lvelocci

Hello all,

the progress on the 72 continues -I have stripped the curret paint (brown) from the car but there is the original below that (and several other coats it appears... should I strip to bare metal for the whole car?

It started with some small body work that resulted in me seeing a bondo repair that kept getting bigger.... found the end but now worried about rest of car and what I may find.

i feel like using 40 grit on a grinder and stripping to bare metal, then sand with 80 grit and 100 to make it smooth. Any thoughts?

MDchanic

I did that once on a "driver" Skylark and I wish I hadn't.

It took forever and a huge amount of sandpaper to do, and then I had to grind the scratches out. It delayed my paint job by a couple of weeks.

In the end, the car got hit about a year later, sat another couple, and I sold it to a kid.

Unless this is a full restore, or you plan on keeping it forever, let sleeping dogs lie, leave paint alone if it's sticking well, and use a good sealer as a base coat.

2¢ deposited.

- Eric

69442C

If you have already started the stripping process using a chemical stripper, you'll need to take all the paint off. Once you start down that road there is no turning back.

DO NOT use a 40 grit grinding disc on the car as you will cause yourself a lot of problems. Aside from removing the paint, you will also remove metal and you'll need to do a lot more sanding to get rid of those marks. Not to mention possible body work to straighten out the panels or body lines/corners.

If you want to strip the car a little easier, go pick up a roll of 3M 100 grit stick on discs. You'll also need to buy the backing pad for your grinder or buffer that these discs will stick to. The dics are 10" in diameter I believe. Keep the RPMs low, maybe 1400 or less and this will take the paint off. You'll make one heck of a mess and it will take some time (better part of day) but it keeps you from woring with the chemical strippers. From there, you'll clean it off, epoxy primer, do any body work, epoxy and body work and then into surface primer. Or do the body work before the epoxy. Might be easier to do a couple of panels at a time if you have a lot of body work to do instead of stripping everything all at once.

This is not cheap to do and you'll need to decide how far you want to go depending on what you are doing with the car. The 3M discs and backing pad may run you close to $150 but you'll be happier in the end.

MDchanic

And if you go with discs, use an orbital sander instead of a grinder.

Non-orbital grinders bite in, leaving deep marks you'll have to sand out or fill later, orbital sanders are much less likely to do this.

- Eric

69442C

Fingers not cooperating on the computer.

The stripping disc pad has a 5/8-11 thread on it so you need to use it with a grinder of buffer. An orbital sander (DA) is limited to a 6" disc. These stripping discs are 10" and get the job done. They work well and will not bit into the metal or do any damage. Used them many time sin the past and they work just fine.

coppercutlass

save your self the time and money on alot of sand paper get it media blasted trust me not worth it i have done it before media blasting will also leave a great substraight for all your body work to follow which is good for a top notch paint job

Allan R

I'd run a magnet over the rest of the car to see how much bondo is there. If it's all good metal, I wouldn't bother with the strip to bare metal unless you're planning to change colors. If you've got lots of bondo on the car, you might want to strip down those areas to see what kind of repair or rust it is hiding?

I like the idea of media blasting. There are 2 methods that I've seen work really well. One is using baking soda solution (which doesn't harm glass or trim pieces) and the other uses ground walnut shells. Not as abrasive as blasting sand but as effective.

MDchanic

Never heard of 'em.

Thanks.

- Eric

coppercutlass

i agree allan r those are your two best methods if there is more than 2 layers of paint i would strip it the under lying layers with heat and weather changes will flex and eventually crack which is why old school 12 coat laquer jobs crack really bad specially if it see's alot of sun im a firm beliver in starting with a clean slate and from years of doing body work the paint work is only as good as the prep work before paint and body work i know people have budgets but if you do it right the first time it ill last for years to come

69442C

Here is a link to the 3M page that shows the pad that goes onto the grinder or buffer. Part number is 05579 and the description notes that one of the uses is stripping. Sorry, these are 8" and not 10". Use with a 3M Stickit 100 grit sanding disc and this will strip off the old paint and take it down to bare metal with a nice 100 grit finish. This backing pad is about 1/2" thick foam so it works well on non flat surfaces. It's not a hard backer like that used with a grinding disc. The key is to keep the speed down so the paint is sanded away quickly. Too much speed will create heat and the paint will start to soften and stick to the sanding surface. I've down several cars this way and it's far better than chemical strippers. It's still a lot of work but it keeps chemicals out of the jams etc. Care needs to be taken around glass, moldings etc if they can't be removed.

http://multimedia.3m.com/mws/mediawe...Vs6EVs6E666666--

lvelocci

Thanks for the great insights and the 3M inforation - will definately look into it.


