This is a technique I created to repair a plastic boat hull.
After doing the repairs on this particular job I have a couple preliminary conclusions. The most important things are as follows:
1) Plastic Compatibility: It's best to use the plastic already on your boat. Nothing will be more compatible than that. I didn't want to cut any part of the boat, so the next best thing is to find the proper plastic. The consensus is that HDPE is the best plastic to do the job. This is easy to find. Most commonly it is found in milk containers, orange juice containers, detergent containers, etc.. Most importantly, look for the recycling symbol. Make sure that it is a #2 plastic.
2) This probably won't work very well if the hull plastic has oxidized or has become distressed through age or drying out.
If the plastic is in relatively good shape, this should work great for you.
The only cost incurred should be what you use in torch gas or electricity for your heat gun.
Thanks for watching.