400 lbs of paint--Good Grief......(long post).....
01-13-2008, 11:54 AM
#16
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Russ,
I know what you're going through as I am also in the process of a strip and paint program. I also found some minor rust in the area behind the drip rails although not quite as severe as you're showing. I used a brass wire wheel on the grinder and removed as much as possible. Then cleaned the surface and applied a acid based surface prep that leaves a coat of zinc phospate.
Don't stress too much on the alum. panels as they are amazingly sturdy. The only area that requires perhaps more caution is the hood.
I used 80 grit to get down to the metal and it seemed to go fairly quickly, put I didn't have the "extra" paint layers to contend with. I down to "clean up" of the irregular surfaces and will be priming soon. Let me know if I can provide any information even if just moral support! I appreciate the effort required!
I know what you're going through as I am also in the process of a strip and paint program. I also found some minor rust in the area behind the drip rails although not quite as severe as you're showing. I used a brass wire wheel on the grinder and removed as much as possible. Then cleaned the surface and applied a acid based surface prep that leaves a coat of zinc phospate.
Don't stress too much on the alum. panels as they are amazingly sturdy. The only area that requires perhaps more caution is the hood.
I used 80 grit to get down to the metal and it seemed to go fairly quickly, put I didn't have the "extra" paint layers to contend with. I down to "clean up" of the irregular surfaces and will be priming soon. Let me know if I can provide any information even if just moral support! I appreciate the effort required!
01-13-2008, 01:31 PM
#17
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01-13-2008, 02:30 PM
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Actually the best thing that you could do...which is what I did with my 928 respray is take it down to the factory primer.....I was able to reduce the grit size as I got closer.....my reasoning at the time was that I had some concerns getting a good bond to the aluminum. I figured as long as the factory primer was still in great shape why expose the metal.
YMMV
Ken
YMMV
Ken
01-13-2008, 02:58 PM
#20
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there was no evidence of (after factory build) repair. Primer, paint, etc., was the same for the rest of the panels I stripped. If the repair happened after factory build, the layers of primer and paint would be different.
very strange indeed......
Stan,
the hatch, front window, and quarter window channels will have to be media blasted due to the rust problem. My restoration guy has s friend that uses a soda blaster to remove this stuff pretty quick.
Ken,
The pipes are Hooker Header units----available from Summit Racing.
Leo,
The holes are the same. Be glad you don't have rub strip holes to deal with as well. I am not happy with my initial hole pluggin', but my resto guy has a new product that will take care of them. It's a two part liquid, and when applied it hardens like steel. Then just grind/sand to form and paint. No filler required.
Removing the paint down to the metal prevents anything from "traveling" up through the "new" paint, as explained to me by my resto guy. The new PPG products he uses are very sensitive to this kind of thing happening, so strip it is the way to go.
I'll be doing the hatch today, then on to the doors......
Thanks to all for the encouragement!!!
--Russ
01-13-2008, 05:16 PM
#21
Drifting
I'll try to respond to as many of the questions and posts as I can.
In many of the tight areas such as the drip rails I too used a brass wire wheel on a grinder and it worked well. I then applied a rust converter. For removing paint in really tight areas I used a scotch brite pad on a mini angle grinder.
Once a car gets to a certain age, I'm all for a total strip down and starting from scratch. Incompatibility of different materials is more of a wives tale then anything these days, especially if the car has been painted properly in the past. Incompatibility rears its head when someone tries to apply a product over a lacquer usually. As I've said before, urethane reducers will attack a lacquer like paint stripper. The reason to strip completely IMO is because a paint job is only as strong as its weakest link. They can say what they want, but these materials do deteriorate over time so I feel its best to start with a solid foundation. Additionally, paint has a minimum thickness and a maximum thickness. That includes all primers as well. If you have 12 layers of material you're going to be at the maximum thickness. When you exceed the maximum thickness paint chips and cracks easily as all of the layers of material expand and contract at differing rates influenced by temperature.
As far as grinding away the zinc coating on the steel goes, you'd have to do A LOT of sanding/grinding to eliminate it. What I would suggest is that when you start to break through to metal, go up from 36 grit to 80 grit. The process that Porsche used on their bodies was pretty good. I stripped my roof down to metal in October '06. It sat exposed for about 5 months. There was some slight pitting which was removed with a few passes of the sander when I resumed work on the car last spring.
Make sure you get all traces of blast soda removed from the vehicle. While it's a great media there's something about the soda that can inhibit adhesion painting materials.
