Mono chassis paint prep

[Doc Watson]

After too many years.... getting set up for a run on the chassis this summer. Its Zintec steel so I was wondering what would be the best way to put an initial primer paint on? I want to use a zinc based primer and will spray it on, thinning the paint to allow capillary action between spot welded areas to get the paint behind. Will be very careful when removing small areas of surface rust from the Zintec with PPE.

I would have liked to use zinc chromate (used on aircraft usually olive green) but chromate is bad stuff and difficult to source in the UK. The final coat will be sprayed and will be black (some early Mk I chassis were deep blue) what would be the best paint for this coat? 2 part epoxy? flexible vapour based paint? and would there be compatibility issues with primer and final paints to keep in mind?

 

[Davidmgbv8]

Doc,
Glad to hear you are making a start. I have used Carboline CZ-11 as my primer because our industrial painters buy it by the barrel and are kind enough to give me a quart now and then. Just do not know if you have access over there.

 

[Doc Watson]

can get it here...by the gallon!!!

 

[Ole Nylende]

I would say; degrease and mild buff with scotch cloth to get good adhesion. Where you have surface rust sand or blast depending on how bad it is, make sure it is fullt removed.
See if you can get some zinc rich primer used for marine or offshore paint systems, thats usually good stuff.
For top coat either ordinary 2k epoxy for cars or some industrial paint.

Would also consider; inside the sills there are no drainholes. Consider drilling a few. After you have finished painting i would apply lanolin wax typical to all areas like the ribs, enginebay stiffeners etc.

 

[Randy V]

Can you buy POR15 over there? It leaves a rock hard finish that’s tougher than powdercoat…. Tough to spray though. I’ve always brushed it on. Good quality brushes and cleanliness make all the difference in getting a smooth finish….

 

[Davidmgbv8]

Yet with POR15 throw away the paint gun after and God forbid if you have to ever try to get it off for a repair because it is really that tough!

 

[Ryan L]

God forbid if you have to ever try to get it off for a repair because it is really that tough!

Sounds like the old Lead paint. I'm currently trying to restore an old pan brake that tested positive for lead paint. None of the paint strippers want to touch it.

as for Andys problem, i would probably recommend getting in contact with 3M or PPG and seeing what they recommend. I know they have all sorts of stuff that you may not come across in a general search.

 

[Doc Watson]

Thanks gents.... once the chaos of end of year marking and exam boards is over I will be on it....

 

[Michel]

Hi Andy
Recently I used an epoxy paint from A company I trustsince years their good quality and stuff
This epoxy 2 compounds paint is advised to be used on motorbike and car chassis with no primer only light prep ; so I used this coat as I needed to protect the new chassis I made during past year , so I just cleaned everywhere I could ( those guys was telling that light rust on few areas could even help this epoxy to stick on !!!!
They advised to do very light coat every 10 mn and a final one just making the surface glossy and let cure for 2/3 hours at 20°C to get satin aspect
So monthes ago When it was a shiny day I processed like they advised and the result wa excellent !!! Then I let it cured for some days
When I compare to another similar chassis I had subcontracted to a powder shop company I can say that the result with this paint is so much better
( lighter on weldings so easy to check in the future and no need to redrill or tap all holes) and 5 times cheaper !!
Coating have been done since monthes and assembly started and no scratches or any flaw appeared ; So I used again this epoxy paint on the whisbones that where spraycan painted directly !!!! it was another success!! They are now matching to the chassis with avery very nice satin aspect
I also used some acetone to clean a polyurethane bonding I did for some panels and the epoxy coat cleaned perfectly resisting wonderfully to this
thiner !!!
Hope this helps

 

[Scott Calabro]

With all the time and effort you’ve put into this Andy, I’d consider getting the tub galvanized. Then paint it whatever top color is most “correct”

 

[Neil]

I've commented on painting before so at the risk of beating a dead horse....

1. Scour lightly with a Scotcbrite pad.
2. Wipe down with acetone, MEK, or denatured alcohol.
3. Spray on a 2-part epoxy primer. Zinc chromate on aluminum, "Steel-It" epoxy primer on steel panels.

