When I try to cut PVC on my scroll saw, I get a rough and ratty edge. Plastic wants to muck up, and it's very difficult to sand smooth.
I'm thinking I may be needing to use a different sort of blade?
Any advice? What's the secret to a cleaner cut?
Much appreciate any insight. Thanks, Nettie
Posted by Steve Aycock (Member # 3612) on :
Are you cutting out shapes or just straight lines ? How thick is the PVC ?
After cutting pvc and some other plastics I'll lightly sand or abrade with a file and then run down the edge with a heat gun to take out the rough edge. Be careful to not overheat the substrate. I cut large PVC panels with a panel saw or even the skill saw with a guide. Use a sharp blade as always and use air to clean the saw when done.
Thin material I cut with an exacto or other hand type razor. The snap off kind sometimes. This takes extra care. I have found that the trick is to make multiple cuts with only minimal pressure. Pressing down too hard leads to a sore wrist and dull blades, and maybe cutting yourself.
Hope that helps a bit !
Steve
Posted by Henry Barker (Member # 174) on :
Hi Nettie,
I cut out PVC letters 3mm or 5mm thick on my scrollsaw, and get the same roughness, but find if I go round with my nail it just drops off, with a little effort, leaving a really nice clean cut.
I have a Hegner Multicut scrollsaw and I use a Nr 9 blade.
Posted by Alfred Toy (Member # 3844) on :
Thin material I would score it once and snap it like cutting glass, you may have to make relief cuts around curves and snap it off in chunks.
[ August 10, 2003, 11:52 AM: Message edited by: Alfred Toy ]
Posted by Joe Rees (Member # 211) on :
Hi Janette, I'm surprised you're just getting around to having this problem. It's heat from the blade friction causing your troubles. Going very slow helps but is not efficient. We buy sabre saw blades with specifically labeled for PVC. Something in the tooth pattern I guess, but they work SO much better. What brand of scroll saw do you have? one of those stationary jobbers, or a hand held 'sabre' saw? If you cannot get PVC rated blades for your scroll saw you are in for contimued problems I'm afraid. Slow it down and try coarser tooth profiles or even those reverse ground type that are thinner in the back than front, anything to reduce friction and keep the material moving away from the blade.
You tend to sacrifice smoothness for heat. The real problem becomes how to smooth out or fill the edges after it's cut.
Posted by Jeff Ogden (Member # 3184) on :
Like Joe said, Slow it down. Do you have a variable speed on your saw? The Bosch blade in mine is about ten teeth per inch and every other one is short. Any blade rated for plastic will work. If you can tape a piece of masking tape on the underside of the cut, it eliminates that ragged edge. That's an old trick from the cutting acrylic days...... A bandsaw gives a nice clean cut if you cutting smaller shapes.
Posted by Janette Balogh (Member # 192) on :
Thanks for the input.
I've actually been having this problem for awhile on cutting small curvy shapes and letters. On a last job, I just had too many little peices to repair, sand, and fiddle with, so I thought there just had to be a better way.
Been cutting usually 1/8" and 1/4" thick peices. I have a rigid scroll saw I'm using. No variable speed on it tho. A band saw is actually on my list of things to buy too.
I really appreciate all your advice. Thanks, Nettie
Posted by Dave Draper (Member # 102) on :
Nettie, This last month we have cut so much stuff with a jig saw, it promted me to make the "Let's talk CNC routers" posts.
We have 3 jig saws, a roto zip, radial arm saw, and one of those table top hobby saws with the round platform, (not a band saw), and a hand router.
We are cutting 6mm (1/4 ) and 13mm (1/2) PVC.
The radial arm saw cut all the strait edges just fine, the router with a home made attachment to cut circles and letter O,C,&G perfectly, and the jig saws to cut the rest. The jig saws have different blades in them and we got different results and they all sucked! Lots of clean up. The little roto zip is great on PVC but a little hard to control for perfection.
My conclusion: any thing that goes up and down is is bad on PVC and anything that goes round and round is good on PVC.
It took four of us 2 days to cut and sand a job that would have taken a router 3 hours to cut with 1 person, who could have been busy doing other things while the router was cutting.
I getting a router! PERIOD! NOW!
[ August 11, 2003, 08:58 AM: Message edited by: Dave Draper ]
Posted by Stephen Deveau (Member # 1305) on :
Nettie
Tooth size per inch is likely the problem.
The finer the tooth size the more fiction and plastic molding because of heat build up.
10 teeth to the inch or maybe less will help solve your problem. Posted by John Smith (Member # 1308) on :
Nettie,,,,,,,,,, have you tried the RotoZip ??? Even the regular hand-held router works well also. I get the 1/4" up-spiral bits from Hartlaur Bits and it does an EXCELLENT job with NO rough edges. Just lay your PVC sheet on the white cheap styrofoam and cut away !!
Posted by pierre (Member # 1462) on :
Yup. Johnathon got it. If you're still unhappy with the edge, using heavy rubber gloves, take a rag and rub the edge with MEK. It will soften and glaze the edge smooth. Don't inhale that crap!
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