Here's my former "bad head". You can see why I'm asking for help. I'll try a mix of BlackLegion's ideas.

That sounds like the way to go. If it doesn't work out I still think the model looks very nice without it. When we get a size comparison I think it should be quite possible to find something like a whfb chaos warrior head or a skull that might do the trick.
Alternatively: Have the thing printed. Send the bronze to one of the forum's more accomplished sculptors and have that person add the head in greenstuff before you have the mould made.

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Sofa General

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WHFB heads would be a "bit" to big each square on the raster you see in the picture is 1mm i guess So the Defilers head pictured there has a diamteer of 3mm.

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Head, mark 2.

Feedback, please.

I like it.

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Hmm, can you:

1) make it a round-topped head?
2) make the eye-slits a little more downturned (i.e. "evil-looking")?
3) give it horns?

This is probably the most iconic head:
http://www.games-workshop.com/gws....e=wh40k

That said, this one might be easier to sculpt (no idea about your matter-printer gizmo):
http://store.miniwargaming.com/images/P ... sp-552.gif

I've no idea whether any of this is feasable with the tech. I agree that it may be easier to simply sculpt the head if it needs casting anyway. I'm sure there are vastly better sculptors on here than I, but I can always have a go at mocking up a head from greenstuff if you give me the dimensions.

1) Yes
2) Yes
3) No, mold undercut issues.

We're not done with tinkering yet, but the prospect of having a real sculptor greenstuff a head is tempting.

The area it needs to fit is roughly a circle 3mm in diameter.

Should people consider that an open-call?  

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I'll be sculpting today (as usual!) If I get a spare half hour I'll have a go at a head.
One thing I did think was interesting was this:
David Laser Scanner

I've not had a proper look at the site yet, but if it works, it could be a great Epic-iser of 40K scale models.

I also found a c4d (?) file of a Defiler here. Don't know if that's any help.

Regards,
Reaver

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Radical (read unpopular?) idea: What about no head? (i dislike them even on 40k defilers)

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My friend the model kit manufacturer just bought a 3D scanner/trace mill.  So many possibilities spring to mind.  

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what angle are you planning to set it for casting and how many parts to the mold?

There may be a way around it, again, same trick as with the conical rivets.

The key is to avoid any sharp angles within the mould - they concentrate the stress and so degrade fastest at those points.

It all depends on where the mold lines will be though.

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The mold line will be horizontal through the cannon, with some meandering, of course.

This means the head cannot have any undercuts, and not just from a mold wear perspective. I have discovered from experience with Illuvitar's scratch defiler that the head needs an essentially cylindrical or conical shape, with very minor indentations or protuberances.

I could certainly live with that as well.  

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Sofa General

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I think that looks much better than your first attempt, but would it be possible to add contours on the sides to give the impression that it's a little less of a peg and maybe hint at the shape of the 40k defiler head without actually needing to do the shape?

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