'Metal ready' and water rinse before POR 15?

[Johnny Graham]

Hi, I have a quick qu..longitudinal nearly ready to go on!

I am applying POR 15 rust encapsulator to the inner longitudinals and heater tubes..it is mostly a combi of surface rust and original surface paint.

POR 15 recommend spraying with metal ready and then rinsing with water before applying rust encapsulator, but mainly it seems if you are painting bright new metal.

This part of the car has lots of crevices and cracks - which I dont want phosphoric acid and water to seep into..I suspect it is OK to paint the rust encapsulator straight on to sanded down rust?.any advice from someone who has been there?

[Rick Cicciarelli]

I used this stuff on my old Jeep Cj. The metal ready is an acid that helps to better prep/etch the surface for better adhesion. It won't hurt anything, and might actually help even on a slightly rusty surface.

[Eric Gibeaut]

I recently read that phosphoric acid should not be water washed after application but be allowed to dry and then apply topcoats to it. I have used this acid many times to remove surface rusting before priming and it works very well. Eric

[Martin Hirst]

I've been thinking about this recently too as I am at this stage in my restoration.

I wouldn't worry about Metal Ready getting into crevices and cracks because those are just the places which will have rust in them. They tell you to rinse the Metal Ready off but I think this is to avoid the powdery residue you otherwise get on the surface which would affect paint adhesion.

Metal Ready is a mixture of phosphoric acid and zinc phosphate, the residue seems to contain a high proportion of zinc. I'm not a chemist, but I don't believe it will do any harm if some remains on the metal.

Is it necessary? I don't know. My feeling is that by removing a lot of the rust you get a more stable surface for the paint. I would say that degreasing is more important.

[David Gensler]

Johnny,
After scraping, blasting, scrubbing, sanding, etc. PPG DX 579, followed by DX 520, applied exactly as per the manufacturers recommendations. This includes a water rinse after each. Dry well with compressed air and towel. Then come back and warm all the seams with a torch to dry out any remaining moisture. Then follow this with a good primer, or in areas like the insides of your longitudinals with a rust preventative primer. Old fashioned Rustoleum Rusty Metal primer is the old dependable standby, msybe even preferable to the high tech expensive stuff where metal cannot be gotten 99.9% clean. For areas where there is to be welding, you can use a zinc welders coating. When you are finished with welding, get primer into and over as much of the area as much as possible. It will be better than when it left the factory. The POR15 is snake oil, a waste of $$ at best, and may lead to future complications (ask me how I know!). There is no miracle cure-all rust encapsulator.
DG

[Johnny Graham]

Thanks all!

The POR15... ...may lead to future complications (ask me how I know!).

How do you know?


The PPG sounds good, I checked their product pdf, but I think my metal is too far gone for that (and I bought POR stuff already!)..

I know that the only real cure for rusty metal is a cutting implement and some new metal, but POR seems to be regarded as the best of the snake oils. I know its putting off the inevitable. One day the car will be stripped, dipped and rotisseried, by me I hope, but she has plenty of miles in her before then.

I dont have compressed air but thanks for the tip about the torch - that will ease my mind that I am not letting water into the cracks and then sealing it in with POR!

[Charles Navarro]

I used the metal ready on a previous restoration and did not rinse. In some areas, the POR got a hazy white discoloration, but almost 10 yrs later, it still looks fine and is holding on great.

[Jason Bobruk]

Best bet is to do a sample section on something way less valuable than your 356. My business is vehicle restoration and I also teach Automotive repair to both trade and hobby classes.

In my trade the views of "metal conditioners" such as por 15 metal ready and many other acid based products has changed dramatically over the past ten years.(Trade Paint manufacturers still sell them but rarely recomend them.) Like all Acids Phosphoric acid IS corrosive. If it is not used correctly and well neautralized with water it will continue to act (even after primers and top coats are used. In My shop We NEVER EVER use any Acid based metal conditioner.

I would suggest that in those areas that are tricky to get to and therefore impossicble to neautralize( like inner longs) Use an alkaline product (We use "deox".(gel and liquid). this product is sold by the same people that import Por15 to Australia. I do not know if its available readily in the USA but am pretty sure it is manufactured in the UK.

"Deox" is not corrosive so if you are unable to neautralize it pefectly it won't eat at your car.

Another great pruduct is "wurth" rust converter we apply it after the Deox gel to finish off the rust. it is usually brushed on and then penetrates the rust neautralizing it . A top coat must be applied after the reaction is complete and within 24 hours. We us Glasurit 2K epoxy primer which also has excellent corrosion resistance . Por15 top coats would also do the Job but we usually go with Glasso because further primers and top coats will be also Glasso (For warranty purposes)

Also never attempt to use any Acid based product on freshly sandblasted metal. This will promote rust at a massive rate..

If you have the spare time I urge you to do a little experiment on some
cold rolled sheet with the Acid based you were intending to use.
1. clean up a sample piece and leave it "raw" untreated
2. clean up a sample piece and treat it properly. (well neautralized)
3 clean up a sample piece and don't neautralize it at all

Leave the samples in the weather for a few days and see what you get
I think you will agree that unless you are able to do a perfect job of neautralizing the acid you should give it a miss.

[Martin Hirst]

That Metal Ready is corrosive is clear - it's designed to etch metal. If you have some Metal Ready residue left in a seam and it comes into contact with water it will dissolve any rust present, and then continue to etch into the steel for some time. If you get water into an untreated seam it will just rust. If no water is present there's no problem either way.

So how much of the steel will be etched away by these residues? My feeling is not very much, does anyone have any hard facts?

[Paul Hatfield]

You might consider doing what I did. I used the full line of POR Products on my car--- inside and underneath. After applying the Metal ready and letting it work, I used many damp cloths to remove the residue. LOTS of damp cloths, that were then tossed out. Made me feel like I was doing the right thing by not soaking everything in water and I could control things. There's a good picture on my website of what the Metal ready residue looks like. Go to www.enginesinback.com and look in the Interior section and you'll see it. Also, for a full dose of how I removed the rust, and applied all the other POR products and sprayed with Wurth, look in the Floors Section. Hope it is helpful to you.
Paul

[KRIS VANDORT]

I used Por 15 1 1/2 years ago in the longitudinals and the driver front fender. i scraped and degreased the fender but just blew air thru the longitudinals. We'll see how it holds up- messy stuff!

Hi, I have a quick qu..longitudinal nearly ready to go on!

I am applying POR 15 rust encapsulator to the inner longitudinals and heater tubes..it is mostly a combi of surface rust and original surface paint.

POR 15 recommend spraying with metal ready and then rinsing with water before applying rust encapsulator, but mainly it seems if you are painting bright new metal.

This part of the car has lots of crevices and cracks - which I dont want phosphoric acid and water to seep into..I suspect it is OK to paint the rust encapsulator straight on to sanded down rust?.any advice from someone who has been there?