VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 extended use of por-15

howdy all
you guys are probably going to frown and laugh at this question at the same time,but if por-15 is such a space age cure all for rust on frames,advertised that all you do is degrease and then paint it on over the rust and stops it in it's tracks guaranteed.has anyone ever tried to say put it on a pited area on a fender that is small and you don't want to cut out and put new metal in,then a little bondo and prime and paint over it.thinking the por-15 would insure that any rust left in the pits will never bubble the paint job???
i figure i'm going to get yelled at for this one.
my second question is why can't they make regular primer and paint that works this good??

jeff korner
southeast indiana

As long as it cures properly POR 15 should work. You will need to be able to abrade the surface to get anything else to bond well to it.

I have used it in a similar circumstance on the body lip where the rear fender bolts to the body. That was 7 years ago. But like chippeer says: The surface must be abraded before any primer, or paint will bond to it.

I won't allow POR-15 in my shop and I know several top end and high quality craftsman body men that won't use that stuff either.

...I've never used it before and I here a lot of talk about how great it is...But I'd like to hear why it is not found in or around your shop J.D. , if you have the time to elaborate...Thanks , Kevin

I used por-15 on a truck I restored(77 Blazer) the body filler would not stick to the por-15, I havent used it since.

Besides what you mentioned, I won't use that stuff because it is really messy to work with and it is hard to get off of hands, clothing and etc. Also, if POR-15 has to be removed from car parts or whatever at a later date, it is almost impossible to remove.

I used por-15 on the frame and bottom of the body when I did my 41 and it has been 12 years and it still looks good. I am working on my 47 and there were some pin hole in trunk channel and a friend that has a body shop told me to try the panel bonding epoxy. Works good because it can be sanded and painted, but the metal has to be clean.

POR 15 has its uses. This is one of those products that tends to be overmarketed as a cure-all for anything rusted. It has many limitations as well, body filler is one of many.
I use it for sealing seams in door flanges and anything that has seams because the capillary action sucks it in and then it cures. Inside door bottoms is another use.
For fixing pin holes as suggested in your fender, that is up to you.
POR advertises the use of screen placed over pin holes in floor pans and then coated with POR15 to seal up the floor.
there are many band-aid type applications for POR15 uses it all depends on what you want to spend and the quality of job you want out of the project.
I use POR 15 but none of the uses are for repair. It works great on the outside of carbs because gassoline wont harm the paint.

I have used POR-15 for many years and just love it for certain applications. No it is not a cure all but it (or other single stage urethane paints) definitely does have advantages over other options. It can be recoated or covered by body filler but has to be significantly abraded first. If you think of the cured surface as a slick, tough plastic (which is exactly what it is) then you can handle it properly.

It can be removed from cloth and skin but you have to get it before it cures. Once cured it is tough and resists nearly every solvent. That is its major advantage over other coatings. So the key is use it properly, like anything else.

The other side of extended use is how do you keep it useable over a long time? I have a quart can that I have been taking small amounts from for over 3 years. All you have to do is keep it away from water. It is cured (actually crosslinked) by moisture in the air. What do I do? Punch a small hole in the top of the sealed can and then squeeze out the amount you need, insert a screw into the hole to seal it. Take out the screw next time you need more.

I am getting ready to sandblast my 1937 Chevy ½ ton pickup frame and need some advice on paint. I read the post for POR-15 and while researching online I found another product called Rust Bullet. Can anyone tell me which of these products is better or is there others I should look at before making a decision?

Thanks Doc

Don't know anything about Rust Bullet. Many of us have used POR-15 and are happy with the result. Just remember it does not come off easily once cured. Also does not have UV resistance. Applications out of sunlight retain their gloss. In sun turns to a flat black surface. Can be overcoated if you want both TOUGH surface and UV resistance.

I use POR-15 on frames and suspension parts as they are mostly out of sunlight.

After reading up on "Rust Bullet" I would say it's a "contender". It is recommended by several "periodicals" and I think it's worth checking out..New Technology w/two new patents...Things are always improving , well , most times anyway...

From reading the MSDS, Rust Bullet is a single stage urethane with some level of aluminum particles. POR-15 is a single stage urethane. The difference appears to be a little aluminum in the Bullet. It is likely enough to qualify for a patent or two but not to materially change the performance. I'll stay with POR-15.