Summary for stainless deck nails rusting Discussion
stainless deck nails rusting is likely a grade-and-environment problem rather than proof the nails were not stainless. Mark Stueve reported that stainless ring-shank nails driven into pressure-treated wood on Florida’s Gulf Coast began showing rust spots around about half the heads after 7–8 months, and the rust returned even after cleaning, wire-wheeling, zinc priming, and re-staining. James Totter pointed to the American Wood Council guidance that pressure-treated wood in coastal areas should use 304 or, better, 316 stainless, noting that newer preservatives are more corrosive than older CCA treatments. Marc Banks added that all stainless can oxidize in a high-moisture environment and suggested bronze or brass for this application. Jim Gorsich warned that wire wheels can embed free iron and compromise corrosion resistance, and also emphasized passivation and avoiding sanding the heads. The practical takeaway is to use a more corrosion-resistant fastener, likely 316 stainless, and avoid contamination during installation or cleanup.
I am a painter and am having trouble with stainless deck nails rusting. The nails are stainless ringshank and have been installed with a nail gun into pressure treated wood. A oil based deck stain was applied after the wood had weathered sufficiently. About 7 to 8 months later rust spots appeared around half the nail heads. We cleaned the rust off as best we could and re-stained. We even took a small wire wheel to the heads then coated them with a zinc primer but the rust keeps coming back. The homeowner pulled some of the nails out and sent them to a lab to see if they really were stainless which they were. I don,t remember what grade. This house is located on the gulf coast close to Ft. Meyers. Can you give me any ideas what is causing this and any fixes. Thank you
Mark Stueve
painter – Englewood, Florida, USA
2005
 | The driver on the nail gun is hardened steel. It leaves a really thin layer or spot of steel on the head of the nail which starts the rust which will continue to spread over time in a salt air climate. ⇦ on eBay or Amazon [affil link] ⇦ on eBay or ⇦ on eBay Amazon [affil link] James Watts If the deck is on the Gulf, there’s probably a lot of chloride in the atmosphere. Most grades of stainless will corrode in chloride environments. Try something powder coated (and don’t use the cheap stuff).
According to the American Wood Council, suitable fastener materials for pressure-treated wood in coastal areas are 304 (’18-8′) and 316 stainless. Since you’ve already experienced stainless corrosion, use the better, 316 grade. The newer wood preservatives are more corrosive toward metal than the banned CCA (Chromated Copper Arsenate). For more information: Go to www.awc.org, search for Corrosion, click on the 1st result “American Wood Council Mold and Moisture in Homes.” Ken Vlach [deceased]
– Goleta, California All stainless steels will oxidize given time and a high moisture environment. The nails are most likely stainless, but of the wrong grade for your purpose, take a magnet to them and see if it sticks, if it does (most likely) you have stainless nails that are high in steel and low in chrome. I would suggest bronze or brass nails for this application as they will have surface oxidation, but will no corrode beyond the surface. Marc Banks Some stainless alloys resist rust better than others, the alloy is fairly important – the first suggestion would be to try an alloy that is more corrosion resistant. I would make more direct suggestions, but I don’t really deal much with stainless – use the search engine on this site and you should be able to find some information that can help. The second suggestion is to make sure that the nails have been passivated – this builds up an oxide layer on the part and provides most of the corrosion resistance. Incidentally, this layer can be compromised by sever sanding and other working, so try not to sand the head of the new nails if you can help it. A third suggestion, the stainless steel is corrosion resistant, but the wire wheel you used probably wasn’t and could have easily embedded free iron into the head of the nails – this iron, then, would be susceptible to rust. More than that I can’t offer – as I said, stainless steel isn’t really my thing. But, use the search engine, the archived letters contain a wealth of information that is fairly easily overlooked by new users. Good luck! Jim Gorsich |
Try Everbrite [a finishing.com supporting advertiser] coating. Hope it helps and good luck!
Goran Budija
– Cerovski vrh Croatia
2005
A. If you’re curious about what causes rusty wood and how to avoid it don’t worry — you’re not alone.
The basics are that rusty wood is caused by minerals in the wood reacting to low-grade metals…To avoid it simply shell out for higher quality metal!
Dan Sazer
– Austin, Texas, USA
July 10, 2019