treating filling aluminiun

Has anyone treated there bodywork before painting it? also whats best kind of filler to use on ali? and does the dented area your filling have to be rubbed down to bare metal before applying a filler?

thank you lee

I used some generic filler:

BIG BOY LIGHTWEIGHT BODY FILLER 250 ML EASY SANDING CARS BOAT METAL RED BC20 57 | eBay

I used a wire brush on a drill to get it to bare metal, then sanded, etch primered and then sanded, then fillered, then etch primer then paint. Or something like that.

That was a break in the paint though, not a dent. I would imagine it is best to get to bare metal if you can, but if not sand it so that the filler has something to key to.

Yes, I've painted a coupele and use this stuff for filler. You'll also want a fine filler for the pin holes it leaves.
You're meant to go back to bare ali, Which I do most of the time.
But I've put it on top of paint before if it's a small dent with no problems, Just roughed the surface up first.
To be honest I don't see a problem unless you've got 3" of filler.

Upol EASY-1, CAR BODY FILLER,3.5 LTR TIN,EASY SAND,HIGH BUILD. | eBay

I heard if you heat the ali at the back gently, the dent is easy to push out
is this true or is someone pulling my ****er

greyhair said:

I heard if you heat the ali at the back gently, the dent is easy to push out
is this true or is someone pulling my ****er

Click to expand...

I read that too, but on looking into it the heat needs to be extreme. Though I guess if you are repainting it anyway...

It's completely true. Google annealing for the whole story.

Short version. Metal cooled slowly is soft. Metal cooled fast is more brittle. Soft metal hardens as it is flexed.

Your dent has hardened the metal and you need to soften it. For alu, this means heat until a piece of wood leaves a mark when rubbed onto the metal, or soap leaves a brown mark on contact. Let it cool slowly. Now it's easy to work, but will harden again as you do so. Re-anneal it until you're finished. Anneal again so that the metal is softer and less likely to crack in the future. A gas blow lamp is hot enough. Don't try for red heat or your alu will disappear before your eyes (and onto your toes).

All metals respond to this, and it's very handy for copper washers that you'd like to use again.

The reverse is also true. If a tool gets really hot when sharpening, cool it fast to harden it. Plunge into cold water or oil.

I tried heating with a blow torch the cooling it quickly with air from compressor. It did straighten out the dents and dings a fair bit but not completely. seen it on YouTube..