The 1st rule in painting is:
A quality paint job can not be put over bad paint... period!
If you want a quality paint job the bad paint has to come off.
Seeing as I am goofing off this holiday weekend I thought I would write up a little "how to". Using paint stripper is a good option and at today's prices will probably cost not too much more than the price of the roll back to get a car to the blaster and back. Maybe a fellow can only afford to do a section of the car at a time or lives in the boonies so blasting the paint off just isn't in the picture. So let's look at an old way to get 'er done.
There are several ways to strip paint off a car. On some cars media blasting is the only way to fly. I like media blasting and use it often. But if I am personally paying for it.... not always. You might get lucky and have a car with resprays on it that will strip off with a razor blade. That may get you to a place where it is only a sand, prime, sand and spray deal. Sanding all the paint off and just deal with the dust and mess. I have done it plenty of times. But, if it is an old lacquer job your sandpaper is going to gum up pretty fast.
I am going to write about paint stripper today. Working with paint stripper is pretty easy. Unless the humidity is high, you won't even break a sweat. And if done right not too big of a mess.
Back in the 60's when I was learning to paint, stripper was the way we got the bad paint off a car. So it is traditional . The only cars that were blasted were rust buckets in the rusty areas, rusty old model "A's" with fenders and other junk like that. We sanded all the paint off IF the car had so much paint on it that it just took too long to be stripped with chemical stripper. We were paid by commission on bid jobs. Every hour wasted was money lost. Paint stripper did a good job then and still does. With some planning and prep work it isn't even hard work. Paint stripper is smelly, can get your attention real fast if splashed on bare skin and it can create some real problems if you just go brushing stripper on your car without taking some steps first.
This how I strip a car with stripper: I take all the trim, handles, moldings, bumpers, etc off the car. Now for you first timers, unless you know what you are doing, leave the drip rail moldings on. They are probably the easiest piece of trim on a car to damage just removing them. I will explain later how to work around them if you are not building a show car. If you are building a show car feel free to ignore all of this and pay some painter to do it. We need the work!
You don't want stripper to get in your jambs, cowl vent, trim, door handle holes, etc. So you need to tape them closed with 3 or 4 layers of good quality masking tape and sand off the paint on the panel edges later. (Re-read those last two sentences... they are important!) Now, go to the paint store to get your tape, stripper and some bondo spreaders to scrape the paint and old stripper off. I use a putty knives to scrape more stubborn areas, some guys don't like bondo spreaders and use only putty knives. Besides stripper ( I use the aircraft type), you will need to hit the hardware store for some 3" bristle brushes (I get cheap throw away ones even though water will clean them). Plastic bristles can melt. Go ahead and grab a 9' wide roll of painter's plastic (about $20). You will also need rags, cheap acrylic lacquer thinner (not the hardware store stuff), gloves, eye protection and some scotch brites too. There will be strong fumes you don't want to be breathing as well. A cheap paint mask should do the job.
Now, take a good look at the car you are going to strip and think about all the places you DON'T want paint stripper to go. Paint stripper is like paint over spray....it will find a way to get where you don't want it. Beside the door jambs and places I mentioned before, I try not to get stripper in fender or quarter panel extension cracks and in the the seam sealed valley by the drip rails. That small joint between the panel above the deck lid that meets the quarter panel on some cars is generally filled with seam sealer. Remember, everything paint stripper gets on will have to be removed or it will come back and bite you later (re-read that too. I will probably repeat it someplace else.) The planning and thinking here will save you problems later. Take your time and really think about it. The thinking and planning is probably the only step in this whole deal that isn't going to cost you some money.... enjoy it.
