P90 Blacktop Jazzmaster

[sirspens]

Oh man, pardon my French but those solder joints look fucked.

Haha. No problem, man. I am NOT good at this.

I've rewired this guitar several times. Last week I upgraded my soldering set up with a bit nicer gear so hopefully I can get some better results. (Which doesn't make up for technique, of course.)

Thank you for the advice. In all of the videos I've watched and advice I've read, no one has recommended sanding the back of pots, even with me specifically looking for how to get pots to hold a solder. Thank you!

[hpr_hpr]

Hate to rag on people but sirpens is right, good solder joints = less trouble. The one thing missing from his rant is keep your tips clean (either with a wet sponge (99c method) or with a brass tip cleaner ($7-9 on Amazon)) and do NOT touch the solder directly to the tip . . . that will EAT your tip (literally and figuratively). NOT that my last set came out looking much better mind you . . . my excuse, I lost my 'good' tip and was impatient enough to 'just get it done' . . . of course once I stared cleaning up and putting stuff away guess what I found . . .

[sirspens]

Hate to rag on people but sirpens is right, good solder joints = less trouble. The one thing missing from his rant is keep your tips clean (either with a wet sponge (99c method) or with a brass tip cleaner ($7-9 on Amazon)) and do NOT touch the solder directly to the tip . . . that will EAT your tip (literally and figuratively). NOT that my last set came out looking much better mind you . . . my excuse, I lost my 'good' tip and was impatient enough to 'just get it done' . . . of course once I stared cleaning up and putting stuff away guess what I found . . .

Yeah. That's the upgrades I made. I got a new tip, brass tip cleaner (which works surprisingly well), and some tip tinner.

All that said, I have a Weller WLC100 40-Watt Soldering Station which is a decent, though not amazing, piece of equipment. And even on FULL heat, I can hold my tip to the back of a pot for several minutes and the solder will, 9 times out of 10, not melt. The iron will cut a hole through my plastic table like butter. (I solder on top of an oversize natural stone tile from a job, not the table, but still.) But it can't melt my solder? Is it because I am using lead-free?

[hpr_hpr]

Nope, (although lead free solder DOES have a higher melting point ~180-190 vs 210-220°C ) more likely it's because the tip is dirty, or faulty technique . . . (weirdly enough a dirty tip, despite melting things like your power cord just fine) does not transfer heat well . . . which results in crummy soldering jobs . . . . but yes, pot casings seem to have an AMAZINGLY good heat dispersion pattern . . . even under perfect conditions it takes a while, though several minutes seems extraordinarily long for a clean iron. What kind of tip do you use, a pointy conical tip is not the thing for pots, and MT10 chisel tip is what you want and then use the flat of the chisel to heat up the casing, move it a 1/4" and put the solder were you were . . . the a small conical tips are for soldering delicate temperature sensitive components and work with PCBs . . . in guitar wiring you can use the narrow end of the chisel though it makes it a little harder harder to get into tight spots . . .

So a final tip . . . do all the wiring you can OUTSIDE of small cavities away from the body and guard with the pots fixed in a jig (lugs to casings, caps to lugs & casings, connections between pots etc . . . much easier to get around things and it prevents 'accidents' were the hot iron touches you recently perfectly finished body or burns a hole in your pick guard . . . slightly longer wires are a smallish price to pay in my opinion . . . then move things into the body (or next to the cavity) to do final assembly . . .

[sirspens]

Nope, (although lead free solder DOES have a higher melting point ~180-190 vs 210-220°C ) more likely it's because the tip is dirty, or faulty technique . . . (weirdly enough a dirty tip, despite melting things like your power cord just fine) does not transfer heat well . . .

Thanks for the advice! I'm going to give it another go this evening.

