How can I solidify without ruining spiked edges? I'm trying to poly model a helmet and I have some extruded spiked edges but when I try the Solidify modifier, my spikes get horribly messed up. Is there any way I can exclude them from being solidified? I've tried to hide them with H but since the modifier applies outside of edit it didnt do anything.
Here is the helmet without being Solidified:


Here it is when Solidified:


I tried checking only rim but that doesnt accomplish what I'm after, which is making the helmet somewhat solid to be printable. I'm not yet familiar with all the tools available so I dont know where to go from here. If I can have a solid interior without the spike distortion it would be perfect.
I would Solidify the outer side, and adjust the spike manually.  


Use the Solidify Modifier.
Set Offset to 1 and adjust Thickness to your liking.  





You can adjust Inner/Outer Crease, if you're also using the Subdivision modifier.
The Subdivision modifier should be AFTER the Solidify Modifier.




Hit the Apply button to apply the Solidify Modifier.


Go to Edit mode
Select the new vertices and scale it down to make it pointy using the Scale Tool.
Shortcut: S