Paint Preparation Questions

[Bergy]

I'm in the process of trying my hand at painting my 29 roadster. I'm a total novice at this and have read all I can find, but have a few questions I'm not clear on. Any suggestions or guidance is greatly appreciated.

I have stripped the fenders to bare metal with zip-strip followed by power wire brush. In the removal process I have encountered multiple body filler spots & types. Is it necessary to remove all the body filler spots to bare metal before priming with an epoxy primer, or is it ok to leave the major fill areas as they are and prime over them? They appear to be tightly adhered as they survived penetration by zip-strip and wire brushing leaves them in place unless I bear down on them.

The zip-strip did not penetrate/remove the coating on the underside of the fenders. Upon reading the z-s label, it stated that it will not remove epoxy coatings. Is it fair to assume that the underside of the fender is coated with epoxy? Also is it ok to re-prime over the apparent epoxy coating after cleaning up with power wire brush. Wire brush does not easily go to bare metal, but to some other hard coated finish. Is this ok?

I also tried to zip strip the front splash guard (the one under the radiator) and it did not remove the coating. It only "melted" the coating to a liquid that smeared around when attempting to scrape. I ended up needing to power wire brush this piece to bare metal. What type of coating am I encountering on this piece?

My plan is to take the parts to bare metal (with the possible exception of the body filled areas, question above??), prime with an epoxy primer, followed by filler and high build primer as needed and then finish of with a one coat urethane color as appropriate. I've read the various opinions on high gloss (base coat/clearcoat) vs duller finish (one coat urethane sytem). It sounds like the consensis is the one coat system is closer to original, where the base coat/clear coat is for those who want something shiny, correct?

I appreciate your guidance and opinions. Thanks in advance.

[Brother Hesekiel]

My advise is that while you can do a lot of prep work yourself, as you have been doing, I would not dare to learn how to paint a car on the very car you love and care about. Find a painter you trust, discuss with him your prep work, and invest a few hundred dollars in a pro doing the actual shooing.

"Closer to original" is a rather arbitrary term. Unfortunately, we don't have the materials that were used in the day anymore available to us. And according to the Judging Guidelines, the fenders and splash aprons were dipped into black enamel and then baked, whereas the body was painted with nitro-cellulose laquer. In plain English, even an all black Model A had different paint on body and fenders.

I would just have a very close look to what Marco did with his fine points '30 Roadster. I would use a quality single stage paint (under NO circumstances use base/clear), and colorsand it with 2000 right from the start, polish it by hand with Mother's chrome polish 'til you have an 80% gloss, then have a pro polish it to a high luster. The cowl and area under the rear fender will not be polished.

[Charles Coe]

You mean the firewall rather than the cowl will not be polished.

[BRENT in 10-uh-C]

To answer your question directly, I'd say the paint under the fenders is NOT epoxy.

FWIW, I personally would not use/trust an old filler. Adding to that, I cannot begin to tell you how many times we have seen vehicles come in that were loaded with thick filler only to strip it and find it wasn't necessary afterall. Proper use of Filler is a tough art to conquer simply because it sneaks up on you. My suggestion is to remove it and see if it is needed, --and if it was, can you remove any additional metal trauma to smooth the surface more?

As you probably know about epoxy, it will stick to anything however I find it does not sand very easy. One additional thought is chipping is usually a direct result of too thick of substrate. Finding a way to get to bare metal (chemical or media) will honestly pay dividends for your final finish.



One other thought is you may want to explore the use of Lacquer paint. This will be a controversial topic here however hear my reasoning and see if any of this applies to your situation.

• Acrylic Lacquer is very similar to the look of what Nitrocellulose Lacquer looked like originally after if is buffed. Therefore this may provide you with the paint depth and texture as original.

• Acrylic Lacquer does not have the best UV Hold-out nor does it resist harsh climates, ....however most of our Model-A's are garage kept therefore not exposed to harsh weather or daily doses of sunshine which we know are detrimental to lacquer's longevity.

