already molded them with PlatSil 73-15.
And am casting both with Smooth On´s Colormatch 325 Slow and a FormX resin called Rhino (slow version).
Silicone was degassed prior to pouring, but not pressured potted. Resins are pressure potted when casted.
I´m running into several problems. 50% of the castings have to be discarded due to different reasons And it´s starting to drive me nuts.
For what I´ve read here in the forum molds that will be used in a pressure pot should have been put in a pressure pot too or you can get distortion when pressure pot casting. Well yes, I´m experiencing these distortions.
Although I degassed the silicone (molds of 1 and 2kg each, powerful pump), most probably there are still bubbles left and therefore the distortion when casting in the pressure pot. I mixed the silicone with a mechanical mixer, which introduces much air in the mix, I have to try mixing by hand I guess. Would that help?.
Is it a must to put the silicone in a pressure pot then?. It´s a narrow one, I could have problems fitting the big mold in.
The other thing is that Platsil 73/15 is shore D15 hardness, might be too soft for the pressure. Anyone uses it?. Should I go for a D20 shore?. The problem there is that it´s viscosity is higher and I need it to be as low as possible. Any suggestions?.
And also, the figures have lots of details that in the negative end in zero, peaks in the mold etc. which tear off after little castings. I´m in the dilema of using a harder silicone, but not sure it would stop happening or if it would be worse...and the viscosity issue remains.
What silicones could you recommend for this kind of small detailed castings?. I can get my hands on most Smooth On and Polytek products here in Spain. But can´t find anything better than what I´m using.
Thanks in advance.