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Plexi, Lexan or ???
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 |
Plexi, Lexan or ???
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. |
Plexi, Lexan or ???
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. |
Plexi, Lexan or ???
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 |
Plexi, Lexan or ???
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/ |
Plexi, Lexan or ???
"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. |
Plexi, Lexan or ???
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. |
Plexi, Lexan or ???
"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 |
Plexi, Lexan or ???
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 |
Plexi, Lexan or ???
No, you don't keep it in a "bath" of kerosene. Just take an eyedropper
containing kerosene and put a few drops right where the drill contacts the glass. Replenish as needed. "Heinz Schnait" wrote in message y.telekom.at... 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 |
Plexi, Lexan or ???
On Fri, 07 Apr 2006 13:26:30 GMT, "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: 2 thoughts 1. If you decide to use the plastic water with a bit of detergent makes a good coolant/lubricant. Keep the cut flooded. 2. I made a lot of panel covers inthe past by laying out the panel in Autocad then flipping the drawing layer with the graphics on it to get a reverse image. I then made an overhead transparency of the graphics and used the transparency over the metal panel. The result was a clear plastic cover with the printing sandwiched against the metal panel. It worked quite nicely. You might want to consider it. |
Plexi, Lexan or ???
Let's talk methodology in the cutting of a decently clean hole. Get a piece
of plywood that is slightly larger than the piece of plexi or whatever you are going to work on. Get a couple of C clamps also. Now, lay the plexi on top of the plywood, and clamp the whole thing onto the workbench with the C clamps. (This is why it's better to cut the plexi to size afterwards, since you will have an extra edge to clamp to, so you dont care if you mar it with the clamps.) You can then drill the holes fairly accurately, without making a big mess. Stability of the work pieces is of paramount importance here, if you want a quality job. Another trick commonly used in the woodworking shop to reduce rough edges around the hole is to lay another piece of plywood on TOP of the plexi before drilling it. This reduces the "tear out" and melting around the edges of the hole. Drill small 1/8 inch guide holes in the exact centers of where you want the holes FIRST. This will tend to stabilize and center the hole saw when starting the hole. If you have a router and circle cutter attachment around the shop, then you can neatly sidestep the entire "hole saw and driill" debacle, since the router, with a straight bit , will cut a MUCH cleaner hole than any hole saw.. Just drill the centering holes, and put the circle cutter on there, and cut the hole, routing out about 1/8 inch of depth on each turn. No burning, no melting. (Clockwise rotation, please) The same discussion on clamping applies here, also. The difference here is that you dont have to apply any pressure to the router when cutting, like you would with a hole saw. The router actually cuts the material out of it's way as it goes. Very little, if any, dressing of the hole edges will be needed afterwards. "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: |
Plexi, Lexan or ???
john graesser enscribed:
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. Having the sheet of glass submerged while drilling dampens out the shock waves and helps to prevent shattering. However, I don't see what the special attraction would be for using Kerosene. Plain old water works just fine. Just make sure you use the correct type of drill bit and a nice slow cutting speed. Kerosene is not significantly more viscous than water, so if you want to really damp things out I'd use a heavy grade lube oil, maybe a 20-50 grade motor oil. Far less flammable, as well. 73 Alf NU8I Scottsdale AZ DM43an |
Plexi, Lexan or ???
"Alfred Green" wrote in message news:UIh_f.345$zf6.180@fed1read08... john graesser enscribed: I seem to recall someone mentioning in the past that glass can be drilled if it was kept in a bath of kerosene, and drilled while submerged. However, I don't see what the special attraction would be for using Kerosene. Plain old water works just fine. Just make sure you use the correct type of drill bit and a nice slow cutting speed. Kerosene is not significantly more viscous than water, so if you want to really damp things out I'd use a heavy grade lube oil, maybe a 20-50 grade motor oil. My experience with Lexan is that oils and/or solvents will cause it to become very brittle and crack at any machined edges, including drilled holes. - Bob W7OV |
Plexi, Lexan or ???
Bob Headrick wrote:
"Alfred Green" wrote in message news:UIh_f.345$zf6.180@fed1read08... john graesser enscribed: 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. However, I don't see what the special attraction would be for using Kerosene. Plain old water works just fine. Just make sure you use the correct type of drill bit and a nice slow cutting speed. Kerosene is not significantly more viscous than water, so if you want to really damp things out I'd use a heavy grade lube oil, maybe a 20-50 grade motor oil. My experience with Lexan is that oils and/or solvents will cause it to become very brittle and crack at any machined edges, including drilled holes. The _easy_ way to drill glass is to use a piece of copper tubing with hole-size for its OD, some powered carborundum as an abrasive, and just enough water to keep it in a slurry. Use a drill press, low RPMs, and light pressure. -- Mike Andrews, W5EGO Tired old sysadmin |
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