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Technical TECH WEEK: Cutting curved laminated glass the cheap and easy way.

Discussion in 'Traditional Customs' started by Morgan91, Feb 22, 2014.

  1. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    Morgan91
    Member
    from Australia

    I recently chopped my 51 chevy and couldnt really find anyone near me that would cut the windshield glass, all the local glass guys said it was a big deal to cut curved glass.

    I did a little bit of research and some experimenting with a couple different ways and found it to be pretty easy and risk free to cut using a sand blaster...

    All you'll need is a small sand blaster (I used one with a 1/4" nozzle) some good quality masking tape (I like the green scotch brand tape) some paint thinner or alike and some patience.

    Im not very good at explaining things and I forgot to take pictures of the actual cuts I did on my windshield but iv got pictures of a practice cut I did on a spare chevy windscreen I had that worked out well so I will use those and try my best to explain how I did it (pretty straight forward)

    basically all I did was mask a 1/8" line (both sides) in the glass where I wanted the cut layering the tape about 3 or 4 times so that it was thick enough to hold up to the sand blaster:

    in this picture I already started blasting but you can see the tape and the paper protecting the rest of the glass.
    [​IMG]


    I then slowly blasted away at the line back and forth (trying not to heat up the glass to much) until I got down to the laminate in the center then flipped it over and did the same on the other side...

    [​IMG]

    [​IMG]

    I found that the laminate was really tough and wouldn't cut very well with the sand blaster so I poured some paint thinner down the cut line and it began to get soft pretty quick, I lit the thinners and the two pieces separated easily..

    [​IMG]

    [​IMG]

    [​IMG]

    I used some 36 grit sand paper to sand the cut line smooth and I was done!

    when I cut down my actual windshield the cut curved around but its exactly the same process, each piece of the windscreen only took me about an hour each to do.


    Sooo yeah..... any questions?
     
  2. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,308

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Thanks for posting. Glad to see it works so well.
     
  3. I have used this method before. works great. Slow and messy but but the results were worth it.
     
  4. 4rod
    Joined: Feb 4, 2008
    Posts: 806

    4rod
    Member

    what about using a glass cutting tool, score both sides then BBQ fluid over the score, light it and it will melt through?
     

  5. fordcragar
    Joined: Dec 28, 2005
    Posts: 3,179

    fordcragar
    Member
    from Yakima WA.

    In theory it might work, but the results might not be what you are expecting. If it were that easy, more glass shops wouldn't hesitate to chop your windshield.
     
  6. racer_dave
    Joined: Nov 16, 2012
    Posts: 206

    racer_dave
    Member

    4rod- that-s how we used to do it at the glass shop I worked at. I like the sandblast idea too though.
     
  7. gnichols
    Joined: Mar 6, 2008
    Posts: 11,146

    gnichols
    Member
    from Tampa, FL

    Interesting. Best grit size? Pressure? Gary
     
  8. I went to several glass shops that supposedly could cut windshields and none of them seemed the slight bit confident in their ability. At 2 or 3 hundred per windshield I dident feel confident trusting any of them. After a little research I decided that I could sandblast my own and make it on the first try. And I did. I used duct tape instead of masking tape (seemed the most resistant to the blast) with quite fine grit media and low pressure in a small cheapo blaster to slowly cut through. You can cut around corners just as easy as a straight line.
     
  9. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    Morgan91
    Member
    from Australia

    I did try that on a test piece but couldn't get it to work....
     
  10. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    Morgan91
    Member
    from Australia

    sorry I am unsure of the grit size although it was pretty coarse. and just normal shop compressor pressure, about 90 psi....
     
  11. carlisle1926
    Joined: May 19, 2010
    Posts: 536

    carlisle1926
    Member

    From experience, I can tell you make sure you use several layers of duct tape instead of that green tape. It doesn't take a whole lot to cut through that masking tape. Also, ALWAYS cover both sides of the glass completely if you are doing it for real. Otherwise, you will have little ricochet pieces of sand making little marks on the glass in areas you didn't think was possible. I usually use at least three layers of duct tape around the immediate area that I will be cutting, and then I use cardboard over the rest of the area that I want to protect. Once you get down to the plastic laminate in the middle, a simple box cutter will take care of that. No need for thinners or fuels that can wick their way into the laminate and cause damage.
     
  12. chrisp
    Joined: Jan 27, 2007
    Posts: 889

    chrisp
    Member

    What media did you use?
    I ask because people talk about sandblasting even when they use glass beads, nutshell, aluminum oxide and well sand...
     
