Rick Mintz wrote:
I am building an amp and will be using a clear plastic over the front panel
graphics.

Wow, getting fancy! All my homebrew amps have front panels that are so
primitive, stone age carving in tablets would've been one step up from
them :-).

I could use some help in choosing the material, such as Plexi or Lexan.
Since I will be drilling couple of 2" holes to mount panel meters, I need
some suggestions for which material is the best to work with. A hole saw in
Plexi is prone to crack and maybe there is a better choice. There also may
be a better method for creating the holes than a standard hole saw.
Suggestions???

A coping or hacksaw can be used instead of a hole saw. Motor-driven
saws like bandsaws or jigsaws, I'm not going to say it's impossible to
get good results with them, but I have never had good luck. It's only a
couple of holes and soft material so a handsaw will work fine.

Plastic shops and fabricators have special-rake drills and hole saws
that make putting holes in plastic sheet much much easier than
attempting to use regular metal or wood tools. If you have a lot of
little holes, you definitely want to buy the plastic-cutting drill bits
for those sizes. If you only have a couple of 2" holes you'll probably
have a hard time justifying buying a special plastic-cutting hole saw
for that size.

Regular metal and wood tools can also be reground to be less likely to
crack plastic sheet. The plastic distributors have little pamphlets
that explain the how-to. I have not found this information on a website
yet.

For any cut where you can see the edge, you then go back and
sand/buff/polish to make it look nice and clear and shiny again.

Tim.

Tim Shoppa wrote:
Rick Mintz wrote:

I am building an amp and will be using a clear plastic over the front panel
graphics.


Wow, getting fancy! All my homebrew amps have front panels that are so
primitive, stone age carving in tablets would've been one step up from
them :-).


I could use some help in choosing the material, such as Plexi or Lexan.
Since I will be drilling couple of 2" holes to mount panel meters, I need
some suggestions for which material is the best to work with. A hole saw in
Plexi is prone to crack and maybe there is a better choice. There also may
be a better method for creating the holes than a standard hole saw.
Suggestions???


A coping or hacksaw can be used instead of a hole saw. Motor-driven
saws like bandsaws or jigsaws, I'm not going to say it's impossible to
get good results with them, but I have never had good luck. It's only a
couple of holes and soft material so a handsaw will work fine.

Plastic shops and fabricators have special-rake drills and hole saws
that make putting holes in plastic sheet much much easier than
attempting to use regular metal or wood tools. If you have a lot of
little holes, you definitely want to buy the plastic-cutting drill bits
for those sizes. If you only have a couple of 2" holes you'll probably
have a hard time justifying buying a special plastic-cutting hole saw
for that size.

Regular metal and wood tools can also be reground to be less likely to
crack plastic sheet. The plastic distributors have little pamphlets
that explain the how-to. I have not found this information on a website
yet.

For any cut where you can see the edge, you then go back and
sand/buff/polish to make it look nice and clear and shiny again.

Tim.

First you should follow all recommendations from your supplier. In
addition, you should use plenty of lubricant, or better lubricating
coolant. I'd flood the thing, and use really slow tool rates (i.e. use
your drill press with the slowest gearing).

rec.crafts.metalworking has some folk who will give you good answers, if
you don't mind sorting through all the political chaff.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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