A quick question about metal bending

Discussion in 'General Slingshot Discussions' started by Kill3rGreen, Jul 17, 2012.

  1. Kill3rGreen

    Kill3rGreen New Member

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    So I have the arm brace left over from my Daisy B52 that I turned into a fish hunter and I was wondering what the tricks are to bending this. I would like to bend this frame into a slingshot and I am unsure if heating the metal will cause strength loss. The tools I have at my dispersal is very limited, wrenches and a hammer along with a pocket torch are what I would like to use. Thanks in advance going to hit the sack now, Catch ya'll on the flip side!
     
  2. Bert the Welder

    Bert the Welder New Member

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    Hello,<br>Took a look at a pic online. It depends on the metal they used. It's a bit of a crap shoot. If it's alum., you could tweak it slowly a bit, but bending with "work harden" it and make it weak/ snap it. If it's steel, it could bend very good or, if it's inconsistent cheap steel, then it could snap too. Just keep this in mind and be prepared to accept a loss if you do bend it. <br>As for the act of bending, anything can work. Leverage is your friend. In my metal shop, I have various sections of pipe to cold bend anything from 1/8" to 3/4" solid bar. Clamp one end into a vise and bend with pipe. If you don't have pipe or if the piece is not straight enough to slip on the pipe, a closed ended wrench can be very useful. Slip the closed end over the rod to be bent and use the wrench as a sort of lever. An open pipe wrench can be used in the same manner, especially if you just can't slip anything over the piece to be bent. Slipping a piece of old garden hose of vinyl tube over the piece will help prevent marring the smooth metal. <br>Heating with a little torch isn't going to help much.
     

  3. bnorman

    bnorman New Member

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    I'm with Bert on this. He did a great job of writing a "how to bend funny metal" in one paragraph.<br><br>I've had some forge experience besides welding. What you need here is a forge, buckets of cold water, and some oil. But allowing as to how that's not in your ditty bag, I can add some blunder to the thunder.<br><br>If I recall correctly, these are, essentially, tempered rods. They were chrome plated (or maybe stainless "18-8" when they came from the factory. If you do a really slooooow bend (like, clamp it in a vice and slip a wrench over it and pull on the wrench), you fight the spring until a bend shows up, when suddenly the metal tends to tear after about 20 degs of bend. But if you bend around a larger curve (say, a 3/4" water pipe) by smacking the rod just ahead of the pipe, then you can pretty much make a 180 bend.<br><br>So, *possibly* you can make safe bends if they are gentle sweeps and not hard angles.<br><br>Unless you have forge experience and pick a 2lb hand sledge (or at lease a 1lb ballpeen), be warned that your common household hammer is going to bounce all over the place. You should therefore count on acquiring knuckles that look like bnorman's. When you are done, the scars on the metal will disappoint you.<br><br>Or you'll get "almost there" and suddenly you have part of the metal in the vice, the other on the floor. Bert warned you about that, and I've certainly made my share of short pieces this hard way.<br><br>Once you have over-bent, they are really hard to un-bend. Somewhere in the fine print, the laws of bending stuff has a phrase that says "Anybody can bend. Only contortionists and people with expensive equipment can properly un-bend."<br><br>If you bend by taking it in itty-bitty steps, and smack each bend stage on the side once or twice very sharply, you might just get what you want. That smacking helps to relieve the stretch stress on the outside of the bend, and helps to relieve the crush stress on the inside of the bend.<br><br>Your rods will look like you've been smacking them hard on the side, however. A file and then some emery cloth would be recommended.<br><br>Itty bitty torch *might* help if you warm up the metal before you smack it. To use heat for bending you have to use enough to change the color of the metal.<br><br>None of the above rules apply the same way to aluminum or copper. Whereas ferrous metals soften when you bend/hit them, al and cu harden as you bend/hit them. Heat is your friend when you work with al and cu. But you are probably working with some sort of steel. Run a magnet against it, test to be sure. Show us the results. If they break, we'll say "told you so." If they bend, we'll take the credit, of course.<img src="http://illiweb.com/fa/i/smiles/icon_biggrin.png" alt="Very Happy" longdesc="1"><br><br>bnorman
     
  4. Kill3rGreen

    Kill3rGreen New Member

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    Show us the results. If they break, we'll say "told you so." If they bend, we'll take the credit, of course. <br><br>Haha thanks both, I will see what I can do.
     
