A couple of questions about copper pipe...

[Elder]

I'm making something non plumbing related out of 22mm copper pipe. I was just wondering what the bending strength of said pipe might be over say a 3-4' length.

Also, would filling the pipe with expanding foam increase the bending strength at all, or would it just help avoid kinking at the bend point. I know I could insert a dowel if I could find one the right diameter but it would have to be a pretty solid snug fit to avoid rattling

Also planning to drill holes across the pipe at different places to insert U bolts, with Well nuts in the ends holding eye bolts and figured the foam would help stop the weakening the the cross drilling would cause.

I chose copper because of the pretty colours it polishes up to, but need to add strength because a broken pipe could injure, and 22mm because the tradeoffs between cost, weight, and strength.

Any suggestions.

[Clive George]

No suggestions, but would I be right in guessing the area this might be used in? :-) If there is the possibility of people heaving on it, copper will almost certainly be too weak - eg it wouldn't be good for a broom handle. If you could get a dowel to fill it, glued in some way, then that would probably give you rather more. At that point worth remembering it's essentially as strong as the wood.

The expanding foam will probably do nothing - not increase the bending strength, nor stop it kinking.

[Elder]

You would be right in that someone would be wearing it. I've just started a business making veggie/vegan friendly floggers etc from recycled materials (had to do something 6 months on the dole applying for 200 jobs and getting 2 interviews was killing me, and I figured it would give the business advisers a giggle if nothing else).

Some of my floggers and paddles use copper handles, as do the Delrin canes (Good old fashioned bent handle canes). So the plan was to try and make restraint bars to match, and build up a set that could be sold individually and in boxed kits.

So far I've managed to make recycled products from cycle tyres, cycle innertubes and spokes, and also "re-purpose" off cuts of insertion rubber sheet and Synthetic "human hair" pony tail extensions.

They won't be suspending a person, just forcing their hands/neck or wrists/ankles into fixed positions. Some of the bars will be shorter at about 2'.

After 10 years in IT I had met some weird people, and needed a change, then got made redundant. A couple of slightly kinky girlfriends in the past is what made me think of it, and then I got to thinking what do vegans who can't use leather do to for toys, and using scrap bike materials cleaned up, I can get them for near free from bike shops, saving them their trade waste fees and also cutting down on landfill. They fill a box, I pay for a courier to collect them.

[ARWadsworth]

I assume that they will not object to a pork sword?

[Andy Dingley]

Copper is useless here, as it will dimple very easily if you pull on it with a chain link or carabiner.

Having made similar stuff before, I used stainless. This was cheap, as it was recycled handrailing being demolished from a posh development that folded (scrapyards are your friend). Mostly though I used cheap black-drawn steel, for more of a dungeon look. Depends on your market

- straight likes grungy dungeon (more of a dom thing going on), gay wanted shiny and clean gym-looking.

[Baz]

Drilling the Copper Pipe will further weaken it!! I suggest a bit of broom handle, sanded and spray paint. Baz.

[Andy Dingley]

Ikea nickel-plated rod kitchen drawer handles work, so long as you mount them in drilled holes, rather than bolting them on-end to the surface. You need to take the bending load on the thick rod, not the retaining screw. You can do this in timber or even MDF (double thickness 3/4") but _not_ in chipboard. Did you see that "hideaway" toy cupboard and spanking horse plan that did the rounds a while back? I never made one, but I had to repair a couple that people had made for themselves, then broken in their enthusiasm.

Screwfix's cast brass sash window pulls (solid ring) used to be good for rope, if you used big enough screws, but they seem not to have them any more. Typical sf...

[Elder]

My fiancée used to be Veggie for 16 years. She quite happily quotes that no dead meat passed her lips in that time. :)

[Elder]

See a lot of my customers are women so far, best sellers include stuff made from cheapo bike tyres in pretty colours. Although I do admit, the more serious Domme's who buy my stuff for their boys do like the seriously blacker than a black thing in the dark inner tube or insertion sheet rubber. The copper proves popular for handles though.

[Elder]

Hence why I asked whether it being fully filled with expanding foam would retain more strength, in the same way as foam cored UPVC doors do, especially the cheaper ones which are just two skins of plastic and a foam core but it can be drilled to install hardware.

I think a wooden core would be a better idea if I can find an suitable interference fit dowel.

[Elder]

I hadn't seen that, but I have seen people turning an IKEA wooden table trestle into a horse. Some even adapted them to make them foldable but still solid.

[The Natural Philosopher]

use custom spring to bend it..and when bent fill it with something more like a loaded polyester resin - car body filler or similar.

That has good compressive strength

[The Natural Philosopher]

the correct material is a loaded polyester resin..pure resin will do, but its expensive, so loading it reduces the volume.And the weight.

[Elder]

I'm actually not bending it. It is straight bars with well nut mounted eyebolts.

I like the idea of a resin filling. I want something to stop the risk of bending when someone is lashed to it if they struggle. Quite often the forces on it will be compression, trying to force feet or hands together. Only time there will be an actual bending force will be when there is a bar attached to a collar in the centre and wrists at the end, or when collar is attached at top, and wrists at the bottom with the bar up the back so leaning forward at the waist would allow the bar to be bent over the back.

[Owain]

I was thinking very fine aggregate concrete with a length of rebar down the middle.

Owain

[tony sayer]

Well can't help you with your original quest but good luck and success making a go of running your own business:))...

[dennis]

Rebar and fill it with molten lead?

[Part Timer]

Quorn sword?

[Elder]

Thanks Tony, been at it since Feb as a test trading thing while signing (official scheme), and going it alone since then with some online sales and local club sales, surviving on overdraft and credit cards. Last weekend I did my first live vending sale at an event in Ireland. While I lost money on the accommodation and transport there, I sold as much in 3 days at a poorly attended vendor mall (most people were in classes and lectures all day) than I have in the last 6 months so I'm looking to pursue that route.

[Clive George]

Being taught how to use your equipment? :-)