Rusty Iron or Steel Fittings on a Leather Bag

Iron, iron alloys and tinplate corrode when in contact with acidic leather, and the Canadian Conservation Institute says that these metals will cause the surrounding leather to become weak, brittle and powdery. Dry storage and avoiding direct contact are its main points.

What the CCI says

• Metal components on leather often show signs of corrosion.
• Iron, iron alloys and tinplate corrode when in contact with acidic leather.
• The corrosion causes the surrounding leather to become weak, brittle and powdery.
• Whenever possible, prevent direct contact between leather and metal by inserting a sheet of Mylar or polyethylene.
• High humidity, over 65 per cent relative humidity, also encourages mould and the degradation of leather.

What to look for

• Orange or brown rust on fittings.
• Dark staining of leather around a rivet or a buckle.
• Leather that is crumbly, powdery or thin close to the metal.
• Fittings that move or have pulled out.

What to do

1. Keep the bag dry and ventilated.
2. Do not pull hard on a rusty fitting, because the leather around it may tear.
3. Do not apply rust removers to leather.
4. Photograph the damage.
5. For a bag that matters, ask a repairer or conservator about replacing the fitting.

Check the metal on any old bag before you carry a load in it. A buckle or rivet that has rusted into the leather may give way suddenly, and it is safer to have it looked at than to find out on the street. Keep the bag dry between uses, and let it air after rain.

If you want to prevent contact between metal and leather on a bag you own, the note’s suggestion of a thin barrier sheet is the principle. A repairer can advise whether a barrier is practical for your bag, since it may be hard to fit without taking the fitting off.

Where this answer stops

The CCI’s guidance is for museum objects. A modern bag may use stainless or plated fittings that corrode differently. We cannot tell from here what your fittings are made of.