Technical Question for the Rust-Oleum paint crowd

Okay, I have a running driving car and I plan on doing body work over a period of time. I've never painted a car before, but I'm strongly considering using Rust-Oleum. My question is as I'm slowly working on the car and cutting out rusted areas and welding in repair patches my plan is priming those areas with Rust-Oleum rattle cans. Eventually I'll have to do some Bondo work to smooth out those areas and wondered if plastic body filler will stick to Rust-Oleum primer? The car will be stored inside during the work except for the occasional drive. After the rust areas are repaired and primed my thought would be to do the body filler work, prime the whole car using a spray gun, block sanding and then shooting the final Rust-Oleum paint all at one time with a spray gun.

So, my question at this time is will the plastic body filler bond to Rust-Oleum primer so I can do the work a little at a time yet giving the patched areas some protection short-term.

Lynn

 

Don't use an oil based primer under body filler it will not stick well. If you ever want to paint your car with automotive paint all the Rust-Oleum paint will have to be stripped off first. Why not use some cheap implement paint with a harder instead?

 

Thanks. One brand of tractor paint I've seen at A local farm and home store is Sikkens (spelling?). Would that be a better choice of product for primer and paint as opposed to Rust-Oleum?

Lynn

 

Sikkens in the construction industry is a good brand.
Cant comment on their paint.
Curious myself what you find out.

 

Like anything, there are levels of product.
My understanding is that you want to use like with like, I.E., don't mix high end with cheap stuff.
The current thinking is to use an etch primer on bare metal, followed by filler, then high build primer, a sealer, then color. Yes, this makes it difficult for slow hobby work to match up to pro level work.
EDIT: Seems it's EPOXY, not ETCH, my mistake. Read the pros in here!

You have to decide if the project will be a full rattle can job or a full pro product job on the same part (body). Obviously doing every little part and bracket with pro stuff is even more effort and costly. You also have to take into account use after completion. If it's going to be garaged recreational use, that's different than a daily driver.
The base is the foundation of all the rest. I will page @anthony myrick since he's got current experience in what can and can't be done here. Hopefully he's got some tips for you.

 

Under filler?
No way I’d risk it
The only issue with cheap stuff is if you decide to go to the next level later. Now you’re removing the cheap stuff.
I’m actually spraying rustoleum now. A bumper piece we built at school. All paint work is 90% prep.
Anywho, I’d can get alkyd enamel from my ppg store for not much more than rustoleum. Lot more colors to choose from.
Can add a catalyst to it.
It’s cheap as well.
Color hold out last longer and it’s a little more chemical resistant.
I’d recommend a cheap quart of epoxy and cheap HF gun. Mix small amounts for the repair areas. Now you got a better foundation for bodywork.
Use a fan and a respirator.
Need that anyway even with the rustoleum.

 

Go to you tube and watch what guys are doing with the higher cost Rustoleum rattle cans and how they prep. Never hurts to see what works and doesn’t!

 

This is what I thought. My experience has been that body filler chemically reacts to etching primer.

 

I have been putting body filler over bare metal for over 50 years, and never had problems with it lifting. A few of the cars I have had for 30 years, so if you want to save money you can skip the etch primer step. A friend who owns a body shop said he tried it and went back to filler over bare metal.

 

Lots of youtube on alkaloid paints (Rustoleum etc). There are hardners available for them. They aren't as UV friendly as regular car paints so they don't last as long. But that's not a big problem for cars that spend most of their lives in the garage.
I've always used bondo on bare metal. Freshly ground with 36 or 80 grit for a good bite.
Look into epoxy sealer primer - since your project will be done over a long period regular primers can allow rust. They are porous to promote adhesion and will let moisture attack the steel underneath.

AI sez: For enhancing Rust-Oleum oil-based enamel paint, the most compatible hardeners are generic enamel hardeners, specifically Valspar Tractor & Implement Paint Hardener or Majic Tractor & Truck Catalyzing Hardener, which significantly improve durability, increase gloss, and speed up dry times. These are typically added at a ratio of roughly 1–2 ounces per quart of paint.

 

