As promised, here is the post on how I cast the water in the diorama.
A warning here: This is a LONG post, detailing the issues I had casting water and how to overcome them. If you want, feel free to skip to the end for my final tips on the subject. I’ll also be posting this to the LCM3 thread I started.
Water, water everywhere, and I wouldn’t wish it on my worst enemy!
Okay, maybe that’s going a little far, but the simulated water in this diorama gave me such a headache that I figured I should make a separate post to explain why and some suggestions for how others can avoid my many, many mistakes.
This is the water I wound up with. It’s tinted, and has waves, but is clear enough to see the bricks of the retaining wall under the water and the LCM3 hull as well.
Be aware that this post only applies to casting large amounts of water. Small streams, ponds, etc, are frankly jokingly easy in comparison and can be made with almost any water simulation material from gloss acrylic media to epoxy resin, etc. For those I recommend either epoxy resin or woodland scenic realistic water.
When I began making the diorama I planned to use smooth-on clearcast 200, a clear urethane casting resin that smooth-on says is perfect for embedding things in, like the LCM3. I’m a big fan or smooth-on silicon and resins for casting parts, so I figured I’d try this. I even called them to confirm it would work and they said yes and that it should be poured in one large pour rather than layered. They said it could be degassed, which means if you have a vacuum chamber (I do for casting parts anyway) then I’d have no issues with air bubbles.http://www.smooth-on.com/Urethane-Plastic-a/c5_1120_1156/index.html
Of course, I wasn’t about to just randomly pour it onto my carefully prepared base and model without testing it, so I tested it in a variety of plastic containers painted with Tamiya paints, to ensure no adverse reaction between the urethane and the paint. Frankly, it cast beautifully. I could degas it to avoid air bubbles, and it hardened overnight. If I caught it at the right time I could even sculpt waves into it by pressing down on it with a small spatula. I could even tint it easily with clear Tamiya paints.
So I ordered over 100 dollars worth of the stuff (remember, large area being cast here!) and did my pour. All my measurements were perfect (checked on a digital scale with a 0.05+-g) and degassed it as usual. It poured, looks great, so I left it to cure for a while.
An hour later I came back to disaster. There were air bubbled rising all throughout it, and it was already so solid waves couldn’t be sculpted. Panicked, I managed to pull the LCM3 free from the nearly-solid water without much damage (luckily), and pry the thankfully-still malleable water out of the diorama and into the trash.
What had happened? Two things: firstly, pouring that much resin at once caused it to cure MUCH more rapidly, even though smooth-on said that wouldn’t happen. Secondly, even though the base was sealed with polyurethane varnish, Tamiya acrylic paints, and then future floor wax gloss coat and left to dry for a week, there was somehow still enough exposed wood and thus moisture to react with the urethane and generate air bubbles. Those bubbles began to drift up to the surface, but got trapped in the rapidly curing resin.
So suffice it to say that was a failure.
On the plus side though I managed to save the LCM3 and only had to repaint a bit of the bow.
After doing so, and preparing the base again, I set about trying again. This time I decided to use polyester resin, namely envirotex polyester resin. This stuff is intended to be layered and is often used by modelers for streams and other such things. As it can also be degassed, the risk of air bubbles is substantially reduced, and it can be tinted with either Tamiya clear paints, or their own tints (I used their own tints to ensure nothing reacted badly).
I read the section on casting water in Mig’s FAQ book, and he says you can sculpt waves the same way as I tried with the urethane resin, by indenting the nearly cured resin with a tool. So I tested this in a variety of container sizes, including a wooden one this time just to make sure. While the resin cast okay, it was difficult getting the waves to form well, but after 4 or 5 tests I felt semi-confident.
This time, following the instructions exactly, I poured the water in layers 1/8 inch thick. The first four layers cast beautifully and I was getting very excited. Then it was time to cast the layer with the waves. I waited until the waves would ‘hold’ based on my test casts, and went at it. At first the waves wouldn’t hold their shape, but finally they started to. Now here’s the issue: Remember when I said this was a large area? Well, by the time I got half way across it the waves began to harden to the point where they either wouldn’t form at all, or would form with all sorts of minor air bubbles/stress marks in them. And trust me, I was working as fast as possible!
Frankly, it looked terrible. The waves didn’t really look all that much like waves, and they had air bubbles/stress marks in them, etc. My only option was to sand down the worst of the areas and then pour a new layer on top. This was not fun and generated so much sanding dust my hair was nearly white by the end!
The final layer went on and it looked…okay, at best. Flat, with no waves, but at least there weren’t that many air bubbles visible.
And then the shrinkage began. Now, understand, I expected a small amount of shrinkage of the resin and the instructions even warn about it. What I didn’t expect was that said shrinkage would tear the paint and front hull ramp off of the embedded LCM3 hull!
Yeah, not happy about that one.
So with the damage to the hull and the flat/unsatisfactory result, I decided to try to remove the LCM3 and redo the water again.
This time I wasn’t so lucky. The LCM3 hull cracked during removal, and the retaining wall of the diorama was also destroyed.
Now I was pissed.
I had avoided using epoxy resin for the water because it can’t be degassed and it can’t be sanded. You can remove air bubbles by letting them rise to the surface and torching them, but if anything goes wrong, there’s no real recovery option. Because its epoxy and very sticky, its also a lot more difficult to sculpt waves into, to the point where most ship and train modelers who use it recommend not even trying and instead topping it with something else to make waves with.
