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pete beadle

Potting MPX green connectors

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Jef Ott

What I do is put a heat shrink sleeve loosely over the wired plug, drop in some quick setting Araldite then apply heat to shrink the sleeve, mopping up the excess as it is squeezed out of each end.

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pete beadle

Hi Jef

One of the more important things I have to evaluate, when considering these suggestions, is assessig how easily they can be done one-handed

This is the main obstruction where the guys making the suggestions say I should consider heat guns, glue guns  and any other system that needs "while you're doing this, use your other hand to......"

What I have to do is see if I can adapt the basic principle of the suggestion, but do it in two stages, rather than with two actions done at once....

So far, I'm favouring Brett's suggestion, but going it in stages, when filling up the plastic heatshrink tubing with smaller amounts of epoxy and  with the connector held in place with Blu-tac all the while......but I'm still very much open to further suggestions......

One thing's for sure though, I'm really very grateful for the help I've received from members in this, and can compliment the guys wholeheartedly on the suggestions received so far, model builders obviously do really enjoy thinking "out of the box", laterally and with due concern for keeping down costs.......

Thanks and regards

Pete

BARCS1702

 

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isoaritfirst

Hold the greenie in the vice an dsqueeze in some hot glue -- then mould it by squeezing, taking care not to burn yourself of course. Once its cooled redress the exterior if needed with a hot chisel.

 

Should be achievable for you Pete. It quicker and cleaner than epoxy, which I always detest trying to get out of the bottle....

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Brett82

Hi Pete

Just a bit of an after thought on the method I tried. It would take a bit of practice but I think it would be do-able even with the one hand. I think if you laid the tape on a table, sticky side up then placed the connector into position and slowly "rolled" it along the tape until it was wrapped around the connector it should be OK. After a few attempts I think I (and you) could even taper it towards the top to look better. 

I would imagine you could use this method with epoxy or hot melt glue so you could try a mix of it and Mikes suggestion. Epoxy is messy and the tape might even help save burning the fingers when you mold the hot melt glue into shape. Just check the glue wont melt the tape you use.

I would get a few pieces of scrap wood and a few strands of wire and make some dummy looms then try different methods and see what is easiest for you. All the suggestions people have made will work, they have all done them but what is unique for you is to be able to do it effectively and neatly with one hand. Hope I have helped in some way and hopefully the pics also helped. Let us know how you get on. 

Brett

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Bernie Jones

Pete, if your need to do this joint one handed then, although more than you would like to spend the Winkler former is easy to us, could have some hook and loop applied to both halves of the former and a heavy block or place on the bench with the other hook/loop tape so the mould is fixed, the MPX is quite a tight fit so could be clipped in then the top put on and screwed together, turned over and the hot glue pumped in, again using the velcro to hold in place unscrewed and the former opened, sure it would work, happy to let you have one to try if you want

Cheers

Bernie

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pete beadle

Hi all

Well, I've made the first connector, and I'm now taking up Bernie's offer of the pukka mould to compare with this 'un to see which I prefer, so, watch this space.....

BTW I don't know if anyone remembers my plea to find out if there was a "standard" way to solder up MPX connectors but, in my perambulations on the potting subject, I seem to have found that there IS, in fact, a preferred system for the layout of the wiring, and this is assessed purely by the number of similar ones I've actually seen....and that is, looking at the ends of the connectors the six wires/connections are arranged -  two black (-) wires at the top, two red (+)wires at the bottom and one white (signal) wire on each side - by more users than any other configuration, interesting.....at least I think so.......

So, herewith "Potting #1"......

The underside was wrapped in blue masking tape, the connector tilted to allow each application of epoxy to run into the "mould" made from the tape, a total of three applications taking the level fill level up to the top edge of the connector, overnight wait to make sure the hardening process was complete, remove the tape, slide a short length of heavy duty, clear shrinkwrap over the connector, shrink in place (butted up to the face of the connector) allowing the "contents" of the pot to still be seen, one tie wrap fitted over the lower/inside end of the clear  shrink wrap for belt and braces location.......looks pretty neat to me - and I've checked - it works!

