BP/W setup - Galvanic corrosion and how to avoid it

[Daniel M. Thomas]

Hi divers.

I am in the process of building an aluminium Backplate rig with a primary use of travel diving. I have found an aluminium backplate and single tank adapter, but I'm having trouble finding a compatible bolt to attach the two together that won't cause Galvanic corrosion. Any ideas?

I am planning to buy:

Halcyon harness kit
OMS Aluminium backplate
Xdeep ultralight Single tank adapter

Open to the idea of buying different items to avoid this problem

 

[Bob DBF]

Have you thought of getting a small zinc, sacrificial anode, to attach to the plate?


Bob

 

[drk5036]

How about plastic?

 

[-Moe]

Have you thought of getting a small zinc, sacrificial anode, to attach to the plate?


Bob

Has anyone actually done this? Totally makes sense if it can be done in a practical manner.

 

[decompression]

I don’t think you’ll be in the water long enough to cause noticeable galvanic corrosion, use stainless steel bolts and rinse thoroughly.

 

[MaxE]

Why not remove the STA after use. The galvanic reaction of dissimilar metals between AL and stainless is a pretty slow process. If your that concerned about it remove the bolts between use. The few hours a year the bolts are touching the AL plate should be a non issue. I’m not an engineer but do install stainless bolts to Al in costal Louisiana, and while not being submerged in salt water, after 9+ years I have not seen any noticeable corrosion. Is the plate anodized?

 

[-Moe]

Check out this thread on an xDeep Facebook group.

Yasir Auleear

 

[loosenit2]

Aluminum Backplate/Galvanic corrosion

Backplate Question

Couple of other older threads on this topic. Theme for both threads is that as long as you rinse well the effects are pretty minimal.

 

[MaxE]

Check out this thread on an xDeep Facebook group.

Yasir Auleear

That is crazy. It does look like the grommet more than the bolt, but rinse and disassembled would prevent any problems. Maybe paint the grommets to prevent direct metal to metal contact?

 

[jgttrey]

+1 on "just unbolt it" between trips. My body will be corroded to uselessness before my AL backplate has any issues.

However, being OCD myself, I am fully sympathetic to making it "PERFECT!". Many camera housings have little zinc anodes. Perhaps one of those would work. West Marine also has some small ones.