I was doing rust removal and welding of my badly rusted out bottom window frame panel and used the KBS system to coat it against rusting again.
I now want to epoxy and buy my first spray gun and paints for the job.
I need to paint at least then bottom panel where the new glass will be install... meaning most of the panel won't be visible but I want to do a good job.

Also my trunk lid has 2 awfully large rust spots maybe as big as a letter size piece of paper. Then there are a few other spots I want to do.

I was looking for a spray gun that can live with my small 2.5 HP Makita AC310H compressor which has roughly 4 cfm max output (very little I know). But the jobs I need to do are rather small, definitely not the whole car. I could also borrow a bigger compressor from my neighbor possibly.

Spray Gun I have in mind to buy:
I checked for a LVLP Spray gun that can live with a smaller compressor. The best I could find was a Sprayit SP-33000 gun. It has decent reviews and I know this is probably a compromise but it seems that the low volume,/low pressure gun also has advantages with smaller jobs, without using a booth. It comes with a few needles and a regulator in the Sprayit kit SP-33310 for about $107 at Amazon (also there is a second gun with the cup at the bottom).


What do you think about the gun?

Then I need to get a decent paint: Base Coat in Black (Code 040) and Clear Coat with Hardener/Thinner

Any suggestions for a decent quality paint?

Can I skip primer? At least for the trunk lid I'd need a primer... probably also for the window shelf after epoxy?

I'd need help for what paints, materials/mixing equipment and sizes I need to order.

Best, Martin

I'll attached a few pictures with the rust holes after removing the rear glass and
a picture of the corner after welding and rust seal coating.
The coat is rock hard.

Attached Thumbnails

     

What year is your car and it that original paint?

I intend to use my touchup gun for shooting 2K epoxy to bare metal. I will thin the paint down enough to go through the gun and shoot as many coats as needed since the areas are quite small.

I painted all the vinyl in my 85 s126 and SEM dye with my Harbor Freight touch gun. At the time I had a small 8 gal compressor and the work is almost perfect. The only flaws were my fault for missing a spot or two on the underside/ bottom of a door panel. Even the dash turned out perfect. Many of the pieces were color change. I know no painter who uses the same gun for epoxy primer/sealer, primer, base and clear but if that's your intent I suggest you look into getting a 3M gun with disposable tips. They come in a huge variety.

The average painter has over a grand in the paint guns he uses on any particular car. I can't do that. At this stage for the both of us I can say that neither of us could tell the difference between HF's Black Widow or HTE gun and the top Sata or Iwata.

For repairing the sheet metal I recommend Fritz's Fabrications on youtube. Fritz actually replaces rusty pieces on a lower rear windshield section exactly in the same location as your car has. To mix small amounts of paint accurately check out Trev's Blog also on youtube.

You said 'newbie,' so I can try to share some of the things which have given me confidence that I can prep my car for the paint booth.

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84 300SD
85 380SE
83 528e
95 318ic

For those small areas I'd use a "rattle can" 2K primer. Eastwood has a good line, Rust oleum and Spray Max also have good ones.

It's not worth purchasing the primer, catalyst, separate tips for the guns, mixing, storing, cleaning, etc. for the small areas you are covering.

https://www.eastwood.com/eastwood-s-2k-aerospraytm-epoxy-primer-gray-black.html

https://www.amazon.com/Spramax-EPOXY-PRIMER-GRAY-SPRAYMAX/dp/B07CVPGQGF/ref=pd_lpo_1?pd_rd_i=B07CVPGQGF&psc=1

https://store.southernpaintandsupply.com/rustoleum-2k-epoxy-spray-primer/

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

I agree with you, Mike. Unfortunately for me I have several rock dent on my car which have rusted from sitting for about two decades. I was lucky to find only one body panel with rust, which is pictured in my thread below. I also had a spot above the muffler which appears to have taken too much heat.