On first posting I forgot to mention the reason i am stripping it is I hate the brown color and am switching to a different color. More important is that the current paint is flaking off with a hand rubbing and is my wife's father's cutlass that i inherited. I suspect i will pass it to my kids - so want to do this right the first time.

Thanks for all the great information - how about a wire wheel (cup shape??) I am okay i am okay with chemical stripper also any recomendations?

thanks

Louie

Tucsonbob

I had a company from Phoenix with a mobile unit come to the house in Tucson (90 miles) and they media blasted with baking soda for $600.00. They were done in 4 hours and gone. I had them leave the bondo and had the body shop dig into that. Thank goodness I did because the owner before me did a terrible job of repair. I would have had a mess if I had left the bondo as it was.

Allan R

Well if you're switching colors, go to bare metal. Chances are good there aren't several layers in the jamb areas. If there is, well you have a lot of work ahead of you.

I don't think a wire wheel is going to give you any great benefits, in fact the 'cup shape' you're describing is sometimes more difficult to control and a regular sander.

Chemical strippers? Unless you know what you're doing and have a) excellent ventilaton, b) proper PPE and c) contaminated waste disposal = this stuff has to be disposed of properly to avoid environmental issues, I would stay away from them. They are highly caustic and could damage or irritate your skin, nasal cavity, and eyes quite easily. Not to mention you would have to wash the area down with more chemicals and still end up sanding the raw surface.

If you have several layers of paint, use an agressive grit first, then work your way down to finer grades to avoid cutting through the metal. Word of caution - don't be in too big a hurry when you're sanding. Take your time and evaluate your progress regularly.

Harmon

If you have a car media blasted...how long do you have to do body work before the metal begins to surface rust? Im about to do this to my 80 olds cutlass.

coppercutlass

I would etch prime the bare metal asap then you can sand the areas that need repair then you can use a high build primer over the etch primer and areas that where filled repaired etc

gearheads78

Epoxy is a better way to go and you can do filler work right on top of it.

coppercutlass

But epoxy doesn't etch into the metal but it is good and resistan to many solvents I would use epoxy on underbody side

gearheads78

It's not needed. Good clean metal with 80 grit and you are good to go. We did the etch deal 20 years ago when I was in the business but today its not needed. Most high end restoration shops do epoxy then filler and then polyester or urethane primer.

coppercutlass

I'm still a big fan of etch primer and poly primer but if you wanna knock two birds with one stone ppg's ncx271 is corrosion resistant and high build but a gallon of good primer is very expensive on my 72 primer alone was 325 and that was only the high build add the etch and poly primer I used it come close to 500 bucks but better materials equal higher quality and years of trouble free good looking paint

Rickman48

Soda blasting can be bare for up to 2 wks, but has a residue that must be cleaned before any paint.
You can rent a blaster and do soda yourself, withut removing rubber and chrome!
Doesn't hurt the environment, either

lvelocci

Hello all,

after reading the responses I set out to find a mobile soda blaster in Halifax Nova Scotia - the only one I found uses a mobile wet soda system (typically for boats so water isn't typically an issue).

Thoughts? Any DIY approaches that I could use if wet soda is not a good choice??

Allan R

The 'wet soda blaster' you're describing is exactly how it's done. Only the sand and walnut shell blasters use dry product. So, don't be concerned. Get a price. Oh, one other thing, although you can leave chrome or stainless on the car during the soda blast process, I'd remove any of it that has rust creeping under it. You want your blast to clean as much rust and crud off the car as possible. I think you'll be happy with the results.

CutlassLegend

My 69 442 I had the whole car soda blasted. I will noever sand or strip and entire car. Way to much time and the danger with stripper is always present. Soda blast is so much more cost effective especially when you consider the time, my time is valuable to me. Good luck

66ninetyeightls

Soda is nice because its safe on glass and britework buts its a pain afterwards because it leaves a residue behind that must be completely neutralized and cleaned before painting.

I use plastic media blasting now. Doesn't heat the metal and leaves no residue behind.

CutlassLegend

Never tried plastic, maybe my next project I will. I like soda also because the neutral alky helps prevent flash rust also.