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funcar  



Joined: 14 May 2014
Posts: 9
Location: Jay, NY

PostPosted: Fri May 01, 2015 2:15 pm    Post subject: paint advice request Reply with quote

I have 1980 931 with original (Alpine white) paint. There are many places on the car where the paint has detached from the galvanized finish, cracked, and is breaking off.

I’m looking for advice on improving the cosmetics. Note that one of the most important features of this car to me is the galvanized body - it is rust free after spending a large fraction of its 35 years outside, and so I don’t want to do anything that will harm the galvanization. Also, I’m most interested in low cost solutions as I can’t afford the easy/obvious one of “send it to a good quality paint shop” (and I'd worry they'd do something that'd wreck the galvanization).

Questions/ideas/Suggestions:

- Paint removal: I learned immediately in a tiny test area that if I use even the lighted sandpaper to get the old paint off, it guts through the galvanization and rusts - so clearly an abrasive or other mechanical means seems out of the question.
From this thread, http://www.924board.org/viewtopic.php?t=29212 , I see others report that a chemical paint stripper works well and won’t hurt the galvanization (does anyone disagree with this conclusion?). Can anyone recommend a particular brand? ( http://smile.amazon.com/Citri-Strip-QCG73801T-Varnish-Stripping-1-Quart/dp/B000QFCP1G ? http://smile.amazon.com/Klean-Strip-Paint-Stripper-qt-brushable/dp/B000KKOR1S ? )
If I decided to take it down to the bare metal everywhere, can anyone point me to a thread or suggestions for how to remove paint from areas near a rubber seal or plastic components?

- Assuming I can get the old paint off in the areas where it is detached, what is the best primer to stick to the galvanized metal? (clearly the original factory primer didn’t stick too well!) MOST IMPORTANT TO ME, will it hurt the galvanization? I see on this thread: http://www.924board.org/viewtopic.php?t=32094&sid=60e69b8e75960202ae6cc0a1245e839a that an “etch primer” is recommended, or a 2 page epoxy primer but I’m concerned that it might damage the galvanized surface and I don’t see that concern convincingly addressed in that thread. Anyone know/understand the chemistry?

- Is there a clear coat that might stick to the galvanized metal directly? Does anyone know of someone who has removed the paint from their 924/931, and either left the galvanized metal bare or clear-coated it? ( I like the galvanized car concept so much that I wouldn’t mind exposing it). Wondering how that might work out long term.

- Do I have any hope of quasi-matching the original paint if I choose to touch up areas only? If so, can I simply buy the factory color (“Alpine white L90E”, in my case, I think) from a place like http://www.expresspaint.com/automotivetouchup/pc/Porsche-Alpine-White-38p4496.htm ? I’m guessing the paint color and brightness is so sun-affected that it is no longer anything like the factory original.
Sadly, I do have lots of big paint chips (from the flaking areas) - is there a place I send one of these off to for them to match it?

- Instead of repainting, does anyone have any clever tricks for hiding spots where the paint has flaked off? The previous owner covered a big spot on the hood with a racing stripe decal. It looks bad because the paint is thick, so in the areas where the paint is chipped off, there is a depression that is visible through the stripe. I imagine it would have looked much better had he filled the depression with thick primer first. If matching the paint is challenging, I guess this is another option.

thanks in advance!

(apologies as some of these topics are partially covered elsewhere (linked above when I’ve found it), and I probably missed some useful advice with my search )
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michaelodonnell123  



Joined: 20 Mar 2015
Posts: 235
Location: New Jersey

PostPosted: Fri May 01, 2015 3:20 pm    Post subject: Reply with quote

I think you are worrying too much about the galvanized finish. That finish is probably long gone by now If I was stripping a car of that age, I'd sand it down to bare metal and re-prime with POR or a zinc-containing primer. Then I would just do a stage one paint job on it. The new paint will protect the metal from rusting. With proper care, you should be able to keep your car rust free.

In the past I have had cars painted by independent body shops and by Maaco. Both did a good job on painting my car for about $600 bucks. I think you should just let one of them paint it for you and don't worry about the galvanization.
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jason c  



Joined: 13 Jan 2014
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PostPosted: Fri May 01, 2015 4:14 pm    Post subject: Re: paint advice request Reply with quote

funcar wrote:
I have 1980 931 with original (Alpine white) paint. There are many places on the car where the paint has detached from the galvanized finish, cracked, and is breaking off.

I’m looking for advice on improving the cosmetics. Note that one of the most important features of this car to me is the galvanized body - it is rust free after spending a large fraction of its 35 years outside, and so I don’t want to do anything that will harm the galvanization. Also, I’m most interested in low cost solutions as I can’t afford the easy/obvious one of “send it to a good quality paint shop” (and I'd worry they'd do something that'd wreck the galvanization).

