Sanding aluminum? - Grille repair

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demon322

demon322

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I recently bought a grille on ebay for my dads 68 Satellite (same grille as 68 Roadrunner.) When I recieved the grille it was in much worse shape than what I was expecting from the pictures and discription. There are several scratches on the grille, some fairly deep. I asked a couple of buddies and they say to try to use sand paper to try to get the scratches out. Anyone ever try this? The buyer will not take the grille back so I need to try to make this one work if possible. Thanks.
 
Member Waggin has a fairly nice write up on here about just such work.
 
I know how to sand an polish aluminum parts... but I don't know how I'd go about the whole grill... well I have an idea, but it's extremely time consuming.

If it were me, and I were at work... I would use my 3 inch DA sander and hit it with 80, 180, and then 320 grit in that order. Then I would switch to hand sanding and hit it with 400, 600, 800, and then 2000 (yes I know there's a jump but aluminum isn't bad). THEN I would hit it with a medium buff compound and then a fine one. We usually don't buff by hand though. We use hard compounds with either the buffing wheel or the hand held air buffer. I would assume you could use some sort of paste type compound and do it all by hand though.

Sorry I'm not too much help. But it works for what I usually have to do. lol
 
Search.......How To:stainless steel trim restoration.....under General Discussion
It's about the same proccess
 
I am pretty sure I would not advise using 80 grit or even 180 on a paper thin grill piece I am also pretty sure I would not use anything other than my hand to do the sanding.....the heaviest grit I have ever seen a polishing company use on delicate parts is 320...... the really DEEP DEEP scratches are usually permanent and will hopefully polish up and kinda disappear.......you get them the best you can then you stop....I know of amatures that have sanded thru the part.....when you do that....its time to visit the aluminum welder to fill it in NOT CHEAP......also be careful when buffing.....you must pay 100 % attention at all times and hold the part very loosely in case it catches...try to always buff in the same direction as the hard edge so the wheel is "stepping off" and not running into the edge..... get the right rouge and boogie....OR you can just the parts to PATMAI in michigan and they will do thier magic and ship them back.... they have done several complicated parts for me on several of my cars and thier work is flawless and remarkable
good luck
 
:withstup:

I wouldn't use 80 grit to start off with on a grille. You'd run out of metal before you even got the 80 grit scratches out.

If its a deep scratch I might consider using 180 if I had enough metal, but only briefly and VERY carefully. I don't think its a good idea on a grille. 220 or 320 would probably be a better start. If the scratches are deep, you might not be able to get them out, just "blend" them in a little.

Anyway, from there I'd work up 400, 600, 800... Maybe up to 1500. 2000 is a waste of time unless you're going for a mirror polish, and even then, I've gotten a mirror polish without it. After 1500 you can switch to a metal polish, a dremel with a buffing wheel might come in handy to finish. But I don't think those were mirror polished deals anyway, so once you start getting up in grits I'd compare the finish to the rest of the grille and see if you're close. Over polish one section and you'll have to do the whole thing!
 
The grille is anodized, right? Don't forget that if you don't strip the whole thing before you start any sort of sanding, that the finish will be different where you sand and where you don't.
 
Thanks for the replies guys. I will get some sandpaper and see what happens. Here are some pics of it for reference. It seems a previous owner also painted the car with the grille in as it has red overspray on it. Guess I need to get some paint stripper for that problem.
 

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tomt966 said:
No, its not anodized
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YES, all the stamped aluminum grilles and are anodized. Otherwize they scratch easy, tarnish, and corrode in normal un-cared-for everyday use.

Spray them with Easy Off oven cleaner (Lye) to remove the anodizing. You will have a tough time sanding through the anodizing unless it's worn off. And it will be only worn off in places to you will have be sanding on one place then not another.

I just removed the anodizing off some GTS rocker spears I got at Fall Fling so I can sand the very fine pits (nice set) and polish them.

