SS into Aluminium & SS into SS

[skippydiesel]

Please advise what product(s) you believe give the best anti-seize protection, when screwing stainless steel (SS) into aluminium and when screwing SS into SS?? 

 

 

 

[facthunter]

SS in SS is dicey anytime it tends to gall and weld,. In other circumstances watch for  dissimilar Metals with salts etc (electrolysis).  Keep dry or seal from moisture. Nev

[danny_galaga]

On 19/02/2026 at 8:45 AM, facthunter said:

SS in SS is dicey anytime it tends to gall and weld,. In other circumstances watch for  dissimilar Metals with salts etc (electrolysis).  Keep dry or seal from moisture. Nev

When I was a first year apprentice I went out with a 3rd year apprentice to fit some cabling to an aluminium hulled boat. He used brass bolts! I probably wouldn't have known better. The owner did and made us come out and replace them all with stainless steel. I got curious and at home I made a battery from some scrap Ali and copper coins with salt water for the electrolyte. From memory each cell produced 0.5 volts, which is pretty significant. Those junctions would have corroded in no time 😲

[onetrack]

I've always had good success with nickel-based anti-seize, but I have also had good results in low-temperature positions using urethane or silicone (silastic) sealants on the threads. Use plenty of sealant so there are no gaps.

 

If in a high temperature location (over about 70°C), use the nickel anti-seize, or use high temperature RTV gasket maker. Permatex Ultimate Red can withstand 399°C intermittently, and at least 200°C constantly.

[Blueadventures]

5 hours ago, danny_galaga said:

When I was a first year apprentice I went out with a 3rd year apprentice to fit some cabling to an aluminium hulled boat. He used brass bolts! I probably wouldn't have known better. The owner did and made us come out and replace them all with stainless steel. I got curious and at home I made a battery from some scrap Ali and copper coins with salt water for the electrolyte. From memory each cell produced 0.5 volts, which is pretty significant. Those junctions would have corroded in no time 😲

Stainless not best, used to penetrate corrosion between the two metals in the marine environment with aeroguard; yep the insect spray. Not kidding either.

Edited Monday at 05:16 AM by Blueadventures

[danny_galaga]

2 hours ago, Blueadventures said:

Stainless not best, used to penetrate corrosion between the two metals in the marine environment with aeroguard; yep the insect spray. Not kidding either.

Better than brass 🙂

[Blueadventures]

2 hours ago, danny_galaga said:

Better than brass 🙂

Only mercury, wipe liberally with mercury and there will be no visible corrosion in no time:)

[danny_galaga]

21 minutes ago, Blueadventures said:

Only mercury, wipe liberally with mercury and there will be no visible corrosion in no time:)

I have no idea what this means. However, the saying "A night with Venus, a lifetime with Mercury" comes to mind 🙂 

[Blueadventures]

2 hours ago, Blueadventures said:

Only mercury, wipe liberally with mercury and there will be no visible corrosion in no time:)

Practical Implications

The destructive effects of mercury on aluminum are particularly critical in industries where aluminum is a primary material, such as aerospace and automotive sectors. The presence of mercury can lead to catastrophic failures if not properly managed. For this reason, the transportation and use of mercury in environments where aluminum is present are heavily regulated. 

In summary, mercury can have detrimental effects on aluminum

[onetrack]

Well, you learn something new every day. Thanks, Blue. I've used mercury in gold extraction, I know virtually all its attributes, but never knew it corroded aluminium.

[Blueadventures]

12 hours ago, onetrack said:

Well, you learn something new every day. Thanks, Blue. I've used mercury in gold extraction, I know virtually all its attributes, but never knew it corroded aluminium.

There was a story about aluminium hulled and cabin  vessels were a mercury filled thermometer broke and the ball of mercury corroded a hole down through the hull. 

[danny_galaga]

1 hour ago, Blueadventures said:

There was a story about aluminium hulled and cabin  vessels were a mercury filled thermometer broke and the ball of mercury corroded a hole down through the hull. 

 

 

 

[facthunter]

Spill mercury in a big aluminium Plane and you will write it OFF . It forms an amalgam with Metals some of which end up with little strength. Not very good around People either. Nev