For the canisters, almost two years ago I made some custom ones for one mask and then never used them again. That seemed like a good start, and I could easily enough make a variation of eyepieces and fabricate something for the exhaust (to fill the hole in the snout). Using these preexisting pieces would save me a ton of work and allow me to produce a new gas mask in a fairly short amount of time.
Let me explain the history of the different canisters, eyepieces and exhaust ports that I have used in my steampunk leather and resin pieces.
The first steampunk leather piece I made (Sept 2008) was the #43 gas mask, copied from a yard sale find. For one of the eyes I molded and cast a camera lens. For the other I used the end of a flashlight. For the combination canister/exhaust I scratch built it using acrylic sheet, screws and a knob from a camera.
The next mask I made was a respirator I call the Bad Air Transmutator. It has no eyes, and I scratch built the pair of canisters. Two months later (Feb 2009) I made Pachydermos, my elephantine gas mask. It had a lot to it, and I scratch built the matching eyepiece bases and caps.
I made a leather covered vacuum hose, and leather trimmed copper ears, and when it came to the canisters I didn't want to scratch build them as well, so I used the Transmutator canisters. My first recycled piece.
Fast forward to July 2009 when I built the Defender gas mask. I scratchbuilt new canisters, and used a camera zoom for the right eye. For the left eye I used the Pachydermos eyepiece. Recycle #2.
For the indy film After the Fall I modified the Transmutator canister design by shrinking it down and covering it with a metal grid. My first two-part canister. That is the canister I'm using on my latest gas mask.
In Jan 2010 I constructed the RHINO gas mask with everything newly scratch built: Eyepiece base, eyepiece cap, canister and exhaust horn.
In June I made the steampunk plague doctor mask Dr. Beulenpest, using the Pachydermos eyepiece base and a new nonagonal eyepiece cap. For the other eye I used the camera eyepiece from #43.
That brings us to my lastest mask Ragnarök, a term which means the end of the cosmos in Norse mythology. For the new exhaust port I'm using the Pachydermos eyepiece base and the Beulenpest cap, along with a circle of drywall sanding mesh and scratch built screen to hold it in place. For the matching eyes I'm using the Pachydermos eye base and a new domed eyecage.