Powder Coat or POR15?

[Davidb]

Hi all, I have just delivered my chassis frame to the sandblasters with the intention of brush painting it with POR15 afterwards. The blaster guy is giving a convincing argument for powder coating. Extra cost of course over POR15 but less work for me-although I am retired... It is January in Vancouver-not a good time to be carrying a sandblasted frame around in the back of a station wagon...
What is the groups experience/opinions? Is there a concern with the heat used in powder coating-about 400deg I believe?

[c42]

I would paint every time. When the powder coat gets chipped and rust starts, it can run under the powder coat unnoticed until it is too late and the powder coat falls off in sheets.

Anyway - painting can be very therapeutic.

Good luck!
John

[RichC]

forget powder coating ; it doesn't last!. Having said that, it's a breeze to wirebrush great chunks of it off the suspension (which I'm currently doing!).
it looks lovely and sounds a good idea at first but i doubt there's many folk (from damper climates admittedly) who'd repeat the expense

[RichC]

hey ! vancouver's pretty damp innit? double-forget powdercoating

[Davidb]

Interesting! I had not heard the concerns about powder coating lifting in damp climates. So much information comes from California and they just don't have that problem! Thanks, Anymore?

[pharriso]

I bought a new chassis & have chosen to coat it with Por-15 as well. Apparently once powder coating is chipped water can get under it & rust spreads, not sure if this is true if you used a zinc rich primer under the powder coating though...

On the topic of Por-15 people advise to hand brush paint rather than roller or spraying. You are supposed to re-coat within 4-5 hours of the initial coat & then top coat for UV protection.

How can you do this when you need to turn the chassis 90 degrees at a time to paint different areas?

I gave my chassis one heavy coat & now have rubbed this down ready for a second coat.. wondering how best to proceed...

[TroonSprint]

The suspension components on my MGB were powder coated and they lasted about two years before a crack appeared, the water got underneath and the stuff came off in chunks. Mind you, I seem to remember from previous usage of POR-15 that it doesn't spread well, or stick well, on clean metal, preferring a rusty surface. I would research that before committing yourself to POR-15. It's the very devil to get off your hands!

I have painted the suspension on my MGB with black Hammerite Smooth, and so far it's holding up well.

Mike

[Grizzly]

If its shot blasted i'd all day get is Epoxy Powder coated. Por15 is ok but not very pretty where as polyester powder coat isn't the hardest wearing (as above) plus heat tends to bring it back off (not good round Exhaust manifolds etc)

When all said and done it depends on who does the coating (always prefer electrostatic coating as you know its got in all the box sections and uprights well), using Por is a bit more fool proof and it does last well (just a bit thick and hard to get a nice finish)

[prezoom]

Another problem with powder coating is, solvents like brake clean will dissolve the finish. I know I will never powder coat a frame again. When I start the next restoration, the chassis will be painted with a two part epoxy finish.

[rgh0]

My preference:

Inorganic zinc primer ( a couple of coats) and top coat of your choice that matches the zinc primer used.I am not sure how well POR 15 sticks to the normal zinc rich primers. I have use metal finish alkyd enamels that match the primer i used. This gives a tough finish that if chipped does not let rust spread.

Cheers
Rohan

[pharriso]

My preference:

Inorganic zinc primer ( a couple of coats) and top coat of your choice that matches the zinc primer used.I am not sure how well POR 15 sticks to the normal zinc rich primers. I have use metal finish alkyd enamels that match the primer i used. This gives a tough finish that if chipped does not let rust spread.

Cheers
Rohan

Rohan, the zinc rich primer was for powder coat: Por-15 must go on bare metal, preferably acid etched.

[rgh0]

All you wanted to know about coating chemistry

POR 15 is a Polyurethane coating - see page 18 of the attahcment

http://www.hrsd.com/pdf/Coatings%20Manu ... IX%20C.pdf

cheers
Rohan

[Davidb]

Rohan, Would page 19 be more appropriate?
db

[The Veg]

I know that the fuel-tank coating kits from POR-15 come with an etch-prep chemical that should be used first for best results. I'm sure you can get this stuff in quantity to use for larger jobs.

Powder coating: it certainly has its uses, but area in close proximity to the ground might not be good due to the aforementioned chipping. The quality of the coat and its application make a difference too like anything else. Fifteen years ago I had great results with powder coat on a motorcycle frame, but that doesn't necessarily translate well into great results on a car chassis.

[StressCraxx]

I have had a race car chassis powder coated. The coater did a good job and it's held up well. It is susceptible to solvents like brake and carb cleaner. It's susceptible to chipping too, but it's pretty tough if the surface prep is good with media blasting. If weld repairs need to be done, the coating has to be burned off with a torch, then locally repainted or re-coated.

POR 15 is a really good product for a road car chassis, prevents rusting and its very durable too.