Heat Generation Desirable?

R

RAG

New member
This is another one of those topics that it difficult to attain a diffinitive answer to - is it desirable to generate a moderate amount of heat when buffing? Presumably this applys to a rotary, as it is pretty damn hard to generate heat with a PC.



I've read articles and heard discussions argruing for both points of view - one saying the less heat generated the better (auto int. article) and the other saying that a MODERATE amount of heat is desirable because it a) softens the clear a bit, essentially giving you a bit more cut and thus allowing you to remove more defect, and b) it allows the clear to "flow", presumably flowing into scratches to some degree.



Typically I err on the side of less heat is better, but every once in a while when I'm compounding and need a bit more cut on a particular scratch, I tend to heat up the spot just a tad to give me a bit more "bite." But what do I know :doh



Thanks yall.
 
This is hard to say. It also depends on the products you are using. Some products seem to break down and do VERY well with a PC type machine. Other products need that heat to help break them down.
 
My opinion is that the motion of the pad is what breaks polishes down, not heat. Think of the abrasives as cracker crumbs. If you crumple a cracker into small pieces, say 1/2" diameter, and then rub them into the countertop, what happens? They break down into smaller and smaller pieces, until they are basically dust. IMO this is what happens with the abrasives in a polish. The solvents and lubricating agents will evaporate, while the abrasives need to be completely broken down to the point of dust or very close, which is when they become functionally non-abrasive.



If you were to increase the heat in the room with those cracker crumbs, would they break down? No, not unless you heat them up enough that they start to burn. The heat from a rotary is more because of the increased friction from the pad. It can spin faster, and concentrate heat better on a single area than a PC can.



I don't disagree that heating up the clear could aid somewhat in removing scratches.
 
It's heat and friction combined which "levels" paint. Heat paint up to about 100 degrees with a finishing pad (on a rotary) and it will burnish paint more than level it because the finishing pad is not providing as much "friction" as a foam cutting pad.



Then you have a wool pad, which creates a mild amount of heat but provides more friction than most foam pads.



Now if you heat up the clear too much then what you are doing is not really removing scratches but driving them deeper into the clear. Around 117 degrees is the heat threshold for rotary use on clears.



Clear coats being heated up to the point where they "flow" is ridiculous. It just doesn't happen that way with todays paints.



Anthony
 
White95Max said:
How does this work? :confused:
Click to expand...



In a nutshell....clears are essentially plastic film, heat them up too fast and they become soft, which allows the paint to "swallow up" (for lack of a better word or description) the scratch.



This is why most clears respond well with just a mild LUBRICATING polish and a mild or medium polishing pad, set your rotary around 1200 rpm's and watch your heat....get an infra-red heat themometer at Radioshack so you can keep a watchful eye on it.



Anthony
 
But the scratch is just full of air, which has a lower density than the clear, so how does the scratch actually move down through the denser clear? If the clear did become soft, wouldn't the clear just seek a uniform level and fill in the scratch?
 
Thanks Anthony, that's what I was looking for. I wasn't necessarily referring to breaking down abrasives, rather I've never really been sure how much heat I should generate on the clear to achieve maximum performance. I've heard "about 100 degrees before," so I will continue to try to operate on that premise.
 
White95Max said:
But the scratch is just full of air, which has a lower density than the clear, so how does the scratch actually move down through the denser clear? If the clear did become soft, wouldn't the clear just seek a uniform level and fill in the scratch?
Click to expand...





A scratch is not filled with anything. It is a void in the paint. Seems you're over thinking this a bit.



Leveling the paint is not a magic trick in which you heat the paint with a rotary and watch the paint "self heal". Leveling is simply the removal of paint to the lowest point of all defects.



There is no target heat range for paint while buffing. 115 degrees F is what you do not want to cross as too much heat = burnt paint. You've all seen that a PC can remove defects, to some degree, w/o heat so you know it is not essential for polishing.



