Read rings
How to put rings
How to read rings
How to report


Note There is some more about this subject in my 9th IGM presentation.

Read rings can be made from metals or plastics.


The use of large short codes makes metal rings similar that plastic rings. There exists also modified metal rings, which are double coded and therefore easy to read from one position by telescope. Some pictures of these can be found on the web site produced by Holmer Vonk  (have a look at Storks and Large gulls). Coloured eloxy aluminium is commonly used for birds of prey.

The problems with metal read rings can be bad stamping, small codes and the wear. Aluminium rings (also eloxy colours) wear out fairly quickly.


There are many different polymer materials, which have been used in colour and read rings. Most common are  amorphous polymers like CA, PVC, ABS and PMMA. Many more polymers can be used. Crystalline polymers would be better in wear resistance and they are used in some projects (for instance POM in German Elsa-stork ring). The problem of many materials is the availability of suitable half-products like two layered sheets for engraving . 

Here shortly from the most common plastic ring materials.

a) CA

In the beginning plastic rings (=bands) used to be made cellulose acetate=CA (= acetate rings). CA can be clued with acetone. The production of CA plastic is decreasing. These rings are normally made from one colour sheets.

I do not know that it is produced as two-layer laminate for engraving.  
I have not tested CA myself, but I think it is not very durable as bird rings.

b) PVC

 PVC-sheets and rings that are very similar to CA-sheets and rings (one colour Darvic or Vinyl). Darvic is a trade name for rigid PVC (polyvinylchloride = PVC-U), but many use it as common name for plastics for bird rings. PVC (or Darvic) is also available as two or three layer engraving laminates, but only 1.5mm (1/16in) thickness (or more). Anyway I do not know any producer for thinner sheets, if someone knows, please, inform me.

Engraved read rings made from PVC last in large gulls about 10-15 years (my estimate), but some birds seem to manage to wear the code unreadable even in a couple of years. The problem is the softness of the top layer. PVC can be clued with many UPVC or rigid plastic adhesives (like plumber clues for PVC-pipes), but they  all do not work , you have to test them (I use  Bison rigid plastic glue ( ), because it is clear,  “Plastmo- plumber clue” works also OK, but it makes the code a bit hazy. Any epoxy I do not recommend.

c) ABS

Gravoply (or Hermes etc) engraving sheets are normally made from ABS-copolymers (ABS= acrylonitrile-butadiene-styrene), they are commonly used for many small engraved bird rings (from about 3mm inner diameter size), because they are delivered from thickness 0.75mm (1/32in). But note, that this material is NOT FOR OUTDOOR USE ! It is not UV-stable and comes brittle. My estimate for these once rolled rings is about 5-8 years. I used to use  this material in twice rolled rings in the beginning also for large gulls. Depending the producer and the batch there are huge differences in durability even as twice rolled (between 5-15 years). These can be  clued with many rigid plastic adhesives. I have used  the  same  as for PVC (Bison or Plastmo-you can search by Google). Note that quite similar engraving laminates (or single colour sheets) are  also made from styrenics (PS=popystyrene), which is very bad material for bird rings. It is cheap but lasts a few years only. Some produces call ABS as modified acrylics, through acrylics are quite different materials.


Acrylics is also used as engraving materials for outdoor use . Acrylics (=PMMA=polymethylmethacrylate) is very weather resistant and  harder than those previous materials. Nowadays I recommend  this material and I use it if only possible. I  estimate  (after testing and comparing the wear resistance of different engraving materials) that good PMMA rings last for 50 years. They stand sand blowing tests about 4 times longer than PVC/Darvic and even longer than codes in steel-rings.

The problem with PMMA is that it is more difficult to roll and more brittle to put on the leg of bird (specially with small diameters). There are special adhesives for PMMA, but Bison seems to work OK, also for this. Note that even here are really big property differences between different producers and colours.

Note that all these  materials are amorphous polymers (plastics), which by nature are  not good against wear.  German ELSA-stork ring is made  acetal (POM= polyoximethylene), which is a crystalline polymer and therefore very wear resistant. The code is laser-engraved and therefore  the contrast and the colours are limited. The depth of the laser marked code is very low. It is injection moulded and therefore every ring size needs a very expensive mould.

