I’ve looked at dozens of images of hop spiders, and the bolts aren’t coming anywhere near the wort. By design, the bolts are slightly above the top of the kettle, as they are supported by the lip of the kettle. If your kettle were even close to being that full, you’d have other problems. Unless the steam of the boil were able to boil off enough zinc to be a problem (is this possible?), this feels like a non-issue. (I think the person who posted that zinc is a nutrient was being facetious.)
I agree that it’s likely a non issue in this case, but I’d avoid galvanized even in this situation if possible.
I know I wouldn’t want the steam to condense on the bolts and fall back into the kettle. Between the risk of poison and the potential for a ferrous off-flavor, that’s enough of a reason to stainless for me.
not sure why your fg suffered from this unless you are suggesting there was not the expected boil off/concentration?
do many of you use a spider, hop bag? i usually just throw them in the boil, but i am not pumping my wort yet and just pour it through a strainer
I just throw the pellets into the kettle as well. Whole hops I put in a nylon bag and loosely tie the string to the kettle handle. I siphon my wort off into the fermenter. Now that I started to up my finish volume I have never had cleaner looking wort.
i’m now inspired to build a hop spider! any other fun gadgets like this that would help out a beginning extract brewer?
Why not just buy 3 of these 5" stainless eye bolts for spider legs?
They would need to be longer than 5 inches (they do offer 8"), but that would work – at least one of the designs use these. I may do that at lunch today (and return the carriage bolts).
I think the ones I bought were longer than 5 inches.
Copper pipe works too. You don’t have to use the exact design they published.
Paul
Sorry, yes misspoke. Our OG wasn’t that high and we had a lot of wort due to the minimal boil. (We also mashed around 158F and added lactose and believe that we had way too many dextrins thus the high FG).
So once again I can start phoning hardware stores in SF… last time it was “excuse me, how long are your wallpaper trays?” Now it can be “Hi, do you carry stainless steel carriage or eye bolts? No, not short ones…” I usually explain it’s for a craft project.
It’s all good… these projects are so easy, compared to real work!
I just drilled a couple holes, one through a little above midway of opposite sides the pvc coupling, and stick a dowel through it that props over the top of the kettle. It is a keg kettle, and so the dowel can’t be knocked off since there is an additional rise of the sides above the kettle opening. Very simple, no metal, works fine. However, I don’t like the clogging of the paint strainer bag mesh, and so use it pretty rarely.
I likewise recommend against using galvanized anything suspended above the boil!
I find if you bring a bottle of homebrew to your local hardware store and explain that you are a homebrewer those folks can get mighty creative and help out a lot with design on these kinds of things. just a thought!
When I built my mash tun 3 years ago this was exactly the treatment I got. I told some young men I was doing this to make beer and I thought they were going to pass out. They practically carried me around Home Depot on a chair. They even chopped the ends off my plumbing supply line so I could make my strainer. They didn’t ask for beer… they were just in awe of being in the presence of Queen Ninkasi. 
This time I went to several busy, understaffed big-box hardware stores and could barely get anyone’s attention. Buy a single 8" SS carriage bolt? I don’t think so. Special order? For 3? Not likely. Tonight we went to our favorite bar for pre-dinner beer (and wine for my other half) and I went to a very longstanding local hardware store across the street and found 8-inch SS eye bolts w/nuts, plus the guy found me the right wingnuts (at first he thought I said “Windex”…). I didn’t even have homebrew with me. 
It was one of those hardware stores where you could say “I’m building a rocket ship and need Krypton” and they would go in the back and find it. I hope these stores survive.
Nice! We used to have one of those stores not far from my house. They had a fat store cat that sat on the counter, a cool collection of pocket knives for sale and even had small brass thumb screws for my 1956 toilet right there in a galvanized bin. The guy said he had never sold one of those in the 15 years he had been working there. Sadly, the store burned to the ground a couple years ago.
Instead of carriage/eye bolts you could use the create a bolt kit. Te threaded rod comes in ss(or galvanized so watch which one you grab) and up to 18" long, though commonly they are 12". Total cost may be slight higher than a bolt, but it’s 100% customizable. The hardware also comes in a kit with all the washers lock washers and nuts you need and are numbered to match the rod.
For mine I just drilled three holes with a step drill bit and inserted 1/2" pvc pipes. I put 90 degree fittings on the ends so it will stay centered.
I actually bought PVC this weekend but really wanted stainless. No real logic, it’s just what I wanted. The PVC goes back… Not that much dough but it will buy a couple of ounces of hops.
Just re-did my spider this morning with 8" SS bolts, washers, and nuts. The first run went great, but it was only a dry stout with one 60 minute addition ( 2 oz ). I will have to see how it does with some of the more hop-heavy recipes.