Questions/ideas/Suggestions:

- Paint removal: I learned immediately in a tiny test area that if I use even the lighted sandpaper to get the old paint off, it guts through the galvanization and rusts - so clearly an abrasive or other mechanical means seems out of the question.
From this thread, http://www.924board.org/viewtopic.php?t=29212 , I see others report that a chemical paint stripper works well and won’t hurt the galvanization (does anyone disagree with this conclusion?). Can anyone recommend a particular brand? ( http://smile.amazon.com/Citri-Strip-QCG73801T-Varnish-Stripping-1-Quart/dp/B000QFCP1G ? http://smile.amazon.com/Klean-Strip-Paint-Stripper-qt-brushable/dp/B000KKOR1S ? )
If I decided to take it down to the bare metal everywhere, can anyone point me to a thread or suggestions for how to remove paint from areas near a rubber seal or plastic components?


If the finish is failing, it should be stripped. It doesn't sound like you're ready for the financial commitment its going to take to do it properly though, even doing it yourself. You'll also need a clean moisture free area to work in.
I use an aircraft stripper, its safe for aluminum. Your best bet is to remove the seals & trim before you strip it. If you don't want to do that, tape it off well. You won't get as well of a job though. Strippers will attack the galvanizing to some degree as well as they are acidic.
You may be better off just touching up the places that are peeling for now.

funcar wrote:
- Assuming I can get the old paint off in the areas where it is detached, what is the best primer to stick to the galvanized metal? (clearly the original factory primer didn’t stick too well!) MOST IMPORTANT TO ME, will it hurt the galvanization? I see on this thread: http://www.924board.org/viewtopic.php?t=32094&sid=60e69b8e75960202ae6cc0a1245e839a that an “etch primer” is recommended, or a 2 page epoxy primer but I’m concerned that it might damage the galvanized surface and I don’t see that concern convincingly addressed in that thread. Anyone know/understand the chemistry?


I don't use acid etch primers, I have in the past but don't anymore. They don't work as well as 2K epoxies. An acid will attack the galvanizing. You're going to have a problem getting a primer to stick the galvanizing. Bottom line, you're going to have to remove the galvanizing. Epoxies have excellent adhesion, they will bite into the galvanizing but can pop it loose as they dry & shrink. If you go directly over the galvanizing, you'll find the epoxy will come loose and if you look at the peeled off pieces, you'll see some galvanizing attached.
Ideally, you'll remove the galvanizing & apply a chromated epoxy, this replaces the galvanizing. If you look at the bare galvanizing, you'll see is a dark grey with a slightly white film- this is the galvanizing sacrificing itself/oxidizing.
When I started painting Porsches 20 years ago, I had a hard time wrapping my mind around the idea of removing the galvanizing but it is necessary to get coatings to stick.


funcar wrote:
- Is there a clear coat that might stick to the galvanized metal directly? Does anyone know of someone who has removed the paint from their 924/931, and either left the galvanized metal bare or clear-coated it? ( I like the galvanized car concept so much that I wouldn’t mind exposing it). Wondering how that might work out long term.


As I explained above, you'll have a tough time getting a primer to stick. A clear coat will not stick-complete waste of time & money. Leaving the galvanizing bare & exposed is not a good option, the galvanizing is there to sacrifice itself to corrosion instead of the corrosion attacking the metal. The paint is there to create a waterproof seal. Without paint, the galvanizing has nothing to protect it. The elements will eventually get through & rust will have its way.

funcar wrote:
- Do I have any hope of quasi-matching the original paint if I choose to touch up areas only? If so, can I simply buy the factory color (“Alpine white L90E”, in my case, I think) from a place like http://www.expresspaint.com/automotivetouchup/pc/Porsche-Alpine-White-38p4496.htm ? I’m guessing the paint color and brightness is so sun-affected that it is no longer anything like the factory original.
Sadly, I do have lots of big paint chips (from the flaking areas) - is there a place I send one of these off to for them to match it?


You can take a part of the car and the color code to a paint store, they can mix the color to factory & tint it for you. It is difficult to match white as there are like 10,000 shades of white. You are correct, colors, especially white, change color with age. I recommend you do a light sand & buff on the part you attempt to match to remove any oxidation that can affect the color. Ideally you would get the color as close as possible & blend it in. Your 924 was painted with a single stage paint so blending isn't possible unless you clearcoat the panel & then the gloss won't match the rest of the car. It would be a waste of money anyway, if areas are failing, the rest will follow.


funcar wrote:
- Instead of repainting, does anyone have any clever tricks for hiding spots where the paint has flaked off? The previous owner covered a big spot on the hood with a racing stripe decal. It looks bad because the paint is thick, so in the areas where the paint is chipped off, there is a depression that is visible through the stripe. I imagine it would have looked much better had he filled the depression with thick primer first. If matching the paint is challenging, I guess this is another option.


