moulding compound
Posted: Sat Feb 05, 2011 10:40 am
anyone ever use VINAMOULD ?
well here it is in use on an engine inlet port:-yamaha_george wrote:anyone ever use VINAMOULD ?
Here's some molds done with the white (middle hardness) Vinamold.
One is a NOS Motobi 250 intake port and the other a Honda vertical 175
twin intake that had some filler/grinding done on it (not by me).
http://www.conservationresources.com/Ma ... n38_08.htm
The Vinamold was shipped in a lidded bucket and looks like a big slab
of tofu.
I bought a Pyrex mixing cup that was oven-safe and microwaved the
Vinamold to melt it. Warning: this will get a pretty strong "hot plastic"
smell in the oven and the rest of the kitchen, so do it on a day when you
can open the windows and air things out, preferably not right before you
want to fix some lunch using the microwave! The compound continues
to have a noticeable smell when cold so you'll probably not want to
leave the stuff sitting in the house.
The Vinamold expands a fair bit when hot. I filled the ports to the brim
and then a minute or so later topped them off again. When I checked
them a bit later they had again sunk noticeably in the center. I don't
think that's a concern for the port molds as it just gives you a little
squishing room without having to put a dowel or something in the middle.
As soon as things were cool I started prying the mold out. The
Vinamold did not stick to the metal, but it does take some work to get it
off the guide and then pushed past that point. I pushed the mold out to
the carb side, not the valve side of the port.
I don't know that this molds any better than the 2 part
urethanes/silicone rubbers, but it was very easy to prepare (no
mixing/measuring) and you don't have to wait while it cures before you
demold it. Being able to remelt molds and reuse the compound will
make the Vinamold much cheaper in the long run when compared to the
other compounds. I bought 2 kg and that is a slab about 12" x 6" x 1.5"
and that will do a lot of ports.
cheers,
Michael