Coating a 6′ x 5′ clothe blanket

30 yrs ago I sculpted a horse and sleigh out of high density foam for my town’s holiday display. To save time and money I took a blanket and coated one side of it with fiberglass resin, then I formed it in the sleigh to look like it was covering the couple’s legs and lower bodies. Although I had to quickly form it before the resin began to harden. It turned out ok and has lasted for 30 yrs. Now it needs to be replaced and I am wondering if there is a better way to do this and what type of resin should I use that does not set up as quickly but will allow the blanket to hold its shape until the resin sets up. I am not a pro at this so any suggestions you may have would be greatly appreciated. If this new blanket lasts for another 30yrs, I think the horse will be dead and so will I.