How much Por 15??

[Eric H]

Anyone have a good idea of how much Marine Clean, Prep and Por15 would be good to have for a 24 foot trailer frame?

Thanks!
Eric

[AlbertF]

Based on my limited use (I bought a couple of pint cans earlier this year), I'd say 2 quarts of POR 15 would be plenty. You'd need about a quart of the Metal Ready prep product.

[marzboy]

I used about 2 quarts for a 30' frame I would buy it in pints because that stuff is really sensitive to moisture. I bought the Marine Clean in the gallon size because you can use it for a lot of things. I would only use Metal Prep on bare metal or if you are welding. Por 15 works best on rust so get all of the paint off and surface rust.

[Frank's Trailer Works]

Eric, I have always painted it on with a brush so my answer would be buy one quart black and two grey pints. You will use the quart and the pint but not touch the second pint. If you do not buy that extra pint, you will run short. The reason for two colors is because one coat is just not enough and the second color allows you to know you covered everything.

however....

Last time around I sprayed it on. I seriously doubt I will ever brush it on again. I used my siphon feed cup gun. The POR15 is just a little too thick to flow through my gun smoothly so I cut it with a little xylene. The results were actually beyond my expectations. The POR15 dried so quickly that I was doing the second coat within minutes. The surface looked as if it had been wrapped in a film. The finished surface of the brushed on has always looked nice and smooth, but this is one step beyond. If you spray it on, I would say one quart will be plenty.
I wish I had some photos of the just POR15 stage. All the exposed parts were next top coated with a two stage automotive paint to match the client's tow vehicle. The entire reason for spraying was to give a better surface for the auto paint. Had a normal frame paint been used, I probably would still be brushing it on.




Please take this to heart, any, and I mean ANY, exposed skin will be hit by the POR15. Once it is on you, it will be there until the skin under it falls off(literally). If you spray it, make sure everything is masked off. The overspray will float in the air and it will fuse to anything it falls on, FOREVER! Keep your air pressure low and mask everything off.

[Wabbiteer]

I have a silver driveway. One quart thinned 8% covered all of the frame generously except two center spars. The next quart was thinned by the addition of 5% thinner and the second coat went on much thinner and easier and really brought out all the highlights an asphalt driveway is capable of.

I had four 8-ounce cans nabbed from a closing hardware store but filled the HVLP paint cup for the second coat then decanted the rest into the 1/2 pint cans, for about 6-oz per can. I still have three of them. Plus, did I mention, a bright aluminum colored driveway less the frame lift blocks outlines.

[barts]

One way to get better shelf life after opening the can is to fill it with propane (I used my torch (NOT lit )) and to place a piece of Saran wrap under the lid. The propane displaces the air in the can and along with it, any moisture. The Saran wrap provides a good seal... I've had cans of similar stuff (a silver moisture cured polyurethane called Aluthane) last for more than a year sealed in this manner.

- Bart

[perryg114]

How do you get the stuff out of your spray gun when you are finished? If the stuff starts to setup in the gun you are going to need a new one.

Perry

[Wabbiteer]

I did not clean the gun between coats (intentional. POR needs to be dry before it fires) and the exterior parts were merely trying to set up, but relative humidity that day was only 20% that day and it was still gummy and cleanable eight hours later. When it came time after dark to clean the HVLP gun I used POR-15 thinner and carb cleaner - Berryman Chemtool B-12 aerosol chocked full of toluene and a couple of other solvents.

Clean the cup and pickup, add solvent and spray the solvent out until it ran clear, that cleaned all the air ports and the exterior parts took a couple of soaks with the B-12. I thought I'd run the HF $20~ gun but it all cleaned up like new, except the pressure gauge glass face surface that semi-melted from the aerosol solvents... The gun comes with a bristle brush, that and a terry cloth rag were just right to get all the hidden spots...

