# Stainless screws into aluminum



## Kiltmadoc (Nov 10, 2009)

Anyone have ideas of what to put on them to keep down corrosion?

So far I have thought of:

1. Lock tite (blue and removable version)
2. Plumber's pipe joint compound

West Marine has nothing in the stores that i have visited here in MA...kind of dumb when you see all the stainless they sell in the store. I have seen on their website "lanocote"...but i need it tomorrow, not next week.


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## remetau (Jan 27, 2009)

I use an anti-seize lubricant that you can get from an auto supply store.


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## Gene T (May 23, 2006)

Agree anti-seize is good. I would also recommend Teflon grease. You should have both on your boat anyway. I also have lanicoat but it is very temperature sensitive, melts as it warms up and turns to cement when it's cold. I like to use it below the water line.

Gene


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## T37SOLARE (Feb 1, 2008)

Tef-Gel is the only thing that works...

Ultra Tef Anti-seize Lubricant Gel


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## GaryHLucas (Mar 24, 2008)

I'd use the blue loctite, I've had great results with it on hundreds of bolts in aluminum. Loctite cures because metal ions act as a catylyst to cause it to cure. It seals the inteface between the aluminum and stainless so no water can get in. If you use a lubricant, and the fastener gets loose water will get in and start the electrolysis that does all the damage. So keeping fasteners tight is as important as keeping the water out.

I've galled a lot of stainless fasteners in my day. So far I have never galled one coated with blue loctite.


Gary H. Lucas


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## SeaFever2000 (Sep 10, 2008)

Tef Gel. Prevents electrolysis also acts as anti-sieze.


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## Omatako (Sep 14, 2003)

I'd second (third?) Tefgel.

It's the best I've ever used even though it is by far the most expensive I've ever used.


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## Kiltmadoc (Nov 10, 2009)

Small rant: I like the idea of tef gel, but I have to order it....so not available today. 

Also: why is the exact same stuff sold in Europe literally 1/2 the price of what is charged here in the USA?!?!
1oz tube from Germany (not including shipping of course) = $11
1oz tube from Jamestown and similar = $20

My cousins, who are over visiting and helping us re-build our wood floors, are stunned at the prices for all boating supplies out here in the USA. Where they work, rebuilding wood boats in Holland, many supplies (like varnish, flooring etc) are 1/2 to 1/3 of the cost compared to here. That's including the 17% VAT! I think that us sailing/boating types are getting ripped off. Of course it could be a matter of supply and demand. 

All that said, I think I will go with blue loc-tite since i can pick it up at lowes


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## Vasco (Sep 24, 2006)

Plain old lanolin. Got a small tub of it years ago from a drug store (it's used as a base for all sorts of ointments) and still have lots.


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## floatsome (Jul 5, 2008)

A small tube of Tef-Gel did all of the refit on our 27-foot boat, with a cm left over. Just ordered second tube in two years: should last five or more.


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## GaryHLucas (Mar 24, 2008)

Tefgel will stop the corrosion, but I can't see it stopping the fastener from coming out, a serious problem on boats. I think it is a great choice for things like clevis pins, sheave pins, things that normally fit loose and are held by mechanical means such as cotter pins.

Gary H. Lucas


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## Classic30 (Aug 29, 2007)

Over here we use Duralac to fix stainless screws into aluminium.

Nasty stuff, but it works a treat - and dries hard helping to hold the fastener in.


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## oceanscapt (Aug 1, 2009)

I use Tef-Gel and Lanocote on the steel hulled/aluminum upper deck yacht I captain. Both do a great job and we use it on every screw except those going into wood.


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## Classic30 (Aug 29, 2007)

oceanscapt said:


> I use Tef-Gel and Lanocote on the steel hulled/aluminum upper deck yacht I captain. Both do a great job and we use it on every screw except those going into wood.


That's funny.. I use Lanocote for *every* screw that goes into wood!


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## floatsome (Jul 5, 2008)

I got a tube of Duralac before I tracked down some Tef-Gel. It works great, but I find it fussier to use than Tef-Gel. It separates into a yellow liquid, and it stains things that it gets on. Tef-Gel is white and easier to deal with if it gets on something it shouldn't -- at least in my hands.


