Working with those bags is really complicated, first you have to break the seal between the two liquids and then hurry up and mix them by rubbing the bag on the corner of a table for 20 seconds (doesn't mix them properly) and then you have to pour the liquid not more than a 1/4 bag at a time in every spots which is very hard to figure out since the bag is made of thick plastic and you dont see the liquid coming out.
I poured the third bag almost completely in one spot (not on purpose) I just tilted the bag and it just came out too quickly and before I knew it it was almost empty. It happened probably at the worst spot, almost no space between the inner and outer panels.
I could feel the heat and see the foam pushing it's way into place really quickly. I dumped the little that was left on the wheel well and I went outside of the van to see if it was warping...
I couldn't see it but I felt the heat with my hand so I knew where the polyurethane was on the inside, then I started feeling the panel swelling on the outside :-(
Not much but I can feel it and it's my fault.
Next time I will remove both liquids without mixing them and store them into two separate bottles just like when you buy polyurethane. Those **** plastic bags are impossible to work with.
I had in mind to put less since the space between the panels was really narrow, it would never have happened if I was pouring it with a plastic cup or something I can see the liquid.
I still think this is the best way to insulate those walls (pouring polyurethane) but you have to use logic, more where you have space and less (thin layers) where it's tight.