What a coincidence. I had also just thought out a design to make my own
rubber vulcanizer. I like to tinker and my workplace has a lot of
oilfield instrument parts which we scrap when they are damaged or
overtaken by new technology.
I have salvaged two 15 in x 13 in x 1/4 in thick top grade
aluminium plates which will be the basis for the top and bottom
platens of the vulcanizer. These platens will be supported by four
corner screw posts and kept apart by strong compression springs. The screw
posts will allow the plates to be brought closer, say from 2.5 in to 2.0
ins to fit the mold frame.
To supply heat to the platens I have stripped two old clothes irons ($3
ea from GoodWill Stores) one for each platen and will tap screw holes into
the iron face so that I can mount them direct on each platen. When
stripped a clothes iron is essentially a horshoe shaped heating element
molded right onto the iron’s base. So there’s lots of mass to distribute
the heat evenly and the element has enough power to burn through old style
wood ironing boards (remember?). All modern irons have thermostatically
I removed that from the iron’s base and intend to screw it direct
onto the platen. This will allow the thermostat switch to sense
the platen temperature direct therefore enable fine temperature
control for each platen.
This is a thought design and I haven’t quite gotten around to
building it yet so bear with me as to when I can report on the
results. I haven’t even bought any rubber sheets yet - the catalog
is in the mail.
Have to ask your advice here :-
is there a particularly standard or ideal distance between the
platens in commercial machines to fit commercial mold frames? Its
only a matter of changing the spring length. I can make thosemold
frames too but its best to conform to what’s available in the
what is the breakdown temperature of the rubber used to make the
molds? That is at what max. temp. will the heat damage the mold?
This will be important as to the type of base metal I can cast. I
do not intend to work with precious metals yet.
I understand the raw rubber comes in sheets 3/16 inch thick. How
many layers these can you stack to build up a mold, say for a figurine 6
inches high? When cured will the rubber meld to form an uniform mass?
I know about RTV silicone molds and resin casting but would rather
work with rubber molds and intend to build or buy equipment only for this
Kelvin Mok (firstname.lastname@example.org)
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