Polishing : too much heat on alu - effect?

dufferin · 06-22-2007, 07:32 AM

what the alu will look like if too much heat is provide during coumpound?

Ken J · 06-22-2007, 07:47 AM

The aluminum will turn brown

dufferin · 06-22-2007, 08:08 AM

I have few spot like that, is there something to do or am I F...

InsideOut · 06-22-2007, 08:10 AM

Sorry to say you are SOL unless you replace the panel.

Yep, a darker grey/brown spot that you may not see until a day or two later. No matter how much you polish, it won't go away...it grows. Basically you burn through the purer aluminum layer and get down to the less pure stuff that oxides quickly. We have one 2"x1-1/2" or so spot by a scratch on an access door we were trying to get out...we use it as an example of "what not to do" when at rallys with a polishing demo. It's a beauty mark...actually, nobody really ever notices it until we point it out.

Shari

Ken J · 06-22-2007, 08:14 AM

The polishing matra is slow speed, keep things moving and a little dab will do ya.....

And you should not apply much presure on the machine - its really a zen thing - not hard at all, just time consuming.

Ken J

dufferin · 06-22-2007, 08:29 AM

I was thinking it was not fair to have such thing, cause I go really slow, I do like 5 pass to get the bright not in a row on the same spot, but one after another.
So I tried to clean up nicely the alu with a good amount of mineral spirit. And guess what it was just some polish residue. I can't see anything now...
I don't know if the panel felt any heat but I did...
Time for a break...
thank you for your help.
BTW InsideOut do you have a pic of your brown spot...

Ken J · 06-22-2007, 08:39 AM

Doesn't sound like you burned it to me - one thought is if you are needing to use a lot of mineral spirits you may be using too much polish - I use Nuvite and most of the polish comes off and I just wipe it with a clean cloth - the only place I've used mineral spirits is around the rivets

Ken J

rebel beck · 06-22-2007, 10:32 AM

Another good thing to use is corn starch. I did not want to use mineral spirits around the windows in fear it would affect my sealing I did last year. The corn starch cleans everything great, fast, and cheap.

dufferin · 06-22-2007, 12:29 PM

post more pics tonight, some are on another post "first step...."

dufferin · 06-24-2007, 09:38 AM

I took a pic of what could worry the other day.
You can see a kind of ghost...
I need to look with a angle under a certain light to see it.
the alu on these spots look like the alu around the window where I can't really go with the polisher.
What could it be... is it the bad brown?
If it is I really don't get why. As yesterday I had to go deep into a big dent so I did put lot of pressure, I went strong on that point and it never get any brown at all and again I was really hard on it.
Which means if it's heated alu on the pic the spot I was working on the door should have melt in comparison.
Any idea?
thank you

rebel beck · 06-24-2007, 10:19 AM

I have that to, hope it's not what we think it may be. Or it could be the presence of Wally

Ken J · 06-24-2007, 08:30 PM

If I can tell what I'm looking at - it looks like some normal discoloration that you get from the heavy compounds and as you go to final coat it brings up the shine - but not sure - it looks more like a blackish color than brown - again that you get from heavy compounds.

Ken J

Streamin 65 · 06-27-2007, 09:21 AM

Quote:

Originally Posted by dufferin

I took a pic of what could worry the other day.
You can see a kind of ghost...
I need to look with a angle under a certain light to see it.
the alu on these spots look like the alu around the window where I can't really go with the polisher.
What could it be... is it the bad brown?
If it is I really don't get why. As yesterday I had to go deep into a big dent so I did put lot of pressure, I went strong on that point and it never get any brown at all and again I was really hard on it.
Which means if it's heated alu on the pic the spot I was working on the door should have melt in comparison.
Any idea?
thank you

I've noticed the same thing after I polished. In a certain raking light, and in certain areas, I can see ghosts in the aluminum. It's strange. I tried polishing those areas again, but it's still there. I don't think it's burned, but also cannot explain why. Here's a pic of what it looks like in broad daylight. It's hard to believe there can be ghosts in a finish that bright, but there is. I've considered trying an acid wash on those areas, but haven't as of yet. I do know that there is one small area in the front that won't polish well at all. It's covered in very small dings from rocks kicking up, so I'd guess the alcad
is gone, or at least damaged pretty bad, as it is brownish. Good luck, and please post back if you find the solution! --dave

dufferin · 06-27-2007, 08:24 PM

I am still at compound process. I'll see if it goes out or fade out when I start with the cyclo.
I'll let you know here.
BTW I tried the cornstarch instead of mineral spirit, and I have to say that it's works perfect. So it's not only an option it the first choice to go with to clean up the polish residue.