Hi.

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

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???

de Rick W1TY

Email:

Rick Mintz wrote:

I could use some help in choosing the material, such as Plexi or Lexan.

Hi Rick,

Lexan has a higher melting point than Plexi. Therefore it's easier to drill
or cut. Plexi tends to stick to the drill bit once it becomes hot. Lexan is
more robust from a mechanical point of view, while Plexi tends to break. So
if you have both available I think Lexan is the better choice.

73 Heinz, OE5EEP

Rick Mintz wrote:
Hi.

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

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???

de Rick W1TY

Email:


In my experience...Lexan is much less prone to cracking but on the other
hand it seems like the surface of Lexan scratches much easier than
Plexiglass. A wipe with a dry cloth or paper towel will leave a 'smudge
If you're gonna use a fairly thin plastic, say 1/8th, I think you'd be
ok with plexi and thats what I would use personally because of that
reason primarily. Some of the cheapo hole cutters can be rather crude
to work with but if you take it slow you should be ok.

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.

Lexan, being polycarbonate, is much tougher than Plexiglass, which is
acrylic. Ploycarbonate is used in everything from RC car bodies to
soft drink bottles to bullet-resistant windows in aircraft.

Ted

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

Posting from Google? See http://cfaj.freeshell.org/google/

"Rick Mintz" wrote in message
...
Hi.

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

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???

de Rick W1TY

Email:


Why not just use acetate sheet to cover the panel. Like what is used with
overhead projectors. If it is just to protect the graphics and not for
mechanical strength that is. Jtt.

On 2006-04-07, James Thompson wrote:
Why not just use acetate sheet to cover the panel. Like what is used with
overhead projectors. If it is just to protect the graphics and not for
mechanical strength that is. Jtt.


or just put a good coat of clear lacquer over the front panel graphics

When I have needed to cut holes in plexi in the past, I always created a
plywood / plexiglass sandwich. Just place the plexiglas betewwn two thin
sheets of plywood and drill thru the whole thing with a hole saw.

On the other hand, you could just mount the plexiglass on top of the meters,
this would protect the meter faces from scratches also. This way, you only
need to drill holes for switches and knob shafts.

"Rick Mintz" wrote in message
...
Hi.

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

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???

de Rick W1TY

I seem to recall someone mentioning in the past that glass can be drilled if
it was kept in a bath of kerosene, and drilled while submerged.
thanks, John.
KC5DWD

john graesser wrote:

I seem to recall someone mentioning in the past that glass can be drilled
if it was kept in a bath of kerosene, and drilled while submerged.
thanks, John.
KC5DWD

Keep a fire extinguisher ready, when you do this! I would not dare...

73 Heinz, OE5EEP