Vacuform kit - interior support

Lonewolf · Post by **Lonewolf** » Wed May 16, 2007 10:53 am

I'm getting ready to build my first vacuform kit, and I'm trying to figure out how to support the kit internally. It's one of the McDaniel's Models kits, an older USS Hermes kit that I picked up a couple of years ago.

My choices seem to be either to build an internal "wheel spoke" framework out of styrene beams, or to fill the interior with expanding foam.

If I go the foam route, when should I use the foam?

a. before I seal the upper and lower hull halves (fill to a flat level, sand down what's sticking up too high, then glue the halves together)

-- or --

b. after the hull is sealed (drill out a hole in the bridge area and squirt the foam in there, hoping it doesn't expand too much and blow out the seams)

I want to provide support for the primary hull (saucer section), and maybe for the interconnecting dorsal. I may or may not reinforce the warp nacelle. I haven't decided yet whether I'm going to mount this kit on a stand or hang it from the ceiling.

Comments? Suggestions? Warnings?

Thanks in advance for any help y'all might be able to give me!

redfinger · Post by **redfinger** » Wed May 16, 2007 11:22 am

I would take the tame and build the frame.....the expanding foam can be trickey, I have always had a hard time estimating how much to use....

You could even use blasa wood or foam board to build the structure with...it doesnt need to be pretty if it will be hidden.

Ashton

Post by **TER-OR** » Wed May 16, 2007 7:32 pm

Balsa is a great option for internal support. It weighs less and can be more structural than styrene. I've used it for the interior on large vacuformed aircraft. Make a channel with styrene and epoxy the balsa in place if needed.

Though you will be surprised how sturdy a vacuformed subject can be. Remember to reinforce the joints, though, and use a hot cement.

Lonewolf · Post by **Lonewolf** » Wed May 16, 2007 9:35 pm

Joints aren't really the issue. I'm more concerned about the saucer section somehow compressing and leaving me with a nice styrene pancake.

I kinda wanted some type of internal support to keep the upper saucer surface from concaving into the lower saucer section. And to support the weight of the resin bridge section.

DX-SFX · Post by **DX-SFX** » Thu May 17, 2007 4:37 am

Use balsa as recommended. Expanding foam can expand and then shrink back slightly distorting the model permanently. A couple of rings made from styrene strip inside the saucer should stop the top and bottom squishing together.

Andrew Gorman · Post by **Andrew Gorman** » Thu May 17, 2007 8:29 am

Anything plastic and round will beef up the domes- acrylic wine glass feet, poker chips, tap light frames, etc. I usually have a Hong Kong scaffold made from bits of sprue inside large vacuform pieces.
Andrew

Lonewolf · Post by **Lonewolf** » Fri May 18, 2007 9:14 am

Thanks for all of the input, folks! It's really helped me.

I think what I'm going to do is follow the instructions for the first part (putting styrene ledges inside the inner vertical surface of the saucer sections so the upper saucer edge has something to rest on, then use balsa to criss-cross inside the saucer and keep the upper surface from collapsing.

Super glue gel should hold the balsa to the styrene, and I've got carpenters glue for bonding the balsa sections together.

Thanks again. I'm now looking forward to building this kit, and I'll be sure to post photos as I go. I have about 10 more vacuform kits waiting to be built (including the dreaded Lunar Excelsior kit), but I kinda wasn't sure how to approach building them. Now I think I can do this!