Paraloid B-72

 

I like to use it when doing conservation projects and stabilizing collection specimens, as well as doing full out-articulations.

 

 

Pros (in addition to being archival and fully reversible)

 

-You can easily change viscosity by adding acetone or by leaving the container open and letting acetone evaporate. This is its greatest attribute. B72 can easily be thinned to a splashing, sloshing liquid the consistency of orange juice and applied to with a paintbrush, or it can be thickened into a slow, heavy, sap. Thin glue is convenient for stabilizing lightweight bones and thick glue works for heavier pieces.

-Non-toxic, very safe to handle.-Goes on clear but color can be altered by mixing in store-bought pigment powders or as I prefer, bone dust (collected with dremel drill sander attachment and mixed very well).

-A relatively fast-drying, glue (4-48 hours depending on viscosity and ambient temp/humidity). Generally dries faster than wood glue and rubber adhesive. Unlike wood glue, it is easily reversed. Unlike rubber cement, it is archival and forms a strong bond.

-Heat softens bond. Can revise glue-job by adding heat in the form of steam (hot plate, flask, rubber tubing) or hot water applied with a syringe. Can also revise glue-job by adding acetone.

 

Cons

-Expands a little as it dries

-Accumulates small bubbles as it dries

-Dries a little translucent

-Doesn't dry nearly as fast as permanent superglues (dries/bonds on contact).

 

For large snakes, B-72 dries too slowly to instantly bond the demi-facets of a rib to the articular facets of a vertebra. You'll need to set up some kind of scaffolding and/or base that will hold the ribs steady while the glue dries.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Snapshot of some notes taken during a B72 lesson and the other attachment is a budget that includes the product itself (it's a solid). Any lab-grade acetone can be used as a solvent. Hardware store acetone works too but I get better results when I use the good stuff. B-72 is available pre-mixed in a tube but it costs a lot less to buy the solid and make your own.

 

 

 

 

 

 

 

The forceps are balanced to lean against a gastralia fragment while the paraloid B-72 adhesive dries. It will be left there for about 45 minutes. When removed, the glue won't be completely dry but the bond will be strong enough to support this brittle piece of the skeleton stability is reached. A concentration of about 60% is being used here, applied with the sharp end of an insect pin. This way worked fine but another approach is to thin the glue to a concentration of 10-15% and administer it with a paint brush. This is Sphenodon puntactus FMNH 197942. If you don't already know, S. puntactus (the tuatara) is one strange and special animal. It's the "lizard" that isn't a lizard...

Specific Products

 

Type: Paraloid B-72

Example: Paraloid B-72 adhesive $33.551 lb pellets. UNIVERSITY PRODUCTS #422-9000

 

 

Type: Rubber Cement

Example: Devcon rubber adhesive $25.382 oz tubes. SEARS #10345

Pros: Flexible. Reversible. Relatively mild adhesive. 

Cons: Amber-colored. Doesn't dry as fast as super/crazy glue. Not good for thinning. Not a resin and so becomes brittle after a few years. Loses stickiness quickly when exposed to the air. Must be applied quickly. 

 

 

 

Type: Adhesive Applicator

Example: Adhesive applicator $2.90. UNIVERSITY PRODUCTS #146-6046

Review: Have used with B-72. A great idea but clogs very fast. Once clogged with B-72, nearly impossible to un-clog.

Pros

-Ideal when working effectively. Narrow, precision, hollow needle tip.

Cons

-Clogs easily. May only be good for one or two applications.

 

 

Type: Non-archival glue gun

Example: Surebonder PRO2-80 glue gun $62.13 includes 90 glue sticks. HOME DEPOT PRO2-80/711R510 (7/16")

Pros: Gun and glue readily available. Cheap compared to professional equipment. 

Cons: Not archival.

 

 

Type: Crazy glue

Example: Aron Alpha 201 cyanoacrylate $6.30.20 g bottle. ELLSWORTH A4-490

Pros

-Bonds on contact and dries almost instantly (<60 seconds). Very convenient when gluing small ribs and digits that must be held in place by hand until dry.

Cons

-Chemically irreversable.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

©DWasserman Oct 2019