Scarp172
02-14-2007, 04:51 PM
This is a guide intended to help those who wish to preserve specimens by casting them in resin. It is intended for adults or children under very close adult supervision. Read all warnings and labels before purchasing chemicals and equipment.
Please note that this is not cheap, nor is it easy. Casting takes practice and a good quantity of patience to do correctly. This is rarely done perfectly the first time, so if you are particularly concerned about losing your specimen I suggest finding a friend who has made successful castings before. If that is not an option then practice, practice, practice! Also a pour is a full-day ordeal and you may want to do multiple pours at once to save time. If you have small children you may want to reconsider your options, due to the dangers of keeping MEKP in your home.
Now that we have that in order let’s begin with an equipment list.
You’ll need:
Your specimen (preferably placed in the freezer as soon as possible after death and not soaked in any alcohols, formalin, acetone or other chemicals. I’ll discuss this later)
A mold
Resin (make sure you get enough to cover your specimen and fill the mold to the desired level)
Catalyst (or hardener, MEKP. I’ll discuss this shortly)
Plain clear carnuba wax and a soft buffing cloth
Latex gloves (the thicker, chemical resistant ones if you can find them at your local home improvement store)
Disposable plastic cups
Toothpicks (quite a few)
Some form of timer to keep you on task
A cool (60°F-65°F) well-ventilated work area
A measuring shot (if it’s one you can part with and you want to be more exact)
Lots of Time
Lots of patience.
Specimen preparation:
Put it in the freezer, in a container so it doesn’t get broken or bumped, as soon after death as possible. Do not soak it in alcohol, acetone, formalin, water, or any other chemicals prior to freezing. If possible leave the specimen in the freezer for a few days until ice crystals have formed on the outside of the specimen. This is moisture condensed from the air and moisture being pulled out from inside your specimen. The freezing does not damage the structure or coloration in any way. While your little friend is chilling, let’s go to the store.
Mold selection:
You’ll need a mold large enough to contain your specimen, but not much larger. Remember that resin is expensive and the smaller the mold the easier the pour. You’re looking for a few characteristics in your mold other than size that are going to be tantamount to a successful cast: Firstly it needs to be smooth. Really smooth. It should not have any ridges, fancy shapes or designs, dimples in the center or any other irregularities. A round cereal bowl or a square cake pan are good choices. This is especially essential for a first time pour, but when you’ve done quite a few of these and get the hang of it go ahead and try some fancier molds. Secondly, it needs to be heat resistant. Thirdly, it cannot be made of plastic.
Personally I use heat resistant glass bowls and dishes like Anchor or Pyrex. They are about the smoothest I can find and they are affordable. I have read of people making their own latex molds or using silicone molds, but I have not done so myself. They seem to be much to soft to use for casting unless an outer support structure is provided and the extra time and money it takes to make them work is not worth it in my opinion.
At the craft store:
At the local craft store you’ll be asking for hobbyist’s casting resin and a bottle of catalyst. You’ll need one small bottle of the catalyst and as much resin as you need to fill all of your molds to the desired level. Read the instructions on the packages to get the general idea of mixing ratios per time for multiple layer pours. Now, read all the warnings on the catalyst bottle. The catalyst MEKP (methyl ethyl ketone peroxide) is a dangerous organic solvent. Do not breathe the fumes, make sure your work area is well ventilated, and don't get it on your skin or in your eyes.
There are different grades of casting resins with clarity being the discerning factor, but the clearer it is the more expensive it gets and your local store is likely to only have the hobbyist grade resin.
Also, you may with to consider purchasing some decorative stones or gravel and even sand as a backdrop to go beneath your specimen, perhaps some felt to glue to the bottom. Got your gear? Good. Let’s head back home.
Workstation setup:
You’ll want a cleared off table space in a well ventilated, cool (60°F-65°F) area. The garage is ideal. Also, if you spill the resin after it’s been mixed with the catalyst it’s quite permanent. Also you’ll want some place to throw your disposable cups. After you’ve mixed the resin with the catalyst in them the heat from the reaction can melt them.
Remove your specimen from the freezer and place on a paper towel. After it has thawed enough that you can bend the legs, brush a small amount of Isopropyl alcohol on the specimen and let it evaporate. Pat dry with a paper towel. You can also do this step while you’re waiting for your first two layers to cure, but I like to get it out of the way.
