Sill Corrosion Repair

[Jay Herbert]

Thought I'd take some pictures of the process I'm going through to repair some corrosion damaged Gen I side sills.

The two sills were off a '95 yellow RT/10.

Both exibit typical galvanic corrosion, and are going to need to be completely stripped and have some patches welded in. They will even require a little "hammer work" as both have a been damaged at the front (sadly from shipping!), one has a minor dent of the exhaust outlet.

The first picture is of the sill corrosion untouched.

The second picture is after the first chemical strip.

The third is after the second chemical strip, note, the grey in the middle of the pic.... turns out in the past someone attempted a repair by samding, filling the hole with bondo, priming (the grey) and repainting. In the repaired area the layers were factory black primer/adhesion promoter, yellow, gray, yellow, clear.

In the unrepaired area it was just: factory black primer/adhesion promoter, yellow, clear.

It looks like it will be to much work to chemically strip the sills by hand, I do not want to sand off the paint on soft aluminum, so I'm looking for a local media blaster that can do the job.

 

[bth1]

I was just going to post the same pictures as I have been stiping the pain on my sills (96 RT). It is amazing how much work it is to get all that old paint off -- even with the chemical stripper.

I was happy to find only one area where the corrosion was all the way through.

 

[Jay Herbert]

I was just going to post the same pictures as I have been stiping the pain on my sills (96 RT). It is amazing how much work it is to get all that old paint off -- even with the chemical stripper.

I was happy to find only one area where the corrosion was all the way through.

You are lucky, the ones I'm working on are also badly corroded at many rivit points and where the lower screws hold it to the car, they had to have some salt water on them at some point. If you did not remove the insulation, do. Much to my surpize, there were many places behind the insulation that had held moisture and had started to corrode, it would have only been a matter of time before the spots would have been holes..

 

[GT40DOC]

Jay,
I did a set that were pretty bad, one sill was real bad(came from Fla. and had salt water damage like you describe). They are a pain to strip, but I would be very careful about having them blasted. They are very soft alum. (as I am sure you know) and would be easy to warp and pit. If most of your sills are good, I would just keep stripping with Airplane Stripper. My sills had many, many corrosion holes, some quite large. After cleaning them very well, we were able to heli-arc all of the holes (except the mounting holes, of course) without having to use any patches. That grade of alum. really responds well to welding. It takes a lot of work to get them straight after your patch work is done, but it can be done.....Doc

 

[Jay Herbert]

Jay,
I did a set that were pretty bad, one sill was real bad(came from Fla. and had salt water damage like you describe). They are a pain to strip, but I would be very careful about having them blasted. They are very soft alum. (as I am sure you know) and would be easy to warp and pit. If most of your sills are good, I would just keep stripping with Airplane Stripper. My sills had many, many corrosion holes, some quite large. After cleaning them very well, we were able to heli-arc all of the holes (except the mounting holes, of course) without having to use any patches. That grade of alum. really responds well to welding. It takes a lot of work to get them straight after your patch work is done, but it can be done.....Doc

After I finally got in the hang of it (been a while since I've done this ), the paint is coming off pretty good now, so I'll be going the chemical stripping direction. You are right, it is very soft, I was surprised it was not work hardened more, and plenty thick to weld on.

Here is a picture with all the paint removed.... two pretty big holes:

Also, taking out the insulation is a must, specially if there are holes.... if you leave it in, the chemicals will go through the holes and get in the insulation. Wanna lighten up your car? The insulation weighs as much as the sill... maybe more!

