Hotrodding the GS

<BR>Thanks for the tips guys. Great minds and all that!



A buddy and I went milling around in the hardware store trying to figure out some reasonable way to cut those plastic vials. He comes up with a great idea to cut the vial with a hacksaw, and use a stack of standard 5/8" washers for the cut length.

I figured the cut length needs to be adjustable, so I add the threaded fasteners to adjust the spacing.

This has some potential.



Looks about right.



Just might work.



Holding the saw blade against the washer is easier than it looks. Zips right through in about 2 seconds flat.



This is promising.



There's quite a burr there.



That burr doesn't just flake off. The kerf from the cut is still attached to the main body.
The material isn't so much cut as just bulldozed around the corner.



The excess plastic must be removed with a razor or exacto knife. Ever try and run a razor around the outside of a soft plastic round? I try a few and find that it's going to be too time consuming.

Back to the drawing board on Sunday. I'm rattling around the shop trying this and that, looking for some ideas. I give JJ a call about 7pm. And we start what turns out to be a 2-and-a-half hour marathon con-fab!

We tried lots of different things, razors, cutters, and more razors. And there was much comic relief to be had. JJ says, "Try doing that." I say, "Ouch!" He says, "That didn't work eh?"

Finally JJ convinces me that I should use a hot wire cutter. Convince is probably the wrong word. Really, there was nothing left for me to try. It should be noted that JJ first suggested using a hot wire cutter right after I selected the plastic vial as part of the design. And I was convinced a hot wire cutter wouldn't work.

At this point, the only trouble is I don't have a hot wire cuter. Not to fear, I grabbed the propane torch and a box knife blade! (This was also probably JJ's idea from a while back.)

Pictures and band-aids to follow. I'll get some shots up later tonight.

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Make up a mandrel out of wood that slip fits the plastic tube. An exacto knife blade in a holder cuts the plastic as you rotate the mandrel. Blade is on pivot so it is rotated into position for cut and swung out of the way to remove cut piece and reload the next "victim". This will make a good clean cut. Could also use new utility blade if a stiffer blade ( and bigger blade) is desired. Might be easier to rig up with a clamping block to allow a blade change every 20 or 30 cuts.

Think "manual lathe". I believe you could rotate the plastic tube by hand grasping the cap end. The open end buts up against a stop for getting the length right each time. Your other hand puts pressure on the cutting blade holder while you rotate the tube. Maybe three time around it should be cut through. No burrs or trimming needed.

You and JJ are reading from the same playbook!

It turns out the friction against the blade from that sort of cut into soft plastic is too considerable for a simple fixture. The torque required to turn the vial is enough to deform the tube shape, and the cut starts to walk.

Along those lines, a pipe cutter or pizza cutter 'wheel knife' might work. I'm pretty sure we've got it sorted it out using a propane-heated box knife blade, held with a small vice-grip.

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How about a PVC tubing cutter?



Might be the soft plastic will deform too much, but maybe not. Definitely a burr free cut.

Jim

Did you try cutting it with a really hot knife???

Another good idea. An anvil cut, similar to the PVC cutter, was my initial plan. But unfortunately it just deforms the plastic and the cut walks. Boooo!

The cut must deform the plastic because no material is being removed, and the blade takes up space. Look closely at how un-square and un-flat the cut edge of a PVC pipe is. Sure you can get lucky and hold the cutter juuuuust right and get a pretty square cut once in a while. This has got to be repeatable.

We went the flames and knives method. It does a good job and there's no need to deburr the cut. Thanks just the same for your ideas everyone!

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Good for you. I only posted cause I don't want you guys hung up. Glad to hear your moving forward again. I want my part. I rode my buddies 06 multistrada with new pipe and chip work. It was definitely better accelerating than my 1150gsa (although it is much less mass than my bulky GSA). I want more peppiness. I don't have to have just as quick, just want to close up the gap.

Do you have a buddy the builds homebuilt airplanes? You can try a hotwire rig they use for cutting and shaping the foam core. That might work with your jig, just hot wire the bottom off nice and flush!

Hot wire cutters are dead easy to rig, all you need is a method to pull the wire tight, and a means to regulate the power, as someone mentioned if you know a R/C home-builder, you can probably borrow it ready-built.

I would use a rotary cutter though. My wife has one in her quilting tackle, when I was building planes it regularly made midnight trips to my shop for cutting mylar covering.

Like this:http://www.olfa.com/RotaryCuttersDetail.aspx?C=20&Id=70

Hellaciously sharp, and with your jig, I would think would make a very nice job of the cut for $15.00 or so.

<table border="0" cellpadding="5" width="650"><tr><td>Thanks again for your ideas everyone. If these IICE Airs do get built again, many of the assembly processes will benefit from retooling. Or at least a retool of optimistic estimates Seriously though, to make one or two of something, like a hobby item for example, it's easy to invest hours in the build process. Acourse to build 100-plus of something, that's a different story.

Electrically it was easy. Mechanically, that was the problem. You know, it's a complex set of mechanical specs. Part of the shape needs to be exposed to the air, and another part must be watertight. The watertight portion needs to be easy-open with a durable seal mechanism. And whatever you two geniuses come up with for an adjustment mechanism, it must fit inside the watertight portion. Oh yes, you must use a very small standard enclosure, with a mounting flange(s) for zip ties.

Somehow it all got figured out. Only now I have to build it.

You should have heard JJ and me talking at the beginning of this project, and all along during the process. Talk was rife with things like "it'll be easy", "we'll just...", "no problem", and the dreaded "I'll cross that bridge when I come to it." That one is a killer.
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<BR>Assembly report.

As promised, flames and knives.



Makes a nice cut.



A real nice cut.



I did a little assembly marathon today, and my hands hurt! I'll check in later.

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Great job on the cut. Now take some advil and get back to work!

The killer one is "I'll drive off that bridge when I come to it"

Can't wait for the finished producto

All ya had to add was guns and it would have been a party Need me to come help ya...I am a first rate fabricator of the official Redneck School

HR has been flooded by complaints followed by claims to the insurance company for disability.

Oh, wait...

<BR>Assembly report.

I'm about 1/3 of the way done with the done-as-a-full-batch processing. Many of the remaining steps are done in small batches of five or so. The units will be shipped in medium-sized batches as they are finished, maybe 20 at a time. I'll be working on them later this afternoon. And I'm going to try and take one unit the rest of the way through the assembly steps to the last step, partial encapsulation in epoxy. That's the most important step and I need to verify the encapsulation process goes smoothly.

Enjoy your Memorial Day. Cheers!


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Hey, I'm planning to trade my GS for an R1100S. Will the contraption still work?

Yes it will work

You can get a hot knife blade for a soldering gun.