Good materials (durable) for rings could be also PA (polyamide/nylon) and PU (polyurethane), but these are not available as engraving laminates. I have tested PA for rings, but making a series would demand a lot more  work.

One can fairly easy differ some materials by burning tests: PVC does not burn by itself, smoke is pungent with bad smell, ABS burns with black smoke  leaving bits of soot into air (similar like PS or EPS/Styrox), PMMA burns nicely without no smoke and CA burns very well (almost explosive).

Summary: There are many materials as “darvics” and every material (and colour!!) should be tested before using in bird rings. The price of the ring is a minor thing compared to the effort that is made for ringing and resightings in order to get enough data for analysis. However read ringing (=colour ringing) is a very powerful method for many species.


From >>
Glossary of Common Engraving Industry Terms

 Term: Definition

ABS : Acrylonytrile and styrene liquids and butadiene gas are polymerized together in a variety of ratios to produce a family of ABS resins. Rowmark uses ABS resins in the manufacture of the core material for products such as Satins and Mattes. ABS resins are good for interior use products and are selected for their moderate costs and excellent engraving characteristics.

ACRYLIC: POLYMETHYL METHACRYLATE : A thermoplastic material compound of polymers of methyl methacrylate. It is a transparent solid with exceptional optical properties and good resistance to water. It is obtainable in the form of sheets, granules, solutions, and emulsions. It is extensively used for, lighting, fixtures, decorative articles, etc.; it is also used in optical instruments and surgical appliances. The molecular structure of acrylic provides increased protection from sunlight’s ultraviolet rays; material is noted for outdoor durability and colorfastness. Typically marketed under trade names such as Plexiglas and Lucite. Rowmark uses blends in the construction of its various products such as Lacquers, Ultra-Mattes, laser engravable products.

BONDS : Procedure to join together two sheets of plastic or to join plastic to another substrate. It is recommended that the user test any new adhesive or bonding agent prior to use. Many solvent type adhesives will break down plastics or cause bleeding of pigments. Superglue is not recommended.

CAP LAYER : Laminated top piece in sheet materials with multi-ply layers. The Cap Layer is engraved or lasered through to expose the core layer thus providing a color “contrast” between the cap and core.

CORE LAYER : The base layer(s) in a multi-ply sheet. Rowmark provides core layer products in modified acrylic and ABS plastics. The core is the foundation or base that the cap layer is applied to.

DRILLS : A method of putting a hole into a piece of plastic using a press or hand drill. When mounting plastic signs, the hole size should be 1 ½ larger than the mounting screw or bolt to allow for the thermal expansion and contraction of the plastic.

FOIL : A very thin gauge material that is applied as a cap to the core layer. This applied material is sometimes referred to as a "Micro-surfaced" material. Foils are heat transferable to the core. Rowmark uses foils on products such as LaserMAX, Mattes, FlexiColor/FlexiBrass and Metals.

GLOSSY : A smooth or polished surface. Smooth or glossy surfaces are the result of the lamination process of products such as Slickers or Lacquers. Glossy surfaces will show surface abrasions more easily.

HEAT BENDABLE : The material may be heated using industry recognized heat benders. Crazing of the plastic may occur if the material is over 1/16” thick or if improperly heated and cooled.

HOT STAMPING (hot stampable) : Engraving operation for marking plastics in which roll leaf is stamped with heated metal dies onto the face of the plastics. Ink compounds can also be used.


INTERIOR SIGNAGE : Signage produced for indoor applications where UV stability and weatherability are not required.

LASERABLE (laser engraving) : Acrylic core materials with thin cap surfaces that can be easily engraved with minimal wattage at increased cutting speeds. ABS materials are not recommended for lasering applications.

LAMINATED IMPACT ACRYLIC : One or both of the plies of impact acrylic are mechanically bonded together under heat, pressure, temperature and time. The cap is typically between .005” and .010” in thickness.

