aluminium frame

[droid_ca]

I was thinking of doing my frame out of aluminium cause the amount of snow we get and thought that would be good for rust prevention and to help keep the weight down

so I need your opinions to using aluminium over steal

[Shadow Catcher]

Aluminum was my choice for the weight and corrosion reasons. Aluminum is used in many horse trailers (horse urine is VERY hard on steel). I will have to replace the steel screws and bolts used on mine with stainless steel (less galvanic action).

I say go for it.

[eamarquardt]

Aluminum was my choice for the weight and corrosion reasons. Aluminum is used in many horse trailers (horse urine is VERY hard on steel). I will have to replace the steel screws and bolts used on mine with stainless steel (less galvanic action).

I say go for it.

See: http://en.wikipedia.org/wiki/Galvanic_series

Seems to me that using SS fasteners is a step in the wrong direction. SS will drive the Al to corrode more. I think a better bet would be to use galvanized steel fasteners.

I'd do some more research before replacing the current fasteners.

Cheers,

Gus

[Wimperdink]

Seems to me that using SS fasteners is a step in the wrong direction. SS will drive the Al to corrode more.
Cheers,

Gus

ut oh.... I'll do some research for you... I put stainless steel screws on the outside of my trailer to hold the aluminum windows in and the profile trim.... I ran out of SS so I finished with some zinc plated screws with the intention of buying more SS and replacing them after the fact.... If you have available time to wait I'll let ya know what happens. (i'm hoping nothing)



And to keep this thread on track, I'm going to vote for aluminum for its weight and resistance to corrosion. My wazat had an aluminum trailer under it and was a cinch to keep clean.

[Shadow Catcher]

I am looking at this and it appears that SS is better than plain steel with the possibility of galvanized being better yet.
I am also seeing using Lock Tite and or silicone as a way to help prevent galvanic action.

[kennyrayandersen]

Aluminum was my choice for the weight and corrosion reasons. Aluminum is used in many horse trailers (horse urine is VERY hard on steel). I will have to replace the steel screws and bolts used on mine with stainless steel (less galvanic action).

I say go for it.

actually urine and aluminum don't mix so well either
it's a real problem in commercial aircraft.

[Shadow Catcher]

Mega Mini #1 is for sale on ebay and the frame failed evidently. That finite modulus of elasticity bit them in a fortunate place. It was reinforced and I am in contact with the current owner. Ours is built differently but I will have it reinforced and some of the welds TIG welded with a certified welder. They were MIG welded and a bit sloppy and as an AWS weld inspector I would not have accepted them.

[Thomcat316]

As a fastener geek, I'll say:

<geek>
If your stainless bolts are ever going to have salt/salt water/"ice melt"/etc. around or near them, make sure they are well isolated from your aluminum trailer members. Use Delrin or Nylon washers and bushings to isolate the two metals. Good bushings to use look like "top hats" without tops - they are a thin tube of plastic with an integral washer. Make sure to use a stainless washer between the bolt/nut and the bushing to help even the load out, or the bushing may deform badly.

For attaching aluminum skins with stainless screws use "neo-bonded sealing washers", which bond a layer of neoprene or EPDM to the underside of a conical stainless washer, both sealing the penetration and isolating the metals.
</geek>

<blatant plug>
For any of the above items call us at 800-432-3700 - we sell stainless, brass, bronze, nylon, and Monel fasteners and related goods.... Ask sales to see Whitney about the pricing.
</blatant plug>

....or just visit your local "real" hardware store - what they don't have, they can get in a few days, and they like your business.

Thanks for putting up with my commercialism!

[droid_ca]

ok now I'm really confused what would be the better hardeware for using on aluminium

[Thomcat316]

Best to worst to use with aluminum (corrosion-wise):
aluminum screws - no dissimilar metals issue, but needs good engineering for strength
galvanized steel screws - zinc galvanizing is very similar to aluminum and is a thicker layer of zinc than....
zinc-plated steel screws - which are still better than....
stainless steel - which needs to be isolated from the aluminum, or it will chemically eat fluffy white holes into the aluminum.

Don't ever use brass, bronze, or copper - copper ions in drips from exposed wiring have eaten holes in aluminum boats. Bad combination.

The Galvanic Series of Metals in Seawater chart will give you some idea of what metals work OK together in a saline environment, such as northern Utah desert or Massachusetts winter roads...

To answer the question more definitively:
I'd use well-isolated type-316 stainless here in south Florida (where everything corrodes) and use zinc plated steel most other places. I'd tend to want to paint over the zinc plated steel to prevent weathering and accelerated corrosion, but that's me - the guy who made his whole trailer plastic to avoid rot & rust....

[angib]

Boatbuilders fix aluminium parts together with stainless steel fasteners, but sealed with Duralac zinc chromate jointing compound - this works in boats in salt water so that's harsher than any trailer will get.



Getting this product in the US appears to be a big problem. Apparently www.metair.com sell it but probably not to retail customers.

Why not ask a snowmobile trailer company what they use?

[droid_ca]

thanks for the link to that stuff it looks like it will most definitely work for my project

[Shadow Catcher]

A US source for anti corrosion http://www.aircraftspruce.com/catalog/c ... primer.php

[droid_ca]

thanks shadow catcher

[angib]

A US source for anti corrosion http://www.aircraftspruce.com/catalog/c ... primer.php

I would, ever so politely, disagree. Those are primers intended to protect an exposed surface, whereas jointing compound is meant to go in between two surfaces to isolate them.