Guys,
I'm looking to make some joiners to connect flaps around booms. At first I thought I would use regular music wire rod but I remembered a technic a flying bud used years back using drill rod. The drill rod is stiffer in torsion. Looking on line at Grainger's site there are several types of drill rod i.e. - Oil harden, Air hardened, Water hardened. Not being a metallurgist I don't understand what each type is used for.

I think what is needed is one that would allow the 90 deg bends needed to make the joiners without cracking. I was thinking that one might need to heat up the bend point then re-harden. Seems the water harden would be easiest for our application in the home shop.

Anyone use this material for horns or joiners?

Best,        DennisT 

Here is what Allan Perret said over in that thread.

"1-Use A2 drill rod [8888K181] from McMaster Carr for tweakable horn wire"

Here is what Allan Perret said over in that thread.

"1-Use A2 drill rod [8888K181] from McMaster Carr for tweakable horn wire"

Here is the original source for the A2 recommendation.  Derek Moran made control horns as works of art.
http://www.clstunt.com/htdocs/dc/dcboard.php?az=show_topic&forum=103&topic_id=331672&mesg_id=331672&listing_type=search .

Aren't there aluminum rod and aluminum flat stock materials available?  I believe so. Can be tempered after bending and welding.

All that work using steel?

Aluminum? Correct me if I'm wrong, but the same amount of work with not nearly the same amount of weight?

 JMHOWNTN

Just My Humble Opinion Worth Next To Nothing. 

Guys,
I'm looking to make some joiners to connect flaps around booms. At first I thought I would use regular music wire rod but I remembered a technic a flying bud used years back using drill rod. The drill rod is stiffer in torsion. Looking on line at Grainger's site there are several types of drill rod i.e. - Oil harden, Air hardened, Water hardened. Not being a metallurgist I don't understand what each type is used for.

I think what is needed is one that would allow the 90 deg bends needed to make the joiners without cracking. I was thinking that one might need to heat up the bend point then re-harden. Seems the water harden would be easiest for our application in the home shop.

Anyone use this material for horns or joiners?

Best,        DennisT 

  A2 Air-hardening tool steel. I got it from McMaster-Carr. Derek put me on to it and it works very well. I did some test parts and tested them to destruction. Its not as stiff or springy as music wire, but after brazing and heat-treating it was a bit stiffer and almost could not be broken from fatigue. You can bend it through a huge angle, bend it back, with no obvious damage.  Very much tougher than music wire and was not brittle near the braze or near the heat-treated section.  The music wire, treated as I usually do it, broke pretty quickly in comparison. I was much happier with the results,  and am not going to worry about breaking down the road like with music wire.

     Brett

Brett,

Does it harden only near the brazing or did you heat-treat the whole wire?
And does it harden by itself as it air-cools after the heating?

Lauri

If the steel is not heated to "critical" about 1650F, or cherry red, it will not harden at all and will remain "annealed". 

The bending will do some work hardening, which may account for the part being more stiff.

Phil