• Acrylic Lacquer is not as harmful for the average hobbyist's body as opposed to an isocyanate filled urethane paint. Acrylic Lacquer also is more forgiving for the novice painter to use, ...especially in a non-booth environment.

One final thing to ponder... Lacquer has received a bad 'rep' during the 50s - 70's as they were applied over ½" thick areas of Bondo, --or that Putty-in-a-tube called Nitrostain. Ironically over time I have been fortunate to examine many vehicles (several Model-As) that still had the factory original paint. Surprisingly these finishes still polished up to look extremely nice. If you think about it, the issues that give Lacquer paint a bad name have been the substrates, and not the paint itself.

Now with that said, the quality level that metal is being straightened/planished these days provides for less fillers needed. Adding to that, the quality of modern catalyzed fillers is much superior to what was available some 40 years ago. While I am not saying that Acrylic Lacquer is for everyone, I am saying I think it deserves a second look for some folks.

.

[pooch]

I would not trust your notion that the stripper did not penetrate the filler.

Remove it all.

Wash all your parts with boiling water and scrub.

Stripper will be in every crevice and has been pushed in more with the wire brush.

I can just guess how much stripper has been pushed under your fender bead seam .

Try a heat gun and putty knife scraper under the fenders.

After digging out all the old filler, you will be surprised most times why it was ever put there (laziness probably ) and the ding not just smoothed out in the first place.

[Tinbasher]

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Yes, get it down to bare metal. Then clean it up (Sanding, sandblasting, etc. depending on how rusty the panel is.) Then go on with your epoxy primer. Invest in a set of ASF sanding boards. 6" 15"and 21". These will make your job much easier and you'll end up with a much better job. Eastwood sells them. They are foam rubber with a Stainless steel face and rods you can add or subtract to make the board more or less flexible. They stepped my work up another level. Sand the epoxy with 120 grit sandpaper and then work your filler. 80, 120 and 180 grit. Then coat the panel with epoxy to cover and then 3 coats of high build primer. (Wet on Wet) Let this dry for 3 to 5 days and block sand again with 180 followed by 240 grit sandpaper. Then apply 3 coats of high build primer with a 20% reduction so it will flow out. Let this dry for 10 days. (It takes any polyester product 10 days to get to a full cure, unless you can force dry it. Then guidecoat and sand with 400 and 600 wet sandpaper. Now you should be ready for Single stage paint.

Hope this helps: The Old Tinbasher

P.S. Brent, I'm surprised you can still get Acrylic lacquer. We haven't had that up here for 20 years. Maybe closer to 30. TB

[31 Woody]

I would also suggest removing the filler so you know how thick it is or was. Before priming, sand the metal with 80 grit on a DA sander to give it some tooth prior to priming.

[Ken Ehrenhofer]

If you must go forward with this painting project I would suggest the following:
Befriend someone local in the hobby who has experience to be a mentor to you. You will need to ask questions as you go. Even a local body shop owner might be a good choice.
ALWAYS remove anything on the part to be painted and start with a good clean bare metal part and build your own foundation.
I use a small propane torch to remove old bondo. A little heat and a scraper and it falls right off.
After removing all previous paint and putty, lightly sand blast to get to the base metal.
Use DP - 90 (PPG Epoxy primer) as a first coat and this will give a good bite onto the base metal.
Then you will need to learn how to Pick and File out the dents and dings (ask for help of your mentor).
You will need to learn how to use an Oxy Acetylene torch for welding and heating.
Then use absolutely the least amount of Bondo to fill out to a smooth surface.
Use urethane primers as fillers primers to fill in the sanding marks and making a smooth surface for future paint coats.
ALWAYS USE 2 COMPONENT MATERIALS ONLY! Do not use any single component putties or paints.
Use PPG Concept 2 component Urethane paints for a top coat. This will give you an extremely shiny surface and will look like the original finish. If you use Base Coat Clear Coat you will have a much deeper more plastic looking shine. This looks good on a Corvette or Street Rod but looks to PLASTIC on an antique car.
Read every magazine and book on body work and painting cars you can find!
Join the local Model A Restorers Club Region and find fellow Model A Restorers who are always willing to provide help and guidance.
Practice on one piece first and see how you do. This will be a long learning curve for you so good luck,
Ken

[Kevin in NJ]

The best advice I can give.

