Re: Cat 777D Mining Truck
The urethane stuff I mold in my shop has do be "degassed", once mixed I place it in a vaccum chamber (with clear top) and pull a vac with a AC vac pump until it boils out. Then when molded you minimize the air bubbles such as you have in a simple hand poured mold.
The vac chamber I have is just a piece of 8 or 10" pipe with a bottom welded on, top machined flat and a piece of 1/2" lexan for a top sheet. Port in side for vac line from pump.
The tires came out very nice.
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Jeff
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