What's the best way to splice two wires together?? Do you guys prefer to use bare butt splice connectors, then solder them, and insulate with a wrap of electrical tape and some heat shrink?

Or is it better to just twist the stripped wires together and solder them WITHOUT using a butt splice connector, and give them a wrap of tape and some heat shrink???

I got a good sized bag of these:
http://www.digikey.com/product-detail/en/31818/A0951-ND/172790

then use a Channel Lock #909 to make the crimps.

Then heatshrink tubing over all of it. Digikey also has heatshrink for MUCH cheaper than any parts store.

Edit: I would dab each wire in dielectric grease before putting them in the butt connector.

Either twisting the wires together real tight & soldering or crimping the wires into each end of a bare metal butt connector then soldering then a wrap of tape over it then slide the shrink tube back over the joint & heat it to shrink it & since your soldering there's no need to use/waste a butt connector

i expose about 3/8" of wire on each side. slip a piece of shrink tubing over one end that will cover the exposed space of the splice. it should be a size that will shrink tightly around the exposed wire. i then slip a piece of shrink tubing on the other end that will cover the whole thing with some space on either end.

i then push the ends together, and with my fingers or pliers crimp down any strands so they merge together as best as possible, and are as round as possible. i then solder the connection.

then slip the smaller tubing over the exposed wire and heat it. that should bring the thickness close to what the wire is with it's insulation.

i then slide the bigger piece over and shrink it. this makes for a cleaner looking splice, as with only one piece of tubing it dips in where the insulation is missing where the actual splice took place.

a few more minutes of work, but makes for a nice splice.

1. Put your shrink wrap over one of the wires to be spliced.

2. Bend each wire into a J hook shape.

3. Hook wires together, then twist/wrap excess ends around itself.

4. Try pulling apart the two wires, if you hooked it right, they won't budge much and not enough to break the electrical connection, unlike if you just twisted strands together which could be pulled all the way apart easily.

5. Now do your soldering, then slip shrinkwrap over and heat that.

Step 3 is the most important.

I use un-insulated tined butt connectors with heat shrink. I usually don't solder. Splice must be good; invest in a quality crimper. I use Klein. Electrical tape is fine but self fusing silicone tape (F4) is better. Always check to make sure you don't put power on without the connector being insulated; you risk a ground short and you could easily burn something up like I just did in my GTX.

Ive used all of the answers.I prefer to twist the wires together and solder,shrink wrap.My hands are bad now so I get my son to twist them together.He can get them so good there is basically no bulge and they are so tight you cant pull them apart.Proper soldering is the important thing.Rocky

Twist, solder, cover and make sure to secure the wires so they don't vibrate or hang loose

The "J", hook, and twist method is called the Western Union splice. It's a recommended method in the aircraft industry. The step everyone omits is a cleaning after the solder connection (you can use iso alcohol or a blast of brake clean will do). This removes the corrosive flux that was in the core of the solder.

Well, I was able to solder some of the connections. But there are two more that are deep under the dash. I tried soldering them, but it wasn't happening. So, I'm just going to use uninsulated butt splice connectors, some dielectric grease, a wrap of electrical tape, and some heat shrink. Hopefully that'll work.

Thanks for all the input guys.

I strip both wires equilength, meeting in the middle,form an X, and twist them back on each other.

Solder and couple heat shrink wraps.

for heat shrink use what's referred to a "dual wall", it has a thin coat of sealant inside it that seals the connection better than standard heat shrink 2¢

Believe me, I would definitely solder them if I could. It's just really tight under the dash, not to mention I don't the steadiest hands. I'm hoping a good crimp will be good enough. At least I was able to get good solder joints on all of the wires inside the engine bay. (not sure if I mentioned it, but this is all for the bulkhead/alternator bypass like the MADD article.

Which is critical? For the charging circuit, I ran a 10g wire directly from the alternator to the starter relay. Then I ran a red and black 10g wire directly to the dash bypassing the bulkhead connector. I was able to get a really good soldered splice connecting the two wires from the back of the ammeter. The two connections I'm having problems with are the ones circled in yellow.