I start the "protect everywhere I don't want stripper" operation with covering the engine bay in plastic. Taping the plastic to the fender jambs and the firewall. I didn't used to do this, but after having to spot in a firewall from a drip of stripper I decided the ounce of prevention thing is a good idea in the engine bay. If the windows are out, I make plastic windows. If the windows are in the car, I cover them in plastic taped tight like I was masking to paint the car. Then, I multi layer tape an inch or so into the old paint going out from the glass. If it is a gasket type window you can lift the edge of the rubber by shoving a cord or electrical wire under it for sanding and painting later... but you don't want stripper creeping under the gasket. If you have already started the body work before stripping the paint, protect those areas too. Stripper in even a small weld pinhole isn't a good thing and any filler or primer touched by stripper would need to be removed.
Now, let's tape the door, hood, and deck lid jamb gaps with at least 3 layers of masking tape covering about 1/2" of the old paint on each side of the gap with tape. Cover the door handle holes, antenna and even the trim holes with tape. That 1/2" of paint we are leaving sands off pretty fast later and it really sucks to look in the trunk later and see where a goober of stripper has drooled from a molding hole down the splatter paint inside the quarter panel. Man, that old GM splatter paint won't hold up to even a tiny bit of stripper! That fender to cowl gap is going to make a big mess if stripper gets into it.
Wheels and tires.... you don't have your good wheels and tires on the car already do you? Cover them with plastic or put the car on stands and cover anything exposed with plastic. That brings up a pet peeve of mine. If you are bringing me your roached out Nomad, T-bird, roadster or what ever to make look great, please don't have $3K worth of new tires and wheels on it that I have to babysit while welding, grinding, etc. Rusty rims and "see air" tires are ok by me. I bet most body men and painters feel the same.
The "protect everything" operation isn't done yet. Cover the floor around the car with plastic. It makes clean up a breeze.
I wear one of those funny looking shop aprons when using stripper. A little bit of unnoticed stripper on a pair of jeans will have you shucking them in world record time! Protect all vital equipment. The affected area of skin burns for quite a while even after the stripper is washed off. This is not a job where you can wear flip flops and shorts. If you don't want to heed that warning please shoot video while you are working so I can see you invent new dance steps. I use dish washing type gloves so I can clean them and use them again.
I suppose those throw away doctor type gloves would work too. If you use the bondo spreaders instead of a putty knife to scrape the old paint and stripper off the car like I do you will get some on your fingers at times so I would give them a little test to see how they held up.
Speaking of those Doctor type gloves... I make masking tape tabs at the wrist to pull them off so I don't have to stick a finger that is dirty with whatever between my wrist and the glove to get it off. Usually fiberglass resin in my case.
Eye protection.... Important! It has been at least 35 years ago I got stripper in my eye when a piece of tape snapped while I was un-taping the jamb edges. I vividly remember the pain. Those of us that have had a bit of lacquer thinner in the eye know pain... it is light weight pain compared to stripper. It will make you cry right down your leg. I was lucky that I was right next to a water faucet. That probably saved my sight in that eye. I would say to keep a bucket of water or hose close by... just in case. The fumes can be strong. Doors open and a mask. Exhaust fan if you have one.
Jeez... this is getting long! If I would have had a clue it would get to this ... I would have probably never started. My two fingers are tired and we are just now getting to the "take the paint off" part. Maybe I should have made a serial out of it. Tune in next week for part two. Well, this part will go pretty fast unless I think of more "back in the day it happened" and other useless stuff. And this stupid little rant made it even longer. (In case you are wondering... I don't do drugs or even drink. Must be 40 years of paint fumes!)
Ok, everything is protected the best we can get it from the paint stripper getting where we don't want it. Let's get with it!