[timtam]

All that said, I have a Weller WLC100 40-Watt Soldering Station which is a decent, though not amazing, piece of equipment. And even on FULL heat, I can hold my tip to the back of a pot for several minutes and the solder will, 9 times out of 10, not melt. The iron will cut a hole through my plastic table like butter. (I solder on top of an oversize natural stone tile from a job, not the table, but still.) But it can't melt my solder? Is it because I am using lead-free?

Something is seriously wrong here. I don't know what it is in your case, but failing to melt solder on full heat ?!

+1 to the importance of the tip. Use a medium thick tip (in good condition) not one of those pinpoint ones designed for finer work; they don't transfer heat as well.

I clean my tip on the wet sponge between every solder joint. A swipe or two on the sponge does it. Then tin the wire with solder and you should be good to go. Sometimes you will strike wire that just will not take solder easily, and some pots too, but that shouldn't be happening every time.

BTW if your pickguard shielding is effective, the wired ground connections between pots don't add anything. The grounded input jack rim grounds the shielding, which then grounds the pots via their rims. When you mount the pots, before wiring them together, check continuity between their backs with a multimeter; it should be fine. In fact if it's not, your shielding is not doing its job. If it is, you don't need the pot inter-connects. You don't really lose by having them, except that with all those extra wires and joints you increase the chance that something else will get shorted out. Which could be the source of your problems.

[sirspens]

BTW if your pickguard shielding is effective, the wired ground connections between pots don't add anything. The grounded input jack rim grounds the shielding, which then grounds the pots via their rims. When you mount the pots, before wiring them together, check continuity between their backs with a multimeter; it should be fine. In fact if it's not, your shielding is not doing its job. If it is, you don't need the pot inter-connects. You don't really lose by having them, except that with all those extra wires and joints you increase the chance that something else will get shorted out. Which could be the source of your problems.

You guys are a wealth of information. I have watched probably a dozen videos on soldering for guitars and never heard a good deal of this stuff. THANK YOU!

I just tried to salvage my pots and switch and whatnot, but I think I am going to have to buy new ones. So... I'm going to have to wait a week or so to give this a go.

[Steadyriot.]

Yea I forgot to add the clean your tip part!
Man there's so many ways to solder, I use a medium conical tip for everything. Pcb's, cables, pots, you name it. Just use the flat edge of the cone for pots etc. to transfer more heat.
I also apply solder directly onto the tip and never had any problems, that's how they taught us in school!

Here's what I do: I wipe the tip pretty regularly and then slightly tin it before moving on to the next joint to keep it slightly wet with solder; I feel this makes the joints flow easier / quicker.

Another life-saver when soldering is one of these:

Solder suckers cost a few bucks but are essential when you want to re-do anything with an eyelet / hole. Just heat the solder (always use a small fresh dab of solder to make it flow quick!) and suck it out with the solder sucker to start clean again.

Another helpful part is using a good rosin-core solder. Something like the AIM rosin core solder should get you there, but check out some pedal building suppliers, most of the time they sell pretty good solder. Hardware store solder is prone to leave residue (though some get by with it without trouble). Don't use flux! No really, don't! Most of the fluxes out there are acidic and will fuck up electronics over time. You don't want any plumbing solder; you need electronics solder.

If you like soldering and want to do it more often, pedal kits are a great way to spend the time and practice soldering more precisely, plus you end up with a pedal! Something like a Bazz Fuss or SHO copy are really simple and fun to build.

[sirspens]

Solder suckers cost a few bucks but are essential when you want to re-do anything with an eyelet / hole. Just heat the solder (always use a small fresh dab of solder to make it flow quick!) and suck it out with the solder sucker to start clean again.

I have a Solder sucker I bought the last time I rewired this guitar, trying to salvage my components. I either don't have as many hands as most people or am not coordinate enough to pull it off. I can play guitar and piano, but I can't get two hands to do vastly different things when soldering...

No flux, huh? I'll have to look into that.

