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Old 02-16-2013, 05:50 PM   #21
VxZeroKnots OP
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Joined: Jun 2008
Location: Durango CO
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Originally Posted by Plaka View Post
Yes. I started welding with a nitrogen gun (worked in the modeling shop at Rubbermaid Commercial, Pretty big projects like the rolliing garbage bins). They're nice, but costly. The heatgun rig I have now works OK and I've done some projects with it, Sinks, etc.

I agree on transferring force, A rigid GRP plate is just like steel in that respect. But you can soft mount it on rubber bumpers if you want. (maybe something like ethafoam blocks.) it may be a thin flexible peice will work fine. it may flex back far enough to touch the cases but it will prevent abrasion of the metal and spread the blow enough to prvefent puncture of the case.

Carbon fiber is a pain in the ass to work with. (I have some along with some carbon/aramid blends). it is a LOT more difficult to turn a corner with it than glass (often you need special clamping or a vacuum setup) because it is so stiff. it also transfers stresses all over the place making design with it tricky. On top of all that, those slick carbon fiber things you see are complete crap. They are made by taking the resin/fiber ratio way up (to the resin side) to give that smooth glossy surface. This makes for a heavier, weaker part. Properly done FRP has a very spare resin ratio, you should be able to see each strand in the finished surface. of course this doesn't look all that great despite being the strongest way to go. Also, the CF stuff you see has been vacuum bagged, again to give that sheet-of-glass-with CF-in-it look. It's window dressing.

Personally if I was going to use sheet material I would use riveted construction. You can do that very cleanly so it looks right. use big head pop rivits and backing washers. The trick is to work out the shape of your plates so when you assemble everything comes together into the right shape. Use thin cardboard (construction board from the craft shop or some office supply places) or 1/8" foamcore board to sort this out. A combination of thermoforming and riviting can be very effective.

If you're determined to weld having a hot air gun (self contained blower) will definitely do you. And they are handy as a spot heat gun (rusted on nuts) as well. The only trick I can really offer beyound following the directions and using native material as rod, is to use a small planer blade as a scraper to clean up exterior welds. You want one about 1" wide by 3" or so if you can find it. they come in sets of 2 or 3 for portable hand (electric) planers). Stiffer than a utility knife blade and very sharp. I use them for finishing the edges of plexi too.

Kydex is killer stuff. Used to line hockey rinks among many other things, You may have difficulty finding it in thick sheets however. You bend nice strait lines with a plexi bender (from platic supply place) or if you have a vacuum source you can vacuum form it in your kitchen (the largest sheet being the size of your oven unless you want to build a heater)
Sweet info man thanks! Looks like CF is out. I'm not making this particular skid for the engine, as I already have one of these
and it is killer. It gouges pretty easy but compared to the Aluminum skid I had on my last bike it is brilliant. It is 1/4" and the "wings" are folded up from the bottom piece and then welded at the bend so the part that sees the most abuse is all one bit. I bought a Hyde racing skid plate and was very unimpressed with the fit and quality of it given the price.

The Hyde is made from 1/8" and the parts are joined via the pop-rivet method you outlined. I ended up cutting it up to where just the pipe guard bolts to the AXP skid plate and then mounts to the pipe with the included band thingies. It has a bunch of little rubber nubbins which isolate the pipe from the skid portion and it seems like those coupled with the shape of the guard are what provide the protection more than the thickness of the material.

My plan is to build a faceted pipe guard which integrates better with the AXP plate out of 1/4" HDPE seaboard and try to use as few separate pieces as possible and weld as little as possible.I already have a rivet gun so I might make some gussets for the major seams and pop-rivet them over the seam to reinforce it, but was thinking of using 1/8" HDPE for that. My research today didn't turn up any UHMW that was black or UV resistant so if you know a source for that I'd love to hear about it. Also, I think the rubber nubbins Hyde uses are silicon rubber for heat resistance because they spend their whole life in contact with the pipe. I don't know where those are sourced from but if you have any insight for a solution there I'd appreciate it.

Thanks for all your input!
I say we take off and nuke the entire site from orbit. It's the only way to be sure

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