Welcome To Signs101.com: Largest Forum for Signmaking Professionals

Signs101.com: Largest Forum for Signmaking Professionals is the LARGEST online community & discussion forum for professional sign-makers and graphic designers.

 


  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Blade for PVC?

Discussion in 'General Signmaking Topics' started by Colin, Jul 21, 2012.

  1. Colin

    Colin Major Contributor

    4,502
    14
    38
    Sep 16, 2004
    Earth
    I need to cut a 48" circle out of a sheet of 3/4" thick PVC. Is there a particular type of Jig Saw blade which won't result in the material "welding" back together from the heat of the blade?
     
    Tags:
  2. SqueeGee

    SqueeGee Active Member

    987
    6
    18
    May 27, 2005
    .
    I haven't had great experiences with jig sawing something that thick. The blade bends which ends up giving you an inconsistent beveled edge. I'd recommend having it cut on a CNC.
     
  3. BBworks

    BBworks Member

    26
    0
    0
    Jul 18, 2011
    There are other options. We use table saws at our shop. You can cut circles on a table saw, check it out on youtube, or you can use a composite blade for cutting acryllic if you are using a jigsaw. For an elipse we go to our router guy.
     
  4. fixtureman

    fixtureman Member

    317
    13
    18
    May 16, 2012
    Medina Ohio
    A router would be a better choice
     
  5. CanuckSigns

    CanuckSigns Very Active Member

    2,886
    204
    63
    Nov 11, 2008
    Ontario
    Colin:

    for the nicest edge possible, I would use a hand held router. there are 2 ways of doing this, depending on whither you are able to drill a hole in the centre of the circle or not.

    option 1) make a circle cutting jig for your router
    http://www.diynetwork.com/how-to/how-to-cut-circles-and-curves-with-a-router/index.html

    option 2) cut a circle from .25" thick mdf (or something else inexpensive) sand it so it's nice and smooth and use a straight cut bit with a ball berring guide to follow the pattern in your mdf.

    I don't think a jig saw is the way to go on this.
     
  6. visual800

    visual800 Very Active Member

    3,578
    161
    63
    Aug 4, 2010
    montgomery, alabama
    if you absolutely have no other option, cut with jigsaw using a large tooth wood blacde and then go back at slower speed and knock debris off. It is a pain and sometimes that all we got is a jigsaw.
     
  7. bob

    bob Major Contributor

    5,170
    267
    83
    Nov 4, 2005
    earth
    You can also drive a nail with a rock. Merely because something is possible does not mean that it's reasonable.

    Cutting circles, especially large circles with anything less than CNC tackle is problematic. Using hand and even stationary tools you're essentially trying to draw a circle freehand with a power tool. Good luck.

    If you opt for a router, it will leave a nice clean edge but it can get away from you in an instant and ruin your workpiece.

    If you choose a jigsaw it will leave a less than ideal edge but its easy to control.

    It fairly easy to rig an extension table on a band saw which will give you a better and far more perpendicular edge but it's somewhat less forgiving that a jig saw in that if you should get off course it takes longer and more effort to get back on track.

    If you go for the table saw like Primitive Pete above, most likely it's because that's all you have. You need more tools.
     
  8. Colin

    Colin Major Contributor

    4,502
    14
    38
    Sep 16, 2004
    Earth
    As the PVC will have a laminated digital print on both sides (inset about 2") before cutting the circle, I think that I'm going to need to use a jig saw.

    I guess I'll go to the store(s) and see what they have for blades, buy a few and try 'em out on a scrap piece. Perhaps there's a "carbide" type of blade? This might help with keeping the heat down? shrug
     
    Last edited: Jul 22, 2012
  9. rjssigns

    rjssigns Major Contributor

    4,260
    198
    63
    Jun 4, 2007
    Home Office
    I've had good success with Bosch blades for everything from Acrylic to DiBond.
    Don't forget to sand then flame polish the edge.
     
  10. TwoNine

    TwoNine Active Member

    537
    2
    0
    Apr 17, 2011
    What helps...A little...Is if you have a jigsaw with a variable tilt on the blade - such as a high end DeWalt or similar. Set the saw so that the blade is at an angle instead of cutting straight up and down - This cuts down on the welding problem pretty significantly. Use that method with a slow blade speed and decent rate of travel and you'll have minimal sanding. But I still always recommend over-cutting them and sanding down, you have SO much more control that way IMO.
     
  11. Colin

    Colin Major Contributor

    4,502
    14
    38
    Sep 16, 2004
    Earth
    Great tip, thanks, I'll try that on a piece of scrap.
     
  12. weaselboogie

    weaselboogie Very Active Member

    3,832
    8
    38
    Apr 23, 2006
    Us
    I have great success with a bandsaw. Make a jig on the bottom side with a nail sticking up about 1/4" and 2' away from the blade. Make a center mark on your substrate on the backside. Feed the material in, underneath , line up the mark to the nail and spin. Once you get this setup you can cut a perfect circle in 10 seconds.
     
  13. Colin

    Colin Major Contributor

    4,502
    14
    38
    Sep 16, 2004
    Earth
    ^^^ That too is a good idea. Thanks. The sign is a double-sided one, and my plan was to lay down the prints first, but I suppose could do this method as you've described, and then apply the prints, which I would have to cut by hand, cover with transfer tape and then apply after the cut using application fluid.

    Hmmmm
     
  14. TwoNine

    TwoNine Active Member

    537
    2
    0
    Apr 17, 2011
    Yeah - lay the print after cutting for sure. Regardless of how you cut it. Otherwise they may even be off from one another from side to side. It's just never a good idea to lay a print/vinyl prior to cutting.
     
  15. Colin

    Colin Major Contributor

    4,502
    14
    38
    Sep 16, 2004
    Earth
    It would be easier to lay the prints down first using the Big Squeegee, I could get the positioning right no problem, but putting the laminated prints down after with transfer tape & fluid would be ok too.
     
  16. Sign-Man Signs

    Sign-Man Signs Member

    284
    0
    0
    Oct 5, 2010
    About two years ago, I had a project that required me to cut about 200, 14 inch circles out of expanded PVC, 1/2 inch thick. I made the attached jig then used a trim router to make the cuts. The router mounts on the left side as shown in the three hole position. I use a 1/4 straight flute router bit. Once set, the router won't walk on you and cuts a perfect circle. The jig is made out of a 3/8 x 8" x 30 inches long aluminum plate I got from the local junk yard for about 20 bucks. Guide marks are at 1/2 inch intervals. Mounting hole size is 1/4 inch.
     

    Attached Files:

  17. Colin

    Colin Major Contributor

    4,502
    14
    38
    Sep 16, 2004
    Earth
    For our common data bank, I just cut the 48" circle using a new 10 TPI jig saw blade. It didn't "weld" the PVC behind the cut like the used one that was originally in the saw. I also ran the saw on a medium speed.

    Thanks for all the replies.
     
  18. bob

    bob Major Contributor

    5,170
    267
    83
    Nov 4, 2005
    earth
    Could you expand on this? Perhaps with photos or illustrations? Your description above is somewhat less than revealing.

    I've been contemplating the notion of a universal jig for cutting most any oddball shaped piece into a circle, ideally without a center pivot ala centerless grinding, and would very much like to understand your setup.
     
Loading...

Share This Page

 


Loading...