Post by atouchofglass on Aug 23, 2008 6:53:16 GMT 10
Greetings All
Was on a similar website and found this gem by a fellow C C er
Thought it would interest everyone here that is doing up a van
To the C C member please excuse my use of your work.....
Can anyone guess who it is?? ;D
Quote
Just for future reference, the bloke at the shop is only partly correct in his information.
Corrosion is also dependent on the surface area of the two metals, as well as with how far apart they sit on the scientific Corrosion Table.
So all things being equal, having aluminium and stainless in contact means the aluminium will corrode in preference to stainless, in a corrosive environment. However, where you have a much larger surface area of ali and a small area of stainless, the corrosion rate is substantially reduced. So a stainless screw (small area) spaced along an aluminium cover strip (large area) results in very little corrosion of the ali. (unless the van is permanently parked near the sea).
I'm in the process of restoring a 1977 Millard, but there is not a hint of corrosion on the ali cover strips from any of the stainless screws, and that's after 30 years!
The other interesting discovery on the Millard is that two different colours of sealant were used around the van.
A cream colour to seal all the ali cover strips, which after 30 years was quite dry and brittle, and a blue colour to seal all the windows and other bits and pieces, and which is still very soft and pliable after the same 30 years.
I'm not sure exactly whether the cream one is/was a butyl mastic, but the blue one seems to match what I remember butyl mastic looking like back in those days.
When I get to the stage of putting the Millard back together, I'll be looking for something that lasts like the blue stuff.
Unquote
Thanks for the info
Atog
Was on a similar website and found this gem by a fellow C C er
Thought it would interest everyone here that is doing up a van
To the C C member please excuse my use of your work.....
Can anyone guess who it is?? ;D
Quote
Just for future reference, the bloke at the shop is only partly correct in his information.
Corrosion is also dependent on the surface area of the two metals, as well as with how far apart they sit on the scientific Corrosion Table.
So all things being equal, having aluminium and stainless in contact means the aluminium will corrode in preference to stainless, in a corrosive environment. However, where you have a much larger surface area of ali and a small area of stainless, the corrosion rate is substantially reduced. So a stainless screw (small area) spaced along an aluminium cover strip (large area) results in very little corrosion of the ali. (unless the van is permanently parked near the sea).
I'm in the process of restoring a 1977 Millard, but there is not a hint of corrosion on the ali cover strips from any of the stainless screws, and that's after 30 years!
The other interesting discovery on the Millard is that two different colours of sealant were used around the van.
A cream colour to seal all the ali cover strips, which after 30 years was quite dry and brittle, and a blue colour to seal all the windows and other bits and pieces, and which is still very soft and pliable after the same 30 years.
I'm not sure exactly whether the cream one is/was a butyl mastic, but the blue one seems to match what I remember butyl mastic looking like back in those days.
When I get to the stage of putting the Millard back together, I'll be looking for something that lasts like the blue stuff.
Unquote
Thanks for the info
Atog
