Paper Weight & Thickness

Discussion in 'Tools of the Trade' started by xyberz, Jan 5, 2007.

  1. xyberz

    xyberz Member

    Joined:
    Oct 31, 2006
    Messages:
    263
    Likes Received:
    2
    Just wanted to ask what's really the difference between the paper weight rating and it's physical thickness?

    Also what weight is the paper considered if I glue 2 sheets of copy paper together?
  2. cgutzmer

    cgutzmer Guest

    the weight and thickness are related but its not exact by any means. Some papers are much denser giving a heavier weight but maybe not as much thickness as another brand with the same weight.

    If your copy paper is 20 lb then gluing two sheets would yield just over 40 lb I would guess (I have no idea if we can even measure this - I kinda doubt it) I say just over because you have to account for the adhesive. Really though when you are laminating you are laminating to reach a certain thickness, not a certain weight....
    Chris
    p.s. I hope my guesses were educted enough ;)
  3. rlwhitt

    rlwhitt Active Member

    Joined:
    Aug 25, 2006
    Messages:
    1,100
    Likes Received:
    0
    I don't know much to add to Chris' post, but I would say at some point if you think you will be doing the types of models that require different types of thicknesses, laminating, etc, you'd do yourself a favor by picking up a digital caliper to measure actual thickness. You can spend a lot on these if you buy them from places like hardware stores, but you can get one for less than $20 at WidgetSupply.com

  4. xyberz

    xyberz Member

    Joined:
    Oct 31, 2006
    Messages:
    263
    Likes Received:
    2
    Hehe, that's what I'm figuring too. But my other question is, gluing 2 sheets of copy 20lb each together, does that give about the same thickness as most models require?
  5. cgutzmer

    cgutzmer Guest

    no, not for a former. I laminate 5 sheets total of 110 lb for most formers. I wouldnt want to try and skin a plane or anything else with laminated paper, I think it would get weird crinkles.
    Chris
  6. xyberz

    xyberz Member

    Joined:
    Oct 31, 2006
    Messages:
    263
    Likes Received:
    2
    I make mostly mecha models. Some car models also. Planes I don't do yet...

    Wow I didn't realize how thick 110lb paper is. So about 5 sheets of 20lb paper would probably equal to about the same thickness?

    Maybe buying the correct weight paper is better, hehe.
  7. charliec

    charliec Active Member

    Joined:
    Jan 19, 2004
    Messages:
    887
    Likes Received:
    0
    In real units about 170 gsm - the thickness would be about 0.25mm. If you're
    thinking about laminating remember that paper has a grain and unless you like curved laminated sheet you've got to glue each successive sheet at right angles to the previous one.

    Regards,

    Charlie
  8. cgutzmer

    cgutzmer Guest

    charlie - really had no idea. I have never had a problem with warping when using super 77 on 5 sheets of 110 lb - could be I got lucky....
    Chris
  9. charliec

    charliec Active Member

    Joined:
    Jan 19, 2004
    Messages:
    887
    Likes Received:
    0
    It's probably dependent on the paper/card - I've had problems with warping even when I pressed (couple of sheets of MDF and a bunch of heavy books) the laminate while the glue dried. Perhaps Oz paper has a more pronounced grain. It may be also a problem with the high humidity in Queensland but it's a bit disconcerting to watch your laminate curling up after you take it out of the press. Laminating the sheets at right angles to each other made the problem go away.

    Regards,

    Charlie
  10. nx13688

    nx13688 Member

    Joined:
    Jan 26, 2004
    Messages:
    128
    Likes Received:
    0
    With US paper, you need to know the "basis weight" in order to make any meaningful comparison. This is the best reference chart I've found on the subject:
    paper weight chart
  11. xyberz

    xyberz Member

    Joined:
    Oct 31, 2006
    Messages:
    263
    Likes Received:
    2
    Wow, that site is very informative about paper. Thanks for the link NX

    Also had another question. When designing a 3D model for paper modeling, most people don't mention any calculation of paper thickness and weight. What's the standard when designing 3D models?
  12. rowiac

    rowiac Member

    Joined:
    Jan 26, 2004
    Messages:
    189
    Likes Received:
    0
    I just measured some standard 20 lb [75 g/m^2] copy paper with my calipers and it came out to .004" [0.10 mm].

    My 110 lb index card stock [199 g/m^2] measured out to .009" [0.23 mm]. These measurements pretty much agree with the conversion chart in the link.

    Grams per Square Meter is a pretty good relative indicator of paper thickness, while weight in pounds is not. In the US, 60 lb index stock is about the same thickness as 90 lb cover stock. As mentioned previously, this has to do with the basis size for the type of paper...what a weird system!

    Roger
  13. xyberz

    xyberz Member

    Joined:
    Oct 31, 2006
    Messages:
    263
    Likes Received:
    2
    From your calculations, 2 sheets of normal 20lb copy paper laminated together should achieve about 0.08 thickness correct?

    If that's the case then 5 sheets would equal 0.2, and wouldn't that be too thick for card modeling?

    And lastly, yes, the American measuring system is the worst out there. For some reason they insist on being different. :cry:
  14. rowiac

    rowiac Member

    Joined:
    Jan 26, 2004
    Messages:
    189
    Likes Received:
    0
    Yes, I would think that 5 sheets of 20 lb paper laminated together would be way too thick for modeling. If you can't get card stock, you could try laminating two 20 lb sheets together and see how that would work. PVA glue might make the laminated sheet pretty stiff though. The solvent based glues like UHU or 3M 77 spray glue mentioned earlier might work better.

    Fortunately many of the US paper suppliers have lately been putting the g/m^2 numbers on packs of paper along with the stupid pound system.

    Roger
  15. xyberz

    xyberz Member

    Joined:
    Oct 31, 2006
    Messages:
    263
    Likes Received:
    2
    So far I've used a Scotch craft stick to glue 2 sheets of 20lb copy paper together. It seems to work okay but in the beginning the paper tends to curl up a little bit. So I combat that by sticking it in between a book. When it dries it works okay.

    The only problem that I notice with the glue stick is if I'm not careful to get all the spots, I may get air bubbles in between the sheets, and that's not good.