RUST

[Mr Vapour]

A thread dedicated to the removal and prevention of the dreaded tin worm.

 

So I spend allot of time reading and researching. In recent times my current situation has me looking at rist, it's prevention, removal and techniques used, what products are common, what products are best to use in what situation. But much of the information is not kiwi and the products and some techniques are not available here or dubious methods. 

 

As we all have old cars and there are some very talented rust removal people here. 

 

Put up products, links to threads and advice and questions.  

 

 

 

[tortron]

cut out the bad stuff

replace with new steel

clean everything up nice

paint with a good paint

[Adoom]

My system is: Cut it out. Weld in patches. Paint repair and any remaining traces of rust with POR15 following the documented prep steps. Overcoat with any other paint if the repair is exposed to sunlight, because POR15 changes colour when exposed to UV light.

[Mr Vapour]

So I pulled the carpet and floor deadener off and have found lots of surface rust and some patches that need to be cut out. 

 

So the plan is to wire wheel the whole floor

 

Should I use acid/converter to get any spots and creators the wire won't get in to, then epoxy over the top 

 

Or should I just use por-15 as a one step process. 

 

I'm going to rat mat the floor so I want to ensure that iys going to last as I won't be able to check in the future.  

[Spencer]

I wouldn't use POR15 anywhere where you can prep the steel and use a epoxy primer. Its expensive and not needed, great for painting the back of rust patches etc. It is just a heavy duty urethane paint the moisture cures, its not magic. It still needs prep.

 

Personally I am fucking over stripping shit with wire wheels, it sucks. So I would use paint stripper and the phosphoric acid to treat the rust, just keep them away from body seams. Use the mechanical stripping anywhere where the liquids could get in and cause more trouble than good. When using the stripper and acid just apply some nuance, take it slow and relax. it may take a few passes but will leave clean white steel (well maybe a little pickled) and dont be scared of using water to clean up, its OK on bare steel if you just scuff the surface with steel wool after. 

[xsspeed]

With treating surface rust as decribed i find a lot of the time (could be product dependent) the steel thats been treated goes dark. Is this the converted iron oxide? If so what is it? Often ill take this off via sand/wire wheel until i get it to white metal

[Spencer]

I'm talking surface rust above, if its heavy scale then smash it mechanically first of course. Some products do turn it black (some have zinc), I use just straight phosphoric acid, the rust stays brown and kind of lifts from the surface when you wash it, then if there is more rust you apply acid again, on my chassis I did maybe 3-4 applications. Same goes for citric acid but that is more for soaking parts as it takes ages, good shit though. You want clean white metal in all cases with the only exception is hard to reach places and cavities, then slap whatever you feel really. POR15, wax, just keep oxygen/water/crap out. The acid can be expensive retail so shop around for bulk instead of shitty stuff that has been branded and marked up 400%

[xsspeed]

I'll try get some photo's of what I mean - this was using a "rust converter" product which was whatever dilution phosphoric acid, but I wasn't sure if it had something else in it that was reacting to make some sort of inert layer (I'm sure some say they turn rust to primer?). I think when I've just used acid and multiple applications it just goes white

[Hemi]

Can buy phosphoric acid in decent quantities at trade shops.

They also sell it as aluminium cleaner in like 1l bottles. It strips the fuck out of anything on the alloy, including its 'seal'

Haven't looked at the cost but it's nasty shit.

[Spencer]

Yea those rust primer things can fuck off. I've tested a few by leaving them outside on steel and they go all soft and shitty, do not want. Remove rust and proper coatings is the only way unless you cant reach it, then there are many products for that purpose that are better than those rust primers.

[Spencer]

And I wasn't hating on POR15 earlier, I do like it for some jobs. Just if you can prep the steel then 2 part epoxy primer gives the basically the protection, costs like 1/4 the price and has WAY better adhesion to clean steel IMO. You can brush on epoxy to your repairs also no problem, looks pretty rank on big areas but still works with a brush.

[xsspeed]

what would you suggest as a type of product for the unreachable?

[Spencer]

A real good cavity wax, one that will stay put. I tested a few on bare steel and left it outside. 

 

This one was my choice

 

http://www.ebay.com.au/itm/5-LT-Mil-Spec-3215-rust-proofing-wax-for-cavity-and-surface-protection-/111831303774?_trksid=p2141725.m3641.l6368

 

There will be others that are as good or better. 

 

You can epoxy prime the back of patches you put in and use it between spot welded seams you replace (clean it out from the spot weld hole before welding with a flat drill) it holds up to the heat better than any common single part, rattle can, weld through primer I have used.

[xsspeed]

cheers, the ol boy who i was getting protec product through was pedaling this product that basically encapsulated the area - not sure how effective it would be spraying inside cavities or not. It apparently sold well with industrial machinery guys who didnt care too much about the finish. I'll try find out what it was/how useful it is

[tortron]

i dumped a load of zinc paint down my chassis rails, then coated with a ton of cavity wax.

[sr2]

I've found CRC rust converter to be a far superior product to Por 15, it's easier to use and costs a fraction of the price (it's even available in spraycans).

For removing rust from components electrolysis works well, is inexpensive and best of all is effective inside cavities where you normally can't get access. There are some pictures and a description in my build thread.

I use Target Cleaning Supplies in Penrose Auckland for Phosphoric acid (Tergophos) only $54 for 5 litres.

[Ghostchips]

i have put POR15 in chassis rails before waxoyl and on farm equipment with success.  Don't recommend as a paint for exterior door/guard panels though.

[flyingbrick]

Haven't read this too thoroughly but be aware there are two different chemicals widely used..

Tannic acid is used in rust converters. I believe it doesn't remove the rust like phosphoric acid does- it just turns it black.

Rust converters don't sit too well with me because I know for a fact that their ability to penetrate rust is severely limited. It's OK probably for extremely light surface rust but for anything else you will find under the very thin black okide there is just normal that (which hasnt been slowed down)

Hope this clears that one up

Edit.

I remove everything I possibly can mechanically and then brush with converter then (when ready) clean back to bare steel and epoxy when ready. I'm absolutely no expert but the converter always manages to pick up a few tiny specs in the steel and turn them black.. I'm happy enough that those have been dealt with (though maybe phosphoric acid would be better )

[Spencer]

Yea man you nailed it, things like the CRC "rust converter" are a tannic acid (only a very small %), they are mostly water by volume and some organic solvent. from my tests they don't hold up well to the elements and I'm not a fan of the adhesion (if it goes on too thick you can sometimes get it off with a fingernail). 

 

Best bet is mechanically removing it or phosphoric acid, you don't want the stronger acid in seams and cavities though. Its much for muchness inside cavities you just need good long term hold out, from my shitty tests (coating squares of panel steel and chucking it outside for ages) some very good wax seems best. Not all wax is equal though so do some testing.

[MaxPower]

chicken mesh then bog for big holes. or nutech, its as good as steel and magnets don't pick it up.