I intend to seal all the metal with Transtar epoxy before I install any of the pieces on the body. I'm sure I understand that the primer/sealer I'm using with have to be removed from the areas where the welding is to be done.

I have a tube of SEM seam sealer, is that stuff any good?

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84 300SD
85 380SE
83 528e
95 318ic

Never tried the SEM sealer. I've always used the 3M stuff.

Seam sealant is used AFTER all the welding/patching/primer is done. It doesn't accept paint well and U-V rays eat it up.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Thanks Clemson and MikeD
For responding and share the 'compromises'.
My car to work on is a 1984 W126 500SEL, original color is 040 black (or jet black). It is a
a solid black, not metallic) and I want to keep it that way. I think the car was repainted a point in time (has also to painted stripes on the sides) but color is the 040 right now.

It is indeed confusing and overwhelming to me how many different products, tools and techniques are out there and to figure out what I'd needed to perform a 'simple' paint repair job.
I have done a lot of sheet metal rust repair, all with my MIG welder and the results are satisfying (to me) and lasting. But I never managed to get satisfying results with the
paint finish by using rattle cans, I hate these cans. One for the result is never lasting (paint is not solid and resilient like the original paint). Two the appearance is not satisfying, it is hard to blend the repair into the existing paint.

Now I am at a point where I want to improve and find a more satisfying solution for the job ahead of me and I want to learn and invest as much as I can afford and what is reasonable for me.
Well I have 4 old Mercedes and most of them will need some paint repair at some point. I don't think I will ever spray an entire car (who knows) but I'd be happy to paint a panel like a trunk lid, a fender or a partial paint job (like the rear window frame) and create a durable surface, blend the new paint into the existing as much as possible.. AND make it look nice. And this in my garage without a spray booth in miserable New England climate.

How to do this without braking the bank?

Thanks MikeD to point out I can use the 2K Epoxy Primer instead of mixing the 2K epoxy primer and shooting with the spray gun.
However if I also did my rusty trunk lid...would you also spray the trunk lid with the rattle can primer?

Sequence:
I guess I understood correctly from where I am right now (having welded, cleaned and encapsulated the bare metal with KBS rust seal)

I need now roughen the KBS surface a bit? t
Then use a filler (Bondo or what product?) and get a smooth surface.
Then spray the 2K epoxy primer (rattle can or Tamco 5310 DTM Primer for instance)
..or does the DTM primer not stick to filler well?
Then spray base coat. Would you consider a single stage.... like the Tamco AG 900 high gloss Polyurethane.
Or do base coat and then clear coat.

I am using Tamco as an example because from where I am right now I seem to understand what they are selling (even though I don't) but I have a feeling they are
talking in a simple language that I can understand.
If I go to the Glasurit website as a newbie I don't understand anything.

Martin

"I want to learn and invest as much as I can afford"?

How much money ya got and how smart do ya wanna be?

Learning to re-paint properly is an expensive and time consuming ordeal. Between the compressor, water separator, guns, CORRECT PPE, mixing/measuring equipment, tarps, tapes, sanders, etc. you'll be in well over a grand not to mention clean-up, prep and possible environment/health hazards.

If you decide you absolutely MUST learn to paint then I'd suggest you purchase a turbine spray rig. If the turbine rigs were available at the costs they are now, I can assure you I'd still be allowed to paint. Doctors, my wife and lung problems put the kibosh on that activity for me.

The Fuji Semi-Pro rig is a good entry level prospect and there are several other companies with similar set-ups.

Here's a good read:
https://www.restore-an-old-car.com/best-hvlp-turbine-for-automotive.html

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

You have library skills and communicate well. The problem is wading through the sales pitches and gleaning the facts and information which is/are applicable to your needs. It's going to take time. I'll give you an example.

I searched for proper prep for the vinyl panels, dash, console and plastic bits for my project. Hour after hour of people in the internet sharing their 'knowledge, expertise and profession opinion.'

