LettersFromFlyoverCountry

LettersFromFlyoverCountry

Well Known Member
Basic wiring question.

What is the BEST method to use to splice wire? For example, the wires from the flap motors or from the Airflow pump? Fast tabs? Knife edge?
 
Bob,
I've tried three methods - solder, crimped knife splices and crimped butt splices. Funny what you learn about yourself when building an RV - I've determined that I am permanently solder-challenged, so try to avoid using the stuff as much as possible. No matter how hard I try, I can't ever get a neat solder connection.

I use crimped knife splices (covered in heatshrink) where there is the possibility of disassembly. Heat shrink covered crimped butt splices for the rest. All splices are subjected to a pretty good yank-on-the-wire check.

Not flying yet - but all splices have maintained static integrity!!!
Booger
RV-8A N192NM
Wiring
 
Are you looking to make a true splice-----or a removable connection??

I consider a splice to be a permanent connection. Solder or butt splice.

Are you concerned about the size of the "bulge" in the wire?? Fast on tabs or knife tabs are a lot bulkier than other setups.

If you are looking for an easily removed connection, "molex" type connectors work well.
 
I've used the sub-d pins covered with heat shrink, soldered wires covered with shrink but the best permanent splices I've found are made by Raytheon I think...not cheap (about a buck each) but are spec. for aerospace use. They have a heat shrink tube, a ring of solder in them and heat activated adhesive. You slip the splice over the wire, twist the ends then use a heat gun..NOT A LIGHTER:rolleyes:....the tube shrinks, the solder flows into the wires then the adhesive fills the ends of the tubing. I believe I ordered them from Allied or McMaster. FWIW, I only spliced one wire permantly in the entire airframe, a ground wire that came up a foot short of the ground tabs. Everything else like flap motors, transducers etc. I put a sub-d or molex connector on.
 
Some sources...

Rick S. said:
I've used the sub-d pins covered with heat shrink, soldered wires covered with shrink but the best permanent splices I've found are made by Raytheon I think...not cheap (about a buck each) but are spec. for aerospace use. They have a heat shrink tube, a ring of solder in them and heat activated adhesive. You slip the splice over the wire, twist the ends then use a heat gun..NOT A LIGHTER:rolleyes:....the tube shrinks, the solder flows into the wires then the adhesive fills the ends of the tubing. I believe I ordered them from Allied or McMaster. FWIW, I only spliced one wire permantly in the entire airframe, a ground wire that came up a foot short of the ground tabs. Everything else like flap motors, transducers etc. I put a sub-d or molex connector on.
Click to expand...

Mouser also sells them in a commercial version (a little cheaper)....

See bottom right of this catalog page...

http://www.mouser.com/catalog/633/991.pdf

Stein sells the larger ones for connecting to the shields of shielded wire...

http://www.steinair.com/hshrink.htm

gil A
 
Good quality crimp splices

When it comes to crimped butt splices I have not found anything better than the little jewels made by Raychem. They provide a moisture proof heat shrink that does a great strain relief also. I have always been reluctant to recommend them to anyone as my supply was an inside line at a major airline maint. shop and I did not know where else they could be purchased.

Now AC spruce has them. I have pull tested them many times and they hold the wires very well. I have used these throughout my project and they have made my electrical life much easier.

One thing you have to watch is damaging some wire insulation when heating the heat shrinks. They take considerable heat to get them to seal properly and automotive type wire insulation will not like this much heat. Aircraft quality wire has no problem.

They do require a special crimp tool.

http://www.aircraftspruce.com/catalog/elpages/edmo4363884.php

Randy C
 
Sold vs. Crimp

Just to clarify...

The RayChem sleeves Rick S. and I mentioned are solder based. The heat gun actually melts the solder at the same time as the heat shrink is shrunk.

The RayChem parts Randy C. mentions are crimp sleeves with a heat shrink cover.


An easy alternative to Randy's connections, which has been mentioned several times before on VAF, is to use a single male and female D-Sub pin, connect them, and heat shrink over the connected pins. This approach has the advantage of a future disconnect, albeit with an Xacto knife involved to remove the heat shrink...:)

gil A
 
splices

To permanently splice wires in my RV7a, I used solder covered with heat shrink tubing. My experience with butt splice connectors over the long haul has not been good so therefore I use solder.

good luck
 
Bob,

All the posts above give you good advice.

The key to the type of connector has to do with what kind of future maintenance do you think the part will require.

My flap motor had to be dissembled and clean at around 70 hours. I was thankful I used mail and female tab connectors so it was easy to remove. Just make sure you put a male and female on the flap motor so you can't connect them backwards when you reinstall the part.
 
Hummmmm

pvalovich said:
Bob,
I've tried three methods - solder, crimped knife splices and crimped butt splices. Funny what you learn about yourself when building an RV - I've determined that I am permanently solder-challenged, so try to avoid using the stuff as much as possible. No matter how hard I try, I can't ever get a neat solder connection.

I use crimped knife splices (covered in heatshrink) where there is the possibility of disassembly. Heat shrink covered crimped butt splices for the rest. All splices are subjected to a pretty good yank-on-the-wire check.

Not flying yet - but all splices have maintained static integrity!!!
Booger
RV-8A N192NM
Wiring
Click to expand...




OH COME ON NOW.... no one is that bad......

Put the solder iron on top of the splice and run the solder into the side of the splice. DONT move it for 5 seconds after removing the iron....

GHEESSSSSSSh
 
Sticky1 said:
OH COME ON NOW.... no one is that bad......

Put the solder iron on top of the splice and run the solder into the side of the splice. DONT move it for 5 seconds after removing the iron....

GHEESSSSSSSh
Click to expand...

I got the impression at the SportAir avionics/electric class last year that solder is discouraged where possible because it can break more easily than other methods. True? False?
 
Solder stiffens the wire-----it can wick up the wire a surprising distance.

If the wire is able to flex, it can break where the solder ends.

Solder is just fine, with the proper strain relief/support for the wire. This would include being bundled with other wires, if the bundle is stiff enough.

Good luck.
 
Hummmm

Mike S said:
Solder stiffens the wire-----it can wick up the wire a surprising distance.

If the wire is able to flex, it can break where the solder ends.

Solder is just fine, with the proper strain relief/support for the wire. This would include being bundled with other wires, if the bundle is stiff enough.

Good luck.
Click to expand...




Yea what he said........when ever I solder i cover in heat shrink and tywrap at both ends to the bundle.....
 
D-sub pins are good for something you might have to replace - just heatshrink over the pins.

Nuckolls method works great for permanent soldered splices. Strip one wire about an inch instead of the normal length, pull one or two strands out and leave them one inch long, then cut the main strand bundle to the normal length. The long strands you pulled out can then be wrapped around the other stripped wire to hold them together. (Don't forget to lightly tin the ends to be soldered and slip the heatshrink on before wrapping.)

http://www.aeroelectric.com/articles/Tech_Tips/Solder_Lap_Splicing/Solder_Lap_Splices.html

One of the weighted, "solder buddies" available at Radio Shack, Harbor Freight, etc. with the articulating alligator clips to hold your wires while you solder helps a lot. Heat the wire to the point it melts the solder when you touch it to the wire; don't melt the solider with the soldering iron. Then secure well as described below.

Sticky1 said:
Yea what he said........when ever I solder i cover in heat shrink and tywrap at both ends to the bundle.....
Click to expand...
 
Last edited:
You must log in or register to reply here.