3D printed coil housing

[Tauc]

Hi all!
I will study some basic 3D printing in a few weeks and i was hoping to print a coil housing for a dd-coil. i have ordered a kit for TGSL from silverdog and was going to make the "standard" double d coil shown in PDF-files here at geotech (http://www.geotech1.com/forums/showt...mplete-Details). problem is, the coil is 27x27 cm. i will have access to a printer capable of printing items of a size up to 270x230x195 mm. this means i will have to change the size/shape of the coil, or print 2 pieces and then put them together (I still want the coil to be waterproof, so it might be a bit harder than printing a single piece)
i was thinking of waterproofing the coil with Marine Silicone Sealant (http://www.ebay.com/itm/HA6-Marine-A...UAAOSwWnFV8uLG) anyone got experience with this?

should i attempt to distort the shape and make it more oval, similar to the one on the left in this picture?

or should i go with the circular shaped (on the right) but just make it smaller, 23x23cm rather than the default 27x27?
any advice for a beginner?

[eclipse]

I have made PI coil with 3D printer 60 centimeters in diameter, 12 pieces or so, glued the pieces together, then used resin and composites to enforce it.
My mistake was making the walls too thin. I wouldn't recommend 0.5mm wall thickness and below.
Also if you put too much harder or use thick layer of resin the heat will warp the plastic, so apply resin couple of times (polyester resin) very thin layers to avoid excessive heat.

[Tauc]

Nice! That sounds promising. Did you manage to get it completely waterproof even after patching together 12 pieces? I will most likely use it where there wont be more water than wet grass but im still hoping to be able to submerge it 50cm or so underwater.