I've done a fair amount of DIY projects before, some that turned out great and some that I shall never speak of, and no matter how clearly I can envision what I want to make, at some point I have to stop myself and think, "Wait, how the hell am I going to put this in that, or house it all, or waterproof it without a whole tube of silicon, etc."
So everyone has, over their prideful years of DIY'ing, developed basic techniques and found certain materials that can get them through most projects that have dead-ended.
So post 'em! But don't say duct tape. I think we can all agree it's an indispensable DIY material.
I'm toying with 3 materials fairly new to me for casting into a mold to cover a headlight I'm making (not to put on the bike, but to put on my head):
1.
Epoxy Resin (not the small double tubes, the kind that comes in a quart can from a crafts store for 10 bucks), because having a see through project would be sweet.
2.
Styrofoam and acetone - the acetone breaks the polymer bonds and turns it back into a monomer polystyrene. Until the acetone dries, it's essentially a plastic "slime" that you can mold with great ease. The longer you flex and mold the slime, the weaker the bonds are and the more brittle it will be.
3.
Fiberglass drywall tape or any fiberglass fabric - probably useful for reinforcing either of the above, especially the polystyrene since it can be brittle (think of the plastic forks that snap when bent).
See, I like building projects from the ground up, so the bike headlight from the "
Total Geekiness" thread that uses a malibu yard light as the lamp body could have been made like
this in my mind. (granted, the malibu light is perfectly sized for a bike headlight and looks professional).