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Experimental Repair

Electric-T

Jun 4, 2017
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Okay so the title is a little misleading. Im not very optimistic this repair will succeed but with a new solder gun on order i figure id learn something.
Its a 260/200 watt Weller solder gun. It quit working, so i replaced the two stage trigger with a SPST toggle switch. This didnt work. After much more troubleshooting i discovered the coil was broken right in the middle. I rewound the coil with roughly the same amount of wire. The whole system is a coil of copper wire, a possible brass plate winding running perpendicular to the interlinking with the copper coil, and an aluminum shaft running through both windings connecting to the tip.
I know this will probably fail but since im looking to learn here, can anyone tell me exactly why or how this will fail? In technical terms. Im very curious about this.
 

davenn

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Sep 5, 2009
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I know this will probably fail but since im looking to learn here, can anyone tell me exactly why or how this will fail? In technical terms. Im very curious about this.

how about some photos of "this coil" so we know what you are referring to
 

Minder

Apr 24, 2015
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Aluminum is not a good alternative to the original single turn copper secondary.
There is 100amp + in the secondary normally so it has to be very low resistance with one continuous loop as much as possible.
M.
 

Electric-T

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I did not replace the copper with aluminum. I used stranded 10 ga. The point is here that i guessed at the amount of turns. Im wondering why that matters in a coil so much if i can produce similar resistance with another method.
 

Electric-T

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Also im a little embarrassed to post a picture. Its not a serious attempt at a coil. I know the thing is junk i was just looking for a theory type of answer. ( resistance is too low, etc)
 

Electric-T

Jun 4, 2017
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It didnt work anyways. Tripped a breaker. I wasnt trying to fix it as much as i was try to understand the theory of operation. Sorry if i was unclear.
 

Minder

Apr 24, 2015
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You probably guessed wrong at the No of turns, was it not possible to count the number of the old coil?
This type of Iron uses the same principle as a spot welder, a single turn-high current secondary to produce high heat at the narrowest point (the tip).
M.
 

Electric-T

Jun 4, 2017
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It was not possible to count. I honestly just stripped a bunch of 10 ga to bare copper, tried to match the amount of wire, and wrapped it. It was just an experiment. It looked terrible. Just thought id try it and see if it could be done. Evidently not
 

duke37

Jan 9, 2011
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A coil needs insulated wire, if you used bare copper, you introduced shorted turns and will get nothing out.
 

Electric-T

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Hahaha lesson learned i guess. I basically wired one big dead short then. I didnt think the enamel coating on the wire insulated anything. Thanks for all the replies. Gun went to the scrapyard and the new one should be here any day now.
 

Electric-T

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I believe the original wire had an enamel coating. Kind of a reddish tint to it. But the wire i used was bare copper. The more i think about it the more i see how i wired a dead short.
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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I know this will probably fail but since im looking to learn here, can anyone tell me exactly why or how this will fail? In technical terms. Im very curious about this.
I am reactivating this old thread since, based on your more recent posts, you still seem to be learning. Below is a picture of your Weller 260/200 Watt Soldering Gun as seen on Amazon.com

71xouNUEXEL._SL1500_.jpg


The heavy "aluminum rods" protruding from the front are actually the end connections of a one-turn secondary winding on a transformer occupying the bulk of the gun above the two-stage red trigger switch. The primary of this transformer is tapped, so activating the trigger inserts all of the primary winding or just part of the primary winding (depending on how far you pull the trigger) in series with the power line cord seen protruding from the bottom of the handle. Depending on whether all of the primary winding or just part of the primary winding is connected to the power line cord determines how much voltage is induced in the one-turn secondary. Typical voltage in the secondary (without a tip bolted in place) will be about two volts. With the copper tip bolted in place, over 100 A will flow through the tip, consuming 200 to 260 watts. The voltage at the secondary is large enough to operate two screw-base "penlight" bulbs located on either side of the gun near the lower of the two secondary winding terminals.

