Advice needed re creating miniature fishtank

[snappycat]

I've just completed a miniature fishtank but would appreciate some advice on how to improve the result. The objects are created using polymerclay (fimo) and sit in one of those plastic display cases you get tiny fossils in. I was aware that in order to pour to a depth of 50mm I needed to use polyester resin. For a first attempt I am not unhappy but would like to improve upon it! I've posted a pic (hopefully!) Showing some of my problems. Firstly I have some weird lines on the sides (by the snail and the heater) I'm guessing this is related to the glue I used to afix these pieces? I used a glue gun. Secondly some, not all, of the stones turned a weird silver colour? I'm not sure whether this is an air bubble? Or whether the clay I used contains something that reacted with the resin? Could anyone advise me how to seal objects to minimise the risk of a reaction? Have considered glue but noticed the resin generated quite a bit of heat and fearful that with glue this will cause blistering.. Which may explain the first query! Also the heat caused the box to warp very slightly - not hugely problematic but would like to avoid if it's possible.... I used the higher end level of the stuff you add (technical!) because the weather is freezing and I was worried it would turn out cloudy ( ended up bringing it in and sticking it under my kitchen extractor hood when the worst of the stink had gone!) Would really appreciate any help or advice - its rather expensive to make mistakes! thank you!

[snappycat]

[mangozac]

I've not used clear polyester before but I understand it's pretty gnarly stuff.

The "weird lines" look like shrinkage marks. You say the resin got pretty hot while curing so that would make sense. Any change you can sand/polish them out?

The silvering of some of the stone is pretty bizarre. It must be something in the stones reacting with the resin. Coating them with an acrylic sealer (not glue) should do the job. There are specific products for this but I've not used any so can't make any recommendations.

[snappycat]

Thanks for that. Can't polish them out because the resin is poured into a clear perspex box to look like water in a fish tank, am assuming there isnt much i can do about shrinkage if its in a container? Will Google for info on sealers. It was only the clay I used to make the rocks that reacted oddly. I think it must be an air bubble on the filter which is annoying as I didn't see it at the time - tapped quite a few out but wanted a few bubbles remaining as I thought it would look more realistic! Plan to have another go with less items in it so should make the rogue bubbles easier to spot!