Resin questions

[Tigerpounce]

Hello! I'm a long time lurker, first time poster.

Casting resin = magic, and I want it.

There are a ton of great tutorials available for small-scale casting (making little ponds and fountains and jewelry) but very little information on using resin to cast bigger items. I would love to make a replica of the Nemo dentist aquarium inside a 2.5 gallon glass aquarium. It's 12"x6"x8".

I'm sure it will take many layers and lots of patience.

Do I need to worry about the layers showing?

Do I need to worry about the taller items not being fully submerged as each layer is added?

Is the weight going to be insane?

Is clear resin clear enough?

Am I nuts?

What am I missing?

Any tips?

Has anyone cast something like this they want to show off?

 

[replicaprops]

With clear resins, you need to be very careful of how much you pour at a time. Take a look at smooth-on crystal clear 206. It is specifically designed to be poured in thick sections.

 

[Tigerpounce]

Thank you! I will. That answered several questions nicely.

I'm hitting the hoby store this afternoon. First I'm going to see how well I can sculpt. It's been a while. I'll be sure to take lots of pics.

 

[rbeach84]

With clear resins, you need to be very careful of how much you pour at a time. Take a look at smooth-on crystal clear 206. It is specifically designed to be poured in thick sections.

The other concern is how much heat is generated (the setting reaction is exothermic) as it will impact your embedded items. Thin pours obviously don't generate as much heat. I'd recommend patience and taking it slowly, allowing plenty of time for complete cures. It would be pretty disappointing if you got well into it and it messed up on you... also, bubble elimination is important.

Lastly, whichever resin you go with, you'd probably want one that isn't super-critical on the catalyst to resin ratio since you probably will 1) not have highly precise measuring equipment and 2) you'll be doing a lot of pours to build up that thickness. In short, you'd want something forgiving.

Regards, Robert

 

[Tigerpounce]

Thank you Robert!

I actually do have access to precise measuring equipment. My husband keeps salt water tanks and has a chemistry degree. Knowing that, does that change your recommendation for a resin? Ratios do not scare me. I'm fairly competent in my maths.

 

[rbeach84]

Thank you Robert!

I actually do have access to precise measuring equipment. My husband keeps salt water tanks and has a chemistry degree. Knowing that, does that change your recommendation for a resin? Ratios do not scare me. I'm fairly competent in my maths.

No, just do your homework on the resin(s) you're looking at so you have a good idea of their performance specs (plus their safety, so yes, get the MSDS' for them, too.) Sounds like you can go for some of the higher grade products since you have access to any needed tools (does this include a vacuum chamber for deaerating?) Best to go into it knowledgeable given the expense of resin and potential for a 'grand mess'. Resin casting itself is pretty simple - except for the chemistry! You can also get some cheap resin 'kit' and experiment a bit to build your skill and confidence before jumping into your main project. Always fun to play around a bit before getting serious!

Cheers! Robert

 

[replicaprops]

With clear casting resins such as crystal clear from smooth on, the resin is designed for different thickness. The 206 is designed for 6 inches or thicker and takes over a week to cure. The reason it takes so long is because tiny air bubbles that you may not even be able to see get bigger from the heat generated during the curing process. So the crystal clear 206 has a 7 hour pot life which gives the air bubbles plenty of time to rise to the surface. The extremely long cure time is so the heat generation is at a minimum to produce the lowest amount of air bubble growth as possible.
You will still get air bubbles unless you put the entire 2.5 gallon aquarium in a pressure chamber, but they should be not so bad due to the long cure time.
This particular resin must be post cured for 6 hours in an oven at about 160 degrees.
The amount of resin you need should be determined by placing all the items you are going to encapsulate in the fish tank and measuring the amount of water you fill it up with to the height you want to fill it. The resin is sold in gallon units, and you mix it 100 to 90. So if your items in the fish tank take up 1/2 a gallon of volume, and it is a 2.5 gallon tank, then you only need a 1 gallon kit from smooth on since they will send you 1 gallon of part A and 1 gallon of part B.
When you mix the 2 parts together take your time and make sure the mix is done completely.

 

[Tigerpounce]

Thank you both for the wonderful advice.

I am going to start small. I'm thinking betta in a wine glass. I have two very rough ones made up. One fell and shattered his back fins, so a good lesson in fragility.