 

[viperstoo]

FYI:
I went through this process a few months ago. Although my sills did not have total *********** of the metal they had extensive pitting in many places under the insulation. After stripping the inside to bare metal I applied two coats of high temperature marine epoxy (good up to 450 degrees F). I also wrapped the exposed fiber insulation, that is between the blanket and the sill, with a continuous sheet of aluminum "foil" to prevent water from being absorbed by the fiber. I plan to remove the sills in a few months for inspection, and periodically after that if I see any indications. By the way, I talked with Chuck Tator while I was working on my sills and his advice was to never wash the car until the sills have totally cooled. I know that I was quilty of washing the car as soon as I had returned from a drive so I've stopped doing that. Also, I have made certain that I bypass the water softener for the outside spigot so that there is no "salt water" being used to wash the car. I never gave the water softener a thought until I worked through this process and tried to determine all the possible reasons for the corrosion. Hope this is helpful

 

[dansauto]

yep lots of work, I used to do this until one idiot complained I charged too much,

 

[GT40DOC]

Jay,
Once I had the sills stripped, repaired, and ready for paint I sat down with my painter who is very experienced in high end autos and "tricky" paint situations. We decided to go with a special primer/adhesion agent, then use base coat/clear coat inside and out. The painter felt that the clear coat added a great bit of protection from the heat and elements to the inside. I also closed off all of the rivit holes and did not use that stainless steel piece used in the Gen 1 cars.

 

[Jay Herbert]

Jay,
Once I had the sills stripped, repaired, and ready for paint I sat down with my painter who is very experienced in high end autos and "tricky" paint situations. We decided to go with a special primer/adhesion agent, then use base coat/clear coat inside and out. The painter felt that the clear coat added a great bit of protection from the heat and elements to the inside. I also closed off all of the rivit holes and did not use that stainless steel piece used in the Gen 1 cars.

What did you use for insulation?

 

[GT40DOC]

Jay,
I re-used the factory Gen1 insulation, minus the stainless steel piece(the insulation can't go anywhere). If you don't have the gen1 insulation, you can use your Gen2, but will have to open up an area for the exhaust turn-outs. I also had some asbestos cloth(I think the real item) that had a heavy gauge alum. foil adhered to one side. I wrapped the cat/muffler with this material leaving the ends open for heat escape. I did my side sills appox. 1 1/2 years ago, and so far, the sills look great. It gets plenty hot here in the summer but am pleased to date.....Doc

 

[Jay Herbert]

A few more pictures.

Inside of the sill where the heat shield was holding moisture:

The corrresponding hole toward the exhaust exit:

and SIX more holes on outside, not visible as they were in the black paint:

Total hole count in this sill = fourteen!

Before I started, thought there was only three

 

[SNAKE BITE]

yep lots of work, I used to do this until one idiot complained I charged too much,

Not sure who your speaking of but besides that guy you totally screwed me when refinishing mine. By the way, many members of the IL VCA looked at my sills after you did them and couldn't believe the the terrible job you did.

Anyone getting these repaired, make sure you have them done locally so you don't take the chance of someone like Dans Auto ripping you off like happeded to me. If not you may end up having to get them done again like me.

 

[Jay Herbert]

yep lots of work, I used to do this until one idiot complained I charged too much,

Not sure who your speaking of but besides that guy you totally screwed me when refinishing mine. By the way, many members of the IL VCA looked at my sills after you did them and couldn't believe the the terrible job you did.

Anyone getting these repaired, make sure you have them done locally so you don't take the chance of someone like Dans Auto ripping you off like happeded to me. If not you may end up having to get them done again like me.

Since Dan say's he no longer does them, guess that is taken care of..... back to the topic

Sorry, just cannot see this being done this way by any bodyshop, just to much labor, they'd have to send it off to be CO2 blasted, or dip-stripped to be cost effective.

I already have over six hours in one side sill and that is only stripping the exterior, the interior should be faster as the chemical stripper will "stay put". It looks like it will take about a gallon per sill (about $20 a gallon at WalMart). I'd estimate 15-20 hours just to completely strip the sill, then the welding repairs and paint.... jeepers. For a body shop: Lets see 15 hours at what $25(?)/hour = $375 + $50 or so materials, that $425 before repair welding and any paint goes on. I guess I could easily see a body shop charging $1000 to properly repair and paint a set of sills with all the masking required and at least three different paints. But I'm just guessing.

Side note, the aluminum wrap around the insulation is attached with steel staples... yep, all rusty.