Your mold needs to be waxed well. Three times is generally sufficient, but make sure they are light coats and you remove ALL of the residue from the inside of the mold. This is imperative. The purpose of the wax is to help fill all of the tiny scratches and imperfections you can’t see and help the finished casting release form the mold easier. Although you may not be able to see any imperfections in the mold itself, you will see them on your finished casting and they can give it a cloudy appearance.
Make sure you have everything you need with you and your schedule is cleared off for the rest of the day.
The process:
Now reread the directions you on your resin container. They will be pretty vague and here’s why: The reaction is dependant on both the amount of catalyst you add to the resin and the temperature. Too much catalyst and your layer will get too hot, too fast and will wither cook your specimen, crack the resin, crack the mold, or any combination of the above and you are done with your pour. Too little catalyst and the layer may take far too long to harden or never completely harden and just remain gummy. By keeping the temperature relatively cool you can control the speed of the reaction. You’ll need to make one layer and let it cure until it’s gummy, but not hard, and not too liquid either. A good way to check is to gently tap the container and see how the resin responds. If you see small swells like waves then it needs to sit for a little while longer, if you get no response at all it’s too hard and you’ve waited too long. The ideal consistency is like pudding. It will jiggle, but not slosh. Be careful that you don’t splash any on the sides of the container as this will create a crack when you have finished. Do not put your fingers in the mixed resin.
The mold will get quite warm from the reaction. If it gets too warm for you to touch comfortably for any length of time, you should add a drop less catalyst to your next layer and may have to add a touch less resin as well.
The guesswork:
If you have a disposable shot glass you can approximate an ounce or so of the resin with the measurements on it, if not then you can use the lines on your disposable cups to approximate your measures. You now need to estimate for yourself how much resin you’ll need to make a ¼” layer in your mold. Do not add any fluid to you mold to estimate this measurement! You’ll have to guess and that’s what makes this so difficult.
Set your mold on a level, heat resistant, stable, surface that will not be disturbed for a good 6-8 hours. Put your gloves on. Do not add your specimen yet! Now put your estimated amount of resin in a disposable cup and add the appropriate amount of catalyst, slowly, drop-by-drop, (according to the package directions) and stir with a tooth pick. You may feel this heat up a bit in your hand. Pour it slowly into the bottom of your mold and set the time for about 20 minutes. Each layer will take 20-45 minutes to cure properly. You should let the first two layers cure until they are thicker than pudding consistency, but not tacky or hard. If there are any bubbles in the layer most of them will rise to the surface when it starts to cure, but you’ll want to poke the large ones and coax them to the top with a toothpick. Now discard the cup and toothpick, bring your timer, and watch a movie, read a book, or otherwise pass the time. When your timer goes off, check your layer with the above method. If it is ready for the next layer repeat the mixing process and pour it on top of the first layer. If it needs more time I recommend checking it every 5 minutes for the first two layers to get a feel for how fast your resin is setting up under the current conditions and mix ratios. This way if you need to change anything for subsequent layers, you’ll know what needs to change.
When you have a good ½” to 1” of resin poured and cured just a bit more (only a bit) than the pudding consistency mentioned above, it’s time to bring in your specimen. You’ll want it as dry as possible and need to remember that you’re posing it upside down. You cannot move the mold to peek at how it’s going to look. Lay it on its back on the last layer of resin that cured and pose it how you want it. Sometimes it helps to enlist a friend to hold certain troublesome limbs in place with toothpicks while you pour the next layer. When you pour the first layer over your specimen make sure it does NOT cover the entire specimen, this is very important! If you cover the specimen with resin in one pour (unless it is a very small specimen) the heat form the reaction can cook it in the liquid resin, which can lead to the specimen bursting and splattering resin all over. Make sure to use at least two pours to cover the specimen, but also make sure the layers aren’t so thin that they will harden considerably faster than the others. This is tricky and you may have to experiment with it to get it right.
After your specimen is covered completely you may want to add a backdrop or background to your pour. To do this make sure the layer covering your specimen is cured more than the normal pudding consistency. This may take an extra 15-20 minutes. It needs to be hard enough to support the gravel, sand, or stones you’ll be using for the background. Sprinkle them on the resin or arrange them how you want being careful at first and watching to see if they sink. If they sink to the next layer they will appear to be floating next to your specimen and trying to dig them out may ruin the previous layer and the entire casting.
