Hi everybody!
I have some questions for you! (Yes again!!!)
I'm removing the cab in the next weeks and I'm not sure what to do with the frame! I've read a lot of thread on Por 25 and it seem's to be a good product!

My questions:

1-Would it be best to sandblast the entire frame before painting the frame? Some people seem to say that Por 25 adhere better on rust has long has there is no flake. So it would be a bad idea to sandblast the frame and I would only loose my money!

2-How much coat would be the best to do for a nice and durable finish?

3-How much paint do I need to order to paint the entire frame and axles?

Thanks for your help!

 

I believe you are referring to POR15.

If your frame has rust, and you have the chance to sand blast it, I would. Ideally, you would put a coat of the POR15 paint followed by the POR15 Chassis Saver top coat. You'll need 1 to 2 quarts for each coat depending on how thick the paint is applied.

 

POR-15 rust encapsulator needs a "tooth" to grip onto. That is, a good solid rusty surface without any loose or flaky rust. Also, a good blasted surface will work even better. It will not hold onto smooth metal or metal that has been ground clean with a grinder. It will peel off in sheet over smooth or ground metal.

POR-15 is a great product but very expensive. I used it on the floor of my F-4, both top and bottom and after it dried I could not scrap it off with the claws of a claw hammer. I think the last time I checked it was about $45-55 a quart. If you want to top coat it you will need to buy more of their specific product which costs about the same. There are other products out there that do the same for less and you can more easily topcoat them with regular paint. Do a search of this forum for "rust encapsulator" , you'll find a lot of posts from members who have used POR-15 and the other products.

I did some research a while back trying to find an cheaper alternative to POR-15, which is a urethane mastic. It started out as a product for painting boat decks. The biggest negative I see with POR-15 is the price and also once the can is opened it starts to harden. POR-15 starts to harden once it's exposed to the moisture in the air. You can retard the drying time by purging the can with argon from a welder and then placing the resealed can in a cold spot like a refrigerator but it will still harden in the can. Also, I found out the hard way no matter how good you seal the can and wrap it in numerous layers of plastic it will contaminate everything in the refrigerator. I stored a can in my shop refrigerator and ended up buying lunch for my two employees.

I found an alternative that is cheaper, easier to hand and I feel should work just as well as POR-15. While doing my research I talked to a paint company who told me about the urethane mastic, the person I talked to suggested using a two part epoxy mastic, which is widely used to paint rusty structures like bridges and water tanks. It's a two part product that only hardens when the two parts are mixed together, you can mix the amount you need and seal and store the rest. When I originally bought it a few years ago it cost $100 for both part A and part B, so it's $100 for two gallons. I had to thin it with lacquer thinner which stretch the product even more. My son just bought the two gallons and it now $175 for both parts, still cheaper than the POR-15. It goes on easy and when dry is very tough, on a test piece I tried to scrape it with a screwdriver, while I was able to leave scratch marks I could get down to bare metal without major scraping. I bought the PPG product from my local hardware store, there are a PPG distributor and I had to special order it.

Click on this link to see more of what I am talking about. Rust Encapsulator

 

RustSeal - Rust Prevention - Stop Rust Paint

I used this product on my frame, works just as well as por-15. I painted this frame with a two inch disposable brush, if I used a better brush you would be hard pressed to tell that it was not powdered. The UV properties are really good, this has been on the frame now for three years. I blasted the frame than painted, did not do the three step process.

 

I've used/am using rust seal. It is cheaper than POR15 and I think it does just a good job. Did some painting last Dec, sealed the can as recommended, finished off the can last week on a mower deck. So it doesn't harden in the can like POR15. With POR15 I found that when the coating is tacky you can spray over it with anything, as evident by a grandsons' wagon which has been sitting outside for 5 years now. Tried spraying over RustSeal yesterday, we'll see how that works.

 

Not anything, I coated the floor of my F-4 with POR-15, let it tack up and sprayed epoxy primer over and it lifted.

 

Hey Bob, could that PPG be thinned enough to spray? Assuming you brushed yours on.

 

I had to thin it a bit to brush it on and I also sprayed it on. I used lacquer thinner, it says on the lacquer thinner can it's for thinning epoxies. The two parts are about the consistency of peanut butter, they do thin a little when mixed together but still not thin enough to brush on smoothly. It takes a little more stirring to get the epoxy to mix than normal paint but not too much more.

 

Wow...
So many answers!
Thanks for your help!
You are helping me so much!

THANKS!

 

I also didn't buy por15 due to the hardening once the can is open since I was unsure how much I had ready to paint of the frame and misc pieces and did not want to waste money.

I eventually went with eastwoods rust encapsulator top coated with their 2k ceramic chassis paint. Looks great (no pictures yet) but can't speak of durability yet since I just completed it.

 

I have been using Eastwood's Rust Converter. It works great on rusty frames and the underside of fenders. It turns the rust into a black, very hard surface that won't come off even with a wire wheel. I like it because it cleans up with water. You can spray it or brush it on. I have been using a cheap 50 cent brush. It dries quickly but needs to be painted with a topcoat (gloss black rattle can 2X Rustoleum works as well as anything) as it is deteriorated by UV rays in direct sunlight (rarely seen by frames and the underside of fenders). The quart size goes a long way. I only pour a small amount at a time into a separate small container as you can't pour it back into the bottle after you have been using it.

 

I used the POR-15 on my frame and as a primer for the cab floor and firewall. It is pretty good stuff. If you follow their directions for prep it will be on there for years. I just used a wire brush and then used the POR brand cleaning products to etch the frame prior to painting it with a brush. I went over it with the POR chassis black top coat. It's not perfect, but very few people see the frame of my truck. The problem that I had was the when I primed the frame we ended up having a cold night (well....cold for central California). After I brushed the primer on, the temp dropped to around 35 degrees. The primer developed a few runs. After they dried I hit them with the angle grinder & went through a couple of sanding disks before I realized that those runs are there to stay.

More or less by accident I found out that if you paint a topcoat on while the POR is still tacky the paint bonds pretty well. I did a bunch of small parts with the POR, then sprayed them with ordinary Krylon spray paint after 2 hours of dry time. Those parts do not chip or peel. Usually that spray paint isn't all that tough, but over the POR it is excellent. I put the leftover POR into a smaller jar & put plastic wrap down onto the surface of the paint. It stores for a couple of months that way. After that, I had a jar of solid material.

That being said, my son did a restoration project & used a Rustoleum product that is sold as a rust encapsulator. His VW project looks pretty good with that.

 

On POR-15, if you punch a hole in the top of the can and pour out only the amount you want to use at a time and then seal the hole with tape it will last a long time. Keeping the taped can in the fridge will make it last even longer. When I did my two trucks I was able to make a quart can last all summer without hardening

 

Remove loose rust and use Tremclad Oilbase (Canadian Tire) . I assume you are not going to be driving on those salty Montreal roads in the winter . Just my 2 cents