Re: Sawing Plastics (was Re: Primary support -update)

I bought a 96"x48" sheet of .177" acrylic at HQ here in Ohio and the guy
cut it with what was basically a circular/radial arm saw hybrid thing. 
It had a sliding arm with what looked like a 10" circular saw on it.  It
was obviously designed for ripping large sheets of stock.  It cut with
no visible melting and a tiny bit of chipping.  Next time I'm there I'll
try to find out more info.

I tried the acrylic on my 10" table saw with a fairly coarse wood blade
and it was no fun.

Tesla List wrote:
> Original Poster: wwl-at-netcomuk.co.uk (Mike Harrison)
> On Sun, 25 Jul 1999 08:28:17 -0600, you wrote:
> >Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>
> >
> >Hi Terry, Brian, all,
> >5.) Cutting acrylic (Plexiglass) this way is NOT a good
> >idea. Usually, it will shatter. For Plexi you need a fine
> >toothed blade running at relatively high speed and a
> >slow, but smooth forward cutting movement. Drilling is
> >very similar (high speed, low pressure).
> Acrylic is a pain to power-saw as it softens at a fairly low
> temperature. I've always had the most luck using really vicious
> coarse, wood-cutting blades rather than fine ones, cutting fast to
> avoid hotspots forming.  It's a bit scary (goggles essential!) but
> works pretty well. All the sign shops I've been to when scavenging
> offcuts use a normal table type circular saw. I asked what blade they
> use & they said it's the type designed for cutting aluminium - I don't
> know about TPI/tip angles etc. It certainly gives a very clean, smooth
> cut with minimal corner chipping.
> At home, I usually use a 6" hand-held circular saw with a nice sharp
> TCT blade (about 10mm pitch) for cutting 6mm sheet. It gives a bit of
> a rough edge, with some chipping, but is fine for opaque sheet where
> the chipping doesn't show up too badly. Obviously as the tooth pitch
> is greater than the sheet thickness you have to be careful not to feed
> too quickly..
> >6.) You donīt need a carbide tipped blade. These blades
> >are usually used when you encounter hard materials (nails,
> >particle board [the glue is a saw killer], G-10 and so on).
> >For equal tooth number, the carbide blade will make a
> >rougher cut (esp. if you plan on reducing the cutting
> >rpms).
> But you do need a very SHARP blade to reduce heating - TCT stays sharp
> for ages, If it's not TCT, it might be adviseable to keep a special
> blade just for use on plastic.