Notice the method of attachment of the copper soldering tip to the aluminum rods. This picture shows that a pair of "set screws" is used to secure the copper. Earlier, better constructed, guns used a threaded steel ferrule that slipped over the ends of the copper wire, which were then bent at a right-angle and pinched between the ferrule and the secondary terminals as the ferrule was screwed down into the terminals. The secondary terminals were not made of aluminum originally but of steel (or perhaps nickel-plated copper). The ferrules allowed a much higher compression force to be exerted on the relatively soft copper, deforming it and forming a gas-tight metal-to-metal seal with very low resistance. The primary reason these guns fail to heat properly is a poor, high-resistance, connection between the copper soldering tip and the secondary terminals. The change to aluminum secondary terminals has guaranteed that the steel "set screws" will eventually "strip out" the threads in the aluminum, rendering the gun useless.

Historically, the Weller soldering gun was the "go to" tool for radio and television chassis-wired component replacement. Parts were mounted on solder terminals and it took a lot of heat to melt the solder securing them. Soldering irons of that era were large and unwieldly. Solder suckers hadn't been "invented" yet, although clever technicians learned to remove the outer shielding braid from coaxial cable, dip it in solder paste flux, and use it to remove solder by capillary attraction. Today you can buy solder wick in various sizes with flux pre-applied. No need to strip out the braid from coaxial cables. But the Weller Soldering Gun is pretty much obsolete and useless for serious electronics work, being replaced by the 40 to 60 watt "pencil" soldering iron or the newer temperature-controlled soldering stations. And for surface-mount devices (SMDs) you really need a hot-air work station.
One comment you made back in the early part of this thread leads me to believe you didn't know anything about inductance, inductive reactance, or for that matter, anything about reactance and how it affects AC circuits:

The point is here that i guessed at the amount of turns. Im wondering why that matters in a coil so much if i can produce similar resistance with another method.
As you have (hopefully) learned by now, resistance and reactance bear only one thing in common: they are both measured in ohms. Reactance, unlike resistance, has an "imaginary" component that is either positive (inductors) or negative (capacitors). Don't get too wrapped around the axle about what this "means" because it is just the way mathematics is used to describe the physical observation of reactance and what distinguishes reactance from resistance.

So... how much "electronics theory" have you absorbed since this thread was started? Built anything yet? Let the "magic smoke" out of any components yet? Acquired a soldering pencil to allow you to do some serious, modern, electronic fabrication? All that is part of the experimental process. You learn by doing.
 

Electric-T

Jun 4, 2017
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I am reactivating this old thread since, based on your more recent posts, you still seem to be learning. Below is a picture of your Weller 260/200 Watt Soldering Gun as seen on Amazon.com

71xouNUEXEL._SL1500_.jpg


The heavy "aluminum rods" protruding from the front are actually the end connections of a one-turn secondary winding on a transformer occupying the bulk of the gun above the two-stage red trigger switch. The primary of this transformer is tapped, so activating the trigger inserts all of the primary winding or just part of the primary winding (depending on how far you pull the trigger) in series with the power line cord seen protruding from the bottom of the handle. Depending on whether all of the primary winding or just part of the primary winding is connected to the power line cord determines how much voltage is induced in the one-turn secondary. Typical voltage in the secondary (without a tip bolted in place) will be about two volts. With the copper tip bolted in place, over 100 A will flow through the tip, consuming 200 to 260 watts. The voltage at the secondary is large enough to operate two screw-base "penlight" bulbs located on either side of the gun near the lower of the two secondary winding terminals.

Notice the method of attachment of the copper soldering tip to the aluminum rods. This picture shows that a pair of "set screws" is used to secure the copper. Earlier, better constructed, guns used a threaded steel ferrule that slipped over the ends of the copper wire, which were then bent at a right-angle and pinched between the ferrule and the secondary terminals as the ferrule was screwed down into the terminals. The secondary terminals were not made of aluminum originally but of steel (or perhaps nickel-plated copper). The ferrules allowed a much higher compression force to be exerted on the relatively soft copper, deforming it and forming a gas-tight metal-to-metal seal with very low resistance. The primary reason these