got it from Mark at LFP, but you have to be a NHTOC club member for that discount. otherwise i would have gotten it from Chickenears from this site. he's got good prices too

 

I would agree and say "do not use a heat gun" The reason for a certain temperature is due to the properties of the metal at around that temperature. From say 40 degrees F to 68 degrees F the metal will have expanded a little compared to the colder temperature.

Now for most it would be a logical conclusion to think that buy using a heat gun you could, and in fact would bring the metal to the correct temperature however that temperature rise would be "to fast" for the metal to expand to "ideal" properties for the recommended adhesion. Furthermore the metal needs to maintain that temperature during the cure time otherwise it will not adhere correctly.

What will happen with the heat gun is it will raise the temperature but for a very short time and it will not maintain that temperature due to the huge mass of metal that will equalize that temperature to the ambient temperature. In other words metal is a good conductor of heat. Thus if you heat a small area (2" X 2") of say a mass of (2' X 6') the mass will basically suck the heat and dissipate it into the overall mass.

Basically what will happen if you try to adhere something at 40 degrees when 68 degrees is recommend is when it does get warm up and the metal does expanded it will break or weaken the bond that was made at the colder temperature.

An example would be to put your fingers tightly together and tap some tissue to the outside fingers. When you spread your fingers the tissue will break. Now if you spread your fingers open and tape the tissue to the outside fingers and then tighten your fingers together the tissue will not break, it will be a little loose, but will still maintain its adherence to your fingers. Your tighten fingers is the cold 40 degrees, the spread fingers are when its warm like 68 degrees.