Hi Gang
I haven’t been here in a while, darn life intrudes on EVERYTHING!
Anyway… I’m hitting the home stretch for my hex, nothing remarkable, just the standard in-line 3DOF hex. While I love the exposed ‘guts’ I am also thinking about some sort of decorative/protective body shielding for it. More precisely, I was looking at the thin plastic body for a 1/8 RC monster truck (a Traxxas, I think) and thought that this would be perfect for a hex, or any other bot.
I mean the ‘truck’ body, the thin flimsy plastic one that you put the decals on etc. This thin plastic is flexible yet tough enough to hold up under moderate abuse. I believe it is vacu-formed stuff. It is very light, and SHOULD be relatively cheap.
I found a plastics-forming company near me, they advertise some vacu-forming, but I haven’t contacted them to find out if they do one-offs or very small runs. I have looked into home vacu-forming kits, but I don’t have the time or space (or money!) to get started in a whole 'nother area of this hobby.
Another ‘minor’ problem with this idea is the artistic side. I would have to make a full-size mold of the body, and the endless possibilities of whether to go tech or organic in the look just have me doing endless sketches, and it ain’t pretty. Then I’d have to make the mold, and begin the vacu-forming. Just too much for my small brane to cope with right now.
Does anyone have any experience along these lines? I’ve seen a few of the body covers done by the wizards here, but are they in that same thin plastic? And have there been any heat buildup issues?
And is it all cost-effective? I wouldn’t want the shell to cost more than the bot, or it simply wouldn’t be worth it to me. Those truck bodies sell for maybe 10 or 12 dollars, would it be something in that range?
My bot will get finished either way, but we all want to wow 'em with bling, right?
RC car bodies are made of Lexan.
OK, learn something new again! But they are vacuum-formed… is it any easier to work with? What would be the best material (most forgiving!) to use? I like the weight and flexibility of that lexan shell, I’ll have to read up on it!
Thanks!
I’ve done some vacuum forming. There are many videos on Youtube showing how to do it with inexpensive materials. You need a mold, as you said that’s really the hard part… Plus a shop vac or similar, an airtight shallow box with small holes on the top, think peg board, and an oven. 
Lexan is used as well as PETG. The latter I think is easier to work with, or is less likely to absorb water. Can’t remember…
Some people call it an art, and if you are wanting to make a lot of one part quickly it is. But it’s not difficult to do a one-off. Good luck with it!
Why would you want to cover up a lovely body? C3PO?
Alan KM6VV
HA…HA…!
I do like the bare techie look, but I’d also like to explore something a bit more sleek, maybe more of an organic look. Seeing as how I really do have my hands full just getting my hex to behave (!), a shell comes under the ‘bling’ heading. I now have the roughest idea of what vacuforming entails (pun intended!) and I think it may just be beyond my capacity in time, skill, money, and brainpower. It might be nice to try, but getting all the stuff set up for just one or two shells is beginning to sound un-do-able.
I’ll contact the plastic forming business near me and inquire about prices etc. That still leaves me with making the mold, which may be within my abilities. When I get some hard info I’ll post it here, hopefully before the end of August.
Yah, like I needed to make this project more complex… NOT.
Jonny would be the one to consult on body work!
I like my 'bots naked!
Alan KM6VV
you called.
Well im using a moulding and casting technique to create parts. its a longer process and maybe more expensive im not sure but i do it this way mainly because its fun to do.
one would simply create a sculpture of the part needed. This can be done by rapping your Robot leg in “kitchen rap” “Cling film” or what ever you call it, then sculpt using clay directly to the part.
like this:
Image taken from the production of MORAV…
here is one i did years ago:
http://i531.photobucket.com/albums/dd355/innerbreed/20081110_180832.jpg
&
The one on the left is the clay and the one on the right is vacuum formed.
i was going for a pounded metal look so the texture didnt matter.
http://i531.photobucket.com/albums/dd355/innerbreed/20081121_150202.jpg
This was also done using Styrofoam: LARGE IMAGE!
img245.imageshack.us/img245/5741 … 126fm0.jpg
then mould it.
you can either vacuum this part or make a **RTVsilicone **mould.
from the mould you can then cast the parts using a two part liquid plasic that cures to a hard polyurethane part. you can see this process in this video.
youtube.com/watch?v=0jsVKUbtYZI
although in the video im casting a solid part. using EasyFLo 120 curing resin you can make a “Slush/Roto cast” by rolling the liquid around inside the mould in till it gels. once cured you can demold it.
youtube.com/watch?v=57gHVdRKneY
good luck.
As i mentioned, i do it this way purely because its fun and nicer to do than making fibreglass parts. vacuum forming might be better.
Umm… wow?
Yes, wow sums it up quite nicely.
If I commit to this (depends on that company) I think your method, wrap and sculpt in clay, is gonna be the way to go for me. I have ‘some’ sculpting ability, so I will need some true artistic inspiration. Your technique provides the technical inspiration.
Thanks!
happy to help. do you know what sculpting material you have in mind?
for this kind of work may i suggest using “Super Sculpey”. it takes ages to dry out and it forms very easily and can create some nice sharp corners if needed.
If you need any tips working with this stuff let me know.
good luck.
Well, that company (which shall remain nameless… grrrr) wasn’t very warm to the idea of working with a hobbyist. They didn’t outright say No, but they definitely would want to make money from it… lots of money. An undetermined prohibitive amount.
I’m going to go back to square one, and consider using sheet metal. I’ll need a small metal brake (used for bending) and maybe a mini pop rivet gun, but all the other tools are standard garage-variety. So goodbye to smoothly curved surfaces, hello angularity and boxiness.
McMaster-Carr lists some sheetmetal working tools, a bit more than I’d like to spend but still possible.
Looks like all those descriptive geometry classes and algebra from years ago may finally pay off. Kind of like origami with sheetmetal, I guess. I’ll always look at that thin lexan and sigh…