Since I'm so slow, and my compressor blows too much oil, AND I have neighbors on one side with 4 little kids, I've been researching this for a long time, IF I ever get to this point in my builds. I have 30 something test panels of clean, shiny metal with every combination I could think of that didn't use cheap, ****ty rattlecan paint, only the "good" stuff, with every kind of clear, and 2K clear, too. Many Rustoleums, a few Upols, and Seymour. Many kinds of primers, even 2K. Very careful about drying time, and proper coats. Some have 3 coats, some 4, some 2. These test panels are suspended in the air, and have been exposed to everything outdoors since Nov. 2024. All rattlecan, all of it.
I panted chopper gas tanks in the 70s with Rustoleum, changed my mind later,Hell, the old stuff took longer to remove by gl***beading off than I thought even possible. That was oil, and it was tough as Hell.
But, I've heard only good stuff about Seymour, 100%. Shop around , you can pay a lot if you're not careful.
I didn't spray too heavy a coat, I took my time. So far, after 17 months exposed, my conclusions so far, is ALL the clear looks like ****, except the 2K . Toss up between Rusto and Seymour for color, but I'm going with Seymour unless I see drastic changes later on my test panels. 2K clear is awesome so far. I used flat and gloss, both paint and clear.
I've gotten some teasing about this, but this will be my only option to paint at home. My garage door faces the neighbor with all the kids, and I don't want them to be exposed. Spray cans will be easier for me to use without the other neigbors knowing. I have a big, tall privacy blocking the view, so they don't see me welding outside, but the smell will cause me trouble from other neigbors if I paint this the "right" way.
Limited colors, yeah, but flat black painted over color to seal, with 2K flat clear is my most likely finished color. EDIT.. I also did cheap, pretend chrome with all the clears, too. The Seymour is slightly better looking IMHO, but it all looks bad. The 2K cleared "chrome" appears to be the way to go that way. Don't want to do it, but all the custom modified crazy **** I've done for bumpers and an insane grille will probably cost 10K to plate, or more. Some of the pretend chrome looks piss-poor no matter what I did.

 

Just to check if I understand correctly. Are you saying do the filler on bare metal after scuffing the metal with course (36 or 80 grit) paper? Or....are you more in favor of using epoxy primer and then filler? I looked at the spray guns at Harbor Freight this morning. One of them was about $30 and had a 1.5 tip. Is that a good enough gun? I have a Accuspray gun I bought years ago and only used it 1 time with marginal results. Perhaps I should use it and get a tutorial from someone with more spray gun experience to get it properly adjusted. I do already have a Harbor Freight touch-up gun with a really little cup that would work well for priming the spots as I do weld-in patches.

From a later post, what's your opinion on the Majic paint and primer? I've found that locally at a Rural King store. I would plan on using their catalyzing hardener in the paint. I'll also take your suggestion and seek out a PPG store in my area and step up my game a notch from farm and home store paint and primer.

FWIW...I'm not aiming at a car-show paint job, but do want it to be presentable. I'm already 73 so durability might not be an issue.

Thanks everyone for the posts.

Lynn

 

Lots of bad/dated info about fillers on this thread.

To your original question no filler cannot go over Rustoleum primer. If you want to prime for a long term project epoxy is the way to go. Do not do filler over bare metal if it is a long term project that will not be primed over right away if you are in an area that has high humidity. The filler will absorb moisture and cause issues down the road.

Etch primer is a collision industry product and should NEVER be put under filler. The acid in it will react with the filler. Also 36 grit under filler is a dated and for some modern fillers will mean less adhesion. 80girt is plenty for the fillers that are available today.

It's a bit of a long read but here is a thread I did on Body filler basics.
https://www.jalopyjournal.com/forum/threads/body-filler-basics.1180243/

 

Epoxy primer then filler, it is an easy recipe.
Rust oleum or non-hardened spray can primer is a recipe for disaster.

 

The cheap HF guns are around $10-15 on sale.
Worth every penny.
Epoxy under filler? For a daily beater….nope
Higher end resto/build…… yes
Etch is a no under filler.
I only suggested an economy 2 part epoxy cause you can repair some spots, apply a couple coats on the repair and keep cruising. Can come back later and do filler.
Or, do the repair, apply filler and prime.
but I wouldn’t apply a filler over etch or a 1 part primer (non catalyzed)

the last time I compared rustoleum/tractor store paint prices, my jobber cost for the ppg store was around $25 more per gallon. Now that’s a large percentage number but not a large added cost to a paint job.

my suggestion is to not over think it. If the goal is a decent daily home paint job then keep that approach.
Prep is the key. Properly sanded, primed, feathered, taped, cleaned.

practice. Shoot the tractor store paint on a practice panel.
You have 3 adjustments. Air pressure, fluid and fan controls. The rest is distance and speed
An HVLP gun likes to be closer to the panel and overlap more. I no longer do the old school 50% overlap on p***es with the gun.
I spray closer, move faster and overlap more like 75% with the newer style guns.

the 1.5 tip on the HF gun is fine for the enamel. That’s a larger tip size than I normally use but works fine.

but practice. Experiment with distance, speed and overlap.

 

Thanks very much Anthony! That info filled in the blanks for me quite nicely.

Lynn

 

Satin equipment enamel with hardener
The satin seems to lay down with a slight texture.
We shot some glossy alkyd a couple weeks ago.
Laid down pretty good

 

As I mentioned earlier about filler on bare metal and regarding Anthony's no epoxy under filler for driver. You cannot let the filler sit exposed in a humid environment for any length of time. It either needs epoxy under it or epoxy over it right away. If your bare metal is flash rusting sitting in the open your filler is absorbing that same water just a quickly as the metal is rusting.

 

Using two part epoxy under filler is a pain but if you give a **** at all and want it to last I think it’s worth the effort and cost. I don’t like working with it because it can be hard to blend if you’re trying to make a panel straight so you need to work over the edges. But there’s nothing that holds back rust better than epoxy and filler adheres very well especially if you scuff it before the filler.
I stay away from the rattle can epoxy and etch primers, I helped a friend in his shop after I sold mine for a couple years and the rattle can primer caused more comebacks and we only used them for covering cut throughs on final primes.