[Randy Gates]

I used 2 pints of POR-15, a jug of marine clean and one bottle of the metal ready. I used the grey POR and silver paint. Although I only used the paint on exterior not the undercarriage on my 20' Globetrotter. I am so happy I chose to paint it on. It is an ugly job on your back but you assure yourself to not miss a spot that way. Long sleeve shirts-double them up, it can bleed through a single shirt. You WILL get it on yourself. Get ready to scrub it off. Cover the ground with the blue tarps-best to save your driveway or shop. Good Luck.
Randy

[Eric H]

Thanks all! This is very helpful!

[VeggieBullet]

All the exposed parts were next top coated with a two stage automotive paint to match the client's tow vehicle.


MMMM
this sounds tempting....So after applying the POR 15 you guys just painted over with automotive paint? So the POR 15 is perfectly paintable?

[Frank's Trailer Works]

I dropped a hammer on the tongue by accident, it didn't chip. I think the key is timing. If the POR 15 cures too much it will make the bond difficult...

[Alumaholic]

POR is not paint.
POR is degraded by exposure to sunlight.
Surfaces that will be exposed to direct sunlight must be topcoated with a POR topcoat.
Automotive paint will cover and dry beautifully, put it will begin to peel and flake in 2-4 years.
Don't ask me why I know this.
P.S. I have used gallons of the stuff.

[Frank's Trailer Works]

Originally Posted by Alumaholic

POR is not paint.
POR is degraded by exposure to sunlight.
Surfaces that will be exposed to direct sunlight must be topcoated with a POR topcoat.
Automotive paint will cover and dry beautifully, put it will begin to peel and flake in 2-4 years.
Don't ask me why I know this.
P.S. I have used gallons of the stuff.

Guess I will be fixing it for free in 2-4 years. Was this two stage you used or a one stage paint?

[VeggieBullet]

well it seems to be a little contradiction on this subject.
But isn't the 2 stage automotive paint kind of the same of the topcoat from POR15?
Thanks

[Alumaholic]

Originally Posted by 62overlander

Guess I will be fixing it for free in 2-4 years. Was this two stage you used or a one stage paint?

I'm not it makes a difference whether it's one-stage or two.
The surface of POR-15 has no porosity.
According to POR-15 customer relations, paints cannot bond unless you use a POR-15 topcoat, or rough it up with course paper first.

I was pretty smug until my paint flaked off.

[Frank's Trailer Works]

I think, I too will stand smug.(many think I always do, so why not)
If my work fails, I will fix it at no charge just like I always have. Just out of curiosity, when one layers primers, paints, or even POR15 is it not normal operating procedure to sand between each and every coat? Two stage automotive finishes dry so hard that if you do not the layers will never bond. Perhaps POR 15 works the same way.

[Alumaholic]

Originally Posted by 62overlander

I think, I too will stand smug.(many think I always do, so why not)
If my work fails, I will fix it at no charge just like I always have. Just out of curiosity, when one layers primers, paints, or even POR15 is it not normal operating procedure to sand between each and every coat? Two stage automotive finishes dry so hard that if you do not the layers will never bond. Perhaps POR 15 works the same way.

Excellent plan.
For some reason, you do not have to sand between coats of POR-15.
POR bonds with POR.
If you scuffed the POR before you applied the two-stage, automotive top coat, you should be okay.
It was so purty, I couldn't stand to scuff it.

[Frank's Trailer Works]

Ken , I agree with everything you said but want to add if you wait more than 48 hours between coats of POR 15 they will not bond to each other. Don't ask me how I know that...
I really think the key is to do the second coat before the POR 15 has time to fully cure, which is less than 24 hours. If sprayed the POR 15 can be scuffed in under two hours time. I think it key to spray the top coat before the POR 15 has set fully also. These are just my thoughts and not what the manufacturer recommends per say.

[Alumaholic]

Concur with your observations. Actually your 48-hour-between-coats, bonding failure is consistent with POR-15 literature. I believe they recommend recoating sooner, especially when its humid.
That's another POR paradox; it cures faster the higher the humidity.
Out in NM I have more time between coats than you do in MD.