Fixing Corten Steel Panels

I've not worked with corten, but it's steel. Why not just use carbon steel screws and let them rust?

Screws are are smaller, if left to rust they would fail after time. The nylon/rubber washer provides a weather seal and allow for expansion and contraction.

I have a galvanized steel building, that's held together with stainless bolts with, (I think), nylon washers. Rubber washers would work too.

I would go with stainless. I'm not sure about the cost of brass, but not only is it softer, if you intend on painting the building, brass or bronze are going to present possible adhesion problems.

Both also contain copper, so you may experience staining.

Corten is a steel with copper content that when the surface oxidises forms a protective barrier that slows the rate of corrosion. I want to use a fixing screw that is not going to promote galvanic corrosion of either the corten plate or the screw.

So presumably the two metals should be close on the Anodic Index, otherwise insulating materials need to be used -nylon etc - which becomes another point of failure.

I forgot. My brain was on galvanized. Lyn's probably right.

Don't they make Corten screws?

If they don't, they should.

the carbon content will promote rust like cast iron. they're designed that way.

What does your Cor-ten steel supplier say?

They would have such information, right?

The anodic index for numbers for the materials discussed here are;

Brass/bronze:.4

Steel:85

Stainless steel: .6

These materials won't do that well in a warm, moist environment.

I still say use carbon steel screws. No worries!

No need to isolate the dissimilar metals either.

Cheers.

Steel should be .85.

Re:
" Brass/bronze:.4
Steel:85
Stainless steel: .6
......
Steel should be .85 "
? ! ?

Lest we lead some astray, don't forget:
all numbers above are NEGATIVE (-) in value

Even the SS will corrode if in contact that is why the sealing washer to reduce the contact area. Brass or Bronze would be worse. The do make weathering steel fasteners from Corten.

Where high-strength bolts are desired, ASTM A325, Type 3 bolts (COR-TEN X) must be used.

If another type of bolt material is used, you must isolate it from the Cor-Ten steel panels with a plastic or rubber washer and sleeve, otherwise galvanic action between the two dissimilar metals will occur.

Where high-strength bolts are desired, ASTM A325, Type 3 bolts (COR-TEN X) must be used.

Similar to what I was going to say based on long-ago experience with high-tension transmission poles. Where the customer wanted weathering steel (Corten, etc) we needed to use the A325 Type 3 fasteners. There had been a case where someone used galvanized nuts on a weathering steel pole--the galvanizing "went away" trying to protect the whole pole from corrosion; of course this left the nuts unprotected, and they then rusted.

I hope they make weathering steel fasteners in the smaller sizes and lower strengths that you need.

Finally got an answer that worked with the builders, architech, inspectors, fabricators......

Double sided tape plus adhesive plus bend a lip at the tob so theat the panels hang.I just tell people that we used sellotape to get a reaction.

Thanks for the help.