Casting beetles in a vacuum chamber

DLJeffs

Member
Full Member
Messages
379
Reaction score
510
Location
central Oregon
First name
Doug
Barry's picture of that big beetle reminded me of this.

This is not a wood working question but I know there are quite a few folks on here who cast various things in resin. When my family lived in the Canal Zone, one thing we got into was going out at night searching for any of the large beetles that would be attracted to the lights. I'd inject them with formaldehyde and then pin them onto a styrofoam board and let them dry. Then we'd pour them in clear two-part epoxy. Dad would square them up on the band saw and we'd sand and polish them in the wood shop at the high school. But we often had a problem. The epoxy was exothermic so generated heat as it cured. That heat caused the air inside the beetles to expand. Since the epoxy was curing, the air had no where to escape and would flow around the beetle resulting in a silver lining, which more or less ruined the whole thing. I always thought pouring them in a vacuum was the solution but we didn't have a vacuum chamber. I still have a few beetles that I'd like to preserve in clear resin and now I have a vacuum chamber. My Canal Zone experience was over 40 years ago so I'm hoping there have been advancements in resins and techniques. So I'm posting this thread asking for any advice or related links from people who have cast resin in a vacuum chamber. Looking for advice about the type of resin, the source, techniques for pouring, especially about trying to minimize the air bubble and entrapped air problem. Thanks. Feel free to send me a message and we can take this off line so we don't tie up forum space too.

coconut beetle.jpg

fire beetle and female rhinoceros.jpg

rhinoceros male.jpg
 
Last edited:

DLJeffs

Member
Full Member
Messages
379
Reaction score
510
Location
central Oregon
First name
Doug
  • Thread Starter Thread Starter
  • #3
Naw, just bugs. These are all fairly common beetles. The top one we called a coconut beetle because they often bored holes into coconuts. The mandibles on that beetle are formidable - we like to stick a pencil in there and watch the beetle cut it in half. Needless to say we were very careful handling those buggers. That one's about 6 inches long not counting the antennae. It's obviously in the family of longhorn beetles.

The middle pair consists of a female rhinoceros beetle and a fire beetle. The fire beetles are cool because like a hummingbird, their colors change depending on how the light hits them.

The bottom one is a male rhinoceros beetle. That one is about the size of a tennis ball. not including the legs. They use the horn to pries open rotten logs on which they feed. The larva will bore into the rotten wood and live in there until they reach maturity. We discovered that the best time to hunt them was right after the first rains after the dry season ended. The rain must be a trigger for them to emerge.
 
Last edited:

FranklinWorkshops

Member
Full Member
Messages
3,558
Reaction score
5,321
Location
Landenberg, PA, USA
First name
Larry
Doug, those are so neat. Brings back great memories of a grammar school project all us kids had to do. I grew up on a farm so had a little advantage on finding and mounting all kinds of bugs. I remember my teacher being shocked at how many I found for the project. I'll bet there are many thousands of species in Panama since the climate would be perfect for them.
 

Wildthings

ASTROS 2019 WORLD CHAMPION VIDEO PLAYERS
Full Member
Messages
6,336
Reaction score
8,399
Location
Gulf Coast of Texas
First name
Barry
I would think dipping them in resin first and hanging to dry. Maybe a couple times. This would seal the beetle for the final pour or two. For the final pour maybe two pours. First one halfway and second one to finish. There's new resin that doesn't heat up like those did back then
 

DLJeffs

Member
Full Member
Messages
379
Reaction score
510
Location
central Oregon
First name
Doug
  • Thread Starter Thread Starter
  • #8
I have to go down to the Bay area in a week or so and I'll stop by TAP Plastics and talk to them about their casting resin and process. Might be able to save on postage if I can buy some in person.
 

DLJeffs

Member
Full Member
Messages
379
Reaction score
510
Location
central Oregon
First name
Doug
  • Thread Starter Thread Starter
  • #9
Well, TAP Plastics wasn't open so I wasn't able to talk with them. From researching resin web sites it seems like pre-coating the bugs is the preferred method. EntomologyToday reported on testing they did on various methods and concluded that pre-coating worked best and then making the final pour with the beetle upside down (better access to the ventral side helped prevent formation of air bubbles when adding resin and gives access to tickle any bubbles away. I did find one site that tried using a vac system and the resin just has too much entrained air and foaming was a problem. Please let me know if you stumble on any related advice.
 

Wildthings

ASTROS 2019 WORLD CHAMPION VIDEO PLAYERS
Full Member
Messages
6,336
Reaction score
8,399
Location
Gulf Coast of Texas
First name
Barry
I would think dipping them in resin first and hanging to dry. Maybe a couple times. This would seal the beetle for the final pour or two. For the final pour maybe two pours. First one halfway and second one to finish. There's new resin that doesn't heat up like those did back then
Well, TAP Plastics wasn't open so I wasn't able to talk with them. From researching resin web sites it seems like pre-coating the bugs is the preferred method. EntomologyToday reported on testing they did on various methods and concluded that pre-coating worked best and then making the final pour with the beetle upside down (better access to the ventral side helped prevent formation of air bubbles when adding resin and gives access to tickle any bubbles away. I did find one site that tried using a vac system and the resin just has too much entrained air and foaming was a problem. Please let me know if you stumble on any related advice.
:yipee: :yipee:
 

ripjack13

ɹǝʇɹɐqpooʍ
Staff member
Administrator
Global Moderator
Forum Moderator
Messages
25,864
Reaction score
29,152
Location
Connecticut
First name
Marc
Feel free to send me a message and we can take this off line so we don't tie up forum space too.
That's not a problem. I'd rather keep it here just in case anyone else doing research may be able to read up on it here.
 
Top