Casting bugs

[blind pig]

Well, I have demoulded the Envirotex item after well over 30 hours in the mould.

There was obvious shrinkage of about 6-7%. Easycast Clear shrinks less than 1% in this same mould.

The results are mixed I'm afraid.

The Envirotex has a slight yellow tinge and almost no smell. It is still slightly soft, can be easily bent and permantely marks with a fingernail (Easycast clear does not). All surfaces are very clear, giving a good view into the interior.

There are many hundreds of pinpoint airbubbles throughout the object. These in my opinion are good enough for something that would sit on a desktop to show something to a mate, but wouldn't be good enough for scientific research or display. It would look terrible under a microscope.

Anyhoo here are the pics:





Thoughts: Envirotex may not be good enough for your needs if for scientific display; it is cool when curing. Easycast clear requires pressure casting which you may not have access to and may damage the insect (?); it also heats up to about 50degrees Celcius when curing. My Dad and brothers' had much better results imbedding mineral specimins with acrylic resin, though the heat factor may be a problem with delicate insects; acrylic can get hot!

Sorry for the results, I hope this has helped though

[Grover]

Well it's not for scientific study, just for decorative purposes, so it seems like it would suit me fine.

Since I'm not actually moulding anything special, more than likely just cubes, I don't think shrinkage would be a real problem.

Have any ideas on how I would go about posing a mantis within the cube though? Think I could move it around with tweezers while it's curing?

Also, I like how you took pictures of your piece with this thread in the background

[mangozac]

Well looks like the next step for you is to pick up something similar to the envirotex and do some experiments of your own then.

Posing might be tricky. Can you use some dabs of a clear drying glue on the underside of the joints in order to lock them in position? Then maybe pour a 10mm high bit of the envirotex, let that cure, glue the bug to that and then pour the rest to cover it?

Please do share pictures of whatever you end up doing. It will be interesting (and educational) to see the results!

[Grover]

The glue might work. Some kind of fake nail glue should be good cause it dries fast and clear.

Now the next question:
Since this resin is slightly flexible, is it still realistic to sand and polish it?

[blind pig]

[blind pig]

[Grover]

[blind pig]

[Grover]

I guess I am learning to cast. I have some experience with plaster, but I've never used resin before.

For the moment, I live in a small farming town and I rarely get to go to the city, so getting advice in person from someone who has experience isn't a viable option. And at least this way I'm getting complete answers to my questions as opposed to googling.

If this works out, I'll be able to make more after my eggs have hatched and the babies have grown up.

If I didn't have help to begin with, I don't know if I would have tried it at all.

[mangozac]

That's a cool looking Mantis! It makes me really glad to see and hear that people are learning stuff from my site

Yep, like it or not, you're going to be casting

[blind pig]

Hell Zac, I learn stuff from this site.

[on topic]

Looking at that critter, you may have to paint the Envirotex or similar into the joints and under limbs and crevices, to get rid of air spaces while filling the mould.

I hope you have a strong sanding arm, or lots of kids to help sand the resin after the mantis has been encapsulated.

[Grover]

That's a good point. Painting resin under the wings and their covers would probably be a good idea.

[blind pig]

Using a brush is something many casters do to ensure detail is taken-up when pouring silicone.

As an addit, the Envirotex, after being de-moulded for many days is now as hard as the EasyCast Clear, cannot be bent or marked with a fingernail.

We have a winner!

[mangozac]

Awesome this is handy to know! Do you think using a vibration table and pouring very slowly would help with the tiny bubbles problem?

[Grover]

This is all good to know. I'm going to the city next week so I'll look for that stuff. If I can't find it, I'll try buying it online.