This is an update for November 29-30. Work has slowed on the Gorgosaurus lately due to the labor-intensive amount of gluing that is required. Rock is still being removed, but at a much slower pace now. This update will once again focus on glue. Glues are so important due to the often badly fragmented nature of the fossil being prepared, its host rock, or both. An American vertebrate paleontologist told me decades ago: “If the was no such thing as glue, there would be no such thing as paleontology”. A bit of stretching the truth, but he did have a valid point. Glues in vertebrate paleontology are usually applied by brush or by an eydropper, though in some cases the fossil can be simply immersed. At times a specimen requires a lot of gluing, a job that takes many hours of work, sometimes stretching into weeks of dripping drop after drop of glue onto a specimen such as a dinosaur skeleton. [Dave notes: Glues can be a nightmare too if not used properly as this link explains].
One bone can takes days of gluing. While necessary, it is not the best (cost-effective) way of doing things. So what to do? Philosopher, Plato (427-347 BC) stated “Necessity, the mother of invention”. How true in paleontology where ideas and tools are sometimes invented on the spot to deal with a specific problem. Such happened to me around 1981. I don’t recall the specific specimen I was working on, but I had a large specimen that required weeks of gluing. Not looking forward to doing weeks of applying glue with an eyedropper, I searched around for an alternative idea. The thought of using a hospital intravenous (IV) bag came up. What if we used glue instead of some life-saving fluid, and inserted the needle into the dinosaur bone instead of someones arm? An IV bag was procured from somewhere and the experimentation began. To make a long story short it failed. The needle kept getting clogged up with glue, sediment, or bone dust. So the idea died, but was not forgotten. In the early 2000’s I again needed an IV-type glue delivery system. Remembering the previous failure, by trial and error I developed a handy glue delivery system I share here.
The pictures (see above and below) speak for themselves, but I add some construction and useage points here:
1. The stand used here is a converted film companies light stand, accidently left behind by a film crew years ago. An old desk lamp with a long articulated arm can also be converted to suspend the glue bottle.
2. The bottle should not be too big- about 150-200 ml should do. It must be made of a material that will not react with the solvents used in your glue. The bottle shown here is a “Nalgene” brand.
3. Three small holes are drilled in the lid, one to receive a small eyebolt, one is an air escape hole and one will receive the tip of the modified medical syringe.
4. The medical syringe tip with have an elongated tip and a circular collar around its base. The collar needs to be carefully cut away at its base.
5. Screw in eyebolt and shove the tip of the syringe into third hole, ensuring a tight fit. Remove the syringe’s plunger- it is not needed.
6. Buy a brass fuel line connector, threaded on one end and tapered on the other (the tapered end would be pushed into a fuel line normally). Take the Nalgene bottle, turn it upside down and drill a hole on the bottom (centered) slightly smaller in diameter than the threaded end of the brass connector. Screw the threaded end of the brass connector into the Nalgene bottle.
7. Now get a plastic eyedropper. The tapered tip will likely be too small in diameter to fit the selection of syringe needles you bought earlier. These needles, though of different gauges, all have the same sized end to connect to the syringe itself. In stages, cut he tip of the eyedropper off, until the right diameter is acheived to receive AND firmly hold the needle. It is a good idea to grind off the sharp point of the needle to avoid injury.
8. Now take the bulb end of the eyedropper and cut it off the top so it receives the tapered end of the brass fuel line connector. It might be wise to take the previously cut plastic eyedropper to a car parts store and find a brass connector that best fits.
9. Slide the eyedropper bulb end over the brass connector. It can be held in place with a few twists of strong wire, or, in my bottle, I sealed it all up with epoxy putty. Construction is now done.
10. Hang the empty bottle on the stand. I used a piece of strong wire bent into an S shape. Adjust your stand and suspend the needle just over the area to be glued. Tighten any screws or knobs on the stand to hold the bottle in place.
11. Fill the bottle, pouring into the syringe or use a small funnel inserted into the syringe. Once the glue level is raised up to the top of the brass connector inside, the eyedropper will fill up and the glue starts to drip onto the specimen.
12. The ml scale on the side of the syringe body is useful now if you want to determine how much glue is being added to the specimen.
13. Because the brass connector protrudes through the floor of the bottle for some distance, it acts as a kind of filter trap, removing many impurities, sand, etc that could plug the needle.
14. A needle suspended over the bone may eventually plug when an iceicle of glue forms and plugs the needle tip. This is easily pulled off.
15. A good tip is to have the needle rest right on the bone, or in a crack or low spot where the glue pools briefly before being absorbed into the bone. A wet needle tip rarely plugs up.
16. Once the glue is running and everything is tightened up, then more glue can be added to the bottle as needed.
17. Dirty or plugged needles are simply discarded or put into a jar of clean acetone for a day.
18. It is sometimes difficult to fine tune the needle in relation to the specimen, so sometimes I just let the plastic eyedropper body just “sag” a bit, having some weight from the apparatus pressing down (see pictures). The glue will still flow.
19. The needle can be taken by hand and moved around a bit to direct glue to nearby areas, but once in place it should be just left alone to drip the glue into the specimen, or matrix if required.
20. Speed of dripping is controlled by amount of glue in bottle, viscosity of glue, and diameter of needle. If the gluing must stop, simply fold up the eyedropper. You can pull off the needle tip and the rest of the glue can then decant into another recepticle. A clothes pin may be useful for stopping or slowing down the flow, but a smaller gauge needle will work best (unless the glue is thicker).
I have used this device on several projects in the past 10 years and only needed to replace the needle tips. This technique works best on thin glues.
All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.