Listen to the experts. Realize they could be very very wrong.

Read the directions and follow the directions made by the scientists at the company. It is especially important to use the correct grit sandpaper as all the modern products need scratch or holes to attach to the previous layers. Understand that during the recoat windows the paints have microscopic holes that the next layer can adhere to. Keep in mind many of the sandpaper suggestions given above may be counter to the products you intend to use- read the directions.

Economical quality priming and filling paints oriented to hobbiest use as sold by Southern Polyurethane (SPI).

I have used a propane torch to get bondo off. Wear a charcoal filter as it puts out nasty gasses. Do not be surprised if you find rust under the bondo.

If you click the link below I have body work hints and places to find more information.

[Bergy]

Thanks guys for the guidance. To bare metal I go. I took this project on as a learning experience, so I really appreciate your guidance. I do have a mentor, but he's not always around when I have that question, so I do appreciate your quick replies.

[pooch]

As long as you do not ask whether bondo over bare metal or bondo over epoxy primer....

[Kevin in NJ]

Originally Posted by pooch

As long as you do not ask whether bondo over bare metal or bondo over epoxy primer....

That is an easy answer.

Depends on how fast you are working.

Shops always go direct to metal cause it is faster. The shops also are putting paint on the same day and will protect the metal.

If you are working slow the epoxy first may be better as the metal is now protected.

Best I can find the best adhesion comes from laying epoxy down first then bondo on during the recoat window when the surface is still 'open'. The is after a talk with the owner of SPI and a discussion of how the products work.

From what I have gathered people often sand with the wrong grit paper for the product they are using. With proper sanding or other means to make the correct rough surface either product will adhere quite tightly to the surface. My favorite is the ones who think 40 grit is best. It has too few scratch per inch which means more flat areas the bondo can not grab onto. It is best to use the high grit that is recommended for more scratch per inch.

Both products will not cure at the surface if it is acid. So use acid products with great care as the surface must be neutralized or it will not be sticking at the surface.

The above comments are based in facts, not opinion, as best I could dig them up over the years. So feel free to go look it up for yourself.

[BRENT in 10-uh-C]

Originally Posted by Kevin in NJ

That is an easy answer.

Depends on how fast you are working.

Shops always go direct to metal cause it is faster. The shops also are putting paint on the same day and will protect the metal.

If you are working slow the epoxy first may be better as the metal is now protected.

Best I can find the best adhesion comes from laying epoxy down first then bondo on during the recoat window when the surface is still 'open'. The is after a talk with the owner of SPI and a discussion of how the products work.

From what I have gathered people often sand with the wrong grit paper for the product they are using. With proper sanding or other means to make the correct rough surface either product will adhere quite tightly to the surface. My favorite is the ones who think 40 grit is best. It has too few scratch per inch which means more flat areas the bondo can not grab onto. It is best to use the high grit that is recommended for more scratch per inch.

Both products will not cure at the surface if it is acid. So use acid products with great care as the surface must be neutralized or it will not be sticking at the surface.

The above comments are based in facts, not opinion, as best I could dig them up over the years. So feel free to go look it up for yourself.

Personally, I would say his advice is 'biased' as it is in his best interest to have someone use epoxy first under the filler. To say his comments are factual can likely be countered by some other Professional. And, I think we would all agree that advice on the Internet is becoming less reliable by the day

The filler resins today are much different than what was available several decades ago. Adding to that, modern sheetmetal having e-coat has changed the game where fillers need to be versatile enough to be used on either surface. One thing that is worth trying is use a thin layer of filler on a piece of masking tape and watch how well it adheres when you pull it off. When it is thick, it pops right off yet when it is thin, it will bend with the tape.

I think the key to what is the most successful is using the least amount of substrates as possible, ...and if that means losing a layer of of epoxy, then so be it. Straighten the sheetmetal first.

