You are a person who is easily manipulated by marketing, and clearly has zero practical experience in this field. I do. There are no epoxys that are good to 500F. None of them. See username, Buildsjets. The epoxy resins that we build jets out of are cured in an autoclave under high pressure, and at best they are good to 350F, and they are absolutely the highest performing epoxy resins you can buy from the likes of Hexcel, Toray, and other industrial companies that do not distribute though Home Depot. To go higher than 350 you need to go to more exotic and toxic resin systems like Bismaelemide, and we don’t like to do that because they are ITAR restricted, so we could not tell our foreign customers how to repair their aircraft when they broke. Dispose-a-plane.

If JB weld were actually good to 500F, we would be building aircraft parts out of it. But, if it were actually good to 500F, it would be ITAR controlled and Bubbas would not be able to buy it at Home Depot.

To your comment about difficulty of removal, JB weld does not melt. No epoxys melt. They are thermosets, not a thermoplastics. But it degrades at around 250f to the point where you can pick it apart with a mild steel pick. I know, because I have done it. The heat-sinking effect of the surrounding steel is negligible when compared to a 3,500F MAPP torch flame directly impinging on the epoxy.