Now pour at least two more layers using the above guidelines as before and let it sit until you can feel no more heat from the mold and the “‘top” which is really the bottom, is not tacky or soft. This may take up to two days. If you need to move the mold from your work area you may do so now, but it still needs to be placed on a level surface and will be giving off smaller quantities of noxious fumes as well as a small amount of heat.
After it has fully cured, place the mold in the freezer for a few minutes. This shrinks the resin away from the walls of your mold and makes removal easier. Remove the mold from the freezer and let it warm for a minute (so it doesn’t shatter either) and place it upside down on a soft surface. Tap lightly on the bottom of your mold until the casting comes free. Admire your handiwork!
Finishing touches:
Now that you have a specimen cast in resin what do you do with it? Polish the outside with the clear car wax you used to wax your mold with to give it a nice clear, shiny finish. You can try to bevel and sand the edges down, but from experience, no amount of sanding and polishing will leave a clear finish. If you sand it, it will be cloudy. Remember this is a polyester resin and not an acrylic plastic. You can add felt to the bottom or felt feet. Smaller ones can be used as jewelry. I’ve seen some very nice framed displays with pictures of the specimen when it was alive (usually for pets that have passed). The possibilities are endless!
Questions and Mythconceptions:
Q: Why don’t you remove the guts/organs/juices and stuff the specimen with cotton or wire?
A: In short because it is unnecessary. In small specimens, such as most tarantulas, scorpions, and ‘pedes, there is not enough fluid or mass to cause a problem during the casting process. The only times where removal of fluids may be needed are in cases of larger specimens such as: a robust female T. blondi or other considerably large tarantula with a full opisthosoma, an obese or gravid specimen, or any larger reptile or vertebrate. Some common sense is involved in the decision. If there is enough fluid in the specimen, it may explode and make a mess, and trust me- it’s a big smelly mess. As for the cotton and wire it is also about common sense. If you have put your specimen in the freezer quickly then posing should not be a problem. If you just can’t get the specimen out of its death curl then wiring is certainly an option. Invertebrate taxidermy is time consuming, tedious work and for the most part does not turn out as aesthetically pleasing as leaving the body intact. If you have a large specimen then by all means do what you feel is necessary.
Q: If you don’t take the guts/organs/juices out don’t they just decay or discolor in the resin?
A: No. I have had no problems with this and as long as you don’t let the reaction get too hot, you will not lose any color for many, many years. Between myself and my father, who taught me, we have done over one hundred successful pours and countless unsuccessful ones. Of the specimens he has from almost 40 years ago, none of the tarantulas have discolored, or decayed, but light colored scorpions (H. arizonensis) have a tendency to darken over time, but they are almost 40 years old. Keeping them out of the sun would help too.
Q: Why don’t you soak your specimens in alcohol/formalin/acetone to preserve colors or slow decay?
A: It’s not needed. I have had no problems with out soaking the specimens. If the specimens are soaked in anything prior to casting the chemical may later the reaction and ruin the cast as well. Also the more fluid in the specimen the slower you have to go, the more layers you need, and the thinner the layers need to be. It causes more problems than it could potentially be worth. As I said before, I’ve seen no evidence in 40 year old castings of any kind of decay or discoloration.
Q: If I send you my deceased spider/scorpion/’pede/insect/other will you cast them for me?
A: No. It takes too much of my time and I cannot guarantee any results. Also the costs to you would be exorbitant. It’s far more rewarding to do it yourself anyway.
One of the 40 year old Aphonopelma sp. mature males in resin.
http://i91.photobucket.com/albums/k300/Scarp172/Aphonopelmaweight40yrold.jpg
My first scorpion who passed in September. H. arizonensis named "Wyatt"
http://i91.photobucket.com/albums/k300/Scarp172/Wyattresin.jpg
Disclaimer:
I am in no way responsible for injuries or damages sustained or incurred to anyone following the instructions in this guide. While I have lent an eye to safety in writing this guide, it is only a guide and cannot encompass the entire scope of situations possible during the casting process. This guide is intended for educational purposes only and is intended for adults interested in learning about the hobby of resin casting. The use of this guide is granted solely to Arachnoboards.com, a subsidiary of Arachnopets LLC. and may not be reprinted, or sold without expressed written consent of the author.
