Mold Making

Okay, John and Cynthia and Margot,

I’ve purchased some Silastic J and I’m ready to go, going to do
the mold with the direct contact, since I don’t have anything to
vacuum it with. The package says 10 parts to 1 part, by weight,
and guess what? No scale! All I have is a kitchen scale. Will
that be accurate enough? Now that I am ready to go, would
appreciate specific pointers, if you’ve time.

Would the kind poster in North Carolina send me another note? I
saved your note, but not the address! Woops! Thanks.

-Elaine

Elaine,

I have never used Silastic J but from the name it sounds to be a
silicon and the J stands for some level of hardness(softness). The
need for accuracy in weighing this stuff is usually not critical,
but you have to be pretty close. Might try a balance scale (2 pans
on opposit ends of a stick with a pivot ((string?)) at the center
point). Use 10 things of equal weight (pennies, quarters, nuts,
bolts, ??? and weigh out the 10 parts then remove 9 of the
counter weights to get the 1 part weighed. Not the greatest but it
will get you going. Most silicons can be stored in the freezer for
a number of days once mixed, something to keep in mind if you mix
too much. (There may be some silicons that this freezing will NOT
work on as there ar 2 main types of catalyst used and one may not
"hibernate" in the freezer.

Use a release on your frames and your piece. Tefelon sprays work
great as they go on “dry” but silicon spray will work too (don’t
over spray/wet the thing being sprayed. 2 light coats better than
one heavy.) The hotter the ambient temperature of the work
area/silicon material the faster it will go off. Weigh out the 2
parts, mix them VERY WELL but don’t whip in any extra air and apply
it using a brush, trying to get all of the bubbles out of the
detailed areas (you might try a blast of compressed air after you
get the first bit of a coating on the piece as the air will pop
many/most/all of the small captured bubbles). Finish adding the
rubber material to the piece and wait til it sets up. I you are
going to make a 2 piece mold turn over the master and first 1/2 of
the mold to put on the second half, be sure to spray the surface of
the first half with release before applying the second part
material.

If you need more help, please feel free to ask.

John and Cynthia/MidLife Crisis Enterprises
Maiden Metals/C. T. Designs/ Bloomin’ Wax Works. etc.

PO Bx 44, Philo
CA 95466
Ph 707-895-2635 FAX 707-895-9332

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