[RonC]

This company advertises lacquer paints for sale

http://www.hiberniaautorestorers.com...ve-laquers.php

[31Abone]

I go with lacquer,I worked in GM body shop Olds Cad. Eugene Or, 1964, no health problems and easy to work with,cars are kept under cover so paint lasts....Calif. is kind of sticky on these paints.maybe some of the new water base paints might get it done also.

[BRENT in 10-uh-C]

Originally Posted by RonC

This company advertises lacquer paints for sale

http://www.hiberniaautorestorers.com...ve-laquers.php

Ron, the acrylic lacquer is likely PPG brand (based on their prices). TCPGlobal is offering their own private-labeled brand of acrylic lacquer for about 40% of the cost of PPG's product.

Just remember when pricing out paint, ask the cost of a sprayable quart. What changes it all is factoring in solvents and additives (hardeners), and whether a gallon is figured at 3qts in the can or 4.

I would steer clear of water-borne paints unless you have the facility to dry it properly.

[Ken Ehrenhofer]

I have said this before and I will say it again. Lacquer is not the way to go.
it has very poor qualities.....that is why your grandmother used to have coasters so the hot or cold drink would not leave a mark on the table.
Let's go thru it Lacquer....Poor scratch resistance, poor pencil hardness test, Poor abrasion resistance, will re-soften in the hot sun, and Salt spray testing is horrible on an air dry lacquer.
NO body shop is using lacquer to my knowledge.
Hibernia makes lacquer for those folks who must have the lacquer look.
IMHO....A polished Urethane single stage will look like lacquer without all of the above problems and you will need to wax it about once per year instead of once per month like lacquer.
Single stage Concept from PPG or other products of the same type will give the best most trouble free long lasting results.
In my humble opinion you can use any paint you want. It is you car. I am just giving you the reasons why restorers use these newer paints.
Base/clear has improved UV protection but also looks like a deep shine unlike lacquer and has a plastic look to it. Looks great on street rods and Corvettes but not on a restored antique car from the 20's
Just my thoughts, Ken

[Tinbasher]

So much information, so little time!!. What do you want? Consider, Cost, Time, Life of the job. Everyone in the Body and Paint industry has a system that works for them. So you'll have to find your way. I work in urethane's, Single stage and Base Clear and can make it look like the old Lacquer. The trick is in the polishing. If you get carried away it will look like plastic. (Too Shiny) Sometimes you want that, other times you don't. I like the new products. I just blew in a Basecoat/Clearcoat job I did in 1990 with out having to do a lot of extra work. I'm working on a Tudor right now that I did in 1975 that's Lacquer and I've had to strip to bare metal and start again. Just my thoughts. Tinbasher

[tbirdtbird]

"Listen to the experts. Realize they could be very very wrong. "

I am still trying to figure out what this means.

Anyone who wants to apply nitrocellulose lacquer, if you can get it, has rocks in their head. If it were so good Detroit would still be using it.

If you like base/clear, remember that a flattening agent can be used to knock back the shine somewhat if you desire

metal all has to go back to bare steel or you will pay a huge price later when the paint begins to fail.

It is not clear to me what has to be done now to get the residue of the zip-strip off.

We just did 4 fenders for an owner who did his own prep. He did not want to sand blast. Sure enough, there ended up being a few small areas that lifted despite our extensive prep....some sort of lacquer residue. (we know for a fact that the previous paint was lacquer).
As a result, we will not touch an owner- prepped panel unless it has been sand (media) blasted. And there ARE blasters out there that can do it without warping. We are using a dustless blaster now, which is like the usual sand blasting but uses water with an additive to stop flash rust. It is very impressive.

[BRENT in 10-uh-C]

A couple things to resurface here.....

PPG (as well as a couple other manufacturers) still manufactures Lacquer paint. The sole reason is because there is a demand for it by the consumer.

We as professionals need to remember that the O/P is a novice, and as such has limited experience dealing with products that we are set-up for. We also need to be aware that someone inexperienced in painting may not have the proper equipment (spray booth, respirators, clothing) necessary to handle/spray the catalyzed materials.