Staining around screwheads; I'm assuming this is rust??

dan4jc

0
Apr 24, 2013
22
I converted to a SWG last summer and have noticed a few of these stains on around my skimmers, as well as around the bolts that hold the rungs onto the ladder. I'm assuming it's rust (even though these screws aren't supposed to rust). Is the simple solution to purchase higher-quality screws and swapping out the ones that are rusting? If so, does anyone have a link to something you would trust? Greatly appreciated!!

IMG_2736.jpg
 
Those are probably low-grade steel screws that are not meant for higher chloride content water. A 316L stainless steel alloy screw would be the better choice as 316 SS alloy is designed for use in brackish water environments. See if you can find them locally at a hardware store or plumbing supply store. Brass or bronze screws would not corrode but they may be too hard to find.

Question - are you pouring any chemicals line bleach or acid near your skimmer?
 
Thanks for the reply, JN. Would it be safe to take one of the screws out and take it with me to Lowe's to match it up? I know they keep the faceplate sealed, but I wouldn't think taking one out would make a difference. I also assume I might as well replace all of them (one at a time) to prevent this from eventually happening to

I do not add any chemicals by the skimmer, other than CYA. I pour bleach/MA in front of the jet on the opposite side of the pool, about 18 ft away.
 
Ok. Just checking. Yes, you can take one out. Pick one on the top above the water line. My personal suggestion and preference is, when you replace them, to lower the water level below the face plate and replace them all, one at a time. That's how I would do it to minimize any chance of leaking or anything shifting. Others may be of differing opinion.
 
I'd take one of the top ones out and take it with me. Just be aware that you're not likely to find 316 stainless at the big box store. They usually have 302 or 304 stainless.

Do you have a make and model of the skimmer?

The screws are most likely #12 x 1". they can be either self tapping or machine threads, depending on the make and model of the skimmer.
 
If I may make an observation (with a little guess because the picture isn't entirely clear) - you'll note that the screws below the water line are not rusting as are the ones at the top. It's only the screw that is near the skimmer mid line that is rusty. I can't see all the other screws, but that's how it appears from the picture.

If so, then what you likely have is concentrated salt building up in the threads of that one screw from splashing and then evaporation. It shows how complicated corrosion can be. People would say, "See, the salt is to blame and the SWG is a bad choice." But if that were true, then the screws below the water line would be rusted out as well.

I wonder if it would be advisable to put a little dab of flexible white silicone caulk on each screw head to keep water out. If done right, it can easily be scrapped off if the faceplate screws need to be accessed. Perhaps it's not necessary but I might consider doing that as an added layer of protection.
 
Thanks for all the info! I'll see if I can find any make/model info in the paperwork and go from there. If not, I'll take one out and head to Lowe's to at least verify size/length, and order something online if I have to. I'm assuming the same is true for the bolts in the steps. I'll have to take that apart in the off-season and see what I can find for replacement parts.

Joyful, I know the other skimmers have some rust spots, but I can't recall if they're at the same location. A little caulk over the heads wouldn't hurt at all, and just another layer of protection. Great idea!
 
If you do go the purchase online route, see if you can find AISI 904L stainless steel screws. It's a high austenitic steel composition that is designed to work in highly corrosive and seawater environments. Obviously it's a highly specialized alloy that is not likely found in a retail outlet but you never know online, you might get lucky and find them...316L SS will work just as well too.
 

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I'd check McMaster Carr online they are one of the best low cost places to find the 316l screws you need.

Wow...flashback!! Back in my working days, the McMaster-Carr catalogue was a permanent fixture on my desk shelf with LOTS of dog eared pages. When the new versions of the catalogue were released, I was like a kid getting a Christmas catalogue.

Do they still make the print versions of their catalogue? I remember they were starting to move everything online.

Sorry, detour down memory lane over {/derail}
 
They do still print them... cut down entire forests to do so. Coming in at 20lbs and 3K pages. I have one on my desk right now.

I may have to get one for old time's sake. I remember when the new editions would get printed that, if you were the first guy in the office with it, you were king of the hill. My copy never left my desk, if you wanted to look up something then you had to stand in my office to do it. The same was true for my Metal Finishing Handbook which was a lot harder to get a copy of if it got lost.
 
Thanks for all the feedback, everyone! This got me thinking about the hardware used to tighten in the ladder and handrails. With all of the splashout in those areas, would it be a good idea to remove the bolts and replace them with higher quality ones as well?
 
Wow...flashback!! Back in my working days, the McMaster-Carr catalogue was a permanent fixture on my desk shelf with LOTS of dog eared pages. When the new versions of the catalogue were released, I was like a kid getting a Christmas catalogue.

Do they still make the print versions of their catalogue? I remember they were starting to move everything online.

Sorry, detour down memory lane over {/derail}
Not necessarily a thread derail because the great part about the online catalogue is that once you drill down to the part you think you need they usually have a linked dimensional drawing of the screw so you're 100% sure it's the right part. Just imagine the catalogue being 300,000 pages :)
 
BTW I had a similar thought to JN's second thought about perhaps not rusting, but scaling. My tap water is ABYSMAL here, and if you look in the washing machine tub where you add the liquid detergent, on sink basins, and just about any pre-filtered location where water touches, you get that Orange looking iron-like deposits. The only location that seems affected is the one where water can splash up, and drip down. That's exactly the formula needed for my source water to make those markings. I don't see a buildup of rust on the screw, just scaling. I'd imagine these screws are fine, and the caulk method would probably work like a champ because it wouldn't allow water to "catch" and slowly drip down. Just my 0.02.
 
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