Galvanized bolts? Need 36 carriage bolts, washers and nuts

[Captain Dirty]

If you don't mind me asking, what kind of premium did you pay for the hot dipped bolts?

FWIW: Bolt Depot prices for 3/8-16 x 3" carriage bolts

Zinc Plated​ $.30 ea​ $10.31/50​ HD Galvanized​ .29 ea​ 10.55/50​ 318 SS​ .90 ea​ 35.82/50​ 316 SS​ 4.73 ea​ 89.43/25​

rScotty probably knows, but others may not be aware that ordinary (not HD galv) nuts will not fit on HD Galv bolts; the galvanized coating is too thick. HD Galv nuts are tapped oversize so there is room for the coatings.

[First time posting a table, not like Word or Excel]

 

[Drewintoledo]

Yes sir!
"Hot-dipped galvanized steel has a thicker zinc coating for better corrosion resistance, making it suitable for outdoor use. Because of the thick plating, only galvanized nuts and washers will fit galvanized bolts. The coating typically has a rough, dull grey finish."
Check out Boltdepot, they have lots of good documentation and reference charts and they are laid out for printing too. I swear I'm not affiliated with them!

 

[Midniteoyl]

They take paint fairly good as well.

 

[buckeyefarmer]

Get them by the box at HD far less than individual.

 

[dstig1]

Great! If you don't mind me asking, what kind of premium did you pay for the hot dipped bolts? You'll be glad you went that way after the table gets wet a few times. Electroplated galvanizing just doesn't last compared to hot dipped.

I used to use stainless fasteners for outdoor furniture, but too much of the imported stuff was made using 303/304 series SS .... which does rust and pit, although not as bad as basic carbon steel bolts.

If you ever do use stainless bolts, it's worth getting 316 alloy. They don't rust. Absolutely required for marine/saltwater use.

You can tell the two SS alloys apart by color after some practice but the easy way is with a magnet:
303/304 is strongly ferromagnetic, i.e. attracted to a magnet.
The preferred 316 is only weakly magnetic or not at all.
Big difference.
rScotty

300 series SS is not magnetic unless heavily cold worked. What is more important than 304 vs 316 to start with, is if the hardware was passivated or not. If not, it is subject to rust spots as you noted. 316 is more corrosion resistant than 304 and is the recommended grade for marine/coastal exposure, but 304 is perfectly fine inland. 316 that is not passivated will be subject to rust stains the same as 304. 303 is considered the machinable grade of the 300 series and is supposed to be much easier to machine than 304 but the tradeoff is that it is not really weldable. 400 series are slightly magnetic. Most stainless mufflers are made from 400 series, I believe due to better high temp corrosion resistance, but don't quote me on that reason.

 

[dboreham]

I'm rebuilding a picnic table. Does it make sense to source bolts, washers and nuts online? If so, does anyone have a good go-to source for low cost galvanized bolts and such? Maybe it's just as pricey to hit a local big box store? So far, boltdepot.com seems like the deal

Perhaps overkill for something commonly available like this, but for fasteners in general and especially when you need something specific in terms of material, finish, strength, etc I love McMaster Carr : McMaster-Carr

 

[oldpilot]

If you can get US galvi, I suppose that's okay, but around here everyone except the rare marine-supply store stocks China-made. For me, there's none closer than a two-hour round trip.

I live on salt water and have pretty much given up on galvi. I use stainless steel from Amazon. It's China-made and will tarnish eventually, but not evaporate as Chinese gavli does.

 

[BubbaLouie]

I'm rebuilding a picnic table. Does it make sense to source bolts, washers and nuts online? If so, does anyone have a good go-to source for low cost galvanized bolts and such? Maybe it's just as pricey to hit a local big box store? So far, boltdepot.com seems like the deal

Tractor Supply sells by the pounds. That's where I get all types of bolts.

 

[OzarkChris]

I'm rebuilding a picnic table. Does it make sense to source bolts, washers and nuts online? If so, does anyone have a good go-to source for low cost galvanized bolts and such? Maybe it's just as pricey to hit a local big box store? So far, boltdepot.com seems like the deal

You might consider a local Co-Op if you have one close. Our Co-Op carries all kinds of fasteners at about 2/3rd the cost from HD or TSC.

 

[rScotty]

If you can get US galvi, I suppose that's okay, but around here everyone except the rare marine-supply store stocks China-made. For me, there's none closer than a two-hour round trip.

I live on salt water and have pretty much given up on galvi. I use stainless steel from Amazon. It's China-made and will tarnish eventually, but not evaporate as Chinese gavli does.

I got to wondering about something else, since we've been kicking this around for a few days now and the OP has already ordered his bolts.

What I'm wondering is if anyone who didn't know before has learned from this thread that there are different types of galvanizing - with different properties & prices.
Same for stainless.

rScotty