04-15-2007, 11:06 AM | #1 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
| Composite Chassis
After months of taking info from this forum I thought I would try and give some back when I can. So I wanted a composite chassis for a 2.2 crawler. To start I will need a side profile. Easy to make with poster board and a 2.2 chassis with all the shock and link points that work for me. MikeP |
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04-15-2007, 11:15 AM | #2 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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I need a width of 3". The paper side template is tacked to a block of Dow 3" pink insulation foam (scraps from a construction site, roofers use this stuff) 3" is hard to find. I use a band saw to trim it close then sand it down to the template with a sanding block with 60 grit. |
04-15-2007, 11:34 AM | #3 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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Once the side profile is good i can shape it how I want with 60 grit then finish with 220. The foam needs to be sealed with epoxy and a filler. I use West Systems products from West Marine. Epoxy with Silica mixed to a ketchup thickness and brushed on the foam, then sanded smooth using the 60 grit finished with 220. Make sure you don't sand through the epoxy. At first this may take a couple of coats. I got lucky on this one and got it in 1 coat of epoxy. Now I have a plug of the part I want to make. I don't spend a lot of time on the the plug finish. I wet sand and polish the mold. (this is backwards from the way the pro's do it). MikeP |
04-15-2007, 11:41 AM | #4 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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If I left the bottom of the plug flat I would not be able to get the finished part out. Now I need to make a bottom board to match. I used some pastic sheet on the bottom to keep the epoxy from sticking to it. All this is tacked together with 3M 77 spray glue.
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04-15-2007, 11:45 AM | #5 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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Here it is ready to make a mold, everything is waxed 6-10 times with Partall mold release wax.
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04-16-2007, 03:48 PM | #6 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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To start the mold I mix up epoxy with powdered graphite and silica to a mayonaise thickness to use as a tooling surface or Gelcoat and brush it on. Then wait for it to set up a little. Brush on more fresh epoxy then fiberglass cloth, work the epoxy into the cloth with a brush.
Last edited by Mike Poulson; 04-16-2007 at 03:52 PM. |
04-16-2007, 04:01 PM | #7 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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Used about 2" wide strips of 10oz fiberglass, brush on epoxy then lay cloth and work it in. 2 layers of cloth with the overlaping seams should be about right to leave some flex in the mold so I will be able to get the finished part out of the mold.
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04-17-2007, 02:00 PM | #8 |
Pebble Pounder Join Date: Mar 2007 Location: Merritt Island
Posts: 158
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I really wanna see this finished, it has the ability to be a great body with its durability.
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04-17-2007, 02:04 PM | #9 |
I wanna be Dave Join Date: Mar 2006 Location: One Legend.
Posts: 2,134
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Are you planning on competing with this rig?
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04-17-2007, 03:24 PM | #10 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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04-17-2007, 04:08 PM | #11 |
I wanna be Dave Join Date: Apr 2004 Location: SoCal
Posts: 5,027
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Do you plan to run a chassis under this and this as the body?
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04-17-2007, 08:25 PM | #12 |
RCC Addict Join Date: Aug 2006 Location: trying to find out what a TVuPer is.....
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04-17-2007, 08:37 PM | #13 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
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subscribed! Im gonna take a shot in the dark and say he will use a skidplate and crossmembers and use the skin as a monocoque type chassis. Its gonna take some skill to tie the shocks in! Awesome idea, I have wanted to try this or see it done for so long. You build planes or boats too? |
04-17-2007, 09:23 PM | #14 |
Quarry Creeper Join Date: Mar 2006 Location: Juneau Alaska
Posts: 244
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04-17-2007, 10:17 PM | #15 |
I wanna be Dave Join Date: Oct 2005 Location: Columbia TN
Posts: 6,154
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Aw crap, I can here the rule committy's butt holes tightining as I type. Looks cool though. |
04-17-2007, 10:24 PM | #16 |
I wanna be Dave Join Date: Mar 2006 Location: One Legend.
Posts: 2,134
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No tightening here... Just trying to see where he is going with it. It's a neat idea, and looks like he has the skills and resources to pull it off! That said... If he is building it as a standalone chassis, he'll have to run a legal body on it to compete. If he is building a body, well he'll have to replace it to compete. |
04-17-2007, 10:26 PM | #17 |
I wanna be Dave Join Date: Jul 2005 Location: Cedar Rapids
Posts: 2,028
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04-17-2007, 10:39 PM | #18 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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Rules and looks aside it's just something I needed to build, I get one of those ideas in my head that just wont go away. I figure throw it together see how it looks get some input and go from there. John, I learned how to make composite parts from the airplane forums so I could build R/C boats (outriggers). Aluminized Fiberglass, now that sounds cool, I getting kind of tired of the CF look. Yahooo..... after digging out the foam plug no flaws to fix. I polished it with 220, 400, 600 wet. |
04-17-2007, 11:01 PM | #19 |
Quarry Creeper Join Date: Jan 2006 Location: SLC
Posts: 382
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I made paper templates to cut the pieces needed to fit the mold, I had enough left overs for 3 layers of 3k plain weave. The roof will be done in 2" strips and the sides will be one piece. The strips in the roof will overlap giving extra layers in the areas where the windows will be cut out. Should be good. After a lot of waxing and then PVA I Brushed on a coat of epoxy with a little silica. The silica will keep it from running to the bottom. Let this coat get tacky, this will help hold down the cloth in the sharp corners. Brush on a fresh coat of epoxy first and start laying in the CF work the epoxy into the cloth, more epoxy then cloth. Working the epoxy from the back side out insures good saturation. |
04-18-2007, 05:07 AM | #20 |
Rock Stacker Join Date: Apr 2007 Location: Monticello, MN
Posts: 94
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That is without a doubt one of the coolest things I have seen. I may have to take a wack at carving out a body. Not sure of my skills though, my truck attempt might end up looking like a Pinto wagon Looking forward to seeing the completed chassis. Matt Last edited by maddog2099; 04-18-2007 at 05:28 AM. |
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