Casting earpiece question

I'm sorry if this has been brought up elsewhere, but I did a search and come up with nothing helpful.

I'm looking for input from those who have made molds and casts for the earpieces. I'm particularly concerned with the rangefinder ear cap - the one with the little prism-shaped jog at the back. I expect this will need to be a two-piece mold, and I know how I would go about making it, but I was hoping to get some input on how to do it from those who have done so already.

This is what I'm thinking; place earpiece front downward in molding box, pour silicone up to the edge of the "D". Let it set up and add some keys with small bits of pre-cured silicone around that base. Allow to fully cure, put mold release on surface of silicone and pour the remaining portion of the mold. That all makes sense, but do I need to have a channel running anywhere into/out of the mold? Should I leave a hole for pouring, or for overflow?

GB

Nothing? OK, well I'll just go ahead with my plan. I'm sure it'll work out.

Sorry GB... never done any casting before?
But your plan sounds workable? :facepalm

Could you MS-paint your explanation? Its probably just me, but Im not 100% sure what your trying to suggest for molding :/

Essentially I'm just talking about a two-part mold - front and back of the earpiece, so I can get the prism shaped part at the back when I cast it. I have no problem making a mold, my only question is should I make it with a pouring hole in it? And if so, where should I put the hole? I've done lots of molds and casts, but never really made a two-part mold before.

you need some sort of pour hole for any 2 part mold, else you won't get any resin in there

i'd put the pour hole on the inside of the earcap, so that it's concealed when you are done.

what you describe sounds good to me. just add in a pour hole.

when i've done 2 part molds, i've used a wood dowel for the pour hole, attached to my piece with a dot of modeling clay to prevent the silicone from leaking under the dowel.

it ends up looking like this:

Excellent! That's exactly what I was looking for and precisely what I wanted to know. It's good to know that what you described is just what I had planned to do... even down to putting the pouring hole on the back of the earpiece. I was mostly just wanting to know if there was anything in particular that worked especially well.

That casting you posted a pic of looks really cool, by the way.

Thanks,
GB