Most of the adhesion problems regarding aluminum are a thing of the past. With the exception of welding, aluminum can be treated just like steel.
I did use paint stripper at various points. There are drawbacks to using it such as the fact that it will damage virtually anything it comes in contact with that's not steel or aluminum. If you have a car with 20 layers of lacquer, by all means use the stripper. But if your car uses modern catalyzed paint forget about it. It will work, but it requires a lot more effort and time spent scraping and reapplying stripper.
The chance of having excess material built up in the door jambs is pretty slim. Unless you have obvious proof otherwise, the paint in the jambs is most likely the original. If you plan to repaint the door jambs or under the hatch, I would just clean them real well (with a solvent) and give them a very good scuff with some Scotch-Brite.
Body filler will not adhere to metal treated with acids like etch primer or rust converter. You must seal the acid based product with epoxy and then apply filler. Most fillers will work over epoxy primer, and some glazing putties will even work when applied to cured, scuffed paint. All of the independent tests I've seen have shown that filler bonds the best with bare steel or aluminum prepped with 120 grit. IMO nothing sticks to metal better then body filler which is why I'm such a huge fan of Slick Sand.
In many of the tight areas such as the drip rails I too used a brass wire wheel on a grinder and it worked well. I then applied a rust converter. For removing paint in really tight areas I used a scotch brite pad on a mini angle grinder.
Once a car gets to a certain age, I'm all for a total strip down and starting from scratch. Incompatibility of different materials is more of a wives tale then anything these days, especially if the car has been painted properly in the past. Incompatibility rears its head when someone tries to apply a product over a lacquer usually. As I've said before, urethane reducers will attack a lacquer like paint stripper. The reason to strip completely IMO is because a paint job is only as strong as its weakest link. They can say what they want, but these materials do deteriorate over time so I feel its best to start with a solid foundation. Additionally, paint has a minimum thickness and a maximum thickness. That includes all primers as well. If you have 12 layers of material you're going to be at the maximum thickness. When you exceed the maximum thickness paint chips and cracks easily as all of the layers of material expand and contract at differing rates influenced by temperature.
As far as grinding away the zinc coating on the steel goes, you'd have to do A LOT of sanding/grinding to eliminate it. What I would suggest is that when you start to break through to metal, go up from 36 grit to 80 grit. The process that Porsche used on their bodies was pretty good. I stripped my roof down to metal in October '06. It sat exposed for about 5 months. There was some slight pitting which was removed with a few passes of the sander when I resumed work on the car last spring.
Make sure you get all traces of blast soda removed from the vehicle. While it's a great media there's something about the soda that can inhibit adhesion painting materials.
Most of the adhesion problems regarding aluminum are a thing of the past. With the exception of welding, aluminum can be treated just like steel.
I did use paint stripper at various points. There are drawbacks to using it such as the fact that it will damage virtually anything it comes in contact with that's not steel or aluminum. If you have a car with 20 layers of lacquer, by all means use the stripper. But if your car uses modern catalyzed paint forget about it. It will work, but it requires a lot more effort and time spent scraping and reapplying stripper.
The chance of having excess material built up in the door jambs is pretty slim. Unless you have obvious proof otherwise, the paint in the jambs is most likely the original. If you plan to repaint the door jambs or under the hatch, I would just clean them real well (with a solvent) and give them a very good scuff with some Scotch-Brite.
Body filler will not adhere to metal treated with acids like etch primer or rust converter. You must seal the acid based product with epoxy and then apply filler. Most fillers will work over epoxy primer, and some glazing putties will even work when applied to cured, scuffed paint. All of the independent tests I've seen have shown that filler bonds the best with bare steel or aluminum prepped with 120 grit. IMO nothing sticks to metal better then body filler which is why I'm such a huge fan of Slick Sand.
01-13-2008, 05:29 PM
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And if you didn't know primer is taulk based and will actually draw water to it (this info from Dupont paint rep) for proper moisture pruffing you need to aply a primer sealer- check with your paint guy to see what he recomends.
01-13-2008, 08:42 PM
#24
Three Wheelin'
I've been watching this post as I'm going through the same process. I've gas welded the small holes for the side moldings and add on marker lights and have bought a half pound of alumalloy for aluminum brazing the small aluminum holes. With a little practice the alumalloy does a great job. The nice thing about the stuff is it turns into a liquid before you seriously heat the aluminum body so there is no warping.