MATTE : A low gloss finish achieved during the extrusion or lamination process. Typically durable and resisting finger prints. Does not easily show surface scratches or abrasion.

MICRO SURFACED IMPACT ACRYLIC : A plastic engraving material with a cap, or top layer, around 1 to 2 thousandths of an inch in thickness, compared to a standard cap depth of ten thousandths of an inch or greater.

MODIFIED (modified acrylic) : A modified blend of multi-polymer compounds containing ingredients such as fillers, pigments or additives that help to vary the physical properties of a plastic material. As opposed to Impact Acrylic, this material is not UV stable.

OUTDOOR WEATHERABLE : The ability of plastic engraving material to withstand exterior weathering conditions. Rowmark products designated as “outdoor weatherable” are designed to withstand average conditions and temperatures for up to 2 years without significant degradation. Although no specific life can be designated to any product, Rowmark recognizes that under normal conditions the material will not break down physically. Materials may become brittle and some discoloration or fading will occur when used in harsh environments or exposed for extended periods of time.

PERSONAL IDENTIFICATION : Applications such as name badges, small tags or signage.

ROTATING CARBIDE ENGRAVING : This marking method uses a single or multiple fluted cutting tool which rotates through the work to remove material, leaving a trough of exposed core. As compared to diamond-drag, rotary engraving may result in deep cutting or the complete cutout of a letter or object. The cutter’s tip size determines the width of the cut. In most applications, the spindle micrometer setting controls the depth of cut. This process is suitable for most commercial and industrial work. Unlike diamond-drag, rotary engraving is the only means of engraving plastic materials with controlled depth.

SAW CUTS : As used in Rowmark product specifications, the material can be cut using industry recognized “safety saws”. Safety saws provide a fine tooth high speed cut that produces a clean edge. Rowmark does not recommend circular or table saws because unacceptable edge chipping may occur.

SCORES : A procedure used to cut sheet material. A sharp knife is used to cut the material to a minimal depth. The sheet may be bent or broken completely by hand to produce the necessary finished size of material. This procedure is inexpensive, but not preferred. Acrylics perform better than softer ABS materials using this procedure.

SCREEN PRINTABLE : The engraving sheet will be receptive to most screen printing inks. Due to the variety of available inks, it is recommended that users pre-test the material for compatibility with their inks

SECOND SURFACE (reverse engraved materials) : Clear cap with microsurface or laminated core, machined from the reverse or backside of the material. Back painting is a popular method of achieving a contrast in color. Example: Rowmark Ultra-Matte Reverse

SHEARS : Material can be cut with a pneumatic, foot, or hand shear. Typically hand shears (the most common), can accommodate material that is up to 12 inches wide by any length. While there are two versions of the shear, one for plastic and one for metal, they are actually the same device, but have different upper blades. The plastic-cutting shear has a knife-like upper blade with an extremely fine edge and is intended for cutting flexible engraving stock to a maximum of 3/32” thick. It is not intended for cutting ridged plastics like acrylic and phenolic. See saw cut for additional cutting methods.

THERMOPLASTICS : Capable of being repeatedly softened by heat and hardened by cooling (n.) – A material that will repeatedly soften when heated and harden when cooled. Typical of the thermoplastic family are the ABS, polypropylene, acrylics, cellulosics, polyethylenes, vinyls, nylons, and the various fluorocarbon materials.

TWO-PLY, THREE-PLY : Substrate with thin top layers of contrasting colors. As top surface is removed in engraving, substrates of different colors are exposed, giving a look of fill. Two-ply denotes one different colored layer on a substrate; three-ply denotes two different cap layers on each side of the substrate. Some three-ply substrates have only the core as a different color, so the only way for an observer to see the core is to look at the engraved area.

UV (Ultraviolet) STABILITY : The ability of the engraving material to maintain its colorfastness in UV conditions for a limited period of time. Although colorfastness is a desirable condition, no man-made product will remain colorfast in an exterior environment indefinitely. Rowmark uses UV stable plastic resins and foils in many products to prolong the useful life of the material when used in exterior conditions.