By Jerry Crawford, 98 D-I on Saturday, April 21, 2001 - 02:09 pm: Edit

I came across a LR rear door ladder recently for a good price. Unfortunately, the guy had lost the rivnuts that attach the ladder to the top of the door. When the door arrived and I saw how it was configured I immediatly solved the problem in my head with a couple of steel pop-rivets through those tabs into the door. Rivnuts were invented by the same fokes who brought you pop rivets. Steel Pop rivets are plenty strong - they use them to assemble air planes - and the stress of using the door is down more than sideways. Rather than spend more $$ for the rivnut attachment kit and have another tool I can never use again - well - any engineering types out there who can tell me why this is not a good idea?

By Rob Davison (Pokerob) on Sunday, April 22, 2001 - 03:43 pm: Edit

potential for electrolytic attack from the contact of two unlike metals...

By Mike on Sunday, April 22, 2001 - 04:54 pm: Edit

Jerry:

John at RoverTym can probably get you the exact size of Rivnuts and type that you need (cadium plated as to not interact with the aluminum). If not, let me know the size and I will talk to some of the folks in town.

I have mounted several Rivnuts and did not need a special tool to mount them. John at RoverTym is an expert at this. I mounted my RoverTym Rock Sliders and SafariGard bumper (both of which require Rivnuts) with out the special tools.

Thanks,
Mike

By Jerry Crawford, 98 D-I on Tuesday, April 24, 2001 - 05:58 am: Edit

I just tried the old magnetic solution to the confusion I had going about the material of the doors. They are steel, as is the roof. So my steel rivets won't make carosion.

By gil on Wednesday, April 25, 2001 - 04:58 pm: Edit

what in the hell is electrolytic attack ?

By Jerry Crawford, 98 D-I on Wednesday, April 25, 2001 - 07:33 pm: Edit

actually, I think the term is more correctly "exfolioation", but whatever the correct english, it is the accelerated carosive effect of putting dissimilar metals (aluminum & steel) in contact with one another and adding an acid, like water. Rather than turning what we know as "rusty" the aluminium falls apart chemically & turns to a powderish white/grey substance that errodes the metal. It eventually will disolve the aluminum completly away like rust makes steel go away. The important thing, to me, is this happens whenever you mate aluminum & steel which is why the above chap didn't think using steel rivets in an aluminum door frame was cool. His concern being the steel rivets would eat the door away and leave me with a big hole. A chemist or metalurgist could give you a better answer but that's my slant

By Jerry Crawford, 98 D-I on Wednesday, April 25, 2001 - 07:47 pm: Edit

I just did a web search and the same condition exists whe putting about any metal against aluminum. It's called galvanic action and it occurs at the molecular level. Interestingly, when you annodize aluminum it puts an electrical barrier on the metal that prevents the action from taking place. Isn't the web wonderful? You can learn all sorts of stuff there.

By Jerry Crawford, 98 D-I on Wednesday, April 25, 2001 - 07:51 pm: Edit

...and finally, it can also happen in your mouth if the dentist uses dissimilar metals filling your teeth - lots to watch out for in the new millenium...

By ken on Wednesday, April 25, 2001 - 08:23 pm: Edit

wow man, you are a wealth of information. I can honestly say "I learned something today." I have not had a science lesson in years, but that was great!

By Rob Davison (Pokerob) on Thursday, April 26, 2001 - 01:20 am: Edit

yeah, chew on some aluminum foil and if you have metal fillings in your teeth it will taste like a 9-volt battery... same thing as with the door.

but you say the door is steel.... so, who knows

rd

By Jerry Crawford, 98 D-I on Thursday, April 26, 2001 - 07:06 pm: Edit

I can't think of any other reason the magnets would stick, and I tested them all over the back door. I haven't actually hung my ladder yet so all of this is academic, but I still don't see any reason why it wouldn't work.

By Boris Kaushansky on Friday, May 04, 2001 - 11:36 am: Edit

Solution to mounting with dissimilar metals:

Since I have experience with ocean going sailboats and its common to mount steel hardware onto aluminum masts, us sailors have come up with a solution.

Coat the rivet heavily with silicon RTV. The RTV prevents moisture from entering the joint and the corrosion is limited. It has held up without any signs of corrosion on sailboats for 20+ years in salty environments so I'm sure it will work on the Disco.

Regards,
Boris

By Axel Haakonsen (Axel) on Friday, May 04, 2001 - 12:12 pm: Edit

"yeah, chew on some aluminum foil and if you have metal fillings in your teeth it will taste like a 9-volt battery... same thing as with the door."

You actually tasted a 9-volt battery, Rob? You scare me......

By Rob Davison (Pokerob) on Friday, May 04, 2001 - 01:05 pm: Edit

axel.... man, i hope i'm not the only one that does this (dad taught me). you lick the top of the battery and the more juice the battery has the stronger the sensation/taste/shock...

you need to lay off the norwiegian wood for a while and give this a try.


rd

By Axel Haakonsen (Axel) on Friday, May 04, 2001 - 05:23 pm: Edit

Which one tastes better, Energizer or Duracell?