Please note that this is not cheap, nor is it easy. Casting takes practice and a good quantity of patience to do correctly. This is rarely done perfectly the first time, so if you are particularly concerned about losing your specimen I suggest finding a friend who has made successful castings before. If that is not an option then practice, practice, practice! Also a pour is a full-day ordeal and you may want to do multiple pours at once to save time. If you have small children you may want to reconsider your options, due to the dangers of keeping MEKP in your home.
Now that we have that in order let’s begin with an equipment list.
You’ll need:
Your specimen (preferably placed in the freezer as soon as possible after death and not soaked in any alcohols, formalin, acetone or other chemicals. I’ll discuss this later)
A mold
Resin (make sure you get enough to cover your specimen and fill the mold to the desired level)
Catalyst (or hardener, MEKP. I’ll discuss this shortly)
Plain clear carnuba wax and a soft buffing cloth
Latex gloves (the thicker, chemical resistant ones if you can find them at your local home improvement store)
Disposable plastic cups
Toothpicks (quite a few)
Some form of timer to keep you on task
A cool (60°F-65°F) well-ventilated work area
A measuring shot (if it’s one you can part with and you want to be more exact)
Lots of Time
Lots of patience.
Specimen preparation:
Put it in the freezer, in a container so it doesn’t get broken or bumped, as soon after death as possible. Do not soak it in alcohol, acetone, formalin, water, or any other chemicals prior to freezing. If possible leave the specimen in the freezer for a few days until ice crystals have formed on the outside of the specimen. This is moisture condensed from the air and moisture being pulled out from inside your specimen. The freezing does not damage the structure or coloration in any way. While your little friend is chilling, let’s go to the store.
Mold selection:
You’ll need a mold large enough to contain your specimen, but not much larger. Remember that resin is expensive and the smaller the mold the easier the pour. You’re looking for a few characteristics in your mold other than size that are going to be tantamount to a successful cast: Firstly it needs to be smooth. Really smooth. It should not have any ridges, fancy shapes or designs, dimples in the center or any other irregularities. A round cereal bowl or a square cake pan are good choices. This is especially essential for a first time pour, but when you’ve done quite a few of these and get the hang of it go ahead and try some fancier molds. Secondly, it needs to be heat resistant. Thirdly, it cannot be made of plastic.
Personally I use heat resistant glass bowls and dishes like Anchor or Pyrex. They are about the smoothest I can find and they are affordable. I have read of people making their own latex molds or using silicone molds, but I have not done so myself. They seem to be much to soft to use for casting unless an outer support structure is provided and the extra time and money it takes to make them work is not worth it in my opinion.
At the craft store:
At the local craft store you’ll be asking for hobbyist’s casting resin and a bottle of catalyst. You’ll need one small bottle of the catalyst and as much resin as you need to fill all of your molds to the desired level. Read the instructions on the packages to get the general idea of mixing ratios per time for multiple layer pours. Now, read all the warnings on the catalyst bottle. The catalyst MEKP (methyl ethyl ketone peroxide) is a dangerous organic solvent. Do not breathe the fumes, make sure your work area is well ventilated, and don't get it on your skin or in your eyes.
There are different grades of casting resins with clarity being the discerning factor, but the clearer it is the more expensive it gets and your local store is likely to only have the hobbyist grade resin.
Also, you may with to consider purchasing some decorative stones or gravel and even sand as a backdrop to go beneath your specimen, perhaps some felt to glue to the bottom. Got your gear? Good. Let’s head back home.
Workstation setup:
You’ll want a cleared off table space in a well ventilated, cool (60°F-65°F) area. The garage is ideal. Also, if you spill the resin after it’s been mixed with the catalyst it’s quite permanent. Also you’ll want some place to throw your disposable cups. After you’ve mixed the resin with the catalyst in them the heat from the reaction can melt them.
Remove your specimen from the freezer and place on a paper towel. After it has thawed enough that you can bend the legs, brush a small amount of Isopropyl alcohol on the specimen and let it evaporate. Pat dry with a paper towel. You can also do this step while you’re waiting for your first two layers to cure, but I like to get it out of the way.
