POR 15

[Lucky]

Looking for a bit of guidance here if possible? I know a lot of you guys have used POR 15 products and I'd like the benefit of your wisdom before getting into my grubby bottom.

Obviously the idea is to wire brush off any grime and loose rust before starting with the POR, but what next? How would you actually go about applying it? Do you just use the degreaser stuff and then paint straight on afterwards? Do you need to prime the areas first? Would you use rust convertor before the paint or just paint it straight onto any rust that's left? And when the POR15 paint is actually cured, do you have to overcoat it with normal paint? Or will it be fine just as itself?

Thanks in advance, sorry about the dim questions but it's such a horrid job I want to get it right first time, not have to re-do it all in a year or so. Much love

[myatt1972]

There is a pdf file on frosts website that tells you all about it, I would have posted it but I have no idea how to link a pdf to the forum.
It will stick to anything, it is over paintable if you want to, brush application seems best and whatever you do don't put the lid back on the tin without cleaning the paint off it first or you will be opening it with an angle grinder

[ian65]

I've used litres and litres of it..... it's over-rated, over-priced and has the shelf life of a banana..... but what else is out there that is any better?
As it isn't solvent based, it uses moisture to cure which makes it a total nightmare to work with and store and if you actually get to use a full tin without it going off, you've had a result.
You can paint straight over rust according to their fact sheet, the idea being that the POR15 seals surface and puts a preventative coating over the rust, stopping any more moisture/oxygen reaching the rust and therefore stopping the rust in it's tracks.
In my experience, this is a load of bo**ocks..... I've had items such as radius arms etc blast cleaned back to clean metal, I've followed the instructions to the letter, used all their expensive preparation products and the items have still rusted again within 12 months whilst in storage in my garage... this is before they are even fitted to the car.
The problem being that a single coat remains permeable and the moisture / oxygen just gets in and the rust soon starts ( or continues if it's already there) and rusty surfaces are difficult to fully seal....sometimes even a 2nd coat isn't enough to fully seal it.
Their recommended method is to buy their 'Marine clean' ( just a de-greaser), Metal ready ( a weak acid solution that etches the surface to give a bond) and then the POR15 itself. You don't use a primer paint, the POR15 goes straight onto the bare metal.
At least 2 coats of POR15 are needed to seal the surface and this stuff is UV senstitive so unless it's well hidden under the car, it needs to be top coated with something else.
As Keith says, brush it on but don't get it on your skin.... it has to wear off which takes about a week.
You can't brush straight from the tin.... the second you open the lid for the first time and the POR15 comes into contact with the air, it starts going off. You need to decant a small amount ( it goes a surprisingly long way) into a clean container and then immediately clean every trace of the stuff from the rim of the tin and reseal the tin immediately. If you don't clean it, you won't get the lid off again and when you damage it trying to get it off, the tin will never reseal and your vastly overpriced POR15 will set like rock.
The alternative is to clean most of the paint off then put a layer of cling film over the top of the tin before you put the lid on.
Only pour out the amount of paint you think you will use.... you can't return any excess to the tin.... it will have absorbed moisture from the air and will send the rest of the contents of the tin off.
You don't necessarily have to use their degreaser... any decent degreaser will do.... same with 'metal ready' ... a solution of builders brick acid does the same job.
The most important thing is to give the item enough coats to fully seal the surface.

Steps are:

Wire brush on an angle grinder to get rid of as much rust as possible or shotblast.
Degrease
Etch with acid solution
Wash with clean water
Dry thoroughly with heat gun or blow lamp
Paint on POR15 ( at least 2 coats)
Top coat with UV tolerant paint if the item will be in sunlight.

Final tip is to buy a small tin.... you won't use a large tin before it goes off unless you are painting something massive all in one go.... it's amazing how far it goes.

.

[ian65]

bloody hell.... I've just typed all that out and then found this.....

http://rx7fb.com/viewtopic.php?f=10&t=365

that'll teach me to use the search function

[DKWW2000]

Perhaps I should not comment on this thread as I have never used the paint, but I have always found that nothing can top old diesel engine oil. I have found anywhere engine oil has leaked, rust has not appeared so I have always sprayed used engine oil (preferably diesel) thinned with petrol/white spirit etc sprayed onto metal surfaces not only prevents rust but stops it dead. It also seeps into all corners & stops rust dead, the only preparation other is to apply to a dry surface. To prove this just look under any old vehicle where oil has leaked and there will be no rust.
It is a dirty job to apply but I find it is best done with the old hand spray bottles like those used for bathroom/kitchen sprays & it is cheap
I find it is best done on a dry/hot day as is spreads/seeps very quickly into all corners where paint could not reach, best not done on a drive where oil stains would not be appreciated
I have used it for many years on all sorts of vehicles and also found it re-juvinates old underseal.
Just my thoughts and experience & works well on farm machinery as well.

[spoddy]

got a fella to spray the underneath of my sister's car with waste oil as it's a 1999 in good nick underneath.
but i'd agree with oil dripping onto parts of the car from the engine and zero rust.

the sump plug was not as tight as it should be on the rx8 and some had sprayed back onto the chassis, still has original paint lol.

if going with por15 then the small tins would be the way to go and use it before it goes hard and use old or cheap brushes and chuck em in the bin after.

[Lucky]

Thanks, guys. That's just the sort of thing I was looking for. I read all the official directions and that, but I wanted real-world experiences of people who've actually used the stuff cos as we all know the manufacturers aren't going to tell you all about the shortcomings of their product


One final question; how tolerant is it of heat? I guess you wouldn't use it on an exhaust heat shield in direct radiant heat, but would it withstand, say the 100 degrees or so of a coolant pipe?

[ian65]

once it's gone off, they could use the stuff to coat the bottom of the space shuttle instead of those heat resistant tiles..... you can hold a blow lamp on it and it won't touch it. It's incredible stuff, just not very user friendly. It's also great for repairing fibreglass body parts and for bonding rubber to metal or metal to metal.... I've used it in the past to refix RX7 rear bump stops back to the metal base after the rubber bit has come away..... things stuck with POR15 don't come apart again very easily at all.

[Lucky]

Good times

I'm still wondering what ever possessed me to chose this time of year to start lying on cold, wet concrete trying to de-rustificate the underside of the car. Maybe it's just cos I'm too skint to put any petrol in the ****ing thing

[Hobbawobba]

I got a pack of 6 small semi black tins from http://www.holden.co.uk as they are only a 20 min drive from me. Don't have to worry about the tin going off



I think I remember Steve telling me that it is a good product. But not the most fun job having your head in a wheel well for hours grinding away. I'm waiting til it warms up a bit and I have a few more parts to change while I get under there before I do it:D