Rust repair & painting at home

[Fletcher]

As I progress on surface rust repairs, should I prime as I go with primer from an aerosol can?

 

or leave it bare metal and then sand the whole car and prime with compressor and sprayer?

 

i have a couple job site construction compressors for driving nailguns.   Will these work for painting with sprayer?

 

Any recommendations on sprayers, paints and (seem hard to find atm. Thanks, covid) respirators?

 

thanks

Edited July 17, 2020 by Fletcher
Typo

[VWJake]

As long as the aerosol is compatible withy the paint system you intend to use I guess you’d be ok to prime as you go.

 

As for compressors: while your hotdog or pancake compressors *may* have the cfm  (10-20 or more depending on the gun) to run a gun you’ll have tons of water in the air. You need capacity in addition to the flow. You can probably get by going slow with 15-30 gal, but 60+ gallon is really best. The larger the reserves the less the pump will run (making water vapor). 
 

pick a paint system for the final base or base/clear. They will recommend air flow/pressure/tip sizes for application. From there your local paint supplier can guide you to good guns for primer/base/clear. With all of that then you get a compressor that will handle the load... 

 

my 2c anyway
 

[VWJake]

Oh and I’m using PPG shopline for my ‘73. It’s single stage enamel. I have the option of a clear, but I haven’t decided yet. Devilbiss finishline 4 gun for color/clear

[Mike Self]

40 minutes ago, VWJake said:

you’ll have tons of water in the air.

Regardless of compressor size, if you're gonna paint, you need a water separator in line between compressor and air tool.  

 

I would not leave bare metal after sanding, unless you're in the high desert with 0 % humidity. Give it a squirt with spray can primer just to keep the metal covered.  When I was (very slowly) doing the bodywork on my '48 Fiat, as I finished a section I brushed on Rustoleum "Damp proof primer" just to protect the bare metal.  When I was ready to paint, I wiped it all off with lacquer thinner and properly primed it.   

 

If you're sanding surface rust, use either a self etching primer or other treatment to get the rust out of those tiny pits that will remain.  Otherwise they'll come back to haunt you several years after your repaint.  And I hope you're not using bondo and window screen to patch rust holes!  There are much better ways even if you don't weld.

 

mike

[esty]

to do it right...you should  sand; do the body work; prime with epoxy, if the body work suits you, go to 2k urethane primer, block and sand until the body work suits you, seal again with another coat wet coat of epoxy or 2k, then paint the car

 

but as stated, you are pissing in the wind with a small, low volume compressor

 

[MitchaPaLoOza88]

SEM Self Etch Primer is really good stuff for covering bare metal. Used this a lot while working the welding sections.

https://www.amazon.com/SEM-39683-Grey-Etching-Primer/dp/B000GTIRAU/ref=sxts_sxwds-bia-wc-nc-drs1_0?crid=2YT72ISWDYTWH&cv_ct_cx=sem+self+etching+primer&dchild=1&keywords=sem+self+etching+primer&pd_rd_i=B000GTIRAU&pd_rd_r=c874653e-1cf8-457d-a444-40e5a842f464&pd_rd_w=FqnNg&pd_rd_wg=2UNyN&pf_rd_p=43f4b3f0-0b04-46ba-8a08-2e851d035e17&pf_rd_r=B8E1X41H1A04WRQB8MHB&psc=1&qid=1594998583&sprefix=SEM+self+et%2Caps%2C638&sr=1-1-f3947b35-9c59-4d7a-9603-b751e6eed25b

 

The Eastwood gun works pretty well for the Pricepoint. Get the Pro if you can, the pro will spray primers way better.

https://www.eastwood.com/eastwood-concours-2-hvlp-paint-gun-kit-in-aluminum-case.html

 

They have these inline Disposable Desiccant Snakes. They work great as you won't need to drop tons of money on a drier system for a one time use.

https://www.eastwood.com/desiccant-snake.html

 

Also note self etching primers are not really for total corrosion protection, that really what the epoxy primer layer is for. The most ideal situation would be directly after sandblasting the shell, immediately epoxy seal it.

 

[Son of Marty]

A definite yes on the respirator and cover all of your skin if your using anything more than rattle, cans modern auto paint can be toxic at low levels, so do your research before you pick up a spray gun it's cheaper that way.

[Fletcher]

39 minutes ago, Son of Marty said:

A definite yes on the respirator and cover all of your skin if your using anything more than rattle, cans modern auto paint can be toxic at low levels, so do your research before you pick up a spray gun it's cheaper that way.

Excellent advice.   I assumed it wasn't non-toxic, but I didn't think of suiting up beyond the respirator.  Thanks!  

[tech71]

Rattle can primer is crap, Buy a cheap Harbor Freight paint gun and apply something better like epoxy primer from Eastwood. Epoxy primers are not pourous like other types and the underlying metal wont rust if exposed to moisture before you can get top coat on.

Buy a decent cartridge type respirator that fits properly even if you use rattle can paint. Sounds like you would be using quite a bit of it.

[Fletcher]

52 minutes ago, tech71 said:

decent cartridge type respirator

Thanks! Any ones in particular that you recommend? 

[fjord-tii]

As above, catalyzed primer is the only way to block water, but is not long term. I used a metal etch (at Home Depot, it’s phosphoric acid, so wear gloves, eye protection), and that actually keeps surface rust off for a while. I then used a HF spray gun with a yellow DuPont primer (can’t remember the name), that’s like nails when cured. The main thing is to stay within the primers-top coats system, read the tech literature from the manufacturers. Summit Racing sells mid-range, house brand products online as does  TCP Global. For respirators, I go with 3M and whatever cartridges work for organic solvents. FYI, I wouldn’t doubt Washington state has banned painting cars at home as the solvents, etc. are highly volatile organic compounds (VOCs); try to find a paint booth and/or pro do shoot the paint.

[Son of Marty]

Well both Norton and 3m  are the ones you'll see used on most jobs, I have a 1/2 face Norton and a shopping bag full of cartridges issued by a former employer  that I have no complaints with. 

[AustrianVespaGuy]

Voice of experience here: strip, prep, sand, repair, fill, smooth, etc. to your hearts content.  Then give it to a pro/shop to actually spray it. Especially once you've cut down the price with all the prep work, a good professional spray job is worth it 1,000,000x over what you can do yourself.  Unless you ARE a pro with a properly filtered zero-turbulence paint booth at your disposal that is. . . then might be a different story. Some small amounts of primer protection for a few vulnerable spots is probably OK, but I wouldn't go overboard with it.  Some bare/clean/good metal should be fine for at least a few days/weeks at least prior to actual painting.

Did it work? Sure. Was it worth it? Hell no.  When it came time for the 2002, I prepped, then paid, and stand by that decision:

[MitchaPaLoOza88]

The best saying doing any of this resto work, buying tools, etc...

 

”Buy once, cry once”

 

I’m pretty budget limited myself so usually I use my most affordable tool... Time (and this forum). It’s better to think a little long term if this isn’t just a flip.

[tech71]

Man,I really love Mint Grun.

Lovely!