Coating Comparisons

[Skuzzy]

I rarely do this, but I ran into this video of a comparison of various rust prevention coatings. Maybe worth a discussion. I found it interesting. Don't be put off by the title.

Coating comparisions video.

[J R Jones]

I have found POR primer, especially the gray to have good impact resistance. The Top Coat has been disappointing. It is very long cure during which it has no solvent resistance.
On one suspension job in gloss black Top Coat, after significant cure time, I coated it with two part urethane clear.

I recently did a set of aluminum wheels in red POR top coat with the intention of Chromax clear coating.
The Top Coat instructions are the same as the primer instructions but the paints are very different. My clear lifted the Top Coat on the first two wheels. POR Customer Service had no answers and refunded the POR cost.
I was out $100 clear coat and $200 bead blast cabinet time. I had to re-spray the POR Top Coat.
After ~six weeks I tested KBS two part urethane clear and it was OK. I shot all four wheels and held my breath. It was OK.
It is good to see the Mastercraft AG111 results.
jim

Abarth dusk 2.jpg

[Skuzzy]

I painted my frame with KBS, and used thier top coat as well. I wish I had seen this before I did that.

[Dgc333]

I am a big fan of POR-15. I used it on all the surface rusted areas of my 68 Barracuda back in the 1998/99 timeframe. All the areas that I coated have held up for the past 25 years with no rust reappearing. A non automotive example is the bulked to my basement is steel and I was wire brushing it every year and painting it with Rust-Oleum every year. Back in 1999 I had some left over POR-15 from the Barracuda so I decided to give it a try on the bulkhead. I wire brushed it coated it with POR-15, once cured I primed with the POR primer then top coated with red enamel. Haven't had to touch it since.

One of the other characteristics of POR-15 is it is tough as nails when cured. I have beaten on metal that is coated with it and it doesn't chip or crack.

There are some down sides you need to keep in mind;
1. It does not stick well to clean unrusted metal. It will peal off even if you rough up the surface.
2. It degrades if exposed to sunlight. I had a black truck which was rusting around the windshield. I coated the rust with POR-15 since it levels out nicely and had a good gloss I just left. Within a year it was all chalky and was flaking off. If you are using it where it is exposed to sun top coat it with another paint
3. It is a real ***** to clean up. About the only solvent that effectively cleans up uncured POR-15 is the POR solvent. Wear gloves, it is almost impossible to get off your skin.
4. Once the can is opened it does not keep and will skin over in the can making it difficult to get out. Putting a piece of plastic over the open can then put the lid on helps with getting the lid off without destroying the can and if you store the can upside down the skin will be on the bottom. Best bet is to buy small containers that you use up in one or two days.

[Skuzzy]

The only downside to POR-15 and probably KBS that I have heard occurs when it is scratched to the metal. The rust creeps under the coating and you are not aware of it until sheets of coating fall off.

The brake fluid test was a big surprise.