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Well, after finding more damage than I thought there would be in a couple of spots (see below) I've decided to strip the car down to bare metal. I'm trying to save some money on media blasting so I'll strip as much as I can using chemical stripping and a da sander and have the rest cleaned up at the blasters. I'm new to this so wanted to ask the experts....what should the metal look like when sanded down? When I get past the primer on the car there are still some specs in the metal. Is this rust and do I have to keep sanding until this is gone? I'll post a pic below so you can see what I'm talking about. Any help is appreciated.

Doh!


Here's what I'm asking about regarding sanding to bare metal...

Closer
 

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Couple things, if you use chemical stripping it helps to scor the surface, we use 36 grit on a da (do not sand to metal) just quickly go over the surface with very little pressure to get sanding lines in the paint, it will help the stripper get under the paint. The bottom pic you have is deffinately rust pitting, the best method it to media blast to remove, walnut shell media works well, or you could use rust mort to neutralize the rust but be sure and follow instructions and remove surrounding residue before coating over. Goodluck :devil:
 

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Hmmm... they guys I talked to about having the car media blased said that they use plastic media on the body panels, to avoid warpage, but that it would not remove rust. On the window channels and undercarriage/engine bay they use either glass or sand (don't remember) and that would remove any rust. On the body panels I was told I would have to da sand everything afterwards to remove any rust present which I guess is what I have.

I guess I'll try da sanding a bit before using the chemical stripper to get better penetration and have to figure what method to use to remove the rust pitting :(

Thanks for the reply...Any other options/opinions guys?
 

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bare metal

I just got through sanding my 63 down to the bare metal.I used a chemical stripper along with a roll of 80 grit sand paper.I am now getting ready to resand with the 80 grit to get any spots i missed and then spray some epoxy on it.
 

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I'm new to this so wanted to ask the experts....what should the metal look like when sanded down? When I get past the primer on the car there are still some specs in the metal.
Well, Im no expert but Ill show you what I came up with.

1962 car. It was in primer when I got it, rattle can primer. So I started seeing some spots that were getting some color, yup, that color we dont like, deep dark orange, RUST!!

So I went to town with a DA sander and a large stack of quality 3M discs. Good abrasive pays off. And change them often. So I was curious. How much metal was I removing. And I had all the sanding dust there, on the ground. So there was this pretty big pile of paint chips and who knows what when I swept up the floor.

So I wrapped a nice magnet in plastic and swept the pile of sanding debris I had. Made sure to get all in the pile of floor sweepings. I just wanted to see how much body was on the floor. After sweeping through all of the sanding debris I was almost surprised. I knew there was gonna be some metal in there. But I thought more. Nope. Not bad at all. I got maybe enough metal to fill a one ounce shot glass, total. Thats for the entire car. Not bad.

And my car didnt have any rust. The body didnt have any pitting, I see some in yours. Those pits cant be sanded off. It needs a media blasting, either walnut shells (dont think so) or soda, yes. Problem with soda is you cant guarantee all the super caustic soda is gonna be removed. Problem with paint. But them lil pits will grow too under the nice paint job you lay down. Ive seen both grow under the paint job. Rust or soda contamination. Really, they grow. You can get ridges that keep growing. Looks like a fault line.

And you can put on a rust converter, just acid really. And so you have a lil chemistry set cooking away in each lil pit, cooking and growing.

Sounds bad huh. You either throw acid at it or a caustics agent (soda blast). Where do you win??

Im not sure you do when the panel is pitted so much..

What would I do?? Well. Id go with the soda wash and make sure the guys that did it used a very high pressure wash of clean water to remove ALL of the soda. It will want to rust NOW after that process. Catch 22.

You are trying to get it in raw metal but clean raw metal wants to rust up NOW. And thats where the metal prep washes come into play. I dont like them. They are acid based. But used correctly they pickle the metal and make it perfect for a primer.

So many ways to go.

Here is a mechanical removal of the paint. The metal doesnt want to rust up too soon. I dont know why, maybe cause there isnt any chemical on it to attract moisture. Dont know why but I had it sit for 2 weeks during the stripping and I didnt have any rust show up. Dont dare touch it or let any water get on it, instant rust. JR



 

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Doh!


