Steve Wike

Have finished stripping thetrunk lid. Am using a hand sander with 100 grit emery paper. Making some head way, but something doesn't seem right. Am going one direction. Have some small swirling, like loop stitching marks in metal. Ater I get to clean metal (still seeing red) plan to go over it wet with 350, clean, and then S-Williams GBP 988 Auto Primer. What am i doing wrong? Have some pitting too. 80 grit, different sander? Please advise. The car is inside, so I hope the rattle car primer is OK for a while. Got a new camera, so hope to send in some pictures. Where is the link for direction on downloading pictures? Thanks.

redoldsman

My thought is you should not be using emery paper. You should be using sandpaper. The emery paper is cutting the metal. 100 grit may also be a little aggressive.

Bluevista

Normally you use a DA and 80 grit sandpaper sanding discs to strip paint.
I used a 5" electric Dewalt electric dual action orbital sander and about a million 5" discs when I stripped my Vista Cruiser.

Rocketbrian

Why do some people use chemical aircraft paint strippers? Wouldn't that be alot easier? No dust and no hours of using force. I did try some on the top of one fender and it immediately stripped the paint to the factory black primer. Maybe it's hard to remove the primer or it has to sit alot longer. Of course, stripper must be done in well ventilated areas and is expensive. What makes a sander a dual action? I see references to this all the time.

MDchanic

If you sand, you have a chance of saving old bondo if it looks like it was done well.
If you use stripper, everything goes and you've got to start completely from scratch.

Also, stripper is yucky and goes all over the place.

A dual-action sander will do either regular or orbital rotation.

- Eric

redoldsman

Soda blasting is supposed to be one of the best. I have not used it but I understand it leaves less mess and is the least damaging. It probably is the most expensive too since you have to have somebody do it for you. I have used aircraft stripper and it works very well. It does require good ventilation and makes a mess. You will have to go over it at least twice. I used those plastic bondo spreaders the first time to scrap the paint off and them used steel wool pads soaked in laquer thinner. It does not take all the filler off but you will have to go back and rework it.

mike's88

Actually when I took the 78 to bare metal, I used all methods above, except the soda blasting. Used stripper 1st, then 2nd round using steel wool soaked in stripper. Neutralized with water, then used an elec. d/a with 120 grit. After that, went up to 320. Left a nice pattern, with enough bite for the primer to adhere to. I've heard that soda blasting leaves a residue, which has to be cleaned off very thoroughly before painting.

oldsguybry

lol , I have no stripper , just a couple of good palm sanders and a whole lot of sandpaper , starting with heavy grit and ending with light sandpaper.....I probably sanded 75% of car through the years this way.( not recomended , unless you have an excess amount of time and energy ) when I do the restor , it should be a breeze to get the rest off.

Eddie Hansen

with the comments about emery paper? perhaps that was just a misnomer. Stripping a car by hand without a da sander is just plain torture, I also have used stripper and da sanding, I have even used 36 grit when large patches of bondo that I didn't want were found. you do not always have to strip to bare metal either, if this is the original paint the original primer would be fine unless it is in bad condition, it will require a sealer surfacer. That leads me to another thought, even if your car is inside, primer generally isn't water proof and you run the risk of the primer absorbing moisture from the air, check with your paint guy, it may be better to try and shoot some epoxy primer with a gun then a rattle can, you could rent these items. I am not an expert by any means, I have painted a few cars and there are guys here who really know what they are doing and I am sure they will chime in.

One thing I am thinking about is after I finish my body work, I am going to take an adult ed body shop/painting class so I can paint the color in a proper spray booth, just a thought...

Steve Wike

Thanks to all for the comments! I have been going only one direction with the electric oribtal sander, and seeing streaking. Will change that method. I think I need to get all that "red" out I am still seeing, as it should still be rust. I really hate to go down to the bare metal, but if not, this "red" will come back out again, correct? I hope this non-epoxy primer holds...for a while.
Collierville, TN project

MDchanic

Unless it's red primer...

Photos?

- Eric

Steve Wike

Eric:
The factory primer is "grey" and man, it is hard to get off. I really think it is rust, and not red primer. How do you send pictures? is there a link here on the site with directions...Thanks

Bluevista

Mine was a red oxide colored primer on the inside and on the outside the primer looked almost black and was a bear to get off where the woodgrain vinyl was, probably a dark gray. Where the sun burned the paint off the primer it would wipe off with a wet rag.
I researched it a lot on the body forums before I stripped my paint and about 95% of the professional body guys recommend mechanical stripping over chemical. Paint stripper can haunt you forever if you don't clean every microscopic trace of it off, you'll never get it out of some areas it oozes into, destroys filler and seam sealers, smells bad, and makes a mess worse than sanding IMO. My sander has a shop vac hose adapter, I used it and very little dust went into the air.
You're always better off stripping to bare metal unless it's the original paint in good stable condition and you want to save some bucks, that you can scuff with a scotchbrite pad and shoot right over. You spend more time messing around trying to save stuff than it takes to take all the paint off and do it right. With door jambs and the insides of the doors a lot of guys scuff them then paint or use that door jamb paint adhesion promoter and shoot them but still strip the outside of the body to bare metal.
You can see where any panel seam lead or old bondo shows up and stay away from it so you don't dig ditches with the sander.
BTW, be careful on leaded areas, don't want to be sanding them and putting that stuff into the air or making any low spots.
That primer should be okay if you don't get it wet or expose it to high humidity, air and moisture go right through most spray can primers and the steel will start to rust underneath, keep an eye on it is all I could say.
2 part epoxy is practically bulletproof, nothing can touch that stuff.

69442C

Try to post a few photos so we can see what you are working on and what it is you are trying to remove. Also, it would be helpful to know what you are trying to achieve for an end result. Will this be just a daily driver and paint quality isn't all that important? Or are you trying to achieve a nice finish that would allow you to put the car in a few local shows? Do you have any equipment and the space that would allow you to spray? If so, do you have a compressor or spray gun or are you comfortable using these tools as you can rent/borrow something? As someone already said, you are going about this in manner that is equivalent to torture. If you want to strip the finish yourself, you can do it chemically or with abrasives. The chemical issues have already been mentioned and you are not using the correct abrasives. If the metal is pitted or has some surface rust, you'll need to go with abrasives as long as the surface of the metal isn't too far gone. Post some answers to the above and I'll offer info to go along with what you can do. You need to keep something in mind. The prep work is the most critcal step in painting. If the sanding, cleaning and primer work is done incorrectly, the finish that gets applied will fail in a short amount of time. Rattle can primer is not very good primer and if you were to take the car to a reputable painter, you would likely be told that the rattle can stuff needs to be removed. I wouldn't paint over it. The correct way is to use epoxy primer as it seals the metal and prevents moisture from getting through. The general practice today is to apply the epoxy primer and then do your plastic work over top of the epoxy. The epoxy primer is allowed to dry and then scuffed in the area that will get filler. The other thing to keep in mind is that automotive paint is not cheap. Just the epoxy and final primer is expensive. You need hardeners and reducers to go along with the epoxy and many finish primers are also 2 part systems. This is why the quality restoration shops can charge upwards of $10,000 for a paint job. You can do something for much, much less but it still could cost you several hundred dollars just to get it in final primer with you doing the work. Post a little more and we'll go from there. Almost forgot, don't worry about keeping the sanding marks in a straight line. All of the sanding equipment will sand the metal and leave swirl marks. These marks allow the paint to grab onto the metal and will not be seen once the final primer work has been completed, as long as everything is done correctly.