When to prime/paint the frame

[doommachine]

I am getting close with the frame. Aside from the rear body section and bracing the bare frame is almost complete. Still have the suspension brackets to put on when they arrive. I am thinking about when I should prime the frame, and when to paint it before body panels and stuff starts needing to get attached. Do I use weldable primer or epoxy primer and grind it off when I have another bracket to add.

My thought is epoxy primer and just wheel it off when needed as I go forward. And obviously it needs to get painted before too much stuff goes on it that can't come off without annoyance

[Lonnie-S]

For what it's worth, I elected to use rattle can, Rustoleum automotive primer to cover completed, or semi-completed portions of the chassis as I went along. It's much easier to remove the primer with a wire wheel if you need to, rather than oxidation that has built up over time. That is especially true as the chassis becomes more complete (more joints, tubes, brackets and plates) with time.

I live relatively close to the ocean, so rust creeps in pretty quickly on bare metal.

I used 3M blue painter's tape to keep strategic areas as bare metal, but protected from rust, so I'd have a place to ground my welder. From sad experience, I've found only the more expensive 3M tape actually will come off pretty clean after a year or two.

The cheap painter's tape like from Home Depot is good for areas that you'll only tape up for a few weeks at a time.

Cheers,

[SkinnyG]

I did my Locost frame with Rust Bullet, which needs no primer. It's been holding up reasonably well, but not as durable a paint as I had hoped.

Chassis #2 was (mostly) completed years ago, but when it's done, I will lghtly sandblast the whole thing, Epoxy prime the next day, and then spray colour within the re-coat window (likely the next day) so I don't have to sand the whole frame. I hate sanding.

A weldable primer is good between two surface that you are welding together. For what it's worth, you can do the same with Epoxy primer, which is how I repaired all the rust in my '61 Chevy pickup (blasted and epoxied inside and out of everything, even before closing things up like the rocker panels). Epoxy is a bit more work in that you have to mix it and give it a reasonable time to cure, whereas a rattle can of weld-through primer dries pretty quick. The weld-through primers I've used (from Eastwood) are also an Etching primer, which was best practice before Epoxy primers came along. Epoxy seems to be the new hotness.

[tibimakai]

What color do you guys are painting your chassis?
I'm thinking about something light color, (maybe gray?!) to be able to see(hopefully not) any cracks that may develop over time.

[doommachine]

I was mostly considering epoxy primer. Not sure if 2 quarts is enough for the frame though or if I need a gallon kit. Would be open to something cheaper then top coat it either semigloss black or BRG. I was looking to see if I could get a BRG DTM primer but not sure if that is available.

[rx7locost]

Are you building a show car or a driver? I used simple Rustoleum Clean Metal Primer and their Stops Rust for the color. If you start with relatively clean metal, the metal should be protected for the life of the car. easy to simply grind down to weld or to touchup any dings. There is no need to overthink this IMO.

[doommachine]

Yeah I just picked up some rustolium self etching auto primer. That will do until I am ready for the next step.