 

ROAD TRIP - it'll have that 50s not so perfect look too.......

• Baja California (Tijuana/Mexicali): Frequently used by US customers for lower-cost automotive restoration and industrial finishing through shops like Platinadora Baja and Precision Plating.

• Monterrey/Saltillo: A powerhouse for the automotive and energy sectors, home to large automated facilities like Prince Manufacturing.

• Central Mexico (Toluca/Mexico City): A historical center for general metal finishing with long-running groups like Ecoplating and Estañadora.

 

The 2 part ones are OK but pricey and with a short shelf life once mixed (you can extend it by storing in the fridge)
https://www.eastwood.com/ew-2k-aero...MIso_wr9eqlAMV_ipECB27_xCsEAQYASABEgJPXfD_BwE

 

I've done 'body work' on my stuff all 'wrong', and all 'right' for 60+ years now. Over the years I have discovered there are much better ways, and worst ways to do every step, nearly all of it depends on how the timing of events worked out.

Back in my high school days, I took 3 years of Auto shop. The last year the teacher was an older ex-body shop guy. Back then (early 1970s), the spray primmer and spray paint that was available actually worked pretty well.
Bare and welded metal work can flash rust pretty quickly when exposed to moisture. If you could spray bomb the bare metal with primmer, it was usually OK for a week or two, if it was not raining every day. If there were 3-4 days of rain (or highly humid air), you sanded the primer off before you added body filler. If that body filler was kept inside, you were usually OK for a couple of weeks. It the car was going out into the weather, or it was going to be a couple of weeks before you could get back to it, you had to prime the filler. If it was going to be longer (or in moisture), you covered the filled area and the bare metal with spray paint. When you got back to it, any primer that was exposed to moisture had to be sanded off, or any paint sprayed, had to be removed. This was the process used every time more filler was added. Moisture always meant more work (any filler exposed to water, had to be removed completely), but if the vehicle stayed inside and was worked on every day or two, priming or painting in between adding filler was not required.
One car I was driving got body filler work every night, but if the humidity was going to be high over night or until quitting time (when the body work got started), it got primed. That first one turned out OK (people were much more forgiving then they are now). After it, the next body project was done in a rented garage, and I had a different car to drive home (the body work on that one was a lot faster, and turned out a lot better).
Most of the 'paint jobs' I did were done with the local farm store enamel. It was priced about the same a Rustoleum, but was a different brand with more color options. With all of those, the filler was applied directly over the bare metal, sanded smooth (to my tolerance for sanding level), primed, sealed, and painted with the farm implement paint (most well before any 'hardener' existed, that I knew of). That farm implement paint was good for about 4-5 years before it started fading bad, and started collecting a lot of chips. That worked OK for me, if the vehicle was staying around, it got another round of body work (to my tolerance level) and another paint job using the same color of the same paint brand. Only a couple vehicles hung around long enough for the 3rd round of body work. After all that painting experience, I can still make paint runs with the worst of them!

About every 4-6 years a new hot rod was built, and all of them got the same body work process, with several different colors.

By 2011 when I painted my coupe the first time, the quality of the farm implement paint was going down hill, even with the then available hardener added. The paint quality was getting bad after the 3rd year. When the coupe was repainted in 2018 (its 3rd round), I still did the ****py body work, but I had a friend spray it with real automotive paint (acrylic enamel). That red paint (which was not well cared for) is beginning to fade, and some of the filler work done in 2011 is starting to show up, but the car is still presentable.

 

K13 is correct about humidity and moisture being absorbed into filler, I’ve seen the results. There are some fillers out there that are moister resistant read the product data sheets before using.

another warning about two part epoxy primers, if you wait till after it’s cured paint will not stick to it unless you pre sand and even after that it and may lift a few years later. always read the product data sheets for best results.

 

Whatever you do….
Up to and including gold plating.
It’s wrong.

 

Did that spray OK as is, or did you add any reducer to use the purple gun?

 

I’ve mixed an ounce of primer either epoxy or urethane to cover a small spot, little to no waste. In fact, it’s common practice in a shop to mix the minimal amount of product primers sealers color and clear coats…

 

Reduced at least 25%. Didn’t measure it. I watch how it drips off the mixing stick. Rustoleum doeshave spraying recommendations. Kinda vague.

It needs reduced to spray thru any gun

 

Yes common but - He was looking at spray can refinishing (that I linked). You have to mix the whole can and use it within 24 hours.

 

I don’t recommend rattle can products but then I still buy my epoxy two parts a gallon at a time and I’m retired.

 

I recently did an OT grill (ABS plastic) in 2K satin black and it turned out really nice. Hit it first with SEM Sand Free Adhesion Promoter and then laid the 2K satin black while the SEM was wet. Flowed out very nicely. Same with a chin spoiler I did in 2K gloss black (primer, black & topped w/2K clear gloss). Do it one day and put it to work the next!

The 2K spray bombs are nice for small projects, at least for me. Wear the gear, be safe and protect your health as it's nasty stuff!