  5. JoergS

    JoergS Administrator

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    I use a cheap disposable blow torch for bending steel thicker than 10mm and threaded rods of any size. Threaded rods will break if you try to bend them cold.<br><br>Clamp the rod in the vise and use a steel tube for the bending, just as Bert has explained.<br><br>When you heat the steel rod, just keep the flame on the spot where you want to bend it until it glows bright red. Then bend away, it will be very soft.
     
  6. Kill3rGreen

    Kill3rGreen New Member

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    Thanks JoergS! I am pretty sure the metal is steel as I have tried using many spots of leverage on this frame with no bends yet. I tried slow bending and it just springs back at me. Going camping for the next few days so I will get a good bed of coals going to slowly bend this into shape. I have 1x pink bandset left over I want to throw on this light weight frame which should fit nicely in my back pocket when finished. I'll be sure to post some pics when I get back, maybe I will get some sling hunting in also. :]
     
  7. Bert the Welder

    Bert the Welder New Member

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>JoergS wrote:</b></span></td></tr>
    <tr><td class="quote">Threaded rods will break if you try to bend them cold</td></tr>
    </table>
    <span class="postbody"><br><br>Again, depends on the rod quality. I've got some 3/8" that I bent and squeezed with my hands right over on itself. Not even a crack. Metal used to produce fasteners varies so much. Bought a box of #10, 2" screws a while back from a store I don't usually go to. The just kept twisting off at about half way in, right where the thread started. Won't be using those again. Glad I wasn't installing a railing at a clients house!<br>And yeah, I forgot some of those little torches available now have good venturies, so you can get some good heat. I'm just used to my oxy/propane torches.</span>
     
  8. HonzaS

    HonzaS New Member

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    I bought a propane butane soldering kit for 20 euros. I bend steel and stainless steel rod, diameter to 12 mm. No problem.<br><br><img src="http://www.melichar.cz/images-produkty/4911/035930d-lotlampenset-44799.jpg" border="0" alt=""><br><br><img src="http://desmond.imageshack.us/Himg525/scaled.php?server=525&filename=p7241722.jpg&res=landing" border="0" alt="">
     
  9. Bert the Welder

    Bert the Welder New Member

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    <table width="90%" cellspacing="1" cellpadding="0" border="0" align="center">
    <tr><td><span class="genmed"><b>HonzaS wrote:</b></span></td></tr>
    <tr><td class="quote">I bought a propane butane soldering kit for 20 euros. I bend steel and stainless steel rod, diameter to 12 mm. No problem.</td></tr>
    </table>
    <span class="postbody"><br><br>That's a cool little torch!</span>
     
  10. Kill3rGreen

    Kill3rGreen New Member

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    Thanks guys, I ended up building a roaring fire at camp and laid the rod in coals once there was a good bed and it was hot enough. The results were not so satisfactory tho as I had no tools but an axe on me and it came out rather rough lol. Probably did not help I had a few to many to drink and it was pitch black out..
     
  11. Bert the Welder

    Bert the Welder New Member

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    <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7"><img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7"><img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7"><img src="http://illiweb.com/fa/i/smiles/drunken_smilie.png" alt="drunken" longdesc="30"><br>That's the oldest school method there is for heating and bending and works just fine! Bending hot is quite different than bending cold. Takes practice and getting to know how the metal behaves.<br>"Wobbly pops" won't help! <img src="http://illiweb.com/fa/i/smiles/icon_lol.gif" alt="Laughing" longdesc="7">