  13. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    Morgan91
    Member
    from Australia

    just normal sandblasting garnet.
     
  14. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    Morgan91
    Member
    from Australia

    thanks for the tip dude! Il use that next time!
     
  15. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 3,054

    GearheadsQCE
    Alliance Vendor

    My understanding was that the burning of the plastic was to assure the seal of the glass edges to the center core.

    I don't know if this is true and I have never done it. Just trying to prod an explanation from someone in the know.
     
  16. flynbrian48
    Joined: Mar 10, 2008
    Posts: 7,423

    flynbrian48
    Member

    x2 on that. Even the "dust" from blasting will quickly frost the glass, and you can't polish that off. You won't even notice until the first time you drive into the setting sun. Trust me on that…
    [
    Brian

    QUOTE=carlisle1926;9557037]From experience, I can tell you make sure you use several layers of duct tape instead of that green tape. It doesn't take a whole lot to cut through that masking tape. Also, ALWAYS cover both sides of the glass completely if you are doing it for real. Otherwise, you will have little ricochet pieces of sand making little marks on the glass in areas you didn't think was possible. I usually use at least three layers of duct tape around the immediate area that I will be cutting, and then I use cardboard over the rest of the area that I want to protect. Once you get down to the plastic laminate in the middle, a simple box cutter will take care of that. No need for thinners or fuels that can wick their way into the laminate and cause damage.[/QUOTE]
     
  17. 117harv
    Joined: Nov 12, 2009
    Posts: 6,590

    117harv
    Member

    I have seen some work from a local blaster that has done both rock and wood signs and he says that he used rubber backed tape of some type, where he gets it I dont know. I would think finer grit would work best, and yes cover the whole window as suggested...thanks for he tech.
     
  18. chopolds
    Joined: Oct 22, 2001
    Posts: 6,047

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    Rubber resist tape works best, at least at the cut line...used in the "tombstone" engraving biz!
     
  19. MoparFinman
    Joined: Feb 6, 2011
    Posts: 366

    MoparFinman
    Member
    from Okla

    haven't seen it done this way !
     
  20. summersshow
    Joined: Mar 3, 2013
    Posts: 899

    summersshow
    Member
    from NC

    Cause hes showing another way to do it... Theres more than one way to skin a cat...
     
  21. chopolds
    Joined: Oct 22, 2001
    Posts: 6,047

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    Curved glass doesn't like to be cut with tools made for flat glass!
     
  22. bct
    Joined: Apr 4, 2005
    Posts: 3,107

    bct
    Member

    blasting stencil made by anchor products . also you can use chuncks of old tape measure to cut the laminate. it is thin and flexible
     
  23. bct
    Joined: Apr 4, 2005
    Posts: 3,107

    bct
    Member

  24. summersshow
    Joined: Mar 3, 2013
    Posts: 899

    summersshow
    Member
    from NC

  25. bako48
    Joined: Apr 2, 2013
    Posts: 150

    bako48
    Member

    you can use three layers of 7mil duct tape it works great and sticks good.
     
  26. seb fontana
    Joined: Sep 1, 2005
    Posts: 7,511

    seb fontana
    Member
    from ct

    After being cut and installed how does the glass hold up as far as delamation ?..I've had new glass [from two different places] that lasted only a year and it was just flat glass..
     
  27. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    Morgan91
    Member
    from Australia

    Havent had mine in for very long... so I couldn't tell you. Will let you know in a few years....
     
  28. chopolds
    Joined: Oct 22, 2001
    Posts: 6,047

    chopolds
    Member
    from howell, nj
    1. Kustom Painters

    I chopped the windshield in my 55 Olds, back in 1984, and it still looks good, no delamination, but it's stored inside, though it did spend a years out of doors.
     
  29. jazz1
    Joined: Apr 30, 2011
    Posts: 1,510

    jazz1
    Member

    Good thread,,don't usually learn something new before my first coffee. How was the fit? I have made curved windshields for boats out of lexan and 2 cuts usually turned into a dozen for a perfect fit
     
  30. Morgan91
    Joined: Sep 12, 2010
    Posts: 560

    Morgan91
    Member
    from Australia

    Fit was pretty good I made templatea out of plexiglass first and test fitted them in the rubber which helped a heap the first time I did it I did it ofd mesurments and had to do 4 or 5 cuts before it fit and then I ended up breaking it putting it in cause it was to tight...
     

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