Corrosion Tests

Post by **MoggyTech** » Sat Dec 01, 2007 6:00 pm

I've been doing some tests of various rust treatments/paints, and here are the results incase anyone is interested.

1: 1mm Steel Panel cleaned to bare metal in 4 areas
2: Area 1 treated with Hammerite #1 Rust beater
3: Area 2 treated with black smoothrite
4: Area 3 treated with Hammerite Underseal with added waxoyl
5: Area 4 left bare

Panel left outdoors for 30 days *Each treated area was left bare at edges of the product to test rust creep*

After 30 days each area showed edge rust formation except for the #1 rust beater area, neither area showed rust under the treatment. The bare area was well and truly rusted, and then treated with Loctite 7053 rust converter. This converted the rust and the panel was placed back outside for a further 30 days, but with a scratch placed through each treated area.

Final results.

#1 rust beater area, no edge rust, and no rust in the scratched area.
Smoothrite area, bad edge rust, and rust in scratched area. Underseal with Waxoyl area, very little edge rust and no rust in scratched area.
Loctite 7053 area, zero rust

Obviously there are a stack of products out there, and the above is just a tiny sample. So with the above products, mild rust can be treated with Loctite 7053 rust convertor, then primed with #1 rust beater, and covered with underseal with added waxoyl.

I'm leaving the panel outside to continue the long term effects of these treatments.

Post by **alex_holden** » Sat Dec 01, 2007 6:12 pm

I did have a test piece outside - bare steel with Dinitrol 3125 (similar to Waxoyl) on half of it. No rust at all on the treated half and no signs of edge creep after about a year. Unfortunately somebody thought it was rubbish and threw it away.

Post by **chickenjohn** » Sat Dec 01, 2007 7:32 pm

I dont use hammerite much nowadays- Clean all rust to bare metal (remove trace with phosphoric acid- till no black bits), then zinc primer (2 coats), chassis black 2 coats, then dinitrol (3125 in box sections) of the thicker black Dinitrol for undercoating.

Post by **stevey** » Sun Dec 02, 2007 2:31 pm

Happy to say all rust treated painted with black hammerite ( most of it was black but 3 innerwings were red) and painted with the wayoil underseal. that stuff goes everywhere. in fact im famous for it!!!!

Post by **Kevin** » Sun Dec 02, 2007 10:54 pm

that stuff goes everywhere. in fact im famous for it!!!!

So you are The Famous Sticky Steve

Post by **stevey** » Mon Dec 03, 2007 7:12 pm

What? Does my reputation precede me? or are there 2 of us?

Post by **dunketh** » Wed Dec 05, 2007 11:04 am

Very, very interesting. I'd always assumed 'No1 Rust Beater' would have the same active ingredients as normal hammerite.
I thought it was a just another 'anti-rust' gimmick - until now of course!

I've a friend who rebuilds landrovers and he seems to use red oxide and some kind of rubberised underseal on the chassis. Its all 'trade' stuff but I don't know what its called, its far tougher and more flexible than anything I've seen elsewhere.

Post by **chickenjohn** » Wed Dec 05, 2007 11:31 am

" rubberised underseal on the chassis." stone chip coating or seam sealer are both rubber type undercoatings. They still need paint on top though.

Post by **KirstMin** » Fri Dec 07, 2007 12:19 pm

What happens when you weld said piece of test steel to the underside of a car and it is exposed to flexing, heat differential, mud, grit, stone chips, etc etc? These test conditions (although are interesting) might not actually lead to the correct choice of rust protection due to the environmental differences. For instance, does #1 flex well or will it crack/degrade quicker than the others? How does it repel stones thrown at it? etc etc...

Post by **MoggyTech** » Fri Dec 07, 2007 3:08 pm

Well after another spell out in the rain the results are as follows.
Smoothrite on it's own, very poor, flakes off easily and very bad rust in scratched area, and product lifting due to rust underneath.

#1 Rust Beater Primer, excellent, zero rust at edges or in scratch, great adhesion, does not crack or flake off when panel flexed. I suspect this primer has a high zinc content.

Underseal with Added Waxoyl, no rust in scratched area, but edge rust. Good adhesion, does not peel or crack when panel flexed.

Loctite 7053 rust convertor/primer. Zero rust, good adhesion.

So my future choice for treating surface rust/damaged areas under the car will be.

1: Remove loose rust
2: Treat area with Loctite 7053 and leave for 24 hours
3: Coat with #1 rust beater
4: Underseal with added waxoyl

WRT to treating new welded area. Weld through primer, seam sealer, zinc primer, then suitable topcoat depending on area treated.

Post by **chickenjohn** » Fri Dec 07, 2007 3:25 pm

I've used all the Hammerite products in the past on old cars (when I ran bangers before getting into classics) and was not impressed. Even the No1 rust beater will fail after a few years if painted over rust.

I have also given up on rust converters- having tried all the main brands- they are all rubbish and will fail over time. You paint them over rust and it turns the rust to a hard black layer. However, try scratching this and you'll find rust underneath. After a few years the black layer of Iron phosphate (mixed with resins from the converter) breaks down and the rust is back. Its fine a as a temporary fix, but not a restoration.

Best method is to remove all rust down to shiny steel, then wash with phosphoric acid to stabilise the steel, then zinc primer, paint a waterproof top coat (chassis black or body colour car paint) and finally wax protection.