I'm faced with the same issue as Russ in that I'm doing this in the garage which is under the house. I just bought a small container of a citrus stripper thats not supposed to give off an offensive odor. It also is supposed to stay wet for up to 24 hours. I thought I'd try this stuff before reverting to the harsh stinky stuff. Most of my car has only the original paint but it was on Cape Cod most of its life so the clear coat is checking and there are a couple panels that appear to have a more recent clear coat added. I'm in agreement with J Howell about the weakest link concept.
I'm faced with the same issue as Russ in that I'm doing this in the garage which is under the house. I just bought a small container of a citrus stripper thats not supposed to give off an offensive odor. It also is supposed to stay wet for up to 24 hours. I thought I'd try this stuff before reverting to the harsh stinky stuff. Most of my car has only the original paint but it was on Cape Cod most of its life so the clear coat is checking and there are a couple panels that appear to have a more recent clear coat added. I'm in agreement with J Howell about the weakest link concept.
01-13-2008, 09:13 PM
#25
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I'll try to respond to as many of the questions and posts as I can.
In many of the tight areas such as the drip rails I too used a brass wire wheel on a grinder and it worked well. I then applied a rust converter. For removing paint in really tight areas I used a scotch brite pad on a mini angle grinder.
Once a car gets to a certain age, I'm all for a total strip down and starting from scratch. Incompatibility of different materials is more of a wives tale then anything these days, especially if the car has been painted properly in the past. Incompatibility rears its head when someone tries to apply a product over a lacquer usually. As I've said before, urethane reducers will attack a lacquer like paint stripper. The reason to strip completely IMO is because a paint job is only as strong as its weakest link. They can say what they want, but these materials do deteriorate over time so I feel its best to start with a solid foundation. Additionally, paint has a minimum thickness and a maximum thickness. That includes all primers as well. If you have 12 layers of material you're going to be at the maximum thickness. When you exceed the maximum thickness paint chips and cracks easily as all of the layers of material expand and contract at differing rates influenced by temperature.
As far as grinding away the zinc coating on the steel goes, you'd have to do A LOT of sanding/grinding to eliminate it. What I would suggest is that when you start to break through to metal, go up from 36 grit to 80 grit. The process that Porsche used on their bodies was pretty good. I stripped my roof down to metal in October '06. It sat exposed for about 5 months. There was some slight pitting which was removed with a few passes of the sander when I resumed work on the car last spring.
Make sure you get all traces of blast soda removed from the vehicle. While it's a great media there's something about the soda that can inhibit adhesion painting materials.
Most of the adhesion problems regarding aluminum are a thing of the past. With the exception of welding, aluminum can be treated just like steel.
I did use paint stripper at various points. There are drawbacks to using it such as the fact that it will damage virtually anything it comes in contact with that's not steel or aluminum. If you have a car with 20 layers of lacquer, by all means use the stripper. But if your car uses modern catalyzed paint forget about it. It will work, but it requires a lot more effort and time spent scraping and reapplying stripper.
The chance of having excess material built up in the door jambs is pretty slim. Unless you have obvious proof otherwise, the paint in the jambs is most likely the original. If you plan to repaint the door jambs or under the hatch, I would just clean them real well (with a solvent) and give them a very good scuff with some Scotch-Brite.
Body filler will not adhere to metal treated with acids like etch primer or rust converter. You must seal the acid based product with epoxy and then apply filler. Most fillers will work over epoxy primer, and some glazing putties will even work when applied to cured, scuffed paint. All of the independent tests I've seen have shown that filler bonds the best with bare steel or aluminum prepped with 120 grit. IMO nothing sticks to metal better then body filler which is why I'm such a huge fan of Slick Sand.
In many of the tight areas such as the drip rails I too used a brass wire wheel on a grinder and it worked well. I then applied a rust converter. For removing paint in really tight areas I used a scotch brite pad on a mini angle grinder.
Once a car gets to a certain age, I'm all for a total strip down and starting from scratch. Incompatibility of different materials is more of a wives tale then anything these days, especially if the car has been painted properly in the past. Incompatibility rears its head when someone tries to apply a product over a lacquer usually. As I've said before, urethane reducers will attack a lacquer like paint stripper. The reason to strip completely IMO is because a paint job is only as strong as its weakest link. They can say what they want, but these materials do deteriorate over time so I feel its best to start with a solid foundation. Additionally, paint has a minimum thickness and a maximum thickness. That includes all primers as well. If you have 12 layers of material you're going to be at the maximum thickness. When you exceed the maximum thickness paint chips and cracks easily as all of the layers of material expand and contract at differing rates influenced by temperature.
