I’m relatively new at this and have not even attempted to cast anything in years. Here’s the question: Does anyone make a relatively low viscosity casting resin with a pot life of over 5 minutes? I just need to make 4 rather small 0.25 x 0.5 inches but I need something that will flow easily. What about material for the mold that won’t be mostly air bubbles? TIA
I’ve used Smooth-On products for the past couple of years
They make some urethane resins with with three to 20 minute pot-life I’ve used the three and seven minute products. When mixed they are watery-thin and flow well. I use open-face and some small cavity molds. They flow into the mold well (if its a well designed mold that doesn’t trap air). Take care in mixing to minimize air entrainment. A sweep with a toothpick around the mold seems to free any trapped surface bubbles.
http://smooth-on.com/liqplas.htm
I also use Smooth-On’s RTV products. My current favorite is OOMOO-30
Could’nt suggest a better line of polymers, than Ed’s reply about "Smooth
on" know them well. They supply a myriad of compounds, including a
wild elastomer PMC724, a finicky mix with a 700% elongation rate.
However I have used a sort of poorman’s deairing pump. In a closed
box mold, carefully fold the activator into the silicone, introduce as
little air as possible. Do this in a paper cup, with mold at floor level.
Place your cup as high as possible, support the vessel so it’s floor is
open, with a clear shot at the mold. Cut a hole in it’s bottom, and
let a thin stream drool out onto the mold. The hole must be big
enough to empty it before it’s pot life is over, yet small enough to
stretch the RTV into athin ribbon, this is what snaps the gas out.
A jury rig,? yes, but i’ve made some very dense mold this way.
That’s the “bomb’s away!” method of pouring, and is reputed to work really well.
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