Cardstock: a brief guide to a confusing subject

by William H. Geoghegan

Cardstock specifications can be confusing at the best of times, especially for American modelers who have to deal with the archaic method used in this country for specifying the weight of different papers. We talk about 160 pound card stock, 32 pound ledger, 108 pound bristol, and so on, without really knowing how to compare these metrics to one another. After all, the most important aspects of the paper used in card modeling -- especially for those printing their own models -- are thickness, surface finish (which affects how ink and glue are absorbed, among other things), lamination (will layers tend to separate when the stock is sharply bent or rolled), and color. All of these can have a major impact on the appearance of the printed model, not to mention its "buildability." Ideally, models in the 1:33 scale range are built with stock in the range of .008" to .009" inches thickness, 1:50 models in the .007" to .008" range.

Paper weight as specified in the U.S. system can help a little in determining thickness, but it is very far from perfect. Elsewhere in the world, paper is typically measured in a "grams per square meter" system, which tells you exactly how much one sheet of stock, one meter square, weighs. Not perfect, because density and surface can also affect thickness, but it helps. Just to illustrate the problem, Wausau "Exact Index" is listed as a 90 pound index stock, at 165 g/m2. Wausau's Astrobright card stock is listed as a 65 pound card stock at 175 g/m2. Both are about the same thickness.

The problem arises from something called "basis weight," which probably dates back to the days of hand presses. Papers of different types, or intended for different uses, were traditionally manufactured in different sizes before being cut for commercial use. The basis size for sheets of index stock is 25.5" by 30.5", for cover or card stock it is 20" by 26." The "basis weight" is the weight in pounds of a ream (500 sheets) of paper in the basis size. Even if we compared exactly equivalent index and card stocks (in terms of thickness, grams per square meter, etc.), the index stock would have a much higher basis weight than the card stock, simply because larger sheets of paper are used to figure the weight.

The following table was produced by Lexmark (a U.S. printer manufacturer) to help disentangle the paper weight confusion. It shows the basis weights of six different types of papers, compared to the grams-per-square-meter system. You can see, for example, that the 65-pound Astrobright card stock is actually slightly heavier than the 90-pound Exact index stock (175 g/m2 versus 165 g/m2).

The table might help you navigate the confusing waters of paper metrics. Following the table are some comments about the thickness and other characteristics of card stock commonly used in the U.S., including the stocks recently used by several Polish and one Ukrainian publisher. All of the models tested were of 1:33 aircraft. My sense is that ship models get the same stock and printing quality.


Cardstock weights and metric equivalents

Metric Equivalent
(g/m2)
Basis Weight
(pounds per ream of 500 sheets, sized as shown)
Bond

17" x 22"
431.8 x
558.8mm
Offset

25" x 38"
635.0 x
965.2mm
Cover

20" x 26"
508.0 x
660.4mm
Printing
Bristol
22.5" x 35"
571.5 x
889.0mm
Index
Bristol
25.5" x 30.5"
647.7 x
774.7mm
Tag

24" x 36"
609.6 x
914.4mm
752050---50
902460----
1052870----
10829-40---
1183180----
12032---6774
1313590----
13536-50---
14839100----
16343-60-90100
1764712065---
19953--110110-
20354----125
Note: Card stock weights may vary ±5%
Source:  Lexmark Card Stock & Label Guide: Laser Printers.  Lexmark International, Inc., September 1999


Examples of commonly used card stocks

Paper Thickness Comments
Halinski .0085" Very smooth, sometimes as much as .009" thick
Mały Modelartz .0085" Fairly smooth, occasionally a little rough to the touch. Vast improvement in card stock and printing over the last few years
Wak .0075" to .0080" Fairly smooth stock, slightly textured, good printing
GPM .0090" Smooth, easy to work with. Thickest stock among Polish publishers
Fly Model (Gomix) .0080" Slightly rough stock, printing leaves something to be desired
CardPlane (Modele-Kartonowe) .0085" Fairly smooth stock, good printing. English instructions available.
Bumazhenoye Modelirovanie (Ukraine) .0070" Fairly smooth stock for exterior, printed cardboard for formers, somewhat heavy handed printing. (Available through Paper Model Store)
24# Staples 97 bright printing paper .0040" Very smooth with good printing quality; bright white; nice for very small parts
Borden & Riley 32# ledger .0063" Very smooth slightly thinner stock, great for 1:50 models; not quite as white as their Paris Bristol
Borden & Riley 108# Paris Bristol (#234) .0075" Extremely smooth, fairly stiff, very white, designed for engineering and computer drawing; great for 1:50 and larger models
Wausau Exact Index .0075" Fairly smooth 90# index stock; reasonable inking; thickness makes it a reasonable choice for most common scales
Wausau Astrobright .0090" 65# card stock, smooth, bright white; nice for larger models (upper end of the thickness range)
Wausau Bright White .0085" 65# cover stock, very smooth, bright white (96 whiteness), acid-free; takes inkjet ink very well. Available in 100 sheet packages.