As far as grinding away the zinc coating on the steel goes, you'd have to do A LOT of sanding/grinding to eliminate it. What I would suggest is that when you start to break through to metal, go up from 36 grit to 80 grit. The process that Porsche used on their bodies was pretty good. I stripped my roof down to metal in October '06. It sat exposed for about 5 months. There was some slight pitting which was removed with a few passes of the sander when I resumed work on the car last spring.
Make sure you get all traces of blast soda removed from the vehicle. While it's a great media there's something about the soda that can inhibit adhesion painting materials.
Most of the adhesion problems regarding aluminum are a thing of the past. With the exception of welding, aluminum can be treated just like steel.
I did use paint stripper at various points. There are drawbacks to using it such as the fact that it will damage virtually anything it comes in contact with that's not steel or aluminum. If you have a car with 20 layers of lacquer, by all means use the stripper. But if your car uses modern catalyzed paint forget about it. It will work, but it requires a lot more effort and time spent scraping and reapplying stripper.
The chance of having excess material built up in the door jambs is pretty slim. Unless you have obvious proof otherwise, the paint in the jambs is most likely the original. If you plan to repaint the door jambs or under the hatch, I would just clean them real well (with a solvent) and give them a very good scuff with some Scotch-Brite.
Body filler will not adhere to metal treated with acids like etch primer or rust converter. You must seal the acid based product with epoxy and then apply filler. Most fillers will work over epoxy primer, and some glazing putties will even work when applied to cured, scuffed paint. All of the independent tests I've seen have shown that filler bonds the best with bare steel or aluminum prepped with 120 grit. IMO nothing sticks to metal better then body filler which is why I'm such a huge fan of Slick Sand.
I really didn't want to do a total strip, but the paint is so thick it is chipping in various places, just as JH alluded to....
the soda blasting is supposed to be a really good deal, but requires a lot of soapy/water washing when done (so Paul tells me). I will be using this technique (or just media blast) for the rust areas that I could not clean up with the grinder. Not sure if it will work on the bumper covers (as Stan suggested I do), but will check into that when the time comes.
The primer I'm using is specifically for galvanized steel (for the steel parts--and then a different one for the aluminum), so there shouldn't be any concerns there.....like I said before, just enough to cover the metal so as to prevent it from rusting up.
Anyway, took the hatch off today, stripped it, cleaned up the thumbnail sized rust areas, primer-ed it and reinstalled back on the car. Sure wish I could have used the first hatch Gregg sent me....to bad FedEX busted the crap out of it.
On to the doors tomorrow......
--Russ
Last edited by largecar379; 12-14-2008 at 02:27 AM.
01-14-2008, 04:25 PM
#26
Drifting
The primer that is talc based is what is commonly referred to as 2K, sanding primer, or surfacer. It is the high viscosity primer that acts as a final, super thin coat of body filler, that you block down to make the body perfect. It can draw moisture from the air and it is a good idea to seal it. You can buy sealer, but you can use some reduced epoxy instead so you don't have to buy another product.
01-14-2008, 10:48 PM
#27
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Very nice Russ, can't wait to see it all finished.
I hope you've covered that beautiful interior, would hate to see all that sanding residue and overspray make it's way onto that new leather.
I hope you've covered that beautiful interior, would hate to see all that sanding residue and overspray make it's way onto that new leather.
01-16-2008, 01:20 AM
#28
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Yep, keeping it covered every step of the way, and blowing the interior out every time when I get done grinding/sanding a panel. Not to mention safety glasses, a mask for the dust, and blowing/washing everything down (driveway, yard, my junker Tahoe, etc....) when done.......
didn't get anything done yesterday, and now today, the rain came.
got the driver's door done though, except the mirror. I'll be removing the mirrors anyway for GTs mirrors, so I can't see putting any effort into stripping and painting the flaggers.....
paint was so damn thick there were three hairline cracks in it, running lengthwise, about 10 inches long in the middle/center of the door just below the horizontal ridge (below where the rub strip was). I found some filler under the cracks from a previous repair for a scratch--metal was actually not affected much by the scratch, but a little more grinder work and then a follow up with a 60 grit paper/electric block sander, and you'd never notice it was there. Should be even better with primer coats/block sanding. Another reason to take it to the metal-----
surprised how thick the metal (aluminum) on the door is......makes me feel a little more at ease with the 36 paper, and then a follow up with the 60 on the metal. Probably won't use the 36 on the front fenders/hood as they aren't that thick, but we'll see how it goes after the passenger door gets done.
will try to get the passenger door tomorrow.....
