Paint prep - dealing with surface rust.

[Frank Elder]

There is no substitution for hard work and elbow grease, put your back into it until you are down to bare metal. If your back can’t take it buy a sander....electric or pneumatic it doesn’t matter, then epoxy prime.

If you can’t do this you certainly won’t last through the weeks of sanding and prepping it takes to get a decent paint job......much less the months it takes to make a show winner. 

Edited May 11, 2021 by Frank Elder

[kencombs]

‘Normal’ primers will let water pass thru and absorb water.   Epoxies do not. Those normal primers are usually primer / surfaces  that build a fair thickness intended to be sanded level to flatten the surface.  Epoxies are intended to adhere really well to metal or filler below, seal moisture out and also bond with the following primer or paint coats.  IME it is not necessary to buy the premium priced brands to get epoxy benefits.  I use Kirker with good results.  There are others with similar pricing that work well.   
 

just be sure that if you use an acidic metal prep that your chosen brand of epoxy is compatible.   Not all like acid treatment under them, like Southern Polyurethane. 

[allbizz49]

Etch primer or acid etch isn't necessary with a good epoxy. I have never used them on steel, only aluminum. 

[Marcel Backs]

Glass Shield brand primer was used on my D14 body with excellent results. It dries glossy black making any flaws visible while prepping surfaces. I think epoxy supersedes any of the old style primers. M

[Los_Control]

Discussing paint is like discussing  which oil to run in your engine  

 

For @Wood and Steelpost ... I am curious what kind of paint is on the car? Is it original or a repaint. what kind of paint was used if a repaint? Single stage or 2 stage?

Back in the day these cars were made, they were spraying enamel paint direct to metal with no primer ... how many years did it last?

Not sure when the epoxy primers & sealers were introduced to the car market. In the 1950's 16 year old kids were using their mothers electrolux vacuum cleaner to paint cars in the driveway .... and it worked fine. Simply does not take a rocket scientist to paint. Does require a scientist to make sense of all the mumbo jumbo of all the modern paints and primers to go with it.

 

What I would hate to see is @Wood and Steelto get discouraged over fixing what could be a simple repair in the driveway on a weekend because of not understanding all the modern products.

A 4" grinder with 36 grit paper would remove the bondo showed in a few minutes.  What did the body shop do to prep for the bondo? Did they drill holes and pull the dent ... then leave the holes open? No sealer will work if bondo is getting water from the backside .... The bodyshop returned a inferior product, why the owner is re-doing it.

They wanted to repaint the whole car because they could not color match paint .... even though a repaint was not wanted. I just have no faith in the quality of the body shops work.

Did they even try to hammer & dolly the dent out .... how thick is the bondo? Lots of questions here.

I would like them to grind out the bondo, post pics and then get advise from here on how to repair it.

 

As far as primers go, yes they are not designed to be a finish coat. My only experience is knowing people who had the brown with red oxide primer, they had them for years with no problems ...  Kenny had a 1962 falcon in the 1970's All through school he had that car in brown primer  they would touch it up from time to time. I watch JonathanW videos, he has several cars in primer, the comments are the same as here it will rust ... He says he has used the brown primer with the red oxide in it for years and not had a issue. Been watching him for over 2 years.

I sprayed the rustoleum on my truck cab forward last summer. It sat outside through the winter and one time had 3" of snow on it. I pressure washed it 2 days ago and it looks great.

 

My Uncle painter used gray primer then quit. In a couple years the rust was through the primer and 2 cars had to be brought back to metal to be saved

 

Lets quit trying to scare the guy out of fixing their car.

 

 

[MackTheFinger]

A friend who taught me much of what I know about paint and bodywork used the DuPont version of this with good results. He'd block through primer, wipe down with this stuff and shoot paint right over it. He was and still is considered one of the best bodywork\painters anywhere near here. 

 

http://products.axaltacs.com/dcat/us/en/dr/product/5717S.html?desktop=true

[kencombs]

7 hours ago, allbizz49 said:

Etch primer or acid etch isn't necessary with a good epoxy. I have never used them on steel, only aluminum. 

True, but a lot of people use an acid wash that prevents rust from forming while in the process of finishing body work.  Lots cheaper than primer.  I have some parts in the shop that were treated with PickleX20 years ago.  Kept dry, but very humid it times and still no rust.

[plymouthcranbrook]

I remember using zinc chromate primer on some spot repairs back in the 70’s with pretty good results.  Can’t remember what I used for the overcoat  though. 