Steel-It Epoxy Primer 2 Quart Kit 4210Q | Indcon Supply

Buy Steel-It Epoxy Primer 2 Quart Kit 4210Q. Fast shipping and technical help with industrial and construction products. Free shipping over $100 on qualifying products.

www.indconsupply.com

4. Optional: spray on a top coat with a 2-part polyurethane coating such as:

https://www.aircraftspruce.com/catalog/cspages/ptitopcoats.php

This primer and top coat isn't cheap but they are worth spending money on to protect the investment in time and money that is your build.

 

[Ole Nylende]

I would recommend to clean / wipe down before you do anything at all, then wipe down again when you are ready to spray.
Lets say you have some stains of grease or something containing silicone (like car polish/wax), you will spread it whereever you sand with that contaminated paper. Not a big issue on bare steel but where you have that primed material i would recommend so.

 

[Markus]

Hello Doc,

For bare steel I would say cathodic dip painting is the best - especially with all the pre-treatments offered - see links below.

Factory Restoration | Porsche Classic

Restoration of classic Porsche cars. The Porsche Classic experts have decades of professional experience. With the highest standards of quality and originality.

www.porsche.com

KTL-Beschichtung für Oldtimer, Prototypen und andere Fahrzeuge – ein optimaler Korrosionsschutz

KTL-Beschichtung & Veredelung – Werkstücke bis 16 m Länge, 2.60 m Breite, 3.60 m Höhe und einem maximalen Bauteilgewicht von 5.000 kg. Verarbeitung von Produktgruppen oder Einzelstücken.

www.ktl-wob.de

KTL Beschichtung Oldtimer - Oldtimer Restauration Drowatzky

Die KTL Beschichtung Oldtimer (kathodische Tauchlackierung) ist ein Verfahren zum Korrosionsschutz von Metallen aus dem industriellen Anwendungsbereich.

ktl-oldtimer.de

With Zintec not sure how best way forward is and if it even is possible to apply onto Zintec.....

If possible to remove any (hopefully not) rust from cavities and then "once and for all" coat for good.

Sorry, some page are only available in German.

Regards,
Markus

 

[David mono]

Hi Doc . If you can get PPG DP epoxy primer it comes in different colors but the green one has more rust protection so I have read.

 

[Brandon]

What kind of environment are you in that you need that much corrosion protection? Are you storing this outside at your beach house?

If you already have rust, then clean that off certainly.

Corrosion X Rust Remover | Aircraft Spruce

Corrosion X Rust Remover Remover eliminates surface rust from iron and steel without harmful fumes. It will not harm copper, brass, plastic, rubber or vinyl.

www.aircraftspruce.com

ACF-50 is well-regarded in the aviation industry to get into tight areas through capillary action on both aluminum and steel:

ACF-50 Anti-Corrosion Block Compound | Aircraft Spruce

ACF-50 Anti-Corrosion Block Compound ACF-50 is designed for owners of strut equipped Piper aircraft to comply with new Piper bulletin 5280C requiring lift strut inspection.

www.aircraftspruce.com

 

[Davidmgbv8]

Has anyone else used Steel It yet? I was going to try on my suspension arms. my powder coat was chipping off as I unwrapped them and now after several test fits and little drops are all chipped up.

 

[Neil]

Yes, I used it to paint the aluminum section of the driver's seat in my race car. I get in and out of the car by stepping on the seat and, so far, the Steel-It is holding up just fine. It is a very had, tough finish. I buy it from:

STEEL-IT Stainless Steel Coatings - Oils / Paints / Liquids - Truck

Wild Scooter Parts

wildpowersports.com

 

[Randy V]

Has anyone else used Steel It yet? I was going to try on my suspension arms. my powder coat was chipping off as I unwrapped them and now after several test fits and little drops are all chipped up.

My only concern in putting such a tough coating as powder coat or other on suspension components is that you may not be able to observe developing cracks. This, along with hydrogen embrittlement has been a good reason to not chrome plate such components.
I always fall back on an enamel paint like Krylon “Dove Gray” for these things.

 

[Davidmgbv8]

Agreed, most of the vintage racers electroless nickel theirs but I am having trouble finding someone willing to do it. That is why I was looking at Steel It. When I ordered my SGT I did not know the pieces were going to be powder coated. Now with shortening the upper and lower arms to get the wheels under the body, well I have had to remove with a lot wire brush removal, easy to do on the rods but guess I will have to blast it off of the A arms.