Anodic Protection of Steel Fire Escape

Look for protective paints for steel bridges. Attempt to calculate if your "protection" endevours will not cost more than a new fire-escape, or close to it.

maybe you're talking about "cathodic protection"? i don't understand if the steel fire escape is immerserd in water or is in atmosphere exposure?? can u plese clarify... if it's in atmosphere there's no possibility to use a cathodic or anodic protection...

this works :

http://www.por15.com/#

what essentially you are looking for is an 'electron'ic way to cancel out the reaction which normally takes place in corrosion. there are two ways to accomplice that

1) connect a piece of metal which is higher on the activity series than your 'to-be-protected' target by a conductive wire and ensure that this more reactive bar is exposed to the same environment as the target i.e. same electrolyte. Gradually this more reactive metal will corrode away and will have to be replaced by a new bar/plate to ensure continued protection.This method is known as sacrificial protection.

2) the other way is to continuously provide a -ve charge to your target from a power supply thus keeping the metal from forming and M+ ions which may then take part in any corrosion reaction. the positive part of the power supply may be either earthed of left near to the target using a inert electrode - like graphite. This method requires a continuous supply of power but is suitable for fixed structures at places where grid power is available.

this will need to be sandblasted on a hot dry day to bare metal, with all holes/crevices opened and cleaned. If it is welded, OK, but if bolted or riveted, you may be unable to clean hidden surfaces = fatal weakness.

Then buy a two part zinc powder epoxy primer. This is about 85% zinc by weight and when set it a conductor as the zinc all touches. This stuff is costly.

You can also use a zinc paint, also 85% zinc, that air dries. Not as good as epoxy, but much cheaper. Marine supply places have both in stock

Aurizon has offered the best solution to your problem.

If you cannot or don't want to sandblast I recommend you remove as much of the flakey rust as possible then apply a rust converter before the zinc paint process. Also if you use the single part zinc paint allow it to weather for a for a week or so and when you have a good dry spell [ best after some rain to wash away any salt deposits ] paint it with a two part polyurethane paint to seal the the primer coat as it is porous. and will react as it is supposed to if exposed to the atmosphere.

Thermal Spray Zinc or Aluminum.

Hot-dip galvanize it; this is the easiest route to get a DURABLE zinc-rich coating on the part to ward off rust.

Direct Magnesium cathode to ground will buy you 5 years in acidic soil.

I would agree with the suggestion of having the fire escape removed and hot dip galvanized. Zinc epoxy primers used to be considered the gold standard, but in recent years they have started to fall into disfavor. But be careful who you have do the dipping, a poor job will leave pinholes or may flake off. Thermal spraying with Zinc or Aluminum is another good choice, but the same caveat applies about the quality of the work.

Hello,

your decision to paint is right; after you use zinc rich primer you have to paint zinc rich paints, but never lead based paints. your steel structure will stay longer with zinc primer and paint provided you scrape all the rust.

vijay saradhi

Thank you all for your help. Based on what we have read we have decided to go with the original method of rust removal and using a Zn epoxy base with correct primer. I hope that we can do on-site sand blasting. Zn plating would have been too expensive as there are 5 stories that need to be serviced by two fire escapes. We are looking at new fire escapes as a possible alternative. Once again thanks for all your help and comments. This is great site.