epoxy primer questions - 4130 steel tube fuselage

1

13brv3

Greetings,

Full disclosure- I hate painting, and it hates me :)

I'm restoring an old 4130 aircraft fuselage frame, and need to coat it with an epoxy primer/paint. The frame is mostly coated in 20 year old powder coat that won't even come off with bead blasting at 90 psi, so I'll be recoating over that. Parts of the frame is new, bare 4130 steel tubing, and a small portion is old welded areas where the rust and damaged paint were bead blasted.

My goal is a durable black epoxy finish, which will resist the solvents in the fabric glue (MEK based). I want to shoot a couple coats of this, and be done with it. The tubes are visible, but it's not like an exterior surface where you'd really care about the appearance, so I don't plan to do any sanding other than to scuff the original powder coat prior to applying the epoxy. I understand the black has some UV protection, and the aircraft will be hangared, so it should be sufficient.

I have already purchased the PolyFiber white epoxy primer, but they don't have black, and I'm thinking I'd rather have black. Naturally, I'm doing this all at the last minute since I plan to have it primed this week.

Questions-

1- How glossy is the black primer? A more satin finish would be better for reducing glare, but I can live with glossy.
2- How long does it take to dry? I'll likely be spraying this outside, so I'd hope for the fastest drying possible to limit the amount of contaminants, and to be able to pick it up to move it back inside later.
3- What's the difference between 6700-1 and 6700-4? I couldn't find any info on that.
4- Finally (for now), I see that there are directions to reduce it to make it a "sealer". Is the epoxy not sealed normally? Since my primary concern is rust prevention, I'd of course need it to be sealed. Is the "sealer" mix needed? If so should I spray a coat mixed as primer, then the next coat reduced as sealer?

Thanks,
Rusty
 
Last edited by a moderator:
They are giving you directions to turn the epoxy into a sealer coat of primer, that coat that keeps body work from bleeding into the color, not like a second coat for epoxy.

So doing regular body work you would epoxy prime, use the fillers and different sanding primers to get the paint smooth, then put a seal coat of primer on top of that. If you are leaving it uncoated, dont reduce it at all and even let it set up as long as you can before it gets sprayed as the primer mix.
 
That makes perfect sense about the sealer! I hadn't thought about the other fillers and such that you would use for a normal paint job. That certainly answers number #4.

Thanks,
Rusty
 
Greetings,

Full disclosure- I hate painting, and it hates me :)

I'm restoring an old 4130 aircraft fuselage frame, and need to coat it with an epoxy primer/paint. The frame is mostly coated in 20 year old powder coat that won't even come off with bead blasting at 90 psi, so I'll be recoating over that. Parts of the frame is new, bare 4130 steel tubing, and a small portion is old welded areas where the rust and damaged paint were bead blasted.

My goal is a durable black epoxy finish, which will resist the solvents in the fabric glue (MEK based). I want to shoot a couple coats of this, and be done with it. The tubes are visible, but it's not like an exterior surface where you'd really care about the appearance, so I don't plan to do any sanding other than to scuff the original powder coat prior to applying the epoxy. I understand the black has some UV protection, and the aircraft will be hangared, so it should be sufficient.

I have already purchased the PolyFiber white epoxy primer, but they don't have black, and I'm thinking I'd rather have black. Naturally, I'm doing this all at the last minute since I plan to have it primed this week.

Questions-

1- How glossy is the black primer? A more satin finish would be better for reducing glare, but I can live with glossy.
2- How long does it take to dry? I'll likely be spraying this outside, so I'd hope for the fastest drying possible to limit the amount of contaminants, and to be able to pick it up to move it back inside later.
3- What's the difference between 6700-1 and 6700-4? I couldn't find any info on that.
4- Finally (for now), I see that there are directions to reduce it to make it a "sealer". Is the epoxy not sealed normally? Since my primary concern is rust prevention, I'd of course need it to be sealed. Is the "sealer" mix needed? If so should I spray a coat mixed as primer, then the next coat reduced as sealer?

Thanks,
Rusty

1) do not reduce the epoxy, sealer is for thinning down for applying paint.
Mixed one to one you should get a nice high semi-gloss depending how you spray it.
2) speed and protection do not go together, should ne dust free in an hour and full cure is 60 to 90 days.
3) 6700-1 is a gallon, 6700-4 is a quart size.
4) do 3 wet coats for max protection and decide the next day if gloss is what you want, anything you put over it is for looks only and nothing more.
 
Did you get the frame tubes inspected by an A&E? Filled with Corrosion Block etc...? Taildragger? :)
 
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