If they are beige they could be Sika Biresin G26, a good, reliable and stable polyurethane resin.
Hi I used to sell the stuff maybe 8 years ago but it has a shelf life and generally had to buy, as I remember, 7L of each A and B. RAMPF RAKU-TOOL PF-3700-1 and RAMPF RAKU-TOOL PH-3970-1. This was the stuff that Skytrex used at the time. I used to get it from a company called Amber composites- (they have just changed their name but a google search still brings them up.. I used to sell the RTV silicone for making the moulds. ELASTOSIL® M 4512 and WACKER® CATALYST T 51. I hope that helps. I sorry if it's out of date, but it may be a starting point for you. Somewhere I have written some usage instructions, it you want me to find them I will try. But I will add, some people are allergic to the resin, and everybody should wear mask and gloves, because if you are, you will become sensitised to it, and it will get worse, so don't go there in the first place.
