I got my idea from Games Workshop's Space Hulk terrain article. But when I looked around I did not have any crochet sheets around unless I went out and bought them. I did however find window and door screening and I went with that. I went with plastic screening but i would imagine the metal would work also if not be a little more stubborn to work with.
using a very light spread of PVA glue I glued the bases to the sheet and then after letting it dry I cut and clipped the screen around the bases until it was essentially flush with the side of the base. I then glued down plasticard and some little tube things I had right on top of the screen.
For painting I have the entire thing a base coat of black. I then drybrushed the screen and anything else I wanted with bolt gun metal. For the yellow I used Iyanden Dark Sun foundation because I liked the dull yellow color but that is up to the person. I then dry brushed bestial brown to age parts of the screen and other metal parts I wanted aged. I then used the new citadel washes to complete the base.
I washed Devlan mud over the aged rusted areas sloppily so it went over onto non aged areas. After that dried i washed the entire base with badab black including the yellow parts to give it a grimed aged derelict look.
Hope that helps. If you google Space Hulk Terrain or Space Hulk Bases you will come across other how to's.
Coming soon will be how I make my Crusade era Thousand Sons heads.