Your mold needs to be waxed well. Three times is generally sufficient, but make sure they are light coats and you remove ALL of the residue from the inside of the mold. This is imperative. The purpose of the wax is to help fill all of the tiny scratches and imperfections you can’t see and help the finished casting release form the mold easier. Although you may not be able to see any imperfections in the mold itself, you will see them on your finished casting and they can give it a cloudy appearance.
Make sure you have everything you need with you and your schedule is cleared off for the rest of the day.
The process:
Now reread the directions you on your resin container. They will be pretty vague and here’s why: The reaction is dependant on both the amount of catalyst you add to the resin and the temperature. Too much catalyst and your layer will get too hot, too fast and will wither cook your specimen, crack the resin, crack the mold, or any combination of the above and you are done with your pour. Too little catalyst and the layer may take far too long to harden or never completely harden and just remain gummy. By keeping the temperature relatively cool you can control the speed of the reaction. You’ll need to make one layer and let it cure until it’s gummy, but not hard, and not too liquid either. A good way to check is to gently tap the container and see how the resin responds. If you see small swells like waves then it needs to sit for a little while longer, if you get no response at all it’s too hard and you’ve waited too long. The ideal consistency is like pudding. It will jiggle, but not slosh. Be careful that you don’t splash any on the sides of the container as this will create a crack when you have finished. Do not put your fingers in the mixed resin.
The mold will get quite warm from the reaction. If it gets too warm for you to touch comfortably for any length of time, you should add a drop less catalyst to your next layer and may have to add a touch less resin as well.
The guesswork:
If you have a disposable shot glass you can approximate an ounce or so of the resin with the measurements on it, if not then you can use the lines on your disposable cups to approximate your measures. You now need to estimate for yourself how much resin you’ll need to make a ¼” layer in your mold. Do not add any fluid to you mold to estimate this measurement! You’ll have to guess and that’s what makes this so difficult.
Set your mold on a level, heat resistant, stable, surface that will not be disturbed for a good 6-8 hours. Put your gloves on. Do not add your specimen yet! Now put your estimated amount of resin in a disposable cup and add the appropriate amount of catalyst, slowly, drop-by-drop, (according to the package directions) and stir with a tooth pick. You may feel this heat up a bit in your hand. Pour it slowly into the bottom of your mold and set the time for about 20 minutes. Each layer will take 20-45 minutes to cure properly. You should let the first two layers cure until they are thicker than pudding consistency, but not tacky or hard. If there are any bubbles in the layer most of them will rise to the surface when it starts to cure, but you’ll want to poke the large ones and coax them to the top with a toothpick. Now discard the cup and toothpick, bring your timer, and watch a movie, read a book, or otherwise pass the time. When your timer goes off, check your layer with the above method. If it is ready for the next layer repeat the mixing process and pour it on top of the first layer. If it needs more time I recommend checking it every 5 minutes for the first two layers to get a feel for how fast your resin is setting up under the current conditions and mix ratios. This way if you need to change anything for subsequent layers, you’ll know what needs to change.
When you have a good ½” to 1” of resin poured and cured just a bit more (only a bit) than the pudding consistency mentioned above, it’s time to bring in your specimen. You’ll want it as dry as possible and need to remember that you’re posing it upside down. You cannot move the mold to peek at how it’s going to look. Lay it on its back on the last layer of resin that cured and pose it how you want it. Sometimes it helps to enlist a friend to hold certain troublesome limbs in place with toothpicks while you pour the next layer. When you pour the first layer over your specimen make sure it does NOT cover the entire specimen, this is very important! If you cover the specimen with resin in one pour (unless it is a very small specimen) the heat form the reaction can cook it in the liquid resin, which can lead to the specimen bursting and splattering resin all over. Make sure to use at least two pours to cover the specimen, but also make sure the layers aren’t so thin that they will harden considerably faster than the others. This is tricky and you may have to experiment with it to get it right.
After your specimen is covered completely you may want to add a backdrop or background to your pour. To do this make sure the layer covering your specimen is cured more than the normal pudding consistency. This may take an extra 15-20 minutes. It needs to be hard enough to support the gravel, sand, or stones you’ll be using for the background. Sprinkle them on the resin or arrange them how you want being careful at first and watching to see if they sink. If they sink to the next layer they will appear to be floating next to your specimen and trying to dig them out may ruin the previous layer and the entire casting.
