How to Mold Plastic?
11-11-2002, 02:58 PM
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How to Mold Plastic? OK here's what I'm trying to do. I don't smoke and my current ashtray sucks for mounting switches and things. What I want to do is copy the upper molding of the current astray and then design a base that's flat and allows me to mount switches for easy and descrete mounting.
How do you guys mold plastic? What kind of tools and chemicals would I need? How difficult is it? Is it hard to make plastic so it looks and feels like the GM ashtray plastic? Something sturdy like that.
Thanks,
Mike
<small>[ November 11, 2002, 03:00 PM: Message edited by: buschman ]</small>
How do you guys mold plastic? What kind of tools and chemicals would I need? How difficult is it? Is it hard to make plastic so it looks and feels like the GM ashtray plastic? Something sturdy like that.
Thanks,
Mike
<small>[ November 11, 2002, 03:00 PM: Message edited by: buschman ]</small>
11-12-2002, 01:37 AM
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Re: How to Mold Plastic? hmmm i dont know about molding put theres a product out there that you could mix with some other product to make plastic... thats for sure..
as far as molding and what the above products are called i dont know.. sorry..
you could start from there... and try searching.
Cool shift light like where its mounted.
as far as molding and what the above products are called i dont know.. sorry..
you could start from there... and try searching.
Cool shift light like where its mounted.
11-12-2002, 04:33 AM
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Re: How to Mold Plastic? Hey Guys thanks for the nice compliments. The shift light is one of my favorite installs cause it always freaks people out when it hits <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
As for the molding. I think plaster of paris(sp?) is what's needed to copy the mold of the original ashtray. Can anyone tell me how this stuff is used?
Any advice on molding plastic is appreciated.
Mike
As for the molding. I think plaster of paris(sp?) is what's needed to copy the mold of the original ashtray. Can anyone tell me how this stuff is used?
Any advice on molding plastic is appreciated.
Mike
11-12-2002, 06:19 PM
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Re: How to Mold Plastic? I don't think there are many good high
strength plastics that the home shop can
use. Injection molded plastics use really
high temps and pressures.
There are plastic thermal welding setups
that use consumable plastic rod and a heat
gun type of deal. This might work, but
it's about the same cost as getting set up
for welding, to buy the equipment. However,
the idea of just getting the rods and a
small cast iron pan and a hot plate might
work. Probably more difficult than Plan B,
though, which is...
Our old friend JB Weld. Good, relatively
strong, nearly the right color. If you were
to do a multilayer layup (JB Weld, let it
get tacky and semi-hard, then apply a
couple of layers of fiberglass cloth pre-
impregnated w/ same, then a back cover coat
after -that- tacks up, you might come up with
a pretty stout piece. Not cheap in the little
tubes, but some auto parts and farm supply,
that kind of store have bigger sizes that
are more economical.
For a mold, I would recommend going silicone
rubber. Check ceramics supply places (for
pottery crafts etc.). You could use plaster
but this makes a hard mold with lots of
porosity, unless you pour it as slip. It
doesn't have great release characteristics,
the molded piece will want to stick. On the
plus side it's nearly cheap as dirt, and easy
to carve if you want. I think a good silicone
mold will be better though, and reusable. If
that matters. Silicone will be much more
expensive.
strength plastics that the home shop can
use. Injection molded plastics use really
high temps and pressures.
There are plastic thermal welding setups
that use consumable plastic rod and a heat
gun type of deal. This might work, but
it's about the same cost as getting set up
for welding, to buy the equipment. However,
the idea of just getting the rods and a
small cast iron pan and a hot plate might
work. Probably more difficult than Plan B,
though, which is...
Our old friend JB Weld. Good, relatively
strong, nearly the right color. If you were
to do a multilayer layup (JB Weld, let it
get tacky and semi-hard, then apply a
couple of layers of fiberglass cloth pre-
impregnated w/ same, then a back cover coat
after -that- tacks up, you might come up with
a pretty stout piece. Not cheap in the little
tubes, but some auto parts and farm supply,
that kind of store have bigger sizes that
are more economical.
For a mold, I would recommend going silicone
rubber. Check ceramics supply places (for
pottery crafts etc.). You could use plaster
but this makes a hard mold with lots of
porosity, unless you pour it as slip. It
doesn't have great release characteristics,
the molded piece will want to stick. On the
plus side it's nearly cheap as dirt, and easy
to carve if you want. I think a good silicone
mold will be better though, and reusable. If
that matters. Silicone will be much more
expensive.
11-13-2002, 02:42 PM
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Re: How to Mold Plastic? Great post Jimmy, sent you an e-mail. Kep the good responces coming. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Mike
Mike
