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JimW

Bending backer plates

12 posts in this topic

JimW,

What are you wanting to mount to your yak? Sounds heavy duty.The Wellnuts I like to use have a 200# pull out strength, and you don't need back side access to install them.

Also, I have used various pieces of flat "this and that" to back-up bolted items on a Fish and Dive. Most cutting boards are made out of poly-just like the boats are made of. If so, then they will soften at around 175F. You could put the Board on a hot plate, wrapped in aluminum foil and then quickly bend it around something. However, if the board is real Teflon, you'd need 600F plus to get it warped permanently.Nylon, about 400 F.Wear thick oven mitts! If you used a torch, you would only locally melt the plastic.

 

You could also turn the yak upside down, tape down some siran wrap covered cardboard dams around the spot you want to bolt thru, and cast some epoxy, or polyester resin in place to form a bearing block. You have to kinda know what you are doing with that stuff. I'd even drill the hole in the deck, put vasoline on the bolt(s) and have the bolt in there to form the hole.

 

You could cast plaster in there too, then make a mold and then a bearing block from that...

 

You could stack thin layers of a flexible material to get the shape too...

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I don't think that thickness is important as the backing plate is just spreading the stress. A plastic bucket would give a good supply of already curved material as would thicker plastic barrels that are sometimes available. Try a farm store or larger restraunt for them. smile.gif

 

John

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Two things...

 

JimW, are you really needing a backing plate or was this a question about something else? I'm interested in heat-forming various plastics for another reason and would like moe input on this. Beagle?

 

RJohn, you're halfway right. A backing plate is there to distribute the stress from the fastener. However, it needs thickness (for the engineers out there, effectively moment of inertia) to achieve the distribution of stress. By example, how much stress distribution can a piece of aluminum foil provide? A 1/2" thick aluminum plate? Enough mechanics of materials for one day. HappyWave.gif

 

Chris

 

 

[This message has been edited by Porter (edited 02-12-2002).]

 

[This message has been edited by Porter (edited 02-12-2002).]

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Sorry guys, I should have narrowed down the requirements a bit. At a minimum I need to mount rod holders and other assorted gizmos including someplace to tie off an anchor on deck. The boat is a wood stripper and I am worried about tear out but also that I might do more harm if I put a flat backer behind it, it's pretty rigid and won't like getting torqued into shape. I can make something up from epoxy/glass but thought some cheap thermoplastic could be easy. And then, of course, if the stuff is easy to form I was thinking I could make deck fittings like cleats, paddle holders, rod holders, underdeck storage, maybe even a skeg, I don't know yet. Maybe I just have too much time on my hands. I think I have to stick a piece in the oven and see.

Jim

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No, don't even think about putting plastic into your stripper. cwm13.gifcwm13.gif

 

You built it. Put an extra layer or two of epoxy and 'glass in there and forget about it. Also, when through bolting, are you familiar with the bent nail trick to clear the wood from the immediate vicinity of the hole so you can fill the area w/ 'poxy?

 

Chris

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You take a small finishing nail, put a sharp 90-degree bend in the tip end, no more than 1/4" long. Chuck the nail into your drill and insert, carefully, into the hole you already drilled for the bolt, using care to pierce the core (wood in this case) with the tip of the nail. Fire up the drill and it should clean out the core for a small distance around the drilled hole (sometimes helpful to sharpen the tip slightly). Place tape over one side of the hole, fill with epoxy, let it cure, then re-drill for diameter of bolt. Now you have no wood exposed anywhere near the hole and a stronger bolt location to boot. smile.gif

 

Chris

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Just a humble suggestion. If you still need a flexible thermo form plastic, I have worked with a material called Kydex. It heat forms around 200-250 degrees and is pretty tuff and comes in colors. Alot of knife makers use this as sheath material. Just my 2 cents.

 

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My wife is an Ocupational therapist and makes braces out of a flesh colored plastic You boil and then shape quikly while it stiffens. I have made some backpacking accesories with it. It is thiv about 1/8 inch but tough as steel.

Barrell

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