Rickresource Rickenbacker Forum

Warning, Will Robinson! Chemistry/Science lesson approaching!

Recall that one of the basic laws that govern the transfer of heat involves the mass of the material involved:

ΔQ = mCΔT

in which, for the material receiving the heat,

ΔQ = the amount of heat transferred
m = the mass of material
C = the heat capacity of the material (a physical constant for that material)
ΔT = the difference in temperature between the two materials involved

One also can consider the transfer from the perspective of the material from which the heat flows; the amount of heat that flows, ΔQ, must be the same for both (conservation of energy). The larger the mass, the larger the amount of heat that can be transferred (note that time is not involved in the equation ... that is an entirely different problem with a different set of equations).

Although a bit simplistic, this roughly gives an idea of the nature of the difference between a soldering gun and a soldering iron. However, each tool has its advantages in practice, and the bottom line is actually that it's a matter of technique/skill.

doctorwho wrote:Recall that one of the basic laws that govern the transfer of heat involves the mass of the material involved:

ΔQ = mCΔT

in which, for the material receiving the heat,

ΔQ = the amount of heat transferred
m = the mass of material
C = the heat capacity of the material (a physical constant for that material)
ΔT = the difference in temperature between the two materials involved

One also can consider the transfer from the perspective of the material from which the heat flows; the amount of heat that flows, ΔQ, must be the same for both (conservation of energy). The larger the mass, the larger the amount of heat that can be transferred (note that time is not involved in the equation ... that is an entirely different problem with a different set of equations).

Leave it to Gary to grossly oversimplify something!

Well yeah, he did...

So, give us the whole story, then.

That equation works great for two of material at given temperatures, but doesn't cover the case where you might add additional energy from an external source. You can transfer an incredible amount of heat from a small mass to a large one as long as you can continually replace the heat transferred away...

westaussie wrote:I have two guns, one 25w the other 100w.

A 25W gun or iron is way too small to use on guitar electronics. A 40W iron is a much better choice. The 100W gun is overkill and will melt the plastic insulation on wires fairly quick. It can be useful, though, for soldering to the pot bodies and pickup bases - Anything with a lot of metal that sinks the heat.

ken_j wrote:The magnetism in the transformed of a soldering gun can affect some electronic components in a negative way. I have never had a problem soldeing anything a a guitar on my almost 40 year old Ungar iron. It has interchangeable heating elements at various wattages and is a precursor to todays soldering stations. To solder to the back of a pot simply sand the back of the pot and tin it along with the wire end before soldering.

I once killed my Horseshoe by getting a soldering iron too close...

emac.

cjj wrote:That equation works great for two of material at given temperatures, but doesn't cover the case where you might add additional energy from an external source. You can transfer an incredible amount of heat from a small mass to a large one as long as you can continually replace the heat transferred away...

Yep, the equation cited obviously doesn't include time as a variable, nor does it include heat conduction in three dimensions ... but I didn't really want to break out the partial differential equations in spherical coordinates ...

beatlefreak wrote:

westaussie wrote:I have two guns, one 25w the other 100w.

A 25W gun or iron is way too small to use on guitar electronics. A 40W iron is a much better choice. The 100W gun is overkill and will melt the plastic insulation on wires fairly quick. It can be useful, though, for soldering to the pot bodies and pickup bases - Anything with a lot of metal that sinks the heat.

Perhaps the ones I am using are different, - for me the advantage of the 100w is that on fine work (small wiring etc, circuits etc.) is that it requires less than one second to melt the solder sufficiently and to impart sufficient heat to make a sound joint.
There is less time for heat dissipation. Melting of insulation for me would mean a lack of proper preparation and failure to apply proper technique. In practice, it's not a problem I have.
It does require proper technique for success, - properly cleaned surfaces are paramount. Precise control of the appliance and good timing are essential, but then we're all guitarists - that's what we practice.

doctorwho wrote:

cjj wrote:That equation works great for two of material at given temperatures, but doesn't cover the case where you might add additional energy from an external source. You can transfer an incredible amount of heat from a small mass to a large one as long as you can continually replace the heat transferred away...

Yep, the equation cited obviously doesn't include time as a variable, nor does it include heat conduction in three dimensions ... but I didn't really want to break out the partial differential equations in spherical coordinates ...

Bring 'em on!

Oops! Sorry nerdy engineering PhD surfacing... must... resist...

You two need to demonstrate you really were/are worthy of the education you received.

beatlefreak wrote:A 25W gun or iron is way too small to use on guitar electronics. A 40W iron is a much better choice.

So I've been told but all I ever see in a retail environment is a 25 watt iron, or the guns...

FWIW I wired up my 1976 4001FL from the ground up, using the original parts that were badly rewired, with the 25 watt iron. It appears to be a leakproof job so far, other than the fact that I must have inserted the stereo jack incorrectly because the ROS jack get both pickups on both channels. But I believe I did the soldering correctly, so I think it's something about how I pushed it into the cavity.

cassius987 wrote:... It appears to be a leakproof job so far, other than the fact that I must have inserted the stereo jack incorrectly because the ROS jack get both pickups on both channels. But I believe I did the soldering correctly, so I think it's something about how I pushed it into the cavity.

You have to orientate the jack so it just slides into the cavity made for it. If you look at the shape, the hole shape, and work easily, you should be able to get it to fit in and not close the switch mono-ing the pups all the time.

cassius987 wrote:

beatlefreak wrote:A 25W gun or iron is way too small to use on guitar electronics. A 40W iron is a much better choice.

So I've been told but all I ever see in a retail environment is a 25 watt iron, or the guns...

Mm? For "normal" low voltage thin lead soldering (as in guitars) I always use my little 18W iron, and have never had any problems (nor in more critical applications than guitar electronics). For soldering onto the back of large 24mm all-metal pots that 18W iron is a little weak.

Wiker wrote:

cassius987 wrote:

beatlefreak wrote:A 25W gun or iron is way too small to use on guitar electronics. A 40W iron is a much better choice.

So I've been told but all I ever see in a retail environment is a 25 watt iron, or the guns...

Mm? For "normal" low voltage thin lead soldering (as in guitars) I always use my little 18W iron, and have never had any problems (nor in more critical applications than guitar electronics).

Yeah, but that is 18 metric watts.