Heat is a tricky thing to control but can be a "tool" for an experienced detailer. If you cannot get the results you need with aggressive polishes & pads you can heat the paint up a bit to soften it, which makes it easier to abrade and level.
 
White95Max said:
My opinion is that the motion of the pad is what breaks polishes down, not heat. Think of the abrasives as cracker crumbs. If you crumple a cracker into small pieces, say 1/2" diameter, and then rub them into the countertop, what happens? They break down into smaller and smaller pieces, until they are basically dust. IMO this is what happens with the abrasives in a polish. The solvents and lubricating agents will evaporate, while the abrasives need to be completely broken down to the point of dust or very close, which is when they become functionally non-abrasive.



If you were to increase the heat in the room with those cracker crumbs, would they break down? No, not unless you heat them up enough that they start to burn. The heat from a rotary is more because of the increased friction from the pad. It can spin faster, and concentrate heat better on a single area than a PC can.



I don't disagree that heating up the clear could aid somewhat in removing scratches.
Click to expand...





I agree. I dont think heat has anything to do with polishes breaking down. It is caused buy friction and working time. Yes friction causes heat, but even if you didnt have the heat, they would still break down. Heat is just there because of the friction. This is my opininion.
 
MichaelM said:
A scratch is not filled with anything. It is a void in the paint. Seems you're over thinking this a bit.
Click to expand...





It has to be filled with something right? :p You don't create a black hole everytime you scratch something. There must be atmospheric gases entering the microscopic valley that is the scratch.
 
A black hole in a scratch would be an awful lot of stuff. They’re black because there’s soooo much stuff in them that the immense gravitational pull keeps light from getting out. Brings new meaning to the word fillers. At least the scratch wouldn't be visible. (Hey, there's a product idea!)





PC.
 
White95Max said:
It has to be filled with something right? :p You don't create a black hole everytime you scratch something. There must be atmospheric gases entering the microscopic valley that is the scratch.
Click to expand...



:nervous:



It is a moot point. I understand that you must believe that scratches can be "driven deeper into the clear" when heated as Mr. Orosco said. As stated, "Clear coats being heated up to the point where they "flow" is ridiculous...". For a scratch to sink or be pressed deeper the paint underneath the scratch would need to be fluid and the upper scratched layer solid. Doesn't work like that. Perhaps he didn't quite literally mean "driven deeper into the clear", can't say.



You asked earlier "If the clear did become soft, wouldn't the clear just seek a uniform level and fill in the scratch?". Again, clear paint, when heated to only ~100 degrees, does not flow. It gets soft and easier to abrade.
 
the other pc said:
They’re black because there’s soooo much stuff in them that the immense gravitational pull keeps light from getting out.
Click to expand...



I guess that's why I'm not an astronomer. :o
 
I think read on the auto international website that if you heat the clear coat up above 110 degrees (I don't remember what the exact amount they said was, but this is in the ball park) that you risk driving the scratch deeper rather than removal and thus one should keep heat to a minimum. Driving the scrath deeper huh? Didn't make sense to me, but again, what to I know.
 
TVR paintwork correction



Thought this was an interesting article concerning heat. This guy apparently runs his buffer up to 3400 rpm (to heat the paint up) and uses a non-abrasive polish, just the abrasiveness of different pads to level the paint.



It's supposedly safer to the paint, being that not much is removed, but I'd imagine it's VERY risky.
 
I have been doing this high heat and high speed with presta cleaner 1500 polish on hoods and trunks with severe defects for 15 years and it does work. Hoods and trunks are the major trouble areas on most cars and this method does work on those hard clear cars.



This is for skilled PRO USE ONLY!
 
MichaelM said:
Again, clear paint, when heated to only ~100 degrees, does not flow. It gets soft and easier to abrade.
Click to expand...



:werd: Cold paint is harder and harder to polish. A little heat makes it soft enough to let the polish work.
 
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