Here's what I'm asking about regarding sanding to bare metal...

Closer
These specks are in the metal,dont know what it is,Ive seen this when I had the roof,QP stripped.To keep a manageable mess what I do is tape off a section,strip this section,clean it up and move on too the next section.
[/IMG]
 

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Just the clarify,what you are seeing are not pits,these specks are in the metal.Try this,get some sand paper and sand the area in the picture,after you sand this area look and you will see these specks,they will look a little lighter in color but you will see them.
 

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Well the specks you are seeing are in fact rust laying mostly dormant for years under paint or any repairs that where performed. Most the time it will be on the top panels and maybe somewhat heading downwards on the side of the car. I have seen this on many many older cars as for lacquer paints and primers back in the hayday. When you find that older NOS panel (White Tag) the primers they have on these panels wasn't the best protection from moisture. This was the base primer GM used. Remember things where still done by the human hand and not all panels have the same quality or thickness of material as others sprayed that day. I personally have owned 7 older veh's that have had this rust on the metal. 3 of them still having the original paint at that time. The worst was a 1968 Chevelle SS from Georgia. I media blasted it and the specs all showed up. I started chasing then down with a small dremel tool and wire wheel. It took way to long. Here is an old trick I learned from an Old School Bodyshop Owner. He had a 55 chevy with the same kind of rust and he showed me the car before he did this procedure. This car literally had orange spots the size of raisins all over it. He puts on all this protective gear and takes out a spray bottle and started spraying muriatic acid on the rust (literally the whole panel) He then tells me to come back in about 5 hours and he would let me see the progress. I went back and He showed me his progress. It was astonishing. He stated he still needed a few more hours but holy cow. It was almost like new. The metal looked as if new. He stated the trick is to keep the Acid wet and flowing. He stated on big jobs he will use a large weed sprayer. You can even use a red scotch bright pad on the stubborn spots as you spray the acid. After the Rust is gone then you wash the panel with Metal wash, rinse, Pre Cleano the entire area, let dry, Then sand and ready for prime. I did this method to my Chevelle 14 years ago. It was crazy how the rust just ran off of the car. You will see the pits that are where the orange specks are sitting in the metal afterwords. But to this day the paint still looks beautiful on that car. I wish I had some pics of it. I sold it like a dummy many years ago. This is a method I use now. It does take time. I have also seen guys that do nothing except sand over it and prime and paint. Seen some of these cars years later and some still look really nice. Basically it is gonna be up to you on how much work you wanna spend digging into it. There really is no easy way of removing the specks as it looks to have a few in the pics. Hope this helps and sorry for it bein so long. I have a NOS fender for my 69 that I need to sand and do this treatment to as for the orange specks forming. I will try to do a small spot on it and get some pics for ya.

P.S. I should have mentioned. The cars I have seen this on are usually from warmer climates such as California, Texas, Arizona. The car would see alot of sun but not alot of rain. Cracked the paint from all of the sun and thats where the rust starts. I dont notice these specks to much on the cars originally from this area. The rust tends to be a little larger by now.
 

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Oops, looks like I left out the most important part in my other post. The company I have used for media blasting follows the Walnut shell with Garnet (Blastech Kent Wa). The Walnut shell is good media for stripping paint, primer, sealer etc as well as does a good job with body filler removal and it is a low impact media, the Garnet is more agressive and will blast the rust pits. IMO soda works well in a general sense, it does remove paint very well but has a harder time with rust and body filler.
 

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I would think muratic acid would be a last resort,this stuff IS BRUTAL.It eats everything it comes in contact with,concrete,glass,fingers......................I used Captain Lees Rust Remover years ago,got it at the auto paint store.Believe it or not,Navel Jelly works too.
 

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I see nothing wrong with a metal rust converter. If you are very conservative with it. It will do its job and then you can follow up with some laquer thinner to clean it off. Just dont go walking off in between.
 

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Muriatic acid AKA pool acid is very cheap and it will work to completely remove rust. I like to use it best in containers for small parts though.

