The Robot Group   Fiberglass Eagle UserPreferences
 
Help Search Diffs Info Edit Print View
 MoinMoin Wiki   FrontPage   RecentChanges   TitleIndex   WordIndex   Help 

Using Google Sketchup and Pepacura Designer, this person sized sculpture was formed out of cardboard and covered with fiberglass. See the image at http://www.flickr.com/photos/grayconstruct/1434134883/

Creation of the cardboard sculpture: A while back I had one of those thoughts. I was at the local chicken place with a friend and I thought wouldn't it be cool to build a life sized statue, Something that looked like an eagle but more like a chess piece. 10 seconds later I had sketched my vision on a napkin and we looked at it with awe. In that moment I knew I was going to spend the next few months building the thing. I started with Google Sketchup, a free tool for 3d CAD. Many cad programs are very difficult to learn but after doing about 1-2 hours of the fun tutorials I was cookin! I produced a drawing of the thing. I used flat shapes like triangles and trapezoids to make it easier. I discovered Papecura Designer. A tool that will unfold a CAD design of arbitrary complexity into a set of cutouts with fold lines and glue tabs. It is a great tool and can be used for free if you donít need to save your customizations or a reasonable price if you want full functionality. It does a remarkable job of optimizing the folds and flaps. I build a 3 inch paper model of my sculpture and it was what I wanted. Since I didnít have a projector I couldn't automate the scaling of the model to my life-size 5'4" so that was some extra work. I used the compass and ruler in Sketchup to measure each of the angles and edge lengths and hand enlarged my unfolding printout onto the white back of sheets of Christmas wrapping paper and cut them out keeping tolerances mostly within 1/16". Then I got some good stiff cardboard boxes from around town. I transferred the wrapping paper stencil onto the cardboard and cut it with razor knife and half cut where the folds go so they would cleanly bend to edges. I decided not to paint it and thus I kept the blank side of the cardboard facing outward as I made the fold scores. I used duct tape to build the thing and make sure everything aligned. There were some slight discrepancies due to my hand drawn and transferred enlargement and the thickness of the cardboard. If i needed internal stiffening I added it into the CAD model and produced them. When it all fit together I settled on some access points for adding lighting and wiring and such and then hot glued it all which is firmer than duct tape. I bought sheets of fiberglass cloth and the fiberglass resin mix from auto parts stores. Thanks to Les for showing me the ropes with this construction material. I stretched the cloth over the cardboard, sometimes tacking it in place with hot glue (The glue lines can show through if you arenít going to paint) and painted on the resin with disposable brushes $0.25 from Walmart. Laytex gloves and a vent fan blowing is important even outside, this stuff is nasty and stinky. It sets in 20 minutes so you mix it and apply in very small batches. Larger batches of resin set even quicker due to internal heat release. With practice you learn how not to waste too much. Edges of the fiberglass cloth become sharp and need to be sanded (use dust mask). Apply multiple layers of cloth/resin where needed for extra stiffening. Some areas I used 1 layer, others 2. I am quite happy with the way the fiberglass darkened the cardboard. From a few feet away people often think it is a welded metal like tarnished copper or something and are shocked to find out its actually cardboard!

Future ideas: You could do alot with this stuff. I mean you could Sketchup a new body for your car or something and then produce it.... out of cardboard!!! Without complex metal working tools! I have not exposed the sculpture to water. I think it might have a few tiny leaks and the cardboard might degrade and affect the appearance but the fiberglass would still be solid and rigid. It is one of the lightest affordable strong products and could be used to make large robot parts. If you want a smooth car like finish, you will need to apply Bondo. This resin has more filler but the stuff I got sets quickly so itís hard to get smooth, it would have taken lots of more work in the sanding and re-filling pits, shaping edges, etc so this project didn't need that. You may be able to use a cheese cloth or burlap type material instead of fiberglass cloth. That is the most expensive component here. Test your material on test cardboard pieces to see if it works well with the resin to make smooth and strong shapes. I havent tried, but it may be possible to scrape or sand the cardboard away from the inside or have some sort of saran wrap or releasing agent to produce a lighter and yellowish translucent object that could be internally lit.


PythonPowered EditText of this page (last modified 2007-10-03 11:38:28)
FindPage by browsing, searching, or an index
Or try one of these actions: LikePages, LocalSiteMap, SpellCheck