Antenna Dishes

[Scotaidh]

Most excellent! I shall be ordering some Alves Apoxy forthwith, or maybe sooner (Thirdwith? Fifthewith ?)

<snip>

Psssst! TH? There's no "l" in "Aves" ... just so John and Linda know what to ship to you.

[kerick]

I tried this last night, worked pretty good.
Get a real drafting compass, not the kids craft kind. Replace the pencil lead with a frisket cutting blade. This will appear to be at right angle to the line you will be cutting. Drill a small hole in whatever plastic dome or sphere you wish to use. (Hobby Lobby has different sizes for people who make their own Christmas ornaments.) Place the point of the compass in the small hole you drilled and rotate the compass, scratching a line as you go. One or two times around will give you a nice scribed line or keep going until you cut all the way through. You're not cutting as you would normally with a knife but scratching you're way through. I've used this to cut circles in sheet plastic and scribe lines on cone shapes. Plus the small hole is now you're exact center. Place a piece of masking tape on the back of the dish with a doubled up portion centered over the center hole to give yourself a handle when sanding the edge. I could take pics if that would help explain.
Update- Here's a pic of what I meant. It's more like scribing your way through the plastic, not cutting.
http://i624.photobucket.com/albums/tt32 ... 0_0853.jpg
In my case the center hole gets covered up anyway.

[ajmadison]

I tried this last night, worked pretty good.
Get a real drafting compass, not the kids craft kind. Replace the pencil lead with a frisket cutting blade. This will appear to be at right angle to the line you will be cutting. Drill a small hole in whatever plastic dome or sphere you wish to use. (Hobby Lobby has different sizes for people who make their own Christmas ornaments.) Place the point of the compass in the small hole you drilled and rotate the compass, scratching a line as you go. One or two times around will give you a nice scribed line or keep going until you cut all the way through. You're not cutting as you would normally with a knife but scratching you're way through. I've used this to cut circles in sheet plastic and scribe lines on cone shapes. Plus the small hole is now you're exact center. Place a piece of masking tape on the back of the dish with a doubled up portion centered over the center hole to give yourself a handle when sanding the edge. I could take pics if that would help explain.

BTW, if you want to avoid the small hole in the center, use a piece of sheet scrap and tack it in place with a small drop of superglue. When you're done, slide a knife edge under the scrap and pop it off. You'll still need some clean up, but depending upon the thickness of the material you're cutting, it won't be the crater left by the compass point. Often the scrap doesn't protect perfectly, so you'll still have some small mark at the center, so you'll still have an indicator of the center.

[kerick]

Or you could just cheet and call them geodesic domes.
http://i624.photobucket.com/albums/tt32 ... 0_0856.jpg
Found in the cake decorating/wedding craft dept.