corrosion avoidance for this project

[Justin_NSA]

I'm fixin' to purchase a SCAD Solo holding tank monitoring system from Sailor Solutions. I'm ordering the internal probe because (dangit) my tank is 5052 AL. I need to drill for the hole. SCAD recommends their aluminum adapter plate to easily mount the probe. (see link to dwg). Before I pull the trigger, my question/concern is the right way to fasten the plate to the tank for security and to avoid corrosion. Should I use AL rivets? Won't SS bolts cause galvanic corrosion? Is there a better way to fasten the plate?
http://www.scadtech.com/sites/default/files/adaptorPlate.pdf

 

[KD3PC]

One could use nylon "hardware" in this case.

 

[Ralph Johnstone]

Should I use AL rivets?

I suppose if you were an absolute purist, you'd use aluminum rivets to keep the metals as similar as possible. If you're a realist, SS fasteners are also acceptable. The theory here is that the anode (part that corrodes - the tank wall) has a relatively large surface area and the corrosion will be spread out while the anode (part that is protected - SS fastener) is relatively small. Any galvanic corrosion on the aluminum will be very small over a large area.

Out of curiosity, if you go with SS fasteners, are you looking at using sheet metal screws or nuts and bolts ?

 

[Justin_NSA]

Thanks guys. I found another site that specializes in inspection covers for all sorts of tanks. It looks like they agree, SS will be fine. Nylon might get old and brittle. I will see if the 1" NPT hole for the probe is big enough to work locknuts behind it. Without a special (homemade) wrench, I don't see how I could tighten them. I may have to use screws. That's why I thought perhaps rivets.

 

[Ralph Johnstone]

Now that you're satisfied with the fasteners, an even more important consideration is the sealing compound to be used. In critical applications such as this , I've used Permatex #2 which sticks to everything including the boat two slips over from you. Messy as hell but far better than the alternative.

 

[jssailem]

Permatex #2 which sticks to everything

Used it when I reinstalled my waterpump... It took a week of showers to get it out of my hair.... Don't ask...

 

[Justin_NSA]

Thanks guys. Yep, that was the next concern.

 

[Ralph Johnstone]

It took a week of showers to get it out of my hair

Good Lord, I would think you'd have to tear out your hair to remove the Permatex.

Something you don't want to go overboard with.

 

[Justin_NSA]

Good Lord, I would think you'd have to tear out your hair to remove the Permatex.

Something you don't want to go overboard with.

"Overboard"? Is that a description you want to use here? You know how we digress
Thanks for the tips guys. Can I get the sealer at an auto parts store? I ordered a new crimper from MainSail's site. The good one I have doesn't do heat shrink connectors well at all. I searched and MS had the best price on one made for these. I trust his judgment.

 

[Ralph Johnstone]

Can I get the sealer at an auto parts store?

That or any big box hardware store. Be sure it's #2 as this stays flexible once it dries.

 

[Gunni]

Used it when I reinstalled my waterpump... It took a week of showers to get it out of my hair.... Don't ask...

Isopropyl Alcohol is the solvent...Very Strong Rum alternatively.