Casting earpiece question

Gypsyboy

Active Hunter
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
 

tubachris85x

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

Gypsyboy

Active Hunter
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.
 

stormtrooperguy

Sr Hunter
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:

 

Gypsyboy

Active Hunter
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
 
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