Tips for building Vacuform kit

Squall67584 · Post by **Squall67584** » Wed Aug 15, 2012 2:24 pm

I'm about to start building a vacuformed kit, and was thinking about whether it would sag over time. The kit is of a flying wing, so the overall body is really thin and wide. I was thinking about putting a layer of Aves on the inner sides of both halves so they're more sturdy when put together. Is there any reason to not do this? Any other tips on how to keep a kit of this type sturdy would be appreciated!

Kylwell · Post by **Kylwell** » Wed Aug 15, 2012 2:40 pm

You'd be better off with gently applying some expanding foam. It's rigid and lighter. Or you could glue some Evergreen angle stock along the wing.

Ziz · Post by **Ziz** » Wed Aug 15, 2012 3:26 pm

You could also go the standard boat building route of making some kind of internal skeleton. For a wing shape, I'd use brass rod for the length of the wing and styrene strip cut to fit the cross section.

TazMan2000 · Post by **TazMan2000** » Thu Aug 16, 2012 12:15 am

Be careful with the expanding foam. Some stuff is so strong that it will bend window frames as it expands, so you can imagine what it will do with a vacuform kit. There is, I hear, some new stuff in the hardware stores that just expands to the available space and doesn't cause pressure, but I haven't tried it. I would recomend trying it out on an old model before you try it anywhere else.

TazMan2000

seam-filler · Post by **seam-filler** » Thu Aug 16, 2012 6:53 am

Another problem with expanding foam and vacuum-formed styrene is that the solvent in the foam can be 'hot' enough to warp or even melt through the styrene (ruined 1/48th Convair B36 is my evidence!).

One or two brass rods along the chord of the wings should be enough to stop sagging and maybe a rib or two cut to the wing cross-section. Personally, I've used a few blobs of epoxy (I hate CA) to hold brass rod instead of one long run - even the heat from epoxy can distort thin styrene - it also allows for a bit of expansion & contraction in the plastic in the years to come.

Good luck.

Squall67584 · Post by **Squall67584** » Sat Aug 18, 2012 5:00 pm

Thanks for all the tips guys! I made a trip to hobby lobby today and found some 1/8th inch cellufoam sheet that I'll cut to shape to use inside the halves and will use a thin brass rod to keep it straight and even. I'll post a build thread soon.