[hpr_hpr]

If you have problems with the sucker try this https://www.amazon.com/Aven-17542-Desol ... ering+wick it requires less coordination, put it on the solder, heat it up and it sucks up the solder, just remember to keep it hot till you remove it. The drawback over the sucker is that it gets used up as you cut off the used part (filled with solder) before moving on to the next job.

And yes DEF +1 +1 +1 on the right solder. Hardware, big box store stuff is (mostly) for plumbing (in building applications wire is rarely - if ever - soldered, it may even be against code for all I know) were they use butane torches (not irons) to solder and a separate source of flux, different technique entirely. Good rosin non acid flux core . . . definitively . . . NO (additional) flux from a can EVER on electronics. I think Mouser and DigiKey will also have 'the good stuff'. Also, you don't need anything over 1 mm in diameter, that's just to much solder (and again results in crummy jobs), 0.8 is good, 0.6 maybe . . . it may be too thin (not enough solder) for pots . . . never tried it that thin . . . anything thinner is for wired PCB components or even surface mount stuff. Bigger is not always better here . . .

[sirspens]

With everyone's input (and having to wait until I had enough free time), I got some work done on this project today.

I got the cavity shielded. Which I think went pretty well.


Then I completely rewired the guitar, with my new soldering tip and other upgrades. I went by this wiring diagram:


Got it wired up...

I knocked off the bridge ground right before I took this picture, but got it fixed.

My soldering still isn't fantastic, but I think it is much better this time around.


It doesn't work. Doesn't make a peep. And I can't figure out why.

The struggle goes on.

[timtam]

Do you get anything when you plug it in with the pickguard off ? If it's only dead when you put it all together, chances are you have something shorting to the copper. Maybe the switch terminals ? Or some of the hot connections to your pots look to have quite a bit of bare wire hanging out there - they could be contacting the copper or other terminals or the pot body.

[HNB]

Is your volume turned all the way up? You can also try doing the toggle output just to your jack. (Skip going to volume and tone.) That would help you see if the problem is with the pots there.

[sirspens]

Thanks for everyone's suggestions!

I got back to working on the guitar this afternoon. I got out all of my testing equipment, sat down, and immediately saw the problem. For some reason I had switched the ground and live terminals on the switch. Crazy.

I fixed it, and it works fantastically. Quiet as a mouse due to the shielding.

It is just about finished. I have a few more things to go. For one, my standard P90 screws aren't long enough to get the P90 high enough. I found some that are 2.5mm longer than the ones I have, so I am going to give them a try. If they don't work. I may have to put a shim in.

The P90 / Jazzmaster pickup combination is very interesting. I am using 1M pots, giving it a LOT of brightness. I am also using a .022uF cap, so there is a lot of range in the tone knob, taking it even darker than the rhythm circuit on a JM. Once I can get the P90 up a bit higher, I think it will sound really good.

What I didn't expect is how good the middle position sounds with just a bit of dirt. It has the articulation of the JM pickup with the growl of the P90 behind it.

[RandyRandom]

Thanks for everyone's suggestions!

I got back to working on the guitar this afternoon. I got out all of my testing equipment, sat down, and immediately saw the problem. For some reason I had switched the ground and live terminals on the switch. Crazy.

I fixed it, and it works fantastically. Quiet as a mouse due to the shielding.

It is just about finished. I have a few more things to go. For one, my standard P90 screws aren't long enough to get the P90 high enough. I found some that are 2.5mm longer than the ones I have, so I am going to give them a try. If they don't work. I may have to put a shim in.

The P90 / Jazzmaster pickup combination is very interesting. I am using 1M pots, giving it a LOT of brightness. I am also using a .022uF cap, so there is a lot of range in the tone knob, taking it even darker than the rhythm circuit on a JM. Once I can get the P90 up a bit higher, I think it will sound really good.

What I didn't expect is how good the middle position sounds with just a bit of dirt. It has the articulation of the JM pickup with the growl of the P90 behind it.

looks awesome! reminds me of something that tom delonge of blink 182 would prolly play