Clear Resin Casting of Arthropods for Use in Education, Outreach, and Research

Summary

Here we show key steps in the process of creating high-quality, resin-embedded arthropods for educational instruction and outreach.

Abstract

Our prior work published a protocol for creating resin-embedded arthropods of medical importance for use in educational and outreach activities. This protocol has been adopted by diverse initiatives aiming to create a mounting technique that minimizes damage to the arthropod, creates a safe product for handling, and preserves the ability to see morphological characteristics for identification. Our protocol has evolved and is currently creating resin-embedded arthropods with improved quality thanks to the purchase of additional equipment and process modifications. We present this improved protocol with steps to minimize bubbles, adapt to different types of arthropods, and create final polished blocks with visibility from six sides. We also outline biosafety concerns from fumes during the resin curing, use of power tools, and from dust generated while sanding and polishing resin blocks. This visualized protocol will facilitate the adoption of clear resin casting of arthropods to a broader community. The list of equipment and consumables we have adopted over several years of trial and error will allow other programs to judge if this protocol is a viable option for adoption.

Introduction

Undamaged, high-quality specimens are critical resources for teaching arthropod identification skills to trainees^1,2. Often, teaching collections contain delicate pinned or pointed specimens that may be missing key features from frequent handling or may be difficult to view from several angles to understand the spatial relationships of key identifying features³. These can be frustrating for students and teachers alike, and rare, difficult-to-collect, and non-local species may be restricted or altogether absent from teaching collections for fear of destruction of the samples.

Protocol

CAUTION: The hazards associated with the resin production protocol include exposure to toxic fumes from uncured resin, contact with uncured resin and catalyst, use of power tools, and dust production during the cutting/sanding/polishing steps. A fume hood or well-ventilated area and nitrile gloves are needed when working with uncured resin. If resin or catalyst comes into contact with skin, wash area immediately with soap and water. When cutting/sanding/polishing cured resin blocks, a properly fitted half-face respirator needs to be worn.

1. Specimen and label preparation

NOTE: The preparation of specimens depends ....

Results

Successfully embedded specimens will be surrounded by clear and colorless resin, with all sides smooth. The specimen will be clearly visible from any side of the resin block. Specimen features important for identification, such as color patterns, scale shape and size, and other anatomical features, will be visible with the use of a dissecting microscope. Less desirable features of the resulting arthropods in resin sometimes result when a layer of air bubbles covers the specimen, scales ar.......

Discussion

Preparation of specimens

Preservation methods can depend on the specimen being worked with. Common specimen preservation methods include 70% ethanol or freezing, both of which are compatible with resin embedding. These methods are useful in preserving key features of the specimen, such as coloration, scales, hairs, and other physical characteristics.

Preparation of resin layers and placement of the specimen

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Air compressor	California Air Tools CAT-1P1060S Light & Quiet Portable Air Compressor, Silver	California Air Tools	https://a.co/d/07y4iGha
Air compressor hose	California Air Tools HFH25.25 Hybrider Flex 1/4in 25ft Hybrid Air Hose with Quick Connect Air Fittings , Blue	California Air Tools	https://a.co/d/0cboxu7J
Bandsaw	G0803 9” Benchtop Bandsaw		https://www.grizzly.com/products/grizzly-9-benchtop-bandsaw-w-laser-guide-quick-release/g0803z (Analog Machine)
Belt Sander	Bucktool 1 X 30 in Bench Belt Sander with 5 in Disc with Wrench Storage and Easy Belt Cover Off	Bucktool	https://a.co/d/017GmVQI
Buffing wheel	6 inch Benchtop Buffer Heavy Duty 1/2 HP; Includes two buffing wheels	Central Machinery	https://a.co/d/0iGsbSCu
Disc sander	BUCKTOOL 5.0A Belt Disc Sander 4 in x 36 in Belt and 6 in Disc Sander with 3/4HP Direct-drive Motor and Portable Al Base	Bucktool	https://a.co/d/08AsKXva
Polishing wheel pad x2	Replacements Pads for Buffing Wheel	Enkay	https://a.co/d/07WajxZ5
Pressure pot	CALIFORNIA AIR TOOLS 255C 2.5 Gallon Pressure Pot for Casting, Blue	California Air Tools	https://a.co/d/0j3vGi3P
Shop vacuum to collect dust	BUCKTOOL 1.2 HP Auto Start 750CFM Dust Collector with 3 Dust Collection Bag, 5.4 Cubic Bag Capacity and 5 PCS Reducer for Woodworking DC50	Bucktool	https://a.co/d/0cEA39ii
Water bath	JOANLAB digital thermostatic water bath	JoanLab	https://a.co/d/0gJLNyWG
Consumables
Buffing wheel polish, red	SCOTTCHEN Red Buffing Polishing Cutting Compound Coarse, Jewelry Rouge	Scottchen	https://a.co/d/caLtcNL
Buffing wheel polish, white	D2903 1-Pound Buffing Compound	Woodstock	https://a.co/d/061T4kWU
Half face respirator	3M Rugged Comfort Quick Latch Half Facepiece Reusable Respirator 6502QL, NIOSH	3M	https://a.co/d/0g3wMldi
Half face respirator filters	3M Particulate Filter P100 Respiratory Protection, 2097/071184 (AAD)	3M	https://a.co/d/05a6ydbM
Resin	Clear-Lite Casting Resin, Tap Plastic	Tap Plastic	https://www.tapplastics.com/product/mold_making_materials/casting_products/tap_clear_lite_casting_resin/75
Resin catalyst	MEKP Liquid Catalyst, Tap Plastic	Tap Plastic	https://www.tapplastics.com/product/fiberglass/polyester_resins/tap_mekp_liquid_catalyst/40
Resin & Resin catalyst (Alternative)	Clear Casting UV Resin, Solarez (MEKP Catalyst included)	Solarez	https://solarez.com/solarez-clear-casting-uv-resin.html
Sanding belts	Red Label Abrasives 4 X 36 in 600 Grit Silicon Carbide	Red Label Abrasives	https://a.co/d/0hkYmjI7
Sanding discs	1 x 30 2000 Grit 9 Micron Blue Polishing Belt with Cushioned Ultra Flexible Mylar Backing	Pro Sharpening Supply	https://a.co/d/01pCnNnN
Sanding discs	Norton Metalite R228 PSA Disc, Pressure Sensitive Adhesive, Aluminum Oxide, 5’’ Diameter, Grit 80	Norton	https://a.co/d/0cqqdpMq
Silicone molds	Square Silicone Molds for Resin, Large Resin Mold Glossy Deep Square Molds 6.6''x 2'' w (with 2 Small Square or Rectangular molds)		https://a.co/d/06Qasc1G
Transparency sheets	Ohp Clear Printable Transparency Film 8.5 x 11 Inches for Overhead Projectors, for Laser Printers	Craftiff	https://a.co/d/07L2g0AT