sunroof

[Andrew T]

Hally,
if you search the various sections of the site for sunroofs you will find a fair bit on this subject.
There is two camps, those who don't like em and if your car has one its worthless, ( I must have paid over the odds then LOL) and those that don't mind if their car has one.
The question usually stirs up a hornets nest, strangley not this time.

Mine has a sunroof, does not leak.......car goes out in the rain, not an issue to me.
Its now showing signs of electrolysis/corrosion on the frame so is going in to be removed and refurbed and put back in a week or so. Its been in that long they are not available for direct replacement.
Its part of my cars history, so its staying.

As Vinny say's better to have a good one with a sunroof than a crap one without.

Andrew T

[lee bishop]

electrolosis, isnt that the art of hair removal??? using electricity?? LOL

yes mine too has a sunny, but i took my own out, repainted it myself as im not lazy, and got the seal to sit better so it too dont leak. was fitted to my car in 1981, but eventually will be replaced by a skin/webasto

[Banishit]

I have gone from a smallish glass sunroof see above LOL to a huge webasto one LOL

probably devalues the car by at least 3 grand

[Andrew T]

electrolosis, isnt that the art of hair removal??? using electricity?? LOL

yes mine too has a sunny, but i took my own out, repainted it myself as im not lazy, and got the seal to sit better so it too dont leak. was fitted to my car in 1981, but eventually will be replaced by a skin/webasto

Lazy………ooh harsh! More of a case of wanted a good job done!

Electrolysis – Also the decomposition of a chemical compound (i.e Aluminium) by an electric current. Aluminium frame in a steel panel, just asking for it!

Andrew T

[lee bishop]

i think that is just called 'dissimilar metal corrosion' no current reqd....
if you have two different metals and heat them, you end up with a small voltage, this is called a thermocouple......
the best metals to produce the highest voltage is alumel and chromel ( bet nobody has heard of those )

[graham John]

Background

The nickel-chromium system shows that chromium is quite soluble in nickel. This is a maximum at 47% at the eutectic temperature and drops off to about 30% at room temperature. A range of commercial alloys is based on this solid solution. Such alloys have excellent resistance to high temperature oxidation and corrosion and good wear resistance.
Oxidation Resistance

The introduction of small amounts (<7%) of chromium to nickel increase the sensitivity of the alloy to oxidation. This is because the diffusion rate of oxygen in the scale is increased. This trend reverses after addition levels increase above 7% chromium and increases up to an addition level of approximately 30%. Above this level, there is little change.
Oxidation resistance can be attributed to the formation of a highly adherent protective scale. The adherence and coherence of the scale can be improved by the addition of small amounts of other reactive elements such as zirconium, silicon, cerium, calcium or similar. The scale thus formed is a mixture of nickel and chrome oxides (NiO and Cr2O3). These combine to form nickel chromite (NiCr2O4), which has a spinel-type structure.
Heating Elements

A marked increase in electrical resistivity is observed with increasing chromium additions. An addition level of 20% chromium is considered the optimum for electrical resistance wires suitable for heating elements. This composition combines good electrical properties with good strength and ductility, making it suitable for wire drawing. Commercial grades include Nichrome and Brightray. Small modifications of to this composition may be made to optimise it for particular applications.
cheeRS

[Banishit]

good to have a science lesson on the BB

[graham John]

culture page should be added to options list, eh Dave?

cheeRS

[Frosticles]

i think that is just called 'dissimilar metal corrosion' no current reqd....
if you have two different metals and heat them, you end up with a small voltage, this is called a thermocouple......
the best metals to produce the highest voltage is alumel and chromel ( bet nobody has heard of those )

[Andrew T]

Background

The nickel-chromium system shows that chromium is quite soluble in nickel. This is a maximum at 47% at the eutectic temperature and drops off to about 30% at room temperature. A range of commercial alloys is based on this solid solution. Such alloys have excellent resistance to high temperature oxidation and corrosion and good wear resistance.
Oxidation Resistance

The introduction of small amounts (<7%) of chromium to nickel increase the sensitivity of the alloy to oxidation. This is because the diffusion rate of oxygen in the scale is increased. This trend reverses after addition levels increase above 7% chromium and increases up to an addition level of approximately 30%. Above this level, there is little change.
Oxidation resistance can be attributed to the formation of a highly adherent protective scale. The adherence and coherence of the scale can be improved by the addition of small amounts of other reactive elements such as zirconium, silicon, cerium, calcium or similar. The scale thus formed is a mixture of nickel and chrome oxides (NiO and Cr2O3). These combine to form nickel chromite (NiCr2O4), which has a spinel-type structure.
Heating Elements

A marked increase in electrical resistivity is observed with increasing chromium additions. An addition level of 20% chromium is considered the optimum for electrical resistance wires suitable for heating elements. This composition combines good electrical properties with good strength and ductility, making it suitable for wire drawing. Commercial grades include Nichrome and Brightray. Small modifications of to this composition may be made to optimise it for particular applications.

cheeRS

Google rules??

Andrew