A Kirkham, only smaller...

slider701 · #1 (**permalink**) 02-11-2010, 05:02 PM

Quote:

Originally Posted by bmwmech1

You may have hit on an avenue worth pursuing... although milling a body would not be my first choice, I might contact them about CNC milling me a scale wood buck... then I could use that to hammer out a metal body(s). I don't know that aluminum would be my first choice, since TIG'ing that thin of aluminum might be dicey, but a copper body could be done with relative ease and soldered together, then filed and finished as per usual. This is something worth looking into... I must say thanks for the idea! I'll keep everybody posted...

Garey

The other thing you could do, if you have a plastic model that is the correct size, is make a plastic or silicone mold/splash of that body. This will then serve as a mold for you to pour an epoxy or similar hard plastic to make a hard buck to use.

Take a look at the "Plastic Casting > Urethane" video in the following link:

http://www.acucast.com/multimedia/

I have never used these guys in the link above but they have a good video of how a rapid prototype part is made, from the SLA process of taking a CAD file and making an initial part through how they can make functional plastic parts for prototypes at a fraction of the cost of an injection mold tool.

I have used these guys in the link below and the cost is extremely reasonable, just no fancy videos on their web site.

http://theprototyper.com/

bmwmech1 · #2 (**permalink**) 02-11-2010, 05:18 PM

Quote:

Originally Posted by slider701

The other thing you could do, if you have a plastic model that is the correct size, is make a plastic or silicone mold/splash of that body. This will then serve as a mold for you to pour an epoxy or similar hard plastic to make a hard buck to use.

Take a look at the "Plastic Casting > Urethane" video in the following link:

http://www.acucast.com/multimedia/

I have never used these guys in the link above but they have a good video of how a rapid prototype part is made, from the SLA process of taking a CAD file and making an initial part through how they can make functional plastic parts for prototypes at a fraction of the cost of an injection mold tool.

I have used these guys in the link below and the cost is extremely reasonable, just no fancy videos on their web site.

http://theprototyper.com/

I have and will have to do some mold making/casting for this project, but I don't know if it will work for the body buck, although it's a great suggestion... when you're doing any type of hand/hammer forming in this size/scale, most of your shaping is accomplished through annealing the metal, to soften it and then hammering it to shape. Having the wood buck serves both purposes, since it is hard enough to stand up to the repeated hammering and also it won't melt during the annealing, if you have to do it on the form. That's why I thought a wooden buck would be so functional. I have a backup plan of laying up the body in fiberglass, but that's just not as true to the 1:1 as I'd like to go, given the option of both... thanks for the 2 links, I may end up using the second one for some stuff on this build even!

Garey

bmwmech1 · #3 (**permalink**) 02-11-2010, 10:21 PM

So I got alot of the rear suspension tubes knocked out tonight... still lots left to do, but it's starting to look like an AC frame at last! I milled pockets in the main tubes to catch the front uprights, milled slight holes in the rear crossmember for the rear uprights and milled slots in the tubes to catch the gusset plate. All of that made lining everything up a lot simpler and stronger. Still plenty of brackets to add, but it's getting closer to being done... enjoy!

I'll post another update over the weekend... maybe I can get the rear suspension brackets done... we'll see.

Thanks for watching!

Garey

thudmaster · #4 (**permalink**) 02-11-2010, 10:41 PM

This is great to watch your car come together. I know it is a bit off but are you planning to polish the body, brush it or paint it?

bmwmech1 · #5 (**permalink**) 02-12-2010, 06:24 AM

Thanks Ed, the build has been well received here, so it's a pleasure to share it with everyone. And what better critics than a bunch of Cobra owners, right? Gotta make sure it's right... Anyways, the body is still up in the air. I had originally thought and planned to shape a buck from EPS foam and lay 'glass over it for the body, but I am now going to pursue opening a conversation with the Kirkhams to see if they can do a scale CNC wood buck for me to hand hammer a metal skin over. (If Tom or David reads this, feel free to PM me...) That would open the door to a truly accurate model, but I,m not sure about TIG'ing aluminum that's thin enough to be correct in scale, so it may have to be done in copper. (Again, if the Kirkhams read this, they would have a better insight into the possibility of using aluminum.) It is, as you've said, a bit down the line, but I'm still thinking about it!

Thanks for watching,

Garey

bmwmech1 · #6 (**permalink**) 02-14-2010, 10:34 PM

I hope the open house weekend was a smash, wish I could have flown out for it... maybe next year I will. Thought I'd post up some pics for all of you weary eyed travelers who did get to go...Well, my goal was to get the chassis completed this weekend and I'm 8 brackets and 8-10 tabs shy of being there. It's really starting to look the part, now. Some of the stuff I had to fab and solder was a real treat... the tension arm mounts and the upper differential mounting brackets were a real pain, but worth the aggravation! I should be able to get the rest of the stuff fabbed and on the frame by tomorrow night, so I'll post another set of pics then. I have quite a few hours of solder joint clean up to do, once the chassis is complete, then it's onto the birdcage... enjoy!

Thanks for watching!!!

Garey