Regards

Pete

BARCS1702

potting_004.JPG

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Jef Ott

At the risk of teaching grandmother to suck eggs... Just one thing Pete, you are using quick setting epoxy aren't you?

The quick setting stuff is generally more pliable after setting, and a little flexibility at the point where wires meet the epoxy, is better than none.

 

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Scram
49 minutes ago, pete beadle said:

BTW I don't know if anyone remembers my plea to find out if there was a "standard" way to solder up MPX connectors but, in my perambulations on the potting subject, I seem to have found that there IS, in fact, a preferred system for the layout of the wiring, and this is assessed purely by the number of similar ones I've actually seen....and that is, looking at the ends of the connectors the six wires/connections are arranged -  two black (-) wires at the top, two red (+)wires at the bottom and one white (signal) wire on each side - by more users than any other configuration, interesting.....at least I think so.......

I now do it this way and the reason is that if for some reason you connected the wrong wing, or wrong set of cables, you cannot blow the servos with wrong polarity connection.  I don't like pairing up the +ve and -ve wires either.

I recently did the potting for the cables in the fuselage when I repaired my Vampire nose.  This meant wrapping the shrink wrapped connections with masking tape (blue 3M tape) and then filling with epoxy.  To get the epoxy in, I used a syringe with a 4" length of fuel tubing jambed on, sucked up epoxy into the tube only and inserting the tube inside the tape to inject the glue.  Needed about 3 goes to fill the mould.  Only trouble was, it ran out slowly under the tape because I needed to maintain a shoulder to set the MPX into the fuselage seat.  Bit of cleaning up needed but still succeeded in potting the wires.  I think I would have been better wrapping the MPX firmly and then trimming the set epoxy back later.

I suspect your main problem Pete, is in maybe having to pot the connection with the wiring harness installed in the wing?  Else, with the harness loose, as Mike said, holding the MPX in a vice would solve a lot of your difficulty.

Another advantage of using hot glue would be that the pot is flexible - a bit.  the hard edge of an epoxy pot is where the cables may still fracture if there is a lot of flexing at that point.

Just my 2p worth.

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jetpipe

Epoxy will create another potential failure point where the wires exit it. Better to use a flexible material like hot glue or silicone.

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martynk

Have you tried this stuff?

http://www.heatshrink-online.co.uk/heatshrink/cat_146271-31-Coloured-AdhesiveGlue-Lined-Heatshrink.html

I used to use it a lot when I was installing aerials (Amateur Radio) and other outdoor circuits where I has to prevent water ingress. It works very well. Just make sure you get it right first time.. its not easy to remove

 

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pete beadle

Hi all

I really appreciate all the help I have received from forum members on this, and other, subjects:yes:

The main thing I found out when trying to pot these wires to the MPX green connectors was that my "hot melt" gun was absolutely useless!

As some of you know, I used to work for Henkel "Supergloy" many years ago and they used to make a brilliant heat gun but, as ever, I went for the cheaper alternative and it was/is useless. So I went back to Henkel and bought a heat gun from them and, needless to say, it works a treat - a pricey treat but a treat nonetheless

The previous "cheapo" heat gun just wouldn't have worked with the mould Bernie lent me (thanks very much Bernie) but the Supergloy gun. used in the way Brett advised, worked a treat. The finished item looks exactly the same as the pic I posted earlier, so I didn't bother to take another one - my apologies for those waiting for a second pic

Anyway, thanks to all who featured on this string, I DID take careful note of your comments, I DID appreciate them and I'm now waiting for a flyable day to "prove" the potting - hopefully that will be soon, in the meantime, I've got other repairs/re-furbs/rebuilds to do and am in the building room most days.....

Thank you one and all

Pete

BARCS1702 

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Scram
1 hour ago, martynk said:

http://www.heatshrink-online.co.uk/heatshrink/cat_146271-31-Coloured-AdhesiveGlue-Lined-Heatshrink.html

I used to use it a lot when I was installing aerials (Amateur Radio) and other outdoor circuits where I has to prevent water ingress. It works very well. Just make sure you get it right first time.. its not easy to remove

I like to use this type every time I have to re-join my mains electric hedge trimmer cable ..............  :frantics:

Adds strength and seals out moisture where the outer insulation has been removed  :thumbsup:

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