Are you sure this is the factory paint? Factory coating aren't that thick. The factory single stage paints arent known for peeling either, I have seen other white '80s peeling though. Could have been a bad run at the factory I guess. Typically, its the clears on the metallic colors that peel. It's caused from UV rays breaking down the coating.
Can you post some pics?
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jason c  



Joined: 13 Jan 2014
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PostPosted: Fri May 01, 2015 4:39 pm    Post subject: Reply with quote

michaelodonnell123 wrote:
I think you are worrying too much about the galvanized finish. That finish is probably long gone by now If I was stripping a car of that age, I'd sand it down to bare metal and re-prime with POR or a zinc-containing primer. Then I would just do a stage one paint job on it. The new paint will protect the metal from rusting. With proper care, you should be able to keep your car rust free.

In the past I have had cars painted by independent body shops and by Maaco. Both did a good job on painting my car for about $600 bucks. I think you should just let one of them paint it for you and don't worry about the galvanization.


Good intention, not good advise.
Por is not intended for surfaces not containing rust, It's not recommended for areas exposed to sunlight (UV rays) and isn't easily topcoated.

"Good" is subjective. Your not going to get a quality job for $600. The car needs to be stripped, primed with an epoxy, primed with a primer surfacer (not necessarily high build) and painted .
Any one of those stages will cost more than $600 to do correctly.
I have friends that worked at m......, I know what their practices are. You're not going to get a quality job for $600 anywhere. I cant even buy quality materials for that. For that price you'll get a scuff with ajax or comet with a scotchbrite pad and a coat of the cheapest paint they can find. On top of that, they aren't going to give you a warrantee.
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michaelodonnell123  



Joined: 20 Mar 2015
Posts: 235
Location: New Jersey

PostPosted: Sat May 02, 2015 12:27 am    Post subject: Reply with quote

Each Maaco is independently owned and operated. It's not fair to lump them all in as bad. Here is a pic of my Miata that I had painted at Maaco for $600 bucks. This was about 4 years ago and it still looks fantastic. Not single issue with it. It still shines like new, the paint is deep and no bubbling or cracking anywhere. There are good shops and bad. And yes there are good $600 paint jobs from my personal experience.



Below is a pic of my second Miata that I had an independent shop paint for $800 dollars. Again - it looks very good.


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jason c  



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PostPosted: Sat May 02, 2015 10:56 am    Post subject: Reply with quote

Again, "good" is subjective, I'm sure there are may things I see when looking at paint that you probably don't see (I've been painting cars for 23 years). I can't tell you how many times I've seen people drool over paint jobs that I can tell look terrible. The average person only sees shine, they don't notice all the little things. I'm not saying your cars look bad, in fact it looks like you take very good car of them but its impossible to tell what the paint truly looks like in low light grainy pictures, that's not your fault, its just reality.
I don't even have to know what the car looked like before the paint, $600 is not going to get a quality job, you can't get quality materials for that. If the average everyday shop charges $60 an hour, let's say material is half the cost ($300), thats 5 hours. There's no way a shop is going to properly prep, paint, buf, polish & detail the car in 5 hours.
You might get them to spray it with minimal prep & cheap materials for $600 but that isn't what I consider quality. Its not necessarily the length of time its been painted, its the time it spends in the sun. UV light will break down cheaper paints much faster than a quality one.

The op is not going to get his car stripped, prepped, primed, blocked, prepped, painted including even minor bodywork for anywhere close to $600, not even in mexico. Lol
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michaelodonnell123  



Joined: 20 Mar 2015
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Location: New Jersey

PostPosted: Sat May 02, 2015 12:55 pm    Post subject: Reply with quote

Two more pics of the Miata. It might not be a quality job to somebody with a very critical eye but for a paint job that cost $600 bucks it is looking good to me.






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Fifty50Plus  



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PostPosted: Sat May 02, 2015 1:35 pm    Post subject: Reply with quote

Michael. it looks good but then it's a Miata. My money is with Jason and his advice. I have Maaco paint all my race cars because they charge me around $300 and the paint outlasts the car. Street Porches deserve some love.
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brian19600  



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PostPosted: Sun May 03, 2015 10:22 am    Post subject: Reply with quote

Michael they look nice.

How much would you guys expect someone to spend on the average 924, which no matter how much you pour into it, will yield 3-4k tops.
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funcar  



Joined: 14 May 2014
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PostPosted: Sun May 03, 2015 12:41 pm    Post subject: Reply with quote

Thanks for the replies especially Jason C for the thoughtful and detailed comments.
A few follow-ups below:


jason c:
Quote:
I use an aircraft stripper, its safe for aluminum.