Given enough time, this muriatic acid will do the trick but is very noxious to the mucous membranes of the human body. Be careful! One whiff and you will know.

Concrete etches very quickly with this stuff. Do I here someone say repave?
 

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Discussion Starter #13
Wow…Thanks for all the info guys...

JR- your posts were some that helped me make the decision to dive into this myself…great job on getting the car to metal.

I knew muriatic acid sounded familiar…I have a bunch for the pool but I think I’m going to try a couple of things before going that route. I’m doing this on my patio and considering how much paint stripper has fallen on the ground thus far, I’d probably create some big problems with the acid on the concrete.

Using acidic/basic media/solutions to clean things up worries me since you have to make sure all of it has been removed afterwards or it can screw your paint up but if it’s needed, its needed.

Damn ZR-1Jeff, that panel you stripped looks great, in fact that is what my front fender that I stripped looks like. Hopefully this is just on the upper panels (trunk, roof). What did you use to strip yours down like that (QP??)?

1969NovaSS – Thanks for the ideas and the detailed explanation. It may be what you’re talking about…I think this is under the stock paint/primer maybe just didn’t seal that great…and the car is a Southwestern car so that may be the reason like you stated.


I guess I’m going to strip a couple more spots down to metal on each panel and see if this is everywhere or just on the top panels and we’ll go from there.

Thanks again for all the ideas…I’ve been lurking on the site researching things for a while and this is my first post…I appreciate all the responses.
 

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Using acidic/basic media/solutions to clean things up worries me since you have to make sure all of it has been removed afterwards or it can screw your paint up but if it’s needed, its needed.

My brother has been painting doors for labs 20 years now and cleans everything off with laquer thinner and nothing has failed yet. This is why I found the system works for me.

Im talking about doors that get abused daily and have to deal with alot of different enviroments and chemicals. Probably more so than any car will ever endure.
 

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My brother has been painting doors for labs 20 years now and cleans everything off with laquer thinner and nothing has failed yet. This is why I found the system works for me.

Im talking about doors that get abused daily and have to deal with alot of different enviroments and chemicals. Probably more so than any car will ever endure.
Door paint is not car paint, use a wax and grease remover.
There is a difference between automotive lacquer thinner and hardware store
lacquer thinner. You DO NOT want to wipe the car down with the automotive type. It dries WAY too fast. Who knows what's in the hardware type, it won't cut much of anything.
You want the contaminates to float to the surface and be wiped away while still wet. Ain't gonna happen with auto lacquer thinner.. unless you're prepping at really cold temps (which is a No No).
 

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Discussion Starter #16
My brother has been painting doors for labs 20 years now and cleans everything off with laquer thinner and nothing has failed yet. This is why I found the system works for me.

Im talking about doors that get abused daily and have to deal with alot of different enviroments and chemicals. Probably more so than any car will ever endure.
Any particular brand/product you would recommend? I'm sure you can tell from my questions that I'm a bodywork newb
 

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Door paint is not car paint, use a wax and grease remover.
There is a difference between automotive lacquer thinner and hardware store
lacquer thinner. You DO NOT want to wipe the car down with the automotive type. It dries WAY too fast. Who knows what's in the hardware type, it won't cut much of anything.
You want the contaminates to float to the surface and be wiped away while still wet. Ain't gonna happen with auto lacquer thinner.. unless you're prepping at really cold temps (which is a No No).
He uses a two part epoxy on his doors. Is it really that much different? He says its been used in the trade for years. He has been running his company for quite a long time.

I trust him since he has been doing it a whole lot longer than I ever have. I didnt get this info from the internet so I wouldnt know what everyone else uses.

Im curious what chemicals are in wax and grease remover that make it a better choice. Isnt it Mineral spirits?

I would never clean paint guns with mineral spirits. Isnt mineral spirits an oil based solvent?:no:

I think his philosophy is that Lacquer thinner is the most powerful and cleans the best.

Coincidently one of the laboratories he services tests these very chemicals and stores them. They develop medical drugs here in New Jersey.
 

