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How to make strong pushrods

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#3
Heatshrink and hot-glue binding two wires together . . . interesting.

Carbon fiber linkages are generally done in much the same way -- two short metal Z-bends heatshrinked and CA'ed onto the ends of a carbon fiber rod. shrink the heatshrink, slide the linkage to fit, then a drop of thin CA at each end of the heatshrink to lock it in place. The lighter CF rods are super stiff and light, but can't handle shock loads (surface hits the ground in a crash). The CA bond will generally break before the rod shatters, saving the rod in a crash. Only big downside to these is CF rod is a bit harder to source.

Hard to say if a CA joint would be much of an improvement over the hot-glue with only metal rods -- something else is more likely to break if overstressed with hot glue, but neither glue should break in normal use . . . but even music wire will bend a bit more than a CF rod would tolerate.

Interesting option to keep in a back pocket ;)
 

rockyboy

Skill Collector
Mentor
#5
I like using bbq skewers and wire too. I split the bbq skewers in half to save on weight, and then wrap sewing thread around the joint 20 or 40 times like fly tying. Then soak the thread in CA glue or hot glue. I haven't thought that would work with metal to metal joints and have resorted to solder, which can be a real pain at times. The heat shrink/glue method you have looks pretty good as an alternative.
 

kdobson83

Well-known member
#6
I personally just use the wire off of the utility marking flags. U can get 100 of em for like $8 at Lowe's. It's super stiff wire but small enough with a small amount of drilling have fit in every servo linkage I've tried so far. But I can see in some applications where I need longer wire where this method would help with putting two of my wire together to make one super long wire. Will have to remember this in the future. Thanks! ��☺
 

Hai-Lee

Old and Bold RC PILOT
#7
Great idea for colder climates but the Hot melt softens in hot climates and when planes are secured in a car parked in the sun. This can lead to "migration" and either a lengthening or shortening of the Pushrod especially in transit to or from the field. On this I speak from sad experience. Epoxy or CA under the Heatshrink also work well as long as the end is bound to the pushrod prior to the fitting of the heatshrink.

As for the Heatshrink/Hotmelt combination you could try the glued heatshrink as the integral glue has a far higher melting temperature and a stronger grip and it is really mess and hassle free. The glued heatshrink will work on almost any combination of pushrod material and end material.

The need for shock protection of your servos can be achieved by using a less rigid metal end on the pushrod, (like a paperclip on smaller models), with a "V" bend in front of the control horn.

Great and proven idea just needs a few tweaks for those who are subject to higher temperatures.

With many viewing this thread I will ask if others could post their methods for functional rigging systems, (Guy wires etc) and functional Pull-Pull control systems as used in WWI aircraft.

I have a very strong and light method of fitting guy wires to FB wings but the fuselage tension adjustment is giving me a bit of a headache. Similarly I have a simple fitting and tension method for Pull-Pull control systems including wing warping but I would like one a bit lighter (for use in models <36").

Any ideas or existing methodologies are sought.

Thank You:black_eyed: