although I have played 40k since 2nd edition, i have never seen anything about what the tau use to make the hulls for their vehicles and crafts. my Deathwatch party has decided it is their purpose in life to destroy utterly the Tau. The issue commonly comes up it the Tau use magnetic metals or a composite on their craft (my group also has an obsession with jump packs and using them to mount and breach any vehicle they come across. I know this is a lot of fluff type stuff but it has game ramifications for them. personally i think they use a composite but i didnt know if anyone else out there knew. thanks and happy playing

I think Tau armour is some sort of composite plastic. I think its on the latest tau codex, but I also could have totally made that up. :/

I think Imperial Armour 4 describes the armour type as nano-crystalline alloy, composition unknown.

So it sounds like a metal alloy of some description.

The magnetic properties would have to be up to you then. Use whatever is better for your campaign.

The Tau use a crystal material that is supposedly similar to Graphite, and so therefore would have NO magnetic qualities what so ever.

I hope this helps.

I am not sure where you got graphite reference. I could not find it. What is your reference.

On that note I better correct my earlier reference. The material is described in Imperial Armour 3 not 4.

"The devilfish is constructed of dense nano crystralline metals. These advanced metallic compounds are lightweight, malleable, strong and corrosive resistant. How the Earth caste manufacture these alloys is unknown, but for their weight and depth they have remarkable protective properties, and help reduce the vehicles weight, assisting its speed and flight characteristic."

Another unobtainium metal I guess.

As not all metals have strong magnetic properties, like aluminium, I would think its magnetic properties depends on you and your group

I'm not taking it from any source material from within the 40k universe, but I am a chemist Graphite being a form of Carbon, is formed of nano crystal structures in a tight covalent latice.

Oh, I see. The nano crystal cyclinders that can be formed (nano tubes) might be used potentially to store large amounts of electricty (future batteries). But I am not sure about its use in armour.

Graphite does not have a great hardness to it. It is scratchable with fingernails, not a great trait for armour.

However graphite is used in steel manufacturing to make carbon steel.

As the armour is described as a metal alloy, Graphite could one of the additives. Sort of like a carbon steel and other metals in an alloy.

Graphite may not be magnetic, but other ingredients in the alloy could be. Especially if one of the ingredients is Ferrous.

So I still maintain that the Tau armour could possibly be magnetic, and you should use whatever fits your story.

I also apologise if I appear to be blunt or rude. I like to debate about things