So fast forward a month and I rebuilt the LCM3, rebuilt the diorama retaining wall, chiseled the polyester resin out of the base, and got everything back to ‘ready to cast’ stage. Once again, I ensured the base was properly sealed with several layers of polyurethane, several layers of Tamiya paint to simulate the depth of the water, and several layers of clear gloss to prevent anything from reacting. Once again I tested the epoxy in a variety of different containers, and made sure it didn’t react negatively with anything.
As per the envirotex epoxy resin instructions, I made sure to cast in several thin layers, this time without trying to put waves in at all. Air bubbles were rapidly torched out with a kitchen crème brulee torch, which thankfully didn’t melt the LCM3. In end I wound up with a perfectly clear, tinted water base I was happy with. No shrinkage, no tearing off of the LCM3 hull paint, etc.
So now it was on to the waves.
There are several ways to make waves, but the typical ones are using either acrylic gloss gel, or woodland scenics water effects. I chose the woodland scenics product as it was fairly well reviewed online and I even found a nifty youtube video on how to apply it. Simply put, you squeeze it on, and then trowel it out with a popsicle stick. It shrinks a lot when it dries, which can take several days or even weeks for thicker layers, but this helps to hide some of the popsicle stick marks so its not necessarily a bad thing.
So I applied it, and waited a few days, and was horrified.
Why? Because if you’re making large amounts of smooth waves, then there’s one significant issue: No matter what, when you push this stuff around with the popsicle stick, you will be getting air bubbles into it, not to mention those made just by troweling it out or squeezing it out of the container. With turbulent water this doesn’t matter, in fact it adds to the effect. But if you’re making smooth, gentle flowing water, then these air bubbles stand out in the waves. A LOT. And even though I was very careful in applying this stuff, if you have even a single air bubble every four or five waves, that’s still way too many, especially given the size of the area I was casting.
And yes, this had already been applied to the diorama base when I noticed it. Grrrr….
Queue three days of removing the water effects gel using rubbing alcohol and a scraper (which works but be gentle not to scratch the easily-damaged epoxy water!).
After this issue I did a bunch of tests. I took clear acetate and spread every known wave-making material I could get my hands on to see what it looked like when it went clear. I applied it as carefully as possible, agitating it as little as possible to get as little air into it as possible. I then let it dry a week.
I tested woodland scenic realistic water, their water effects, acrylic gloss gel, both medium and heavy, and modge podge gloss and supergloss.
Woodland scenic realistic water wouldn’t hold a wave shape no matter what. It’s not really intended to, it’s more for doing small streams of flat water.
Woodland scenic water effects traps and holds air bubbles, which become worse as it shrinks. This doesn’t matter if you plan to paint over it, or want to use it as a waterfall, but if you want clear waves, its terrible.
Liquitex acrylic gloss gel, both medium and heavy, have the exact same issue. No matter how careful I was, I wound up trapping air in the waves.
Modge podge supergloss is also useless. It reacted the same way as the woodland scenic liquid water, and wouldn’t hold a wave shape. In fact if I didn’t know any better I’d say they’re the same product. They’re even the exact same color.
Modge podge clear gloss: This worked! Air bubbles quickly rise to the surface, and need to be popped manually. It won’t hold large waves, but for gentle rippling of a moving river or stream it’s perfect! It only has one major issue. Anything thicker than a thin layer takes forever to dry normally. I’m talking on the order of weeks. I waited three weeks and there were still a half dozen waves that hadn’t gone clear. The online instructions say you can speed up the curing with heat and a low humidity environment. So that’s what I did. Using a rolling toolchest, and two brooms, I positioned my food dehydrator above the water, set it to 125 degrees, and left it for two days. By the end of day two if was clear and perfect. I sealed it with a little Tamiya clear green-tinted future floor wax, and voila, finally a good wave simulation, IMO!
So for those who have skipped down, or those doing searches for how to cast large areas of water, these are my tips:
1) Work in a clean, dust-free environment. Nothing is more irritating than a perfect coat of water with a couple of flakes of dust accidentally embedded in it.
2) For large areas of water, use epoxy resin. Yes, it will need to be layered, but it works beautifully, doesn’t shrink, and air bubbles can be removed fairly easy. Tint it with either envirotex’s own tints, or with Tamiya clear paints. Also, DO NOT try to degas it. This will only generate a huge amount of air bubbles you’ll never get rid of. Ask me how I know.
3) For waves, do NOT try texturing the resin itself. This can work in small areas or small streams, but IMO is not worth the risk, especially if you’re embedding a model in the water.
4) For large, turbulent waves or waves you plan to paint over with an opaque paint layer, you can use anything from woodland scenic water effects, to acrylic gloss media, it won’t make much different. But for smoother, flat ripples, use only modge podge. For the life of my I don’t know how you can get a clear, air-bubble-free result using anything else.
5) Speed up the drying of modge podge with a food dehydrator or something similar. Be very careful that it doesn’t get too hot though, so hair dryers or heat guns are not recommended. Otherwise expect it to take weeks to truly fully cure, depending on your temp and humidity.
6) Both modge podge, and epoxy resin are technically ‘soft’, and can’t be sanded well. When they’re dry, coat them with an acrylic varnish like future floor wax to protect them. That way you can later clean and dust your water without scratching it.
7) For smaller bodies of water like streams, puddles, and wells without much water movement, almost anything will work. The woodland scenic realistic water works well but takes a while to dry. This is what I used for some of the larger puddles in the diorama. Epoxy works well for this too. Theoretically urethane resin or polyester resin could work too but I honestly wouldn’t risk it unless you have nothing else you can use.
I do hope that anyone planning to cast water who stumbles across this reads it, takes it to heart and has a better experience than I did. I now feel like I can cast amost any size area of water, but on the other hand, given how frustrating doing so was, I’m not sure I ever want to again!