Dents in poly hull question

Looking for suggeastions to remove dents / bulges from a poly hull. They are in the center of the hull so most likely not from sitting on a rack.

Will a heat gun work? How should the heat be applied? From the outside or inside of the hull? If heat is used what type of material should be used to push against or brace the hull (metal/ pyrex glass etc?)to help it return to it’s origional shape?

Have you tried…
Just leaving it out in the sun for a few hours? My friend had a dent like yours and that’s what did the trick.hth

Had the same problem
and live in an apartment. My patio where I keep my kayak gets almost no sun. I asked the dealer, a good place to start, how to correct the dents. His response was a) leave in the sun on a hot day b) apply heat from a blow dryer to the dent c) if that’s not enough heat, use a heat gun. A) wasn’t pratical so I tried b. B) worked. I applied the heat on the inside since the dent was pushed to the inside. Used a kiddie single blade paddle to push against the dented area, and it worked. I was warned that if I needed to use a heat gun, be careful not to burn the poly, those guns get might hot.

Success
Success. I put the boat in some homemade kayak saddles then pointed a painters flood light (moderate heat) up at the dents from under the hull and pointed a hair dryer down at the dents from inside the hull and kept working the dents with my bare hand. When it became to hot to work with my hand I backed off on the heat sources that way I had some sense and control of when I might be reaching a critical point of no return in terms of the application of heat to the plastic.

Memory
You might find some of these dents return on their own…a statistic of what some refer to as a memory with the plastic.

Memory question?
If they return, any idea how long that usually takes for them to show up? My thought on heating both sides of the plastic was that it would discourage this. Don’t have a lot tied up finacially in this boat, so willing to experiment as I have built and repaired some boats and like to add to the knowledge base.