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Impact modified acrylic for sign faces? And maybe formed faces?

Discussion in 'Electric Signs & Channel Letters' started by Gene@mpls, Jul 17, 2020.

  1. Gene@mpls

    Gene@mpls Very Active Member

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    I have wondered about this for a long time. I have ordered pan polycarb sign faces fpr years and polycarb comes in clear and white signgrade. I am now mostly retired and spend most of my time with a laser at my old shop. I use a lot of Gemini Duets plastics, both solid and with an overlayed color for engraving and noticed it was way more flexible than normal acrylic... it is impact modified acrylic... and you can do a lot of things with it. So I inquired about impact modified acrylic with my suppliers and most did not know what I was looking for but E&T stocks white 'sign grade' in .177 in large sheets and also sell it in rolls [not sure how wide]... the rolls made me wonder if what I have been getting was modified acrylic rather than Polycarb. It is wonderful stuff and cuts nicely on the laser so we use it rather than .125 ACM if it needs contour cutting and it works a treat. I would love to get some clear and some .22 if it is available. Can someone enlighten me about this. Old inquiring minds want to know. Thanks Gene
     
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  2. JBurton

    JBurton Signtologist

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    So I'm a fan of the Gemini Duets materials, but in my experience with Impact Modified in .177, it acts more like acrylic than it does lexan, and it definitely does not behave like the duets series. Perhaps it's more of a range of acrylics that are all considered impact modified acrylic? Polycarb is definitely more resilient than impact modified though.
    We only use it on Lowe's face replacements, and it's the worst. As you can imagine, a +6' W cut from acrylic has a strong tendency to crack right up the corner of the W, where Lexan will flop all over the place before it cracks. I forget who we do these for, but they insist on impact modified.
    I'm a firm believer in polycarbonate. One of my first experiences was when I was 14, running the CNC, I was told to go cut down the drops from a sheet of lexan. Not having much knowledge other that running the router and clearing brush from a billboard, I grabbed an axe and went to town on the sheet... pounded it right into the ground. Not my proudest moment...
     
  3. Zendavor Signs

    Zendavor Signs Member

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    I always thought engraving plastics were ABS, and that was why they were so expensive. Looks like only a couple of Rowmark's are ABS, the rest are impact modified acrylic. I agree with JBurton that "impact modified acrylic" is likely a broad category. Duets ADA plastic is a much more rigid plastic than Rowmark. We can't use Duets in Vista curved signs because they will crack, whereas Rowmark does fine.

    As for polycarb vs acrylic, I always try to steer toward acrylic (4ft x 10ft and smaller) because I hate the way polycarb yellows. It looks so crappy even after just 2-3 years sometimes. We were going to re-install some channel letters for a customer recently, and the faces were polycarb with white translucent vinyl on the face. I guess that's one way to get around the yellowing.
     
  4. Johnny Best

    Johnny Best Very Active Member

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    I've used Uvex made by Eastman Chemical that was a high impact plastic that came in large rolls of clear. This was before lexan (polycarb) became popular. Uvex was softer and flexible than acrylic and not as breakable. It was used for forming pan faces and formed faces by the use of a large oven that would draw down and vacuum form over wood cut out letters or whatever the mold was.
    Acrylic was used for all the flat sign faces and channel letters because of it being more rigid.
    That was a long time ago and have not seen any Uvex at the plastic distributors I go to.
     
  5. Johnny Best

    Johnny Best Very Active Member

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    You might be looking for Vivak petg high impact plastic. If E&T does not have it, try Piedmont Plastics.
     
  6. Gene@mpls

    Gene@mpls Very Active Member

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    Thank you Johnny, you are the Best. Got my Google going and find that Uvex is Cellulose Acetate Butyrate, and seems mostly used in goggles. The PETG looks more promising but sez it is not UV stable. We actually laser a fair bit of petg [and I use it for my filament 3D printer exclusively, and as a point of interest is used on US submarines for printing]. I will pursue that further. Thanks from another old phart.
     
  7. CanuckSigns

    CanuckSigns Very Active Member

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    Grimco in Canada has 3 options for roll stock for backlit cabinets, acrylic, polycarb and impact modified acrylic. We try to use polycarb where possible because it's easier to fabricate, but impact modified acrylic is good stuff as well, it doesn't yellow like polycarb, and has almost the same impact strength. Price is almost the same per foot.
     
  8. Zendavor Signs

    Zendavor Signs Member

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    FYI - Cellulose Acetate Butyrate (CAB) is what Gemini uses for their formed plastic lettering
     
  9. Johnny Best

    Johnny Best Very Active Member

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    SunPlastics that use to be located in Hallandale, FL And made formed plastic letters many years ago was bought by Gemini because of SunPlastics formed letter abilities.
    Gemini did a lot of experimenting and work on that duets plastics over the years.
     

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