--Russ
Last edited by largecar379; 12-14-2008 at 02:27 AM.
01-17-2008, 02:11 AM
#29
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no paint on the doors and front fenders as of this afternoon.
this is progressing nicely, and I made it thru the front fenders without too much fuss. I did find that on the (far front lower) passenger front fender, there was a quarter inch of filler on it, below the line running from the upper part of the fender opening to the front bumper cover. someone previously had failed to align the fender (it needs to be pulled out slightly) with the front bumper cover, and instead just added filler to make the fender and bumper cover line up. really stupid......really cheapo.
As you can see, there's a hell of a lot of material removed. dust mask, safety glasses, ear plugs, wet the area down to prevent dust from getting everywhere, portable fan to blow the material away from me while working, etc,.........and then wash it down after getting done for the day.
these pictures show the bare metal with the 36 paper, before going back over it with a 60 paper to smooth out the first raw cut. the block sander with 60 paper really helps, as it take out most of the scratches left by the 36 paper and grinder. it is more work, but I think there will be less primer needed to fill, even though Paul said not to worry about the 36 paper scratches. Anything that helps make it smoother should be a good thing.....
I am using a primer specifically for aluminum to just do a first coat on it, to prevent any oxidation from starting before my restoration guy get a hold of it. The steel sections were painted with a primer that is for galvanized steel, again, just a minor coat on it to keep it from rusting before it goes to Paul's paint shop. Once there, they will blast the rust areas, bumper covers, headlight dimple areas (too hard to get the grinder in there), then start on the body areas that need building up, and then it's primer and paint time.......
the mirrors are untouched as previously noted, as I anticipate replacing them with GTS mirrors.
I still have some minor things to do like removing the front spoiler and hood badge, and finishing up the fender areas and lower windshield cowling not done today. I should get that and the hood done tomorrow, weather permitting......
For those of you who are keeping track of this nonsense, I now have about 10 hours labor in this including the hatch change-out. I should have about 15 hours total by the time all panels are stripped with the 36 paper and then sanded with the 60 paper. At $80 per hour (the going rate around here), you can see that my labor is going to save me a big chunk of $$$ doing it myself.
--Russ
this is progressing nicely, and I made it thru the front fenders without too much fuss. I did find that on the (far front lower) passenger front fender, there was a quarter inch of filler on it, below the line running from the upper part of the fender opening to the front bumper cover. someone previously had failed to align the fender (it needs to be pulled out slightly) with the front bumper cover, and instead just added filler to make the fender and bumper cover line up. really stupid......really cheapo.
As you can see, there's a hell of a lot of material removed. dust mask, safety glasses, ear plugs, wet the area down to prevent dust from getting everywhere, portable fan to blow the material away from me while working, etc,.........and then wash it down after getting done for the day.
these pictures show the bare metal with the 36 paper, before going back over it with a 60 paper to smooth out the first raw cut. the block sander with 60 paper really helps, as it take out most of the scratches left by the 36 paper and grinder. it is more work, but I think there will be less primer needed to fill, even though Paul said not to worry about the 36 paper scratches. Anything that helps make it smoother should be a good thing.....
I am using a primer specifically for aluminum to just do a first coat on it, to prevent any oxidation from starting before my restoration guy get a hold of it. The steel sections were painted with a primer that is for galvanized steel, again, just a minor coat on it to keep it from rusting before it goes to Paul's paint shop. Once there, they will blast the rust areas, bumper covers, headlight dimple areas (too hard to get the grinder in there), then start on the body areas that need building up, and then it's primer and paint time.......
the mirrors are untouched as previously noted, as I anticipate replacing them with GTS mirrors.
I still have some minor things to do like removing the front spoiler and hood badge, and finishing up the fender areas and lower windshield cowling not done today. I should get that and the hood done tomorrow, weather permitting......
For those of you who are keeping track of this nonsense, I now have about 10 hours labor in this including the hatch change-out. I should have about 15 hours total by the time all panels are stripped with the 36 paper and then sanded with the 60 paper. At $80 per hour (the going rate around here), you can see that my labor is going to save me a big chunk of $$$ doing it myself.
--Russ
Last edited by largecar379; 12-14-2008 at 02:27 AM.
