how can i make a crucible to solder my flexshaft?

[out of stock]

just as the title states im looking to silver solder my flexshaft.

whats happening is my collet is slipping no matter how tight i wrench it.

its a 8mm to 1/4 collet from kintec (the one with the two grub screws) i was told it was garbage so i ordered the octura from ose.

i want to solder my flexshaft as i hear it adds strength and grip. i saw a video of someone using a homemade crucible filled with silver solder.

he cleaned the shaft first with a wire brush them cleaned with alcohol then heat it up then dip in solder for several minutes.

feel free to help as i may need it. thank you.

[kfxguy]

i heat my shaft up till the solder flows into it. when it covers everything, i give it a slight sling while still hot. you may need to reheat at this point. that gets the extra uneven solder off. I will tell you, once i stripped out one shaft, (was before i started soldering them) it would not grip even when i soldered it.

[Chilli]

A crucible might be a little overkill. Get a nice strong iron like a Weller 60 watt with a big chisel tip. Make sure you use some flux to help the solder adhere and run smoothly. Just smear it on the area to be soldered before applying heat. I use the Bernzomatic Flux that comes with cheapo propane torch kits and it works fine.

[tlandauer]

Not related to your soldering, I have an Octura collet 8mm to 1/4 on my DF 45 Sniper, I like the Octura collet. Having said that, I did encounter the exact same problem you had. One trick I learned from Fluid is to use Anti-Seize on the threads, it allows you to tighten further w/o damaging the collet, there is a lot of galling you don't realize which prevents your effort of havng it really tight enough to grab the cable.
http://www.amazon.com/Permatex-81343...eize+lubricant

[Allrc]

My son is great at this. He even does them at the race site for racers if they bust a cable. I'm not saying this is a perfect way, I'm saying it's our way and it works. Although we use Aeromarine 1/4 to 3/16 it should also work with any collet stepped to your stub shaft . In your case it looks like 1/4 cable stepping to 8mm.
What you need
1. Bernzomatic torch and wire brush
2. Cable
3. Collet
4. Stub shaft material (we use an old stub shaft for this)
5. Silver Solder
6. Silver Solder Flux

Steps
1. Put the collet on the 8mm stub shaft and tighten grub screws. You just need to tighten to hold, not overtight.
2. Wire brush the collet end of cable, heat the cable and brush some more. There's oil in there. It needs to come out.
3. Add flux to cable end to about one inch. Don't be stingy.
4. Heat end of cable and start tinning to about one inch from end. The key to tinning here is sufficient flux and getting a solder starting to flow on the end. We take the hot cable during tinning process and wipe with a wet paper towel turning the shaft while wiping. You'll want to use enough paper towels so as not to burn yourself. Now as you look at cable you'll see bright shiny solder that has tinned correctly. Add more flux and keep redoing this process until you see bright shiny solder from the tip to one inch up the shaft. Set aside.
5. Add some flux and tin the 1/4 inch side of your collet. Do this in a fashion to avoid getting solder in grub screws. You don't have to tin very far in.
6. You are now ready to join and solder collet to cable.
A. Add some fux to 1/4 inch side of collet.
B. If someone else is not there to assist set the torch while locked on, on a flat surface pointing up and away from you.
C. With the cable in one hand ( keep handhold at least 8-10" away from cable end) and stub shaft with collet in other hand apply flame to both to bring solder to a shiny melting point and slide cable into collet.
D. Remove both from heat and turn the stub shaft around and around continuously while holding cable from turning. Within ten seconds or so the collet will lock on and the solder joint is complete. Your cable will be perfectly straight and there won't be any vibration.
E. As a final step we often add a little flux where cable just enters collet, heat it up just on the end and spin in a wet paper towel. This gives a nice finish look.

If you can't quite get it, come race with us and we'll help you.

Thanks,
Bill Brandt

[kfxguy]

SO....every time you need to grease the cable, you have to unsolder?

[longballlumber]

SO....every time you need to grease the cable, you have to unsolder?

It sounds like his is describing the process when using a square drive system. The motor end has a square end and the prop end uses ferrule that gets solderd onto the flex shaft, then the set screw connect the harden stub shaft.

This system is used by many Nitro boaters on the west coast.



Flex shaft with ferrule (and square) - http://www.bonzisports.com/store/squ...ule-p-309.html

This is the stub - http://www.rocketcityracing.com/octu...3-1-4-in-long/

Later,
Mike Ball

[Mattwarner]

ive tried loads of times to solder the end of my flex and i cannot get the solder to stick? i am cleaning thoroughly with brake cleaner, sanding the flex, using flux and getting it nice and hot with a propane torch and still it balls up and runs straight off?? Ive tried rosin core and flux cored solder, does it need to be silver solder?

[Allrc]

Mike is correct. I should have correctly used the word ferrule as opposed to collet. Brain fade. I am a North West US racer. And this can be used with clamp down style motor collets and square drives as long as you are not using one piece cable and stub shaft. If I misinterpreted your purpose my bad.

Bill Brandt

[Allrc]

Mattwarner I believe silver solder with flux for that is key. Just wipe it down and try again. Don't be stingy with Flux.

[longballlumber]

Mike is correct. I should have correctly used the word ferrule as opposed to collet. Brain fade. I am a North West US racer. And this can be used with clamp down style motor collets and square drives as long as you are not using one piece cable and stub shaft. If I misinterpreted your purpose my bad.

Bill Brandt

Sorry Bill,

I don't know why I put East Coast. I really was thinking West Coast. Brain fade on my part too....

[rickwess]

ive tried loads of times to solder the end of my flex and i cannot get the solder to stick? i am cleaning thoroughly with brake cleaner, sanding the flex, using flux and getting it nice and hot with a propane torch and still it balls up and runs straight off?? Ive tried rosin core and flux cored solder, does it need to be silver solder?

I've never had any success doing this with a torch. A 60W soldering iron, acid flux and silver solder works well for me. A light sand and cleaning with rubbing alcohol before you apply the flux helps a lot.

While you are soldering, angle the flex so the liquefied flux doesn't run down towards the prop end. I also clean the flux off with rubbing alcohol when I'm finished soldering.

[RandyatBBY]

I basically solder in the air with a Brazing solder 56% silver, borax flux, tongs and jewelers torch. I do have a ceramic pas but it is just to keep the desk safe.

If the flex shaft is new this method works well. I have to ultra sonicly clean used shafts and some times it still will not work.

[oscarel]

Get one of these from Lowes heat, add solder, prepare cable, dip in.

[rickwess]

If the flex shaft is new this method works well. I have to ultra sonicly clean used shafts and some times it still will not work.

Excellent point. It sounds like the OP is trying this on a flex that has been used.