Handy Hints

Crystal Clear 200 Series

There are six grades in this series of water white rigid polyurethanes for castings weighing from 100 grams up to 6 tonnes. Small castings using CC 200 and CC 202 should be poured into room temperature silicone rubber moulds, either platinum or condensation type two part RTVs. When using CC 204 and CC 206, the moulds need to be heated up to 60° C prior to pouring. For castings which require a High Heat Distortion (HDT), use CC220 for small castings and CC 221 for large. Both these grades must be poured into pre-heated moulds and cured for 4 hours at 60°C followed by 4 hours at 100°C.

Crystal Clear Gel Coats

It is also possible to create a gel coat with Crystal Clear 200 or any of the "Smooth-Cast Series" of P.U. plastics. By adding a thickening agent and using a vacuum chamber to de-air the mix, a very clear gel coat is achievable. This is ideal for thin laminate sheets, brush coatings and hollow castings.

All castings in Crystal Clear grades need to be looked at individually and we have had many years of experience in processing these grades. Please consult us on any designs and we will be able to give full technical advice. There is also more information on the www.smooth-on.com website.

This hint appeared in our July 2006 Broadcast Newsletter.