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## Classic30 (Aug 29, 2007)

floatsome said:


> I got a tube of Duralac before I tracked down some Tef-Gel. It works great, but I find it fussier to use than Tef-Gel. It separates into a yellow liquid, and it stains things that it gets on. Tef-Gel is white and easier to deal with if it gets on something it shouldn't -- at least in my hands.


In my experience, once you work out how to use the stuff, I think you'll find Duralac the better solution. You won't find this in any manual, but in my experience:

1. Try not to get it on your hands - it's toxic! 
2. Pre-drill the hole and run the screw in and out to tap the hole to the thread.
3. Hold the tube *upright *and dip the screw/bolt in the liquid to get the stuff *on the thread only!!*
4. Put the cap back on and wait a couple of minutes for the stuff to "flash off" (*dry* tacky).
5. Screw it in.
6. Using a rag, rub off any excess that has squeezed out around the head.

If you're putting a stainless pad or plate or something like that on aluminium, squeeze a little Duralac onto a rag (do not use directly from the tube) and wipe it thickly around the contact surface, trying not to get it anywhere else - wipe up any runs immediately. Proceed from Step 3 above.

Try it. It works fine. I learnt this the hard way..


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## donradclife (May 19, 2007)

+1 on Tef Gel--carried at all decent chandleries. I just bought another tube at the little place on Bannister wharf in Newport.


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## brak (Jan 5, 2007)

no one said anything about sealants (polyurethane like 4200 or sikaflex 291 etc). They create a good barrier and commonly applied when stainless screws are used with aluminum rigging etc.


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## Classic30 (Aug 29, 2007)

brak said:


> no one said anything about sealants (polyurethane like 4200 or sikaflex 291 etc). They create a good barrier and commonly applied when stainless screws are used with aluminum rigging etc.


Sealants generally (certainly the ones you listed) don't contain any anti-corrosive properties, so, even if you got the crew head coated properly the thread isn't going to have any protection - being squeezed out as the screw goes in - and the fitting will corrode from the inside out.

Might take some years, but I've seen this happen on my own Hartley mast.

That's why Duralac, Lanocote and the like were invented...


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## Leolind (Dec 29, 2012)

Over 40 years we have used lanolin, Duralac and Tefgel. Lanolin is OK but it sticks and lasts less than Tefgel, and is very affected by temperature (from runny to very hard). Tefgel is best for fasteners that you might need to remove within a year (but it cannot be painted over). Duralac is the best for stopping corrosion permanently (we have stainless screws in aluminum and no corrosion after 20 years). It dries like paint to somewhat lock the crews in place, and can be painted over. For unpainted places, the only disadvantage is the yellow colour, although one can wipe off most of it, leaving only a tiny yellow ring visible around the screw heads.

Not finding any source of Duralac in the USA, I brought in 5 tubes and am now selling 3 on Ebay.
Leo


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## Lou452 (Mar 2, 2012)

Can I ask what about an alumimum rivet? Easy to drill. Will not back out. Not sure I read what the fastener was going into. Might be a bad idea I do not know. Good Luck, Lou


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## Barquito (Dec 5, 2007)

Leolind - Glad to hear about your e-bay sale. However, the OP was a few years ago. Don't think it will help too much.


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## SolSailor (Dec 30, 2012)

Over 3700 views so far on his thread... With only 19 posts in 2010. I have faith that this topic will interest enough that Leolind's post just might find some interested buyers. Maybe not the OP, but does that really matter? I actually viewed this thread a few months back when I was mounting a rail to my mast and wondering what others were using. I had a tough time stomaching the Tef-gel price also.


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## smurphny (Feb 20, 2009)

I usually use Loktite to avoid pullout but for just corrosion/electrolysis, Penetrox is a good product. It's made for connecting dissimilar metals in electrical installations on buss bars and really anywhere two dissimilar metals come into contact. I've used it for lots of things. I just used it when installing a new motherboard in this computer as the heat transfer lube on the main computer chip.


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