Picture below was just test sampling the end of this spear. The one of the bottom is raw with the factory anodizing still on it. This was sanded with 220, 320, then 600. Then buffed. Still some fine nicks in there. I think I need to be more aggressive with the 220 or my rubber deburring wheel.
 

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If they were not anodized they would not still be around. They would have turned to powder by now. lol
 
Nice work for playing around, autox! If I can hijack for a sec, I've got a question along the same lines.

My Dad's 69 Dart's grille was sprayed bombed black sometime in its' past. Would I need to hit it with the oven cleaner FIRST, or after I've sanded off the black? What grit should I start with on the paint?
 
jd340 said:
Nice work for playing around, autox! If I can hijack for a sec, I've got a question along the same lines.

My Dad's 69 Dart's grille was sprayed bombed black sometime in its' past. Would I need to hit it with the oven cleaner FIRST, or after I've sanded off the black? What grit should I start with on the paint?
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Oven cleaner first. That should take off the black. Spray and let set for 10 minutes or so. Oven cleaner will probably dry. Then scrub off with fine brillo pad and water. damp dry off and reapply. Will take many applications. Better to go in steps than have the chemical eat it up.

For just paint probably 320 to start. But experiment.
 
I'm not exactly sure what you mean when you say anodized. Is that what gives the grille a somewhat hazy finish? If I sand and polish the grille is it possible to get it close to factory appearance? I bought it as a gift for my dads car that is being totally repainted so the grille needs to look as nice as possible. I will be using the original headlight bezels so it will need to match them as closely as possible.

Also, oven cleaner was mentioned. Should I use this to get the red off of the grille instead of the paint stripper spray? Or will both be needed? Thanks again.
 
Sorry guys, for mentioning 80 and 180 grit. I use it on stainless trim but I haven't done a grill yet so I didn't really realize they were thin.

I've gotten too used to go stuff like this. I hate stainless....

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demon522 said:
I'm not exactly sure what you mean when you say anodized. Is that what gives the grille a somewhat hazy finish?
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Yes, it gives a slight haze. Try sanding the backside in a small section and you'll see it is very hard to sand. Then try the front that is pitted and worn and you'll see certain section might sand and others are hard like there's a protective coating.



If I sand and polish the grille is it possible to get it close to factory appearance?
Click to expand...

Close. Yes.


I bought it as a gift for my dads car that is being totally repainted so the grille needs to look as nice as possible. I will be using the original headlight bezels so it will need to match them as closely as possible.
Click to expand...

It takes a lot of work. The bezel will need to be done the same.


Also, oven cleaner was mentioned. Should I use this to get the red off of the grille instead of the paint stripper spray? Or will both be needed? Thanks again.
Click to expand...

Use paint stripper first.
 
80 grit on an aluminum grille?!?! Holy cow Zach, it's time to report to the Bad Advice Room. You've got detention buddy. LOL!!!!
 
If you google anodize you'll find the process explained. Now lets say you chemically defeat the anodized surface and rub a scratch until the area is extremely thin. The you get a buff through ( hairline crack ). This happens to professional restoration companies often. If the part isn't reanodized the thin aluminum will disappear like a leaf rotting away. Everything from detergent to rain, to the exhaust from the car in front of you will eat it up.
Clear coating will help prevent this where the part isn't reanodized but the clear coating will need to be redone periodically.
 
Ok. I think I am about ready to give it a try. Very nervous that I will do more harm than good. At the very least I would like to get my money back out of the grille if I can't improve the appearance so hopefully I don't make it much worse.

So, the process should be 1) paint stripper to remove red overspray. 2) Attempt to sand scratches out, working my way up to finer grits as I go. 3) polish grille 4) Hope for the best.

Sound about right? Thanks. I've never attempted anything like this before.
 
ALMOST..... once you have it lookin good with polish & buffing.....have it clear powder coated that was it will stay like that for quite a while...... somewhere there is a pwder coater that I have heard does a pretty good job and aint hard on the eyes......... .........thinkin.............thinkin...........thinkin.......I think that chick has a cuda...but her names escapes me LOLOLOL
 
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