[Frank Elder]

3 hours ago, MackTheFinger said:

A friend who taught me much of what I know about paint and bodywork used the DuPont version of this with good results. He'd block through primer, wipe down with this stuff and shoot paint right over it. He was and still is considered one of the best bodywork\painters anywhere near here. 

 

http://products.axaltacs.com/dcat/us/en/dr/product/5717S.html?desktop=true

Good stuff even tho I am hopelessly addicted to single coat industrial imron fleet type paints.

[wagoneer]

Saw this on Facebook - pretty good for rattle can paint job

 

https://www.facebook.com/photo/?fbid=10226483517494666&set=gm.10158348436718719

 

 

[Wood and Steel]

On 5/11/2021 at 2:13 PM, Los_Control said:

For @Wood and Steelpost ... I am curious what kind of paint is on the car?

 

What I would hate to see is @Wood and Steelto get discouraged over fixing what could be a simple repair in the driveway on a weekend because of not understanding all the modern products.

A 4" grinder with 36 grit paper would remove the bondo showed in a few minutes. 

 

 

After prepping the rest of the body, the car still has about 65% of the paint still on it. It's was repainted with a single stage at some point. I would guess sometime in the 80s-90s by the condition it was in, but I'm far from an expert on that.

 

There is a lot more filler than what was shown in the picture, which is why I really don't feel like taking it all off. That was just an easy picture to take with the lighting.  The majority of it's on the driver side where it got hit, but there's little patches here and there on the rest of the body.

 

On 5/11/2021 at 2:13 PM, Los_Control said:

What did the body shop do to prep for the bondo?

 

... The bodyshop returned a inferior product, why the owner is re-doing it.

 

 

The shop did hammer it out before putting filler on (I removed the interior door panels before I took it to them to make sure they would), but the surface wasn't flat and the panel alignment was off, along with other issues I won't bother complaining about here. I was dumb and didn't look it over very well before I paid them. I guarantee I won't make that mistake again. I tried getting them to do something about it, but it didn't do me any good.

  

On 5/10/2021 at 4:46 PM, Los_Control said:

... I had a squirt bottle with ospho in it, wetted the area walked to the shop and grabbed a clean rag and walked back & wiped it off. Took about 1 minute total time.

 

You can see the film left on it. If this was bare metal would protect it from rust til washed off. When washed off you need to seal it with primer right away.

So this will remove your rust easily .... But will not fix your problem.

 

As suggested above, the bondo acts like a sponge and collects moisture. I would say digging out the bondo and start fresh is best answer. Panel is already rusting under the bondo & spreading out to where you can see it.

 

 

I tried citric acid first as per a previous suggestion since I had some on hand. I ended up leaving it on over night covered with plastic wrap. It didn't do an awful job, but it didn't get it all and I didn't like having to clean it off with water. I tried Ospho and it worked spectacularly well.

 

As far as water penetrating the Bondo like a few people have mentioned, I removed a couple of spots to see what it looked like underneath. I found no rust under either spot, which makes me think the rust is just around the edges. Since the Ospho seemed to remove the visible rust from the edges, do you guys think that would be enough? I was also thinking, if the filler does absorb moister, would it not also absorb the acid and kill the rust underneath if there is any?

 

On 5/6/2021 at 5:05 PM, Los_Control said:

You have a honest good question. The answer is not clear.

Typically people are using high dollar paint to restore these vehicles ... I am fine with that. There will be no talk about Rustoleum paint.

 

Just use what you want ... I have a strong opinion and you should do what works for you.

Mine is a driver quality truck ... you care about shows, you may not want to go Rustoleum.

 

 

I wasn't going to admit it here, but since it has been mentioned at least twice on this thread, I am planning on trying out Rustoleum marine topside paint and primer.

[Los_Control]

@Wood and Steel I want to be the first to say I am just a dumb ass. I am trying to learn also. I ask here a lot and have learned a lot.

So keep coming back and ask. We all learn together.

 

My avatar shows a old truck that been sitting in the field for 20 years ... No serious rust other then surface rust from sitting in the weather ... many here would consider it a parts truck. Really has been a challenge for me.

 

I want to say that what I have learned, these old cars used a single stage DTM paint (direct to metal) Basically is what Rustoleum is. I assume is better quality then what they used 70 years ago. But if your car is 65% original paint, Rustoleum is the equivalent to whats on there now, just better after 70 years production.

