# Screws for outdoor use



## Terry Jackson (Jan 4, 2008)

I have an Aristo Tower and brought it in to clean it up. Some of the windows have fallen off so am regluing them onto the frames. My question is what kind screw will not rust when outside for a long long time. The screw threads look sorta like a wood screw and they go into plastic. Had a hard time getting the screws because they had rusted. What would be a better screw to replace them with? Something a little better. Stainless steel, brass, etc. What holds up the best?


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## eheading (Jan 5, 2008)

For my money, there is nothing that resists corrosion as well as stainless steel. Although on my RV I have had good luck with nickel coated brass too. I don't think I've ever seen that on screws. I generally just stick with stainless steel hardware if I can get it.

Ed


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## Madstang (Jan 4, 2008)

Galvanized, or zink coated, but not sure if the zink will last.

Bubba


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## Randy Stone (Jan 2, 2008)

Stainless is the way to go, but remember there are different grades of stainless steel. 

I bought stainless steel lag bolt at Home Depot and used them outside. With in 6 months they had a rusty apearance. 

304 is the most commonly used in military equipment. 

Note that in the chart below, most grades are compared to 304. 

300 Seriesâ€"austenitic chromium-nickel alloys 
Type 301â€"highly ductile, for formed products. Also hardens rapidly during mechanical working. Good weldability. Better wear resistance and fatigue strength than 304. 
Type 302â€"same corrosion resistance as 304, with slightly higher strength due to additional carbon. 
Type 303â€"free machining version of 304 via addition of sulfur and phosphorus. Also referred to as "A1" in accordance with ISO 3506.[6] 
Type 304â€"the most common grade; the classic 18/8 stainless steel. Outside of the US it is commonly known as "A2", in accordance with ISO 3506 (not to be confused with A2 tool steel).[6] 
Type 304Lâ€"same as the 304 grade but contains less carbon to increase weldability. Is slightly weaker than 304. 
Type 304LNâ€"same as 304L, but also nitrogen is added to obtain a much higher yield and tensile strength than 304L. 
Type 308â€"used as the filler metal when welding 304. 
Type 309â€"better temperature resistance than 304, also sometimes used as filler metal when welding dissimilar steels, along with inconel. 
Type 316â€"the second most common grade (after 304); for food and surgical stainless steel uses; alloy addition of molybdenum prevents specific forms of corrosion. It is also known as marine grade stainless steel due to its increased resistance to chloride corrosion compared to type 304. 316 is often used for building nuclear reprocessing plants. 316L is an extra low carbon grade of 316, generally used in stainless steel watches and marine applications, as well exclusively in the fabrication of reactor pressure vessels for boiling water reactors, due to its high resistance to corrosion. Also referred to as "A4" in accordance with ISO 3506.[6] 316Ti includes titanium for heat resistance, therefore it is used in flexible chimney liners. 
Type 321â€"similar to 304 but lower risk of weld decay due to addition of titanium. See also 347 with addition of niobium for desensitization during welding.


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## eheading (Jan 5, 2008)

That's a great summary of the different stainless alloys, Randy. My limited experience has been that type 304 for small hardware is about as good as it gets. In my working days, we were working with caustic chemicals, and used a lot of type 316 stainless. That was superb, but it is (or was) pretty pricey, and I'm not sure how easy it is to get screws and other hardware in that alloy.

I enjoyed reading the whole list though. It has been a long time for me, and I had forgotten a lot of the info. Thanks for posting it.

Ed


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## Terry Jackson (Jan 4, 2008)

Thanks for the info. Now I will go to Lowe's and see what I can find.


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## Naptowneng (Jun 14, 2010)

Good info above, 304 stainless is very good material for our outdoor needs.
I will also say that brass screws should give many years of service as well. (100% brass, NOT brass plated). Should be cheaper then SS, and as it weathers will turn dark while the SS will stay bright metal. This perhaps will give you a choice of appearance if they show

Jerry


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## armorsmith (Jun 1, 2008)

Fasteners in all the stainless grades are available, depending on how deep your pocket and long your arms are. Two good sources for purchasing are McMaster-Carr (www.mcmaster.com) and Fastenal (www.fastenal.com). For fasteners, the 304/18-8 grades are the most common, and there for the least expensive and most available. The 316 grades are available, but as was said earlier, they are pricey. For the purposes we are using them, the 304/18-8 grades will do most of us fine. 

Bob C.


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## Ray Dunakin (Jan 6, 2008)

I've been able to find a lot of stainless nuts, bolts and screws at Ace. If I can't find it there, I usually get it from McMaster-Carr.


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## SE18 (Feb 21, 2008)

I made a switch throw from a brass barrel latch I got from either HD or Lowes. Within a year, it was completely rusted. The box it came in didn't say it was plated. The plating must have been really light coat. I guess buyer beware for brass screws as well? 

DaveV


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## Dean Whipple (Jan 2, 2008)

Check to make sure it's real brass not brass plate with a magnet....


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## Greg Elmassian (Jan 3, 2008)

A lot of brass plated stuff is on pot metal, fails the magnet test... bought some "brass" coat hooks, plated pot metal. 

Greg


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## SE18 (Feb 21, 2008)

I've got a sort of related question to this plating. If I buy, say, a brass plated screw and wish to use it outside and solder something to it (for some sort of project), seems the solder joint will fail once the plating falls off. Same thing for soldering tinplate structures outdoors? I don't necessarily care if the tin or brass rusts, just that the solder joint hold. Applications might include bridge sides, where a real rust look might be nice. You wouldn't want it to fall apart though. I know there are other materials and ways to do it, just asking the question about soldering plated brass or tinplate (like tin can watertower) for outside use.

Thanks in advance 

DaveV


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