Jeff Longtin on mon 3 nov 03
A seldom addressed issue in most mold making books I've seen is the issue of
mold keys. Mold keys are those little bumps that protrude from one mold part
that fit into little holes on the other mold part (for the sake of reference,
key and key hole).
In my early years of making molds I would simply use a carving tool and carve
out key holes after the first piece was poured. This worked well enough but
it tended to result in larger-than-necessary key holes and very UNsymetrical
keys. (This is especially noticable when making small molds.)
A few years into it Don Frith came out with his book and all the molds
pictured had these very professional looking keys. I wondered, "How does he do it,
surely he doesn't spend THAT much time carving out nice key holes, does he?".
(If I'm not mistaken I think he recommended some sort of gizmo's that you could
buy that would automatically do the job for you?)
But that seemed like too much work and definitely too much money for such a
simple problem.
So one day I'm looking around the studio, wondering what I could use to make
nice symetrical round keys and it hit me...steel washers. Only have about
10,000 sitting around the studio so I thought what could be better. I have them in
various sizes so I can size the key to the mold and they have nice rough
edges so they do a good job of gouging the plaster.
Then one day I made a mold out of Densite, a form of gypsum cement, and I
must have spent ten minutes gouging out a hole. (I needed to find some way to
increase the pressure I exert on the washer to give me better boring
capabiilities, holding it with two fingers was not cutting it.)
And it hit me again...a vise grip. With the vise grip I can clamp down on the
washer and use it, the vise grip, to increase downward pressure. (I push down
with one hand while turning with the other. Much like old world drills.)
With the washer and vise grip combo I can drill into almost any kind of
plaster or cement all the while making nice symetrical round key holes.
Of course its a somewhat trivial aspect to the greater difficulty of actually
making the mold but it does result in a very professional looking mold (and
its quick!)
Had to figure out some way to mitigate the old, "Wow, you sure charge alot
for a mold", kind of comments I used to get. Making symetrical keys was one way
to do it!
Take care gang
Jeff Longtin
Snail Scott on mon 3 nov 03
At 08:35 AM 11/3/03 EST, you wrote:
>In my early years of making molds I would simply use a carving tool and carve
>out key holes...[then] it hit me...steel washers...I needed to find some
way to
>increase the pressure I exert on the washer to give me better boring
>capabiilities, holding it with two fingers was not cutting it...
>And it hit me again...a vise grip....
I learned the washer trick from Neil Fryzer in
Santa Fe. A nickel also works in a pinch. (He
clamped the washer in an old-style hand-crank
drill.) Lately, though, since I don't do molds
for public sale or for mass production, I've
gotten a little sloppy and casual. I do most of
my plaster at the university where I work, (out
of my small studio) ;) where they keep a bin
of cheap metal pie servers as all-purpose plaster-
shaping tools. (They resemble a small mason's
trowel, but with a round tip.) The round tip has
about the curvature of a quarter - bigger than
strictly necessary, but ready to hand, with a
sturdy wooden handle. When I leave the Land of
Pre-Provided Plasterworking Pie-Servers, I don't
know that I'd make a special effort to acquire
my own, but if I saw one at the dollar store or
some such, I'd probably snag one to use.
-Snail
John Rodgers on mon 3 nov 03
Nice tip, Jeff. I will have to try it. I have been using "Natch" knives
for a long time to make key holes.
Regards,
John Rodgers
Chelsea, AL
Jeff Longtin wrote:
>A seldom addressed issue in most mold making books I've seen is the issue of
>mold keys. Mold keys are those little bumps that protrude from one mold part
>that fit into little holes on the other mold part (for the sake of reference,
>key and key hole).
>
>In my early years of making molds I would simply use a carving tool and carve
>out key holes after the first piece was poured. This worked well enough but
>it tended to result in larger-than-necessary key holes and very UNsymetrical
>keys. (This is especially noticable when making small molds.)
>
>A few years into it Don Frith came out with his book and all the molds
>pictured had these very professional looking keys. I wondered, "How does he do it,
>surely he doesn't spend THAT much time carving out nice key holes, does he?".
>(If I'm not mistaken I think he recommended some sort of gizmo's that you could
>buy that would automatically do the job for you?)
>
>But that seemed like too much work and definitely too much money for such a
>simple problem.
>
>So one day I'm looking around the studio, wondering what I could use to make
>nice symetrical round keys and it hit me...steel washers. Only have about
>10,000 sitting around the studio so I thought what could be better. I have them in
>various sizes so I can size the key to the mold and they have nice rough
>edges so they do a good job of gouging the plaster.
>
>Then one day I made a mold out of Densite, a form of gypsum cement, and I
>must have spent ten minutes gouging out a hole. (I needed to find some way to
>increase the pressure I exert on the washer to give me better boring
>capabiilities, holding it with two fingers was not cutting it.)
>
>And it hit me again...a vise grip. With the vise grip I can clamp down on the
>washer and use it, the vise grip, to increase downward pressure. (I push down
>with one hand while turning with the other. Much like old world drills.)
>
>With the washer and vise grip combo I can drill into almost any kind of
>plaster or cement all the while making nice symetrical round key holes.
>
>Of course its a somewhat trivial aspect to the greater difficulty of actually
>making the mold but it does result in a very professional looking mold (and
>its quick!)
>Had to figure out some way to mitigate the old, "Wow, you sure charge alot
>for a mold", kind of comments I used to get. Making symetrical keys was one way
>to do it!
>
>Take care gang
>Jeff Longtin
>
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>
KHACHING@AOL.COM on mon 3 nov 03
Regarding the post : Date: Mon, 3 Nov 2003 08:35:27 EST
=A0=A0 From: Jeff Longtin
Subject: Mold making Tip #11
=20
What I do to make keys is pretty simple. I have a selection of marbles, I=
=20
just take one and press it into my clay up clay, making a dent, and the=20
poured plaster does the rest. Simple and easy, no mess.
Elizabeth Simpson
Rancho Cordova California
Snail Scott on mon 3 nov 03
At 08:56 AM 11/3/03 -0800, I wrote:
>(He
>clamped the washer in an old-style hand-crank
>drill.)
I didn't mean that - I meant a brace. The
hand drill works, too, but the brace-and-
bit (or brace-and-washer in this case) is
wery simple, and easier to find, I think.
-Snail
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