The hand rubbed lacquer paints were saved for rolls royce and other custom paints.

Later the 2 stage paints came into play. .... Thats not what you have, rustoleum will be fine if you can match the color ... again take a sample to napa and have them mix a color for you ... They generally use 2 stage paint, I think they can also mix single stage? A small area and a spray can may be all you need.

 

The primer is just a cushion, it gives you a cushion to see what paint would look like, A nice base for putty before paint ... but in the factory they did not not use it.

For me I understand that others use $800 worth of paint, but it is not needed. I am only saying I will not be brow beaten by others with $5k paint jobs ... Just trying to replace what the factory did.

 

If phospho  worked so far, paint it with primer then paint it. It is a old car. And let us know how it comes out a year from now. ... of course keep us updated during this time.

 

[Wood and Steel]

33 minutes ago, Los_Control said:

@Wood and Steel I want to be the first to say I am just a dumb ass. I am trying to learn also. I ask here a lot and have learned a lot.

So keep coming back and ask. We all learn together.

 

My avatar shows a old truck that been sitting in the field for 20 years ... No serious rust other then surface rust from sitting in the weather ... many here would consider it a parts truck. Really has been a challenge for me.

 

I want to say that what I have learned, these old cars used a single stage DTM paint (direct to metal) Basically is what Rustoleum is. I assume is better quality then what they used 70 years ago. But if your car is 65% original paint, Rustoleum is the equivalent to whats on there now, just better after 70 years production.

The hand rubbed lacquer paints were saved for rolls royce and other custom paints.

Later the 2 stage paints came into play. .... Thats not what you have, rustoleum will be fine if you can match the color ... again take a sample to napa and have them mix a color for you ... They generally use 2 stage paint, I think they can also mix single stage? A small area and a spray can may be all you need.

 

The primer is just a cushion, it gives you a cushion to see what paint would look like, A nice base for putty before paint ... but in the factory they did not not use it.

For me I understand that others use $800 worth of paint, but it is not needed. I am only saying I will not be brow beaten by others with $5k paint jobs ... Just trying to replace what the factory did.

 

If phospho  worked so far, paint it with primer then paint it. It is a old car. And let us know how it comes out a year from now. ... of course keep us updated during this time.

 

 

It is kind of funny, I didn't realize all of my quotes where from you until after I posted and re-read it. Everything I responded to was a sentiment that was mention at least once and I just happened to click the quote button on your posts, so don't feel special, haha. 

 

I'm sorry if I wasn't clear as far as the current paint goes, though. The whole car has been repainted once (to a different color). I have already completely scuffed it in preparation for paint, so the touch up ship has already sailed.

I have done a lot of reading, and it seemed the marine paint has better leveling and UV qualities than normal rustorleum. I decided if I couldn't get a finish I was happy with on my own I would save up a few bucks to have it done right a couple of years from now. As it stands now, it's been over a year since I've had her on the road and I really miss it. I just need something I'm not embarrassed by right now.

[Los_Control]

12 minutes ago, Wood and Steel said:

I have already completely scuffed it in preparation for paint, so the touch up ship has already sailed.

Thats ok, main thing is to not lose your head & think it needs $10k worth of paint & body work to drive it.

Serious last week I built a metal shed and sprayed it Rustoleum gloss white.  I probably could have done a better job with a roller & a brush ... I wanted the experience   spraying the same paint I will paint my truck with. While my truck is now a mix of primer, paint, rust ...  It is slowly moving forward.

But in primer it looks ok also  .... sorry you scuffed your paint, wonders if polishing it would bring it back?

 

Think I have said this 100 times, In the 50's kids were using their mothers vacuum cleaners with a paint attachment to paint cars in the driveway.

Today the kids do not even know to put on pants.   We had some great paint jobs from the 50's.

 

You do you, whatever paint you decide .... is part of owning a old car ....

[allbizz49]

Rattle can that sucker and drive it! If you're going to have it painted down the road, just do it. Won't hurt anything and you'll be able to enjoy it. Just make sure whoever paints it strips it. I would definitely hit any filler and bare metal with primer first. Let it sit a day then sand it with 320-400. If you don't, you will see swelling in the paint. Also, I wish I could buy materials to paint a car for 800 bucks, haha. Last one I did had a 3,000 dollar material bill and it was black. Good luck and remember to have fun with whatever you are doing or it's not worth it. 

[kencombs]

There are a lot of paint options today, spanning cheap, inexpensive, costly and as much as you care to spend.  Luckily there are good choices at all levels.

