Why not order this:
http://www.amazon.com/dp/B00F3FJYSQ
get some tin snips and a file (for thinning the edge). That's all it takes.
Methodology
- Use a stock grill to make a cut-out from some stiff cardboard
- Use that cut-out and a Sharpie or other marker to trace the circle on the mesh
- Snip it so it's just slightly too large (basically, follow the traced circle, but don't go too much inside the marker tracing)
- Trim that with the snips and file until it fits
- If you can't get the holding ring back in place easily, thin the edge (without reducing the size of the circle; so file straight out from the center)
- If you want to attach a dust shield, organza is a nice fabric; could try spray adhesive (use a smaller circle cut-out such that the spray only gets on the outer part of the grill, rather than sticking the fabric to the entire grill surface), or maybe a glue stick. I tried and can't recommend Super or Krazy glue or kids' glue like Modge Podge or whatever. They will work, but can be messy.
Hope that helps.
Oh yeah, and
@Nimzerz, get a pair of Q701 pads