Galvanizing video

Trevor · October 17, 2016, 08:58 PM

For all you galvanizers out there, Land Rover Toolbox released a video recently on the subject which you might find interesting.

https://www.youtube.com/watch?v=iQJKvFH-2ts

binch · October 17, 2016, 10:09 PM

Good video! But galvanizing is still more durable then paint ;D

Trevor · October 18, 2016, 05:21 AM

I didn't have a lot of knowledge of galvanizing. I found the fact that you're simply sacrificing the zinc coating rather than the steel interesting (didn't realize that's how it worked). The painting requirements of the galvanized parts, and the products used for that, was info I didn't know either. I thought you could just leave galvanized parts unpainted without ill affect. Apparently not, as with steel you're decreasing the life of the part by not painting...which makes sense when you think about it.

The big take away I got was, if you're not going to keep things clean, it's still going to rot out on you. It's a very good "extender" as it were for the life of a part/chassis/etc, but it still has all the ongoing maintenance requirements as something that was not galvanized....keeping area clean, painted, etc.

Red90 · October 18, 2016, 07:20 AM

Quote from: Trevor on October 18, 2016, 05:21 AM
I didn't have a lot of knowledge of galvanizing. I found the fact that you're simply sacrificing the zinc coating rather than the steel interesting (didn't realize that's how it worked).

Without watching the video, that is not how it works. Zinc won't corrode in a normal water/air/salt atmosphere found in a vehicle application, thus is is not sacrificed. There is no need to paint. The zinc will help prevent exposed steel from corrosion, if both are connected and wetted when the corrosion action occurs. Technically, you could lose zinc from that action, but experience shows the zinc will last basically forever and will not protect neighboring steel very much. As long as the zinc is a hot dipped application, the thickness and durability will be well beyond the service life of the rest of the vehicle.

Trevor · October 18, 2016, 08:19 AM

Probably easiest to watch the video as I'm simply parroting the info there. Although it sounds like some of what you are saying lines up well. The only big difference is the idea that zinc is indestructible...they had an example of a galvanized frame that was in pretty rough shape. It wasn't well cared for though (cleaned), and perhaps had a poor galvanize job done. I dunno.

Red90 · October 18, 2016, 09:27 PM

Had a quick look. A fair bit of incorrect info on cathodic protection. It is commonly misunderstood. The chassis shown at the end was not hot dipped galvanized.

Cruzer · October 19, 2016, 12:15 AM

Not sure how true this is but a couple years back a Brit military mechanic over seas told me the only reason that their defenders didn't have galvanized frames was because military didn't want to spend money on recipirators and have the chance of mechanics getting sick from quick weld jobs in the field.

Just thought I would throw that in there.

Red90 · October 19, 2016, 06:40 AM

I would not doubt it. It is a massive pain to deal with if you want to weld.

Matt H · October 19, 2016, 11:58 AM

Quote from: Cruzer on October 19, 2016, 12:15 AM
Not sure how true this is but a couple years back a Brit military mechanic over seas told me the only reason that their defenders didn't have galvanized frames was because military didn't want to spend money on recipirators and have the chance of mechanics getting sick from quick weld jobs in the field.

Just thought I would throw that in there.

Probably has more to do with the cost than the health of the poor old squaddies? But times change so it could be true? These days Army Defenders have roll cages, power steering insulation and heaters! All things that were inconceivable in my day.

ugly_90 · October 19, 2016, 01:51 PM

There's a few errors on physics in the video. That said, zinc galvanizing on steel is placing a soft metal on a hard one, and it can fail where there's abrasion, and then corrode there, perhaps more so at that point than an only painted surface would.

Mitigation against chassis and body abrasion with rubber mud flaps can be effective.

There's no better option for closed-bar or tube steel than electroplating, as no other coating can properly bond to the hidden inside of the metal.

Particularly old metal has most of the corrosion removed in hidden areas by the acid dip before plating.

On steel petroleum pipelines, they often use electrical cathodic protection, as do ships when arc welding. A bar of metal is lowered into the sea, and used as a ground, becoming heavily corroded and a sacraficial anode, rather than the ship's hull. Electric water tanks use the same concept as well.

It wouldn't be hard for a land rover magazine to bolt pieces of bare steel, aluminum alloy, and galvanized steel together and maintain in a salt spray. Applying a charge and attaching a ground to the correct metals; the results could be evaluated.