MAX Update No. 54: Mistakes, and How Not to Make Them


| 8/3/2010 3:36:13 PM


Tags: MAX, 100 mpg, fuel economy, gas mileage, streamlining, Jack McCornack,

I bet you think I've got this all figured out. Hah! I've been doing my problem solving on the fly, coming up with new techniques and learning from my mistakes, and boy! Have I been learning a lot, or what?

MU54a1Since I don't really mind folks laughing at me, I'm going to share a couple of recent mistakes with you.

I spent way too much time trying to get the hood working, but eventually I threw in the towel and went back to a one-piece nose. To hold the hood between the fenders while fiberglassing the parts back together, I came up with this cool system, of making strips of stiff clear plastic and riveting everything in place through the plastic, with a row of rivets in the hood, adjacent to a row of rivets in each fender. By using aluminum rivets, I could drill them out once the bonding was complete, and then just fill in the rivet holes. Aluminum is softer than the fiberglass reinforced plastics we commonly call “fiberglass” so I knew getting rid of the rivets would be easy.

The bonding back to a one piece nose went great, and the finishing went great except for the rivet removal part, which is when I discovered I'd grabbed a box of stainless steel rivets instead of aluminum rivets.

MU54a2What's the difference? Not much to look at, they're both shiny, but aluminum drills like cheddar cheese and stainless steel drills like kryptonite. The plastic came off easily enough, since trying to drill the rivets got them hot enough to melt plastic, and then a little hotter and they broke loose of the fiberglass and started spinning. I struggled for about two hours before I gave up and ground them off with an angle grinder.

The moral is: measure twice, cut once. Five seconds of reading the box would have saved five hours of work (the three I've spent, plus the two I'll spend prettying up the grinder marks).

:)
8/24/2010 7:34:02 PM

Jack, just gotta say I am a fan. As a controls engineer (read *technician with two engineering degrees*) I am constantly coming up with unique ways to try to test our various customers products. I think your attempts and failures have been brilliant adaptations. Keep up the good work! Max is pure genius!


jack mccornack
8/22/2010 11:41:40 AM

Thanks Jason, and though I seem to be specializing in mistakes lately, it is part of the process and I want to share the whole process. BTW, I wonder if anybody has done a 3D CAD drawing of the Mach5. I'm more of a Thunderbolt Greaseslapper guy myself. And james, I love clecos and use them regularly...I love them so much I didn't want to bond any of them into the body, and I knew that whatever I laminated in there was going to be permanent.


jason_30
8/20/2010 5:25:43 PM

Jack, just think of all the poor losers who make as many mistakes as you do, but don't have a fan base that'll read their blogs, (Oh yes, I'm a fan). I really look forward to seeing the finished body. Personally, I'd be investigating how well a Mach5 replica body would work on that chassis, (Oh yes, I'm also a fan of Speed Racer).


james ralston
8/20/2010 10:02:36 AM

Even better than aluminum pop rivets would have been "Cleco" you can find them in aviation stuff. They are a temporary version of a rivet used in sizing and fabrication for aircraft.





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