When I went to pick up the paint at Finishmasters one of the old guys there told me to wash it all with water, soap and ammonia and shoot a light coat of SEM (~$20) plastic prep on the plastic.

I am painting a 1985 380SE body also and it also is my first paint job.

__________________
84 300SD
85 380SE
83 528e
95 318ic

Thanks Mike,

Yes these are wise words and I appreciate it very much ('expensive and time consuming ordeal').
I am driven by my actual W126 window frame project (I need to get the glass back in) and I must admit that I am not quite
ready to go at the moment even though I like the idea with the turbine rick a lot in order to skip all the questions about my poor compressor set up (which clearly needed to be upgraded 2 or 3 steps in order to serve a HVHP gun.

I short I'll need more time in order to digest and so I am feeling I am back to zero with a rattle can solution for the window frame which is not very visible after the glass is installed.
But for a trunk lid project and others are coming up (next yeear) and I'd need the turbine rick.
Mike I am not sure if the Fuji Semi Pro rig is sufficient for the size of the trunk lid?
Do you think the small rig can do this properly?


For the window frame: I am taking your advise and get a 2K epoxy prime rattle can. And I'll get a rattle can 040 base coat and clear coat.

My idea now for the situation is:
I have used KBS rust seal system on the sheet metal after welding
Now I want to roughen the surface with sand paper and use Bondo in order to create good bond with the rust seal?
Or would you better clean the surfaces and then use the 2K primer, then bondo over it?
Then use the 2K primer and base coat, then clear coat.

How many coats with each (primer, base and clear)


Would this be a reasonable approach that will last?

Best, Martin

No "Bondo" EVER on any area where water might sit/accumulate! "Bondo" has its uses (none that I'd ever consider) but this is not one of them I wouldn't use "Bondo" on my mother-in-law's car!

I am guessing you are using the term, "Bondo", in the general sense and not as a name brand. The only body filler I ever use is the Evercoat "Rage" line and I wouldn't use it for this application.

Use the POR15 Patch and Seam sealer for the window channel or the epoxy putty. I've always used the putty but that is because the Patch is a new product line.

Sand, putty/patch, shape/form/sand, primer then paint.

https://por15.com/products/patch?pr_prod_strat=copurchase&pr_rec_pid=6622112317607&pr_ref_pid=6622112219303&pr_seq=uniform

https://por15.com/products/epoxy-putty

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Thanks Mike,

Yes, I should use the term 'filler' rather than bondo, my apologies.
I had no particular product in mind but why is Bondo not even good for mother-in-law's car? It is widely rated amongst the best fillers but this might be the 3M powers directing the reviews. Evercoat Rage stuff is expensive but why not if it is worth the money...not for this application but on raw metal probably.
But I understand now why a filler is not the right place here for the window shelf that will collect water easily (and will take up moisture).

Thanks for letting me know about the POR15 'filler', the putty/patch products... I'll definitely try this out. If one of them would you use the patch?
The rest is understood, thanks again and you are very helpful.

Best, Martin

How much does the Evercoat shrink?

__________________
84 300SD
85 380SE
83 528e
95 318ic

I really couldn't say. I've never noticed any shrinkage but then again I've never put on more than a "skim" coat (1/8" or less). Much like any filler, if you apply it too thickly, you'll get voids and bubbles. It's just the nature of the beast.

__________________
“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Thanks, Mike. I'm going to need a skim coat on the small section I welded. I have a shrinking disc so if I learn to use it I should be a lot closer than 1/8".

__________________
84 300SD
85 380SE
83 528e
95 318ic

2nd the water separator. Best place to remove moisture is between the compressor and tank (that's the setup I use) with an after cooler and water separator since a hot tank of air makes it difficult to remove moisture. With my setup the tank is cool even after hrs of media blasting.
I have seen many home jobs that are show worthy but most of the work is the body work and prep-actually shooting it takes little time compared to the prep+ the polishing if you go that route. There are lots of U tube videos on the subject.

__________________
Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT