JHowell37

When I painted mine I sprayed the epoxy onto the aluminum which had been sitting bare for about two months. Unlike most folks, I drive my 928, a lot. A lot, meaning I've driven it about 43K miles since I first put tags on it 2 years ago.

A lot, meaning that when we get **** weather, I say, "I wonder how the Porsche does in the snow." And then I proceed to find out.

A lot, meaning that when we got a few nights this past winter when the temps dropped to 3 degrees and most people put their garage princesses away, I took mine out for the evening, just to see how it would do in bitterly cold weather.

And through it all, I haven't had a single problem with adhesion despite the fact that I didn't do any of these magical treatments mentioned. Why? Because I assumed that the chemical engineers at BASF know a little more about automotive paint then I do. So when I painted mine, I followed their instructions. I didn't have any problems.

You can put body filler on bare metal. While it can absorb moisture, It's not hygroscopic (i.e. brake fluid.) It won't draw moisture out of the air. Just don't put it on outside, in the rain and you'll be fine. Most modern body fillers are designed to have best adhesion to bare metal. Someone actually did a test at autobodystore.com and found that evercoat body fillers have the best adhesion to bare metal prepped with 180grit.

Don't wet sand body filler.

You can wet sand some high build primers. The technical info will tell you whether you can or not. If you can wet sand it, go all the way up to the maximum grit allowed. If it says 800 grit, your final blocking should be with 800. The higher you go, the fewer sand scratches you'll have.

4drgl

Great information guys...

Thanks very much. My car will as well NOT be a garage queen. I plan to drive every last mile I can in that car fuel price dependent!!! Probly will not rack up as many miles as JHowell37 but I will drive it very regularly...

I want to stay with one product line all the way through the process, I do not have enough experience to go mixing products together. I am researching this as thoroughly as possible to make sure that I am comfortable with the final outcome, products, and processes that I need use.

I have been looking at the PPG, DBC product lines. That seems to be what my local finish master carries. As well, a friend works at an autobody shop that uses ppg supplies and gets an excellent discount. So he can cut me a break on some of the supplies.

Of all the body work I have ever seen, heard of, and read about, and helped with... The body filler was always applied to bare metal, never on top of anything else and I know there's more than one way to skin the cat...

I am trying to get as much technical info regarding the alum as possible. My timeframe for paint is drawing to a close quickly as the seasons are changing, and I need to get going.

I will look into everything that was mentioned on this thread, and post up my questions.

JHowell37

Actually, you're planning to use the "Deltron" product line. DBC stands for "Deltron Base Coat." Search through the Deltron catalog at the link I sent you. It should answer many questions you may have.

Giovanni

I am reading an SPI article and it mentions "aluminum should have a 80 grit DA scratches... let it sit for 30-60 minutes before applying epoxy!" I am just quoting what's in the article says, hehe. Not saying that is the right or wrong way to do it.

JHowell37

I'm not busting your ***** or anything. I'm just going to expand on your statement.

If that's what the technical manual states, then that is what should be done.

People get into trouble when they opt to ignore technical manuals in favor of internet advice.

Usually when I make a suggestion to someone about what they should do, I'll go find the technical info from the manufacturer and try to summarize it as best as I can. For some reason, when it comes to this stuff, people have a serious aversion to looking for the technical manuals even though every manufacturer has them available online, to anyone.

SPI says to prep with 80grit, fine, prep with 80. PPG might say prep with 180. Should you then prep it with 80 since SPI recommends you do that with their product? PPG is not SPI. You should do what PPG recommends for their product. Can you get away with prepping a panel for PPG with 80 grit. Perhaps. I've never done it, so I have no experience. But if you do opt to go down that road and have problems are your internet advisors going to come and help you resolve the issue?

Go here for a "scientific" study on body filler adhesion.

http://www.autobodystore.com/filler_&_epoxy.shtml

Giovanni

I guess I should clarify that SPI is referring to follow those steps when apply SPI's epoxy, not someone else's product!

JHowell37

I know that, and you know that. But there are many people who take the attitude that if they can do something with brand A, they can do the same with brand B, even if brand B specifies something different. And that is where problems start.