Stop rust from coming out of steel profile

What are they used for?
Environment (acid, alkali, hot, etc etc)?
Why are they rusting (internally presumably)?

How big are the holes?

Silicon caulking as a possible solution?

Grease is the most common one to avoid rust at low deposit areas like holes, thread etc.

Also you can prevent rust by anti-rust solutions like ZORRIK 88 ..

They are steel frames left outside most of the time. The frames are zinc plated (only on the outside) and the inside rusts now after many years.

The hole is about diameter 20mm in a 30mm square box section frame.

They are also used in the food industry, so I am not sure if Silicon caulking would be an option.

If its used in a food application, then I'm surprised mild steel is an option. Everwhere I have work in the food industry, everything was either stainless steel or alumnium.

What about welding plates over the holes to seal them?

I would trat the steel in a pickling acid solution to eliminate the rust, then rinse thoroughly and dip in an oil that would be acceptable to the food industry. Unfortunately, repeating the operation of oil dipping may be necessary over time depending on the environment.

Apply a thin coat of cheap grease

We sell a product that is made from Pure Lanolin, derived from Sheeps wool, and I guarantee you, it will Stop Rust, wherever it is found.

We sell it to the Chicken Houses, where there is moisture from the coolers, and ammonia from the Chickens, very corrosive environment.

This product comes in small containers, and very large containers, and also in different viscosity, and in different grades.

We could send you a sample

Donald

Maybe you should try "great stuff" expanding foam? It comes in a aerosol can and you can buy it at any hardware or building store.

***Do not get it on your skin, it takes weeks to come off!***

Treat inside with rust conversion then fill with cement providing not to heavy.

The Expanding Foam suggested by Stackpoole 77---#5 seems to solve all problems.

Technically-

• you are stopping further Oxygen ingress-hence no more oxidation
• And what Iron Oxide( Rust) is inside--remains Inside.

If silicone sealants are a problem for food contact make sure your foam does not contact food. It is polyurethane and not good for food contact. Also it would be a problem if the frames are heated up any. There are various solutions which will stabilize rust, often by converting it to black iron oxide (gun blueing comes to mind). Flushing this through the hollow interior follwed by sealing the access or even flushing through a sealant coating like a very high solids urethane approved for food contact. You would need a very low solvent or 100% solids coating since the solvent vapour cannot escape from inside the frame.

Powder coat rusting parts...w/approved food coating.......

MR. GUY

Well, think a minute. The exterior of the frames cannot be in 'food-contact' service (legally) because the opening and interior cannot be cleaned and disinfected. Ergo, the 'rust leakage' solution also does not have to be 'food safe'. I think the expanding urethane foam 'plug ' is an excellen, very low cost, easy to implement solution. It can trimmed flush and even be 'sealed' with a food grade silicone sealant to protect the foam from weathering.