 

[Camfab]

Not all "aircraft coating remover" is the same. I used to have some that would make the paint curl up and fall off in 5 minutes. I just bought some from Autozone last week for another project.....all I can say is useless! Wouldn't take the paint off anything. "Klean Strip low odor aircraft remover" complete waste of money. The other stuff, I believe was made by Mar-Hyde. It had a real picture of a Jet on the can and was not low odor.

 

[dansauto]

yep lots of work, I used to do this until one idiot complained I charged too much,

Not sure who your speaking of but besides that guy you totally screwed me when refinishing mine. By the way, many members of the IL VCA looked at my sills after you did them and couldn't believe the the terrible job you did.

Anyone getting these repaired, make sure you have them done locally so you don't take the chance of someone like Dans Auto ripping you off like happeded to me. If not you may end up having to get them done again like me.

Had a hard time reading this, ever hear of "hooked on phonics"?

I didnt say it was you, but since you wanted to get on your soap box and start running your mouth... You misrepresented the condition of those when you sent them, they were full of body filler and much more corrosion then you thought. Look at Jays, yours were much worse. You got what you paid for. In the past I posted photos for everyone to see what it takes to do these, yes so maybe a good local shop could do them based on my experiance. I have lots of other work to do rather than free work to ViperClub members. I hope you got them fixed to your satifaction and found someone that can match black paint...

 

[SNAKE BITE]

yep lots of work, I used to do this until one idiot complained I charged too much,

Not sure who your speaking of but besides that guy you totally screwed me when refinishing mine. By the way, many members of the IL VCA looked at my sills after you did them and couldn't believe the the terrible job you did.

Anyone getting these repaired, make sure you have them done locally so you don't take the chance of someone like Dans Auto ripping you off like happeded to me. If not you may end up having to get them done again like me.

Had a hard time reading this, ever hear of "hooked on phonics"?

I didnt say it was you, but since you wanted to get on your soap box and start running your mouth... You misrepresented the condition of those when you sent them, they were full of body filler and much more corrosion then you thought. Look at Jays, yours were much worse. You got what you paid for. In the past I posted photos for everyone to see what it takes to do these, yes so maybe a good local shop could do them based on my experiance. I have lots of other work to do rather than free work to ViperClub members. I hope you got them fixed to your satifaction and found someone that can match black paint...

All you can do is LIE. Good for you, but I along with everyone who looked at them at the VCA meeting know the hack job you did(you even painted right over the chip film) . Not sure what your talking about free either. I paid you in full before you even received my sills and didn't ask for a dime back. Letting people know how you ripped me off is satisfaction enough.

 

[bth1]

It took me a week of evenings to strip mine--about 24 hours. But it is amazing what you uncover. I was surprised how much time it took using the striper -- but I figure it will save me money at the body shop and also allow him to focus on the repairs.

Jay - for some reason the black primer on the inside didn't just peel right off like the exterior paint. I needed to let it sit for a good long time, go at it with steel wool and then sand it off. The stripper stuff just sort of softened it up instead of making it peel right off.

Unfortunately right before I left to take mine to the body shop my camera's batteries were dead so I couldn't get any pictures.

 

[Jay Herbert]

Not all "aircraft coating remover" is the same. I used to have some that would make the paint curl up and fall off in 5 minutes. I just bought some from Autozone last week for another project.....all I can say is useless! Wouldn't take the paint off anything. "Klean Strip low odor aircraft remover" complete waste of money. The other stuff, I believe was made by Mar-Hyde. It had a real picture of a Jet on the can and was not low odor.

I'll certainly look for the Mar-Hyde stripper for the second sill.

I've found that a simple trick to make most chemical strippers work better is to rough up the paint with heavy grit sand paper before application. I did this for the back half of the sill and it made a huge difference.

Modern chemistry is much safer.... but often slower

 

[HP]

When I did mine, I had to use a heat gun on the end plates - so I assume that area was powder coated, not painted.
Like Jay, I found that scuffing the paint with coarse grit sand paper first, allowed the stripper to work better.

 

[C O D Y]

Good thread.... keep posting pics as you finish them up.