POR 15 advice please

[BruceA]

Hi all

I'm painting a stripped chassis/suspension with POR 15 rust preventative paint. The info says it discolours/ degrades in sunlight if you don't top coat. But as it's the chassis is there any point in top coating as it's unlikely to get much sunlight? Any opinions from those who have used it please.

Cheers

Bruce

[Paul Down]

Probably not the answer you would wish but having used POR15 before I would never use it again.

 

Its strange stuff, you cannot clean the brushes and has IMHO an unpleasant crusty appearance. No doubt it prevents rust but I much prefer ordinary black oil based paint. It is easy to apply , easy to repair if chipped and no problems in cleaning brushes etc. and gives a pleasing finish. A local restorer of Vintage Rolls Royce cars always uses oil paint to good effect and I took his advice.

Edited May 14, 2017 by Paul Down

[Don H.]

I've used POR-15 on a number of things over the years. It's by far the best rust treatment/rust preventative I've ever used.

 

Yes, it degrades when exposed to sunlight and UV. It gets dull and will eventually chalk off the surface. Protected from UV it stays glossy for years.

 

My TRs frame was painted with POR-15 about seven years ago. I topcoated many of the more visible parts, and the car spends most of its time in a garage, usually covered. No issues with POR-15 weathering at all. The frame was never that pretty, so aesthetics weren't an objective in finishing it.

 

POR-15 is indeed one of the most difficult and frustrating finishes one will ever find. I don't even try to clean up -- I use small cans mostly as one-time use as resealing and reusing is pretty difficult, paint only with throw-away brushes, and always wear disposable nitrile rubber gloves and PPE. It goes on streaky with a lot of brush marks, yet reflows smooth and will even run after brushing if the film thickness is too high. It's so hard to spray I don't even consider it. D**ned difficult paint. If it didn't work so well I'd never consider it.

Edited May 14, 2017 by Don H.

[AlanT]

You MUST put this on bare metal. Best if prepped according to instructions. Wont stay on other paint.

 

Works OK on small parts. If I remember correctly you can wash brushes in turps, but only before curing starts.

 

Open the tin and DONT rub the brush on the rim. You must keep the lid and the rim free from paint. If you don't then you wont be able to open it again.

[ed_h]

I'm transitioning to two-part epoxy primers, but have used quite a bit of POR15. I've learned a few things about it:

 

1. Even though POR stands for "Paint Over Rust", I never do that if I can help it.

2. Bare metal surfaces should be blasted or sanded for good grip.

3. If you expect to re-open the can later, keep the rim free of paint and use a layer of plastic wrap under the lid when you close it.

4. Wear gloves and old clothes.

5. Disposable brushes are a good idea, but you can clean them with MEK, acetone, or lacquer thinner.

6. Two coats are best. If second coat is applied when first is past tackiness but still soft, it will bond without sanding. Time varies with temp and humidity, but is measured in hours.

7. If applying two coats to a complex item like a frame, use a different color for each coat.

8. I didn't have too much trouble spraying it, but find that a brush works better on something like a frame. Don't wait too long to clean spray equipment or brushes.

9. If UV degradation is a concern, overspray with a conventional paint before final POR coat is totally set.

[ShaunC]

If you are going to the effort then use Top Coat too, you don't want to revisit the job at a later date.

 

I've only used Top Coat and been happy with the results, tin and aerosol.

 

Decant tin into small jars if you are not going to use it all up in one session.

[John Bracher]

I have to say, despite the acknowledged cleaning issues, I like it!

Do the prep and application as per the instructions, and it seems to be very tough indeed!

I got all my stuff blasted first, washed/soaked in the prep fluid then cleaned, dried and painted.

 

The finish of the 'black' is a bit 'matt charcoal grey', and does apparently go a bit 'bloom' looking in direct sunlight eventually (takes a good while though) so if you find this unnaceptable (on a chassis?) use the gloss topcoat (while the base is still fresh), which is very glossy, like a conventional engine enamel.

Cleans up easily if any oil etc goes on it, no issues.

 

Don't get any (especially the second coat) down into any screw threads, or you will need to drill/tap them free again once hardened! How do I know....!

 

I factored in cheap brushes were way more cost effective than the 'special' thinners, and DO seal the tin with clingfilm/similar after partial use.

Spoon CAREFULLY what you can use in one go into another pot, DO NOT use straight out of the tin!

 

Any spillages, WIPE UP IMMEDIATELY!!!!

WEAR GLOVES, it does not readily come off your skin!

[bonrej32]

I heard that Chassis Saver has a better UV rating than por15. It is less pricey also.

[ed_h]

I've used a product called Rust Bullet, which seems equivalent to POR, but is UV resistant.

 

Ed

[Ian Vincent]

Just to add a footnote to this post.

 

I have recently had a leak from one of the unions on the base of my TR3a brake reservoir and it has dripped down onto the chassis which was painted with POR15.

 

POR15 is removed by brake fluid. It has softened and wrinkled it to the point that it can be peeled away from the substrate.

 

Rgds Ian

[BruceA]

Thank you all very much for the advice. After 3 days hard graft I can report that yes it's revolting, no it doesn't come off skin, and a lot of hard working paint brushes sacrificed themselves to make this possible!

[John Bracher]

Good job!!

Now you just need to do the inside......!

[littlejim]

Good job!!

Now you just need to do the inside......!

A work of art!!