Hello Jason,
Selleys All Clear is a copolymer adhesive and not a silicone.
http://www.selleys.com.au/Selleys-Al...r/default.aspx
The good side - it's neutral cure so works OK with metals including aluminium.
The bad side - it affects polycarbonates (lexan) and polystyrene (styrofoam).
It skins very quickly (I've used it for other purposes) so you need to work fairly fast. Mask off areas you don't want contact, as wiping it off is not possible.
It takes a long time to fully cure if it's over about 7mm thick. It may take forever if it's thick and cold.
Regards,
Tony Barry