I rough up the old paint with 80 grit as the stripper seems to work quicker when I do. I start at the top and work down and don't do a large area maybe a 3' X 3' or so at first. This 3'X3' area will kind of a test area letting me know how the paint is going to affected by the stripper. Do a smaller area if you want. Pour out the stripper and even it out with the brush without working it too much. It needs to be thick enough so there are no "dry' looking places. I don't know about anybody else, but I kinda enjoy watching that old paint wrinkle and pucker up. Sucks when it is lacquer... it just dissolves ... so no free entertainment. But, you can use a bondo spreader to move the dissolved lacquer and stripper to the next area and it will eat the paint off the next area too. When the stripper quits working, use the bondo spreader or putty knife to shove the mess onto a piece of cardboard. Did it clean it to metal pretty well? If it didn't there may not have been a thick enough coat of stripper or it didn't get to work long enough before you scraped it off. To make the paint stripper work harder on the tougher paints you may need to cover the stripper you have applied with plastic to keep it from drying out too fast. After a few areas you will get it dialed in as to how much to pour on, how long to let it work on the old paint and what size areas you are comfortable stripping at a time.
Some kinds of paint are just tougher than others and it may take a couple of times to get it to metal. Now that you know how much stripper is needed you can double the action by working two areas or larger areas. You will get the hang of it before you are done with the 1st panel. Put on stripper... let it work...scrape the sludge onto cardboard....dump the sludge off the cardboard into a garbage bag lined garbage can.... It sure isn't rocket science. Once the top panels are done, start on the sides once again working from the top down. Pour the stripper into a container and brush out of the container for the really flat sides. I sometimes don't strip the inner wheel opening lips or rocker panel pinch welds with stripper if they are going to be a pain to clean the stripper off of. Sometimes you got to make judgment calls. If you run into body filler don't try to get it off with stripper.... you will grind it off.
Now that all the paint is off wipe off all the stripper you can with a rag. Take off the tape from everything except for the windows you have masked up like you were going to paint. Grind off any bondo in the exposed areas. We will do a cleaning with the acrylic lacquer thinner you bought and a scotch brite. I haven't bought clean up thinner in a while, but it seems like it was just over $30 for a 5 gallon can last time. I pour the thinner into an old plastic mustard container. It has a cool little squirter and opens and closes. I use my mustard- thinner-squirter and old scotch brites to clean my bondo board and spreader too. Squirt thinner on the metal.... scrub it clean as you can with a scotch brite torn in half ... wipe it dry with a rag till you have it clean. Several times if you have to. Not rocket science here either. And we will do it again before primer so it is a good thing it is easy to do. We get several chances to get it right.
Now... about those drip rails. Tape up the chrome and dig that nasty, cracked caulking out. I use a flat screw driver. Real high tech, eh? Sometimes it comes out amazingly fast... sometimes you gotta work at it a bit. Chances are there will be some rust under that caulk so be prepared to deal with it.
Take the DA, stripper wheel, what ever you prefer or have and sand those edges of paint off. See, I told you that was going to be a fast thing to do. Now you believe me. The car has been stripped... ! After you toss the plastic that was on the floor and empty the garbage the mess is gone.
Next step.... thinner....scotch brite...clean rags ...we are going to prime the car.
Hey, look... the windows are already masked.
If you have some quick bondo work to do... get 'er done. Save the big body work for later.... a guy needs something to look forward to.
Mask the jambs and tape anything you don't want primer on.
DA the metal with 80 grit and do the thinner... wipe thing again. It isn't necessary I have been told ... but I use acetone for the last clean.
It really doesn't matter if you prime with etch primer or epoxy. This is surface rust prevention. Two coats of either will protect it till you can get to all that other body work you are looking forward to. I don't want to get into the body filler over ground clean metal or over primer debate. All I am going to say is I like the look of filler over bare metal.
Sorry this got out of hand size wise. Guess I had more to say than I thought I did about a simple weekend operation. I got a little cross eyed and my brain hurt a little from trying to figure out write something understandable about something I do on automatic.
If I saved somebody a few bucks or from making a mess... it will be worth it.
If you other painters see something I skipped or said wrong I want to know about it. If you have an easier or better way please chime in and email Staff@Hotrodhotline.com and the staff will get your suggestions added.
I am all about easier and better.