Quoted post said:Originally Posted by Volnix
Sounds like its gonna change the finish too... In a non-oven not homogenized way. Apparently it is some kind of ghetto-powder coating... There are rumours of fumes too...
There are some enamels that say that they can be baked with a heat gun, but maybe those have some special formulation so the coating wont -actually- get baked...
Whats the temperature the physical properties of steel start to change? Maybe thats a bad idea for a bike frame...
How does it make it impervious to solvents??? [IMG]files.cyclingforums.comconfused.pngOpen ↗[/IMG]
The "baking" is done AFTER the paint has air dried ...
Although I presume that with a 600ºF heat gun (I think THAT is the low end of what is available before one has a "hair dryer"😉 that you can possibly heat the object up to close to the maximum available temp, one certainly does NOT have to try to achieve the max temp on the work object ...
FWIW. I can only speak from limited experience, but I reckon the part of the frame which 'I' heated may not have exceed 200ºF by very much, if at all ... but, maybe it did. It could have been 400ºF for all I know since I wasn't keen to handle it before it cooled!
Regardless, I did not find paint discoloration to be an issue ...
And, I am not sure that paint discoloration would necessarily be a problem at 600ºF ... but, there certainly MUST BE a temp at which discoloration will begin to occur.
Silver soldering/brazing is done at around 600ºF, BTW.
ONE CAVEAT. I can say is that in my poorly remembered haste that EITHER I may have tried to speed up the process by moving the "gun" closer to the head tube in the beginning OR (more likely) I did not clean the repainted section properly prior to painting BECAUSE when I inspected the cooled frame I noticed that there was a pin-point sized pock mark in the crevice of one of the joints of one of the two lugs & the head tube ...
That is, any sins of omission in preparation may become evident after baking & cooling!
As far as making it "impervious to solvents" ... make that "normal solvents" ...
Baking an enameled finish just does (sorry, I cannot explain it other than to speculate as to why where I will suggest the poor analogy that it may be like the "skin" on top of cooled pudding which is essentially non-porous ... ); so, I'll say that the "baking" of the paint removes the last of the solvent & thereby shrinks the paint against the surface & thereby becomes a non-porous surface ...
Also, the baking possibly MELTS the paint to some extent & may thereby change the "bond" between-the-molecules ...
The finish on enameled jewelry has a VERY hard surface (typically, kiln "baked" at really high temps, of course ... the enamel is definitely melted).
BUT solvents like MEK & industrial paint strippers WILL have as adverse an effect as one would experience with any "factory" paint finish.
BECAUSE 'I' have not used a heat gun to "bake" the paint on an entire frame, I do NOT know how long it would take ... I probably spent less than 5 minutes ... so, I would allow a one-to-two hours for a bicycle frame & fork.
Decals go on AFTER baking ...
Some Clear Coats may have an adverse affect on some decals -- I think "lacquers" could be a/(the) problem.