Jason, I think you meant to write "safe for galvanized metal", right?


jason c:
Quote:
An acid will attack the galvanizing. You're going to have a problem getting a primer to stick the galvanizing. Bottom line, you're going to have to remove the galvanizing. ...


This makes sense, but it also makes sense to me that there must be a good primer that won't hurt the galvanization, since my car has one that has lasted 35 years and the galvanization below the paint is in perfect condition (as evidenced by having been outside with exposed metal for several years and no rust. michaelodonnell123, this demonstrates your statement that the "galvanized finish is probably long gone" can't be correct in this case). You commented as well that you don't normally see this sort of cracked paint issue on 924s. So, I guess the questions becomes, what sort of primer did Porsche use originally to get good adhesion to the gal ? (you mention that they used a "single stage paint" - do you know what this is and if it can be bought aftermarket?


jason c:
Quote:

Are you sure this is the factory paint? Factory coating aren't that thick. The factory single stage paints arent known for peeling either, I have seen other white '80s peeling though. Could have been a bad run at the factory I guess. Typically, its the clears on the metallic colors that peel. It's caused from UV rays breaking down the coating.
Can you post some pics?


I think it is the factory paint, only because I can't find any evidence of lines, etc when I look under the hood or at edges. The bits that have cracked off look like just one layer (black on the inside, white on the outside - I thought the black was some sort of epoxy primer. It seems unlikely the car used to be black, because everything looks the same white in hard to reach areas. I certainly could be wrong!)

A side view of the right side of the car, which is the worst, showing the rear right fender (worst area of the car) and another spot near the passenger door handle (the one I foolishly sanded a little and clear-coated, now it is rusting some):



So, in summary, the main thing I'm left wondering is: what kind of primer or one-part paint did porsche use that is able to stick to the galvanized finish, without hurting it? Is it possible to get some, or something similar?

It sounds like I'm safe to use aircraft paint remover.

thanks again for the tips and help on this.
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edredas  



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PostPosted: Sun May 03, 2015 5:03 pm    Post subject: Reply with quote

Porsche used BASF/Glasurit primer.

Alklyd based paints don't stick to galvanized steel because they react with it. Otherwise, you'll be fine with whatever road you take. Personally, I like keeping the galvanizing when possible.
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jason c  



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PostPosted: Sun May 03, 2015 10:04 pm    Post subject: Reply with quote

Porsche did use glasurit, it is still available, I use it all the time.
I have seen clears peel but single stage paints peeling is rare. The only other ones I've seen were also from '80. Its possible they used something different during this time for some reason & the failure is in that run of cars.
Aircraft stripper is safe for aluminum (bumpers), its also the strongest/best you can use. The sunroof is fiberglass, don't strip it.
The stripper won't take off the galvanizing. You can not save it though, here's why...
1) any primer will need a tooth to bite onto the surface, so you'll have to sand it.
2)sanding it will take the galvanizing off.
3)you will not find a primer that adheres well to the galvanizing
4)an epoxy primer will not work on the galvanizing either. It will not stick well by because, it will bite into the galvanizing & pop it loose as it shrinks or not stick at all. You'll be able to chip it off when it dries.
5) the chromated epoxy primer will replace the galvanizing.

I know why you want to save the galvanizing, but it can't be done. You will have delaminating problems. I've been painting for 23 years & have done a lot of these cars in that time (my specialty). I didn't want to lose the galvanizing either but you cannot save it. The chromated epoxies are awesome, they have excellent adhesion & rust protection when the surface is prepped properly.
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edredas  



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PostPosted: Mon May 04, 2015 4:26 am    Post subject: Reply with quote

jason c wrote:
1) any primer will need a tooth to bite onto the surface, so you'll have to sand it.
2)sanding it will take the galvanizing off.
3)you will not find a primer that adheres well to the galvanizing



Self-etching primers do exactly that.... self-etch. The factory primer adhered to the galvanized coating it quite well because it was not Alkyd based. I've been painting over galvanized steel for decades and not once have I seen the primer pop loose. Its not about experience, it's about knowing the chemistry of the paints.
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funcar  



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PostPosted: Mon May 04, 2015 4:30 am    Post subject: Reply with quote

edredas, which primer part number do you recommend? (a specific link would be helpful)
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edredas  



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PostPosted: Mon May 04, 2015 7:00 am    Post subject: Reply with quote

funcar wrote:
edredas, which primer part number do you recommend? (a specific link would be helpful)


The primer is usually specific to the project. If you are using a single stage enamel catalyst, you must use a Sealer or the paint will not shine. Also a Lacquer primer will craze and chip with enamel over it. Urethane paint you can get away with pretty much anything as long as the primer isn't lacquer or alkyd. So, I guess the thing I'm saying is, ask the person you are buying paint from to recomend the correct primer for your project.
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