Resin as a preservation technique

I can't find any copyright-free resin pictures! so here's a fossilised spider preserved in natural resin -i.e. amber. CC image by Elisabeth.

Several people have asked me recently about preserving their specimens in resin. It's not the traditional thing for taxonomic collections. But if it does what it needs to do - i.e. preserve the specimen while still enabling you to examine all its important and distinguishing features - then it's probably hard to argue with.

I can only imagine attempting small things like beetles and spiders. Little floaty seaweeds in resin look great in my imagination but the technique wouldn't be very practical for anything much bigger. (and you probably want your entire collection to match aesthetically). I can see resin's appeal because spiders do tend to get all scrunched up in alcohol - perhaps it's easier to spread all their legs out in resin(?).

The main issue seems to be - does it still allow you to see the fine detail that allows you to show you've identified it correctly? If you can get this to work, then that's excellent. But it might take a bit of frustrating experimentation. Followed, hopefully, by success and general elation. But perhaps by you getting cross because you've ruined your specimen. So perhaps don't try things out on something you've only got one of.

I've got a tiny bit of experience with resin, but not with setting creatures in it (it's Art, innit). So I do know that you'll probably want 'crystal resin' because that's completely colourless. The stuff I used was cheaper but practically opaque. You have to buy a tin of resin and also a tiny bottle of stuff which reacts with it to make it set (the catalyst / hardener).

You'll also have to think about molds.  I bought a few for my artwork but they weren't cheap, and most of the commercial shapes were far too cutesy. In the end I improvised something I could get for free, but they sometimes got hopelessly stuck, which wasn't ideal.

I also know that resin heats up a bit when it cures, and that can lead to problems with specimens. The only student I can remember that used resin found his spiders went a bit shrivelly. But perhaps this was because they contained moisture, perhaps they could be freeze-dried first? And I believe you can get a problem with 'silvering' which might be related to the shrivelling, when a gap appears between your creature and the resin. I don't know how it will affect the colours of your creature - perhaps that depends what it is.

I also know that resin really stinks and you'll have to find a well-aired place to deal with it (I would suggest the labs but we've not got a fume hood - other people's labs do, but you'll have to fit round the classes).

I found this video on youtube which is interesting because they essentially make their own mold, based on a cut bit of perspex. But they do have an awful lot of bubbles in there (despite their insistence otherwise). And I'm not totally convinced by the opaque edges. And the insects are all curled round. "Oh" I thought, "perhaps you could pin them first." But then if you're going to pin them... why not just pin them, not resin them (not that that would apply to a spider). Don't forget you've got to attach a label somewhere too.

I spotted this guide by Rhys Brigida who loves encasing spiders in resin. He's American, so everything's dollars and ounces, but it should give you some inside information from someone who's tried it with spiders (albeit mostly large ones).

So. This could be worth some experimentation, and much reading around on the internet will probably help. But only if you're feeling super keen, because traditional methods do work and might be less aggravating. I think it might drive me a bit mad. A big question will be - do you have the extra time to get good at it, and will it be worth the possible extra marks if you can do it well? Remember the important part of this assignment is the identification, not just the presentation.

But I do wish you the best of luck if you want to try.