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Ok, Ill pipe in LOL It sat night, what the heck.

Wax and grease remover comes in two basic types. Water borne and solvent based.

The water borne is best suited for removing the crud that lands on the body before the paint job. It will get the dust and debris off the panel, like already said, float it off onto the clean rag. They dont evaporate too fast so you can actually remove the debris instead of pushing it around on the panel. But, they arent much use for actual oil and god forbid grease. They are alcohol based. They wont touch the oil and grease as the name implies. Alcohol doesnt touch oil. It loves water, hates oil.

Then there is the solvent based WGR. They will take the oils and organic light greases off. But the WGRs designed for body work are not as hot as the standard lacquer thinners, hardware or body shop brands. They allow some working time so you LIFT the gunk off instead of smearing it around. Clean absorbent rags are the key too.

Funny thing about lacquer thinners is there is NO set formula. Yeah, they can be made up of several diff chemicals and called the same thing. I have used a few diff manufactures and some leave a film of who knows what. Some are cleaner but supper fast, no working time.

For me.. I like to use the hardware store brand for the really nasty greasy, oily stuff, its cheap and cuts into the bad oils. And I use it really wet with clean rags, EPA dont look. Then I like to finish up with a product of my liking. Some left over 1.1.1. tric. It removes all the residue of the lacquer. And after that, if its been sitting for a day I like the water borne WGR to remove the dust.

Not even what a shop can do. But Im not a shop. JR


Door paint is not car paint, use a wax and grease remover.
There is a difference between automotive lacquer thinner and hardware store
lacquer thinner. You DO NOT want to wipe the car down with the automotive type. It dries WAY too fast. Who knows what's in the hardware type, it won't cut much of anything.
You want the contaminates to float to the surface and be wiped away while still wet. Ain't gonna happen with auto lacquer thinner.. unless you're prepping at really cold temps (which is a No No).
 

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Ok, Ill pipe in LOL It sat night, what the heck.

Wax and grease remover comes in two basic types. Water borne and solvent based.

For me.. I like to use the hardware store brand for the really nasty greasy, oily stuff, its cheap and cuts into the bad oils. And I use it really wet with clean rags, EPA dont look. Then I like to finish up with a product of my liking. Some left over 1.1.1. tric. It removes all the residue of the lacquer. And after that, if its been sitting for a day I like the water borne WGR to remove the dust.
. JR
Some shops here are using both water and solvent based W&G remover before painting. I do occasionally. The water based removes fly crap better.

Using lacquer for cleaning really greasy areas is fine, the key point you make is to "finish up with a product of my liking". Should be a W&G remover.
Using lacquer and going right to paint is the problem. As you posted, some leave a film, almost all are too fast. This is why I advise to just avoid them as a pre paint cleaner.
 

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He uses a two part epoxy on his doors. Is it really that much different? He says its been used in the trade for years. He has been running his company for quite a long time.

I trust him since he has been doing it a whole lot longer than I ever have. I didnt get this info from the internet so I wouldnt know what everyone else uses.

Im curious what chemicals are in wax and grease remover that make it a better choice. Isnt it Mineral spirits?

I would never clean paint guns with mineral spirits. Isnt mineral spirits an oil based solvent?:no:

I think his philosophy is that Lacquer thinner is the most powerful and cleans the best.

Coincidently one of the laboratories he services tests these very chemicals and stores them. They develop medical drugs here in New Jersey.
There are differences in epoxies, I don't recall exactly what they are but remember from a paint class talking about differences. I only use one epoxy so I didn't pay much attention when they talked about it :sleep:
Each product has a different tolerance to contaminations even similar products from two different companies.
Overall the best chance of success with auto refinish products is to avoid lacquer thinner for pre paint cleaning. I have seen it fail many times, usually resulting in someone bringing the project to the shop for a redo after they tried it themselves.
W&G remover is formulated for pre paint cleaning, lacquer thinner is formulated to thin paint. Why not use the one that is designed to do what you want?
W&G removers, lacquer thinner, reducers, primers, paints, clears are all oil based (except for water based versions) they are made from petroleum.
 
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