Plexiglas Chip Shield

ddickey

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I'd like to make a couple chip shields with a magnetic bottom.
Is there a certain type of Plexiglas I want? One that cuts and drills without cracking?
 

mksj

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Plexiglass is polycarbonate plastic also known as Lexan, not aware there are different types. This type of plastic is much more resistant to impact and cracking vs. something like acrylic plastic that you would want to avoid. I use 1/8-1/4" polycarbonate plastic for shields, built boats many decades ago and we used 1/2" for hatch covers on the deck, dropped a few winch handles on them. Tough stuff. DIslike working with acrylic because it shatters easily into many pieces, the stuff should not be used for machinery shields.

 

Aaron_W

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We have Tap plastics out here which is great to work with. They have a huge selection of materials, tools and "glues". They can fabricate on site as well if you wanted something other than flat sheets.

Tap plastics

I don't know if you have something similar, but worth looking around, much better buying from a real plastics shop than trying to buy at a box store like Home Depot, Lowes etc.
 

AGCB97

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Plexiglas (acrylic) and Lexan (polycarbonate) are not the same. As above acrylic is easily shattered, polycarbonate is not. You can bend polycarbonate with a metal brake W/O heat.
Either would work for lite dust and very small chips but polycarbonate would not break if some thing larger hit it or if it fell on the floor.

Polycarbonate is a little more expensive.

Aaron
 

pdentrem

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I made a sliding chip shield.

 

benmychree

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What I know is that clear shields do not remain so for very long with exposure to chips and coolant/cutting oil. I had one in my shop, and it finally crazed and fell apart.
 

MikeInOr

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Cast acrylic (plexiglass) is generrally stronger than extruded acrylic (plexiglass). Polycarbonate is used in eye glasses and will be much more scratch resistant than acrylic. If it were me I would look into using the proper saftey glass. It should be much more scratch resistant that polycarbonate... but I don't know if it would be cost feasable? What ever you choose Plexigalss (acrylic) would be my last choice.

A sandblasting cabinets usually have a cheap replacable glass protector... this might be worth considering for a chip shield?
 

AGCB97

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Especially for drilling Plexiglass you need to grind a bit so it can't grab I.E. backwards or neutral cutting edge. Lexan not quite so grabby. Drill for good clearance with fastener.
 

MikeInOr

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Especially for drilling Plexiglass you need to grind a bit so it can't grab I.E. backwards or neutral cutting edge. Lexan not quite so grabby. Drill for good clearance with fastener.
I have drilled a lot of acrylic... I have found brad point wood drill bits work best for me. I don't think I have ever cracked acrylic with brad point bits even when drilling close to the edge unlike chisel point bits,
 

RobertB

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Polycarbonate is used in eye glasses and will be much more scratch resistant than acrylic. I
Actually polycarbonate (Lexan ,etc) scratches much easier than acrylic (Plexiglas, etc.). Eyeglasses have a scratch resistant coating applied to them.

You can buy polycarbonate with a scratch resistant coating, but it is very expensive and can be hard to find other than at a specialty plastics dealer, and you often can only get it in 4' x 8' sheets.
 

Bob Korves

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Safety glasses are made from polycarbonate. It is much tougher and less brittle than acrylic, but also much softer and more easily scratched.
 
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