Now pour at least two more layers using the above guidelines as before and let it sit until you can feel no more heat from the mold and the “‘top” which is really the bottom, is not tacky or soft. This may take up to two days. If you need to move the mold from your work area you may do so now, but it still needs to be placed on a level surface and will be giving off smaller quantities of noxious fumes as well as a small amount of heat.
After it has fully cured, place the mold in the freezer for a few minutes. This shrinks the resin away from the walls of your mold and makes removal easier. Remove the mold from the freezer and let it warm for a minute (so it doesn’t shatter either) and place it upside down on a soft surface. Tap lightly on the bottom of your mold until the casting comes free. Admire your handiwork!
Finishing touches:
Now that you have a specimen cast in resin what do you do with it? Polish the outside with the clear car wax you used to wax your mold with to give it a nice clear, shiny finish. You can try to bevel and sand the edges down, but from experience, no amount of sanding and polishing will leave a clear finish. If you sand it, it will be cloudy. Remember this is a polyester resin and not an acrylic plastic. You can add felt to the bottom or felt feet. Smaller ones can be used as jewelry. I’ve seen some very nice framed displays with pictures of the specimen when it was alive (usually for pets that have passed). The possibilities are endless!
Questions and Mythconceptions:
Q: Why don’t you remove the guts/organs/juices and stuff the specimen with cotton or wire?
A: In short because it is unnecessary. In small specimens, such as most tarantulas, scorpions, and ‘pedes, there is not enough fluid or mass to cause a problem during the casting process. The only times where removal of fluids may be needed are in cases of larger specimens such as: a robust female T. blondi or other considerably large tarantula with a full opisthosoma, an obese or gravid specimen, or any larger reptile or vertebrate. Some common sense is involved in the decision. If there is enough fluid in the specimen, it may explode and make a mess, and trust me- it’s a big smelly mess. As for the cotton and wire it is also about common sense. If you have put your specimen in the freezer quickly then posing should not be a problem. If you just can’t get the specimen out of its death curl then wiring is certainly an option. Invertebrate taxidermy is time consuming, tedious work and for the most part does not turn out as aesthetically pleasing as leaving the body intact. If you have a large specimen then by all means do what you feel is necessary.
Q: If you don’t take the guts/organs/juices out don’t they just decay or discolor in the resin?
A: No. I have had no problems with this and as long as you don’t let the reaction get too hot, you will not lose any color for many, many years. Between myself and my father, who taught me, we have done over one hundred successful pours and countless unsuccessful ones. Of the specimens he has from almost 40 years ago, none of the tarantulas have discolored, or decayed, but light colored scorpions (H. arizonensis) have a tendency to darken over time, but they are almost 40 years old. Keeping them out of the sun would help too.
Q: Why don’t you soak your specimens in alcohol/formalin/acetone to preserve colors or slow decay?
A: It’s not needed. I have had no problems with out soaking the specimens. If the specimens are soaked in anything prior to casting the chemical may later the reaction and ruin the cast as well. Also the more fluid in the specimen the slower you have to go, the more layers you need, and the thinner the layers need to be. It causes more problems than it could potentially be worth. As I said before, I’ve seen no evidence in 40 year old castings of any kind of decay or discoloration.
Q: If I send you my deceased spider/scorpion/’pede/insect/other will you cast them for me?
A: No. It takes too much of my time and I cannot guarantee any results. Also the costs to you would be exorbitant. It’s far more rewarding to do it yourself anyway.
One of the 40 year old Aphonopelma sp. mature males in resin.
http://i91.photobucket.com/albums/k300/Scarp172/Aphonopelmaweight40yrold.jpg
My first scorpion who passed in September. H. arizonensis named "Wyatt"
http://i91.photobucket.com/albums/k300/Scarp172/Wyattresin.jpg
Disclaimer:
I am in no way responsible for injuries or damages sustained or incurred to anyone following the instructions in this guide. While I have lent an eye to safety in writing this guide, it is only a guide and cannot encompass the entire scope of situations possible during the casting process. This guide is intended for educational purposes only and is intended for adults interested in learning about the hobby of resin casting. The use of this guide is granted solely to Arachnoboards.com, a subsidiary of Arachnopets LLC. and may not be reprinted, or sold without expressed written consent of the author.