Paint like this

:https://www.ebay.com/itm/312168590071?hash=item48aeb2aaf7:g:nvoAAOSwmBReqyDF

Is more like the paint originally used, a synthetic enamel on Mopars and Fords, but better fade resistance (really important on red tints), gloss and resistance to chalking.  GM used lacquers on almost all their cars from the 40s through the early 80s.

 

Any time you sand metal, there will be scratches on the surface.  Primer is called primer/surfacer for a reason, it fills those scratches and provides a smooth surface.  This gives a more consistent background for a  better looking finish and saves paint.

 

BTW, I'm not pushing the paint listed above, just another example of the choices.  It, or one like it or a low end single stage give very good results without seriously damaging the budget.

[DJ194950]

Summit racing.com  and Eastwood co..com both sell some good paints in the (reasonable price range) both single and base/clear coat types. At least the do not cost $1000's to cover a car/truck.  Only issue you cannot have color match to original types just pick in the area you like.

 

Just a thought.

 

DJ

Edited May 20, 2021 by DJ194950
Change cat to car!

[wagoneer]

I have a slight variation to the topic here - I have some parts and a bag full of original fasteners that look a bit rusty .

 

 

Would you all then recommend a bath in acid to clean them up and some kind of clear coat (wouldn’t that cause binding in the threads?)

 

fasteners are an interesting twist here - would the fasteners (screws,  bolts, nuts) rust faster ?

 

after stripping of surface rust, I usually put a thread sealer on but maybe not for something like fender bolts exposed on both sides. Thoughts?

[Eneto-55]

2 hours ago, wagoneer said:

I have a slight variation to the topic here - I have some parts and a bag full of original fasteners that look a bit rusty .

 

 

Would you all then recommend a bath in acid to clean them up and some kind of clear coat (wouldn’t that cause binding in the threads?)

 

fasteners are an interesting twist here - would the fasteners (screws,  bolts, nuts) rust faster ?

 

after stripping of surface rust, I usually put a thread sealer on but maybe not for something like fender bolts exposed on both sides. Thoughts?

I wouldn't acid-strip them, unless the plating is completely gone, or if you can have them replated at a reasonable price.  Originally most hardware was cadmium plated, but I've wondered how hot tin plating would hold up.  Already in the late 70's the cadmium balls we used to plate with were not produced anywhere in the States, because of the toxins produced during some part of the process of refining.  Hot tin is considered 'food grade' plating, and although I do not remember what chemicals are used in the solution, the process must be considered much safer environmentally.

(Unless there is some product that would remove the rust, and not the plating.  But I'm not aware of what that would be.  Maybe someone else has an idea for this.  As far as using paint is concerned, I would think that the old-style aluminum heat paint would be the best option, because it makes a thinner coat.)

[MackTheFinger]

I don't think any paint looks better than lacquer. OTOH enamel doesn't require as much color sanding, buffing, etc. There are still a lot of single-stage enamels around. I've used the Restoration Shop enamel on a couple of cars and a few motorcycles. It works okay but the metallic isn't anything to write home about.

I painted my '66 Chevy II with a urethane BC/CC when that stuff first showed up. For reasons I can't fully comprehend I then left the car sitting in a fencerow for 30 years. It looks kinda beat but not as bad as it could be.

[Eneto-55]

On 5/19/2021 at 9:26 PM, Los_Control said:

... these old cars used a single stage DTM paint (direct to metal) ....

 

If I understand correctly, you are saying that from what you've seen on the cars you've repainted, there was no primer coat.  But maybe I am misunderstanding what is indicated by "single-coat".

 

Anyway, since I painted the body of my car over 40 years ago, I couldn't remember for sure if there was a primer, or not, but recollected that there was.  I just have one rear fender & 1 front fender that I didn't strip to the bare metal (at the plating shop), so I waited until I could get a chance to sand a spot on one of these pieces, to see if there was primer, or not.  Took a while to get through all the paint, because the original color had first been painted some awful bright green with a brush, then later sprayed over gray.  Anyway, my car, at least, has a dark gray primer under the original top-coat.  (This was the rear fender.)  Unless it was a replacement part, and then I suppose it would have been painted that standard color before it was repainted to match the car.  So I guess that may not be "conclusive evidence". 

I looked at the few pictures I took while doing the body, and I only have one between when it was still gray till it was light Green again, and I didn't have good lighting, and most of it was sanded down to bare metal anyway.