Resin casting

I needed some ammo boxes to put on my M577 to copy a 1/35th scale model I had found on the Internet, that was based on a real vehicle of an Artillery Command vehicle. (I will dig the photos out when I complete the model) I looked for some boxes of the right size but only found smaller ones from TAG which is fine for vehicle clutter and needed something a bit larger. I then constructed four boxes of the desired type but then ran out of card etc and did not fancy making another eight.

I also had an issue with a couple of Dust Tactics buildings that looked bare without proper windows. I then made some window frames which was a bit time consuming, so thought the best solution was to cast some copies of both the windows and crates in resin. Luckily the local toyshop was having a 20% off sale at the time so was able to buy a bucket of Lego to make some boxes to cast in. I have just finished making a big pile of boxes and windows which have been washed and are now drying out. I will be able to undercoat them tomorrow. 

I had some failures which meant throwing out five boxes which were still oozing fluid plus some of the windows were a bit soft but feel like they have set properly. I have another house which needs windows but will probably just make them out of plastic as I'm not sure that casting them is worth the hassle. I am considering wether it would be worth making some cargo loads and barricades out of the resin boxes and then casting them? In the last photo I have sorted the boxes into two grades. One for vehicle cargo and the other for terrain.

Edit- well I have undercoated the windows and have run into further problems. Some of the windows have started to weep liquid and are sticky from undercoating. I have experimented with trying to microwave one of the worst soft castings which seem to have cured it. The surface is still sticky from the undercoat though. I think the main issue is that the windows are too thin for the resin to generate much heat to cure fully. The instructions suggest heating the moulds in an oven which seems like a big effort for four small moulds which would mean having the oven running most of the day. I tried microwaving the moulds which did not seem to do much except burn the wood it was sitting on. Almost all of the boxes are fine unless the resin was not mixed enough which looks like swirl marks. I am going to try another make of undercoat with the discarded boxes to see how they react. At this stage I would not recommend anyone follow my example.