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Cerberus
December 13th, 2009, 02:22
I need a material that can be easily shaped but is fairly sturdy, something easier to work with than wood but not nearly as weak as wax/clay. Any suggestions?

mike_cyul
December 13th, 2009, 03:27
Foam of some sort?


Mike

harleyman
December 13th, 2009, 03:51
YUP...A big block of foam..That is what the designers use for cars anyways....

Terry
December 13th, 2009, 04:15
If you buy polyurithane as components A=resin, B=catalyst. Place the item you want to package in a light plastic bag. Mix the components in a container and as it starts to expand put the bagged item into the foam and it will form around it. When its done blowing cut around the perimeter of the foam to give yourself a top and bottom.

Lionheart
December 13th, 2009, 07:30
Hey Jesse,

I used to do prototyping and found that working in foam and then painting it with a ton of resin (fiberglass style resin) will do the job nicely, creating a glass like surface if done right. The foam really absorbs it well.

Great designers like Guigarro have even used old bread as it acts like foam. Coat it with plaster, then sand and finish with regular surface materials/paints, etc.

Some use foams. Aircraft tend to use 'plastic' like foam that bends (like childs toys), while surf boards tend to use core foams that are more solid and easily sandable. This is the material I have made cars with. Great stuff. You can sculpt with your hands with this stuff, but the dust is horrible, gets into everything. Wear a plastic jump suit if you work with it, and work in an area you dont mind it getting dirty with foam dust.

In the new prototype shops, they make a clay (or similar) model, then make a vacum formed model from that, that is cleaner and all. Their ways are much more cleaner now and lower in dust. Nicer to cool environments that have books, computers, etc.

You might go to the library and look up books on 'model making' and 'industrial design'.


Bill
LHC

Lionheart
December 13th, 2009, 07:36
Also....... Balsa...

By the way, you can make a large model (lets say a brief case size model) by finding a mock-up core (old box, etc), then covering that with bondo, and shaping to finish. You can also go with surf board foam, sculpt it to roughly the shape, and then coat it with resin and bondo, and they finish, then pull a mold from it.


If you have never worked with resin and fiberglass though, you'd probably not want to do this.

If you create an amazing exterior mockup, you can go to a fiberglass shop (really look hard at finding a good shop, like a boat shop that builds boats, etc, and are reliable), and have them make molds and a model from that.. Then you only need to paint and finish.

Plaster is really amazing. You can sculpt it well with sand paper, blocking, etc. Then coat with primer and then use spray on bondo coatings and finish. You can make plaster molds, but plaster 'super heats' when it goes off and turns solid, so you have to be careful as it will burn/warp your plug (part you make the mold from). But its far better then using fiberglass. There are some cool new pour type mold materials you can buy at hobby stores, but they are flexible, so you need to have them in wooden former boxes to keep their shape. After a while, they deteriorate, so you need to keep your plug in a safe place so you can remold from it..


Bill

jmig
December 13th, 2009, 08:02
Bill, Your two posts above are very helpful and informative. You have provided me with much information, I wish I had when I was building the parachute box on top of the ejection seat for my cockpit.

In fact, I may use some of your info and go back and redo parts of it, of which I am not satisfied.

Thank you!
:medals: :medals:

Lionheart
December 13th, 2009, 08:39
Most welcome. Glad I could help.

For making prototypes, remember, you mainly need something that is a plug and that you can make the mold and then parts from it. So wood even makes a brilliant 'core' to make plugs from.

Wood, you can create strengthener lines in the surfaces via a router.

I have made wings for cars (rear racing wings) and control yokes and little toys from wood, (and foam and balsa and plaster), then finish with primer and laquere, wet sand and polish to a mirror finish.




Bill

N2056
December 13th, 2009, 09:05
IMPORTANT SAFETY TIP!

If you go the foam route BE SURE to wear a dust mask/respirator! That stuff is not "lung friendly"

Piglet
December 13th, 2009, 17:02
Renshape is good. I think that's how one spells it. Almost as hard as wood, tho. But it machines just beautifully.

Lionheart
December 13th, 2009, 21:06
If Renshape is that reddish new material they are using, that stuff is awesome.



Bill

Cerberus
December 13th, 2009, 21:17
Thanks for the info. I want to make a small enclosure out of foam before I design it in cad and begin looking for someone with a CNC machine to make it out of T6 Aluminum.

Snuffy
December 14th, 2009, 03:17
Thats kinda going about it backwards don't ya think Cerberus? Usually you do the prototyping in cad then build a physical model. (So long as the model you build in cad isn't sufficient for your needs.

Just a thought ...

Lionheart
December 14th, 2009, 10:10
Thats kinda going about it backwards don't ya think Cerberus? Usually you do the prototyping in cad then build a physical model. (So long as the model you build in cad isn't sufficient for your needs.

Just a thought ...

Actually sometimes its better to make a quick rough prototype to get an idea of the area and fit.

For instance, car companies make sketches and art first, then the cad and models, and sometimes the models preceed the cad and the cad is made from the models.

A person, when actually having the model in front of them can sit there and change alot of minute details and things where you wouldnt really see them in a cad screen.



Bill

wombat666
December 15th, 2009, 03:50
FWIW we use a blue wax that we sourced in Italy for mastering car model parts and shells, as well as a very high density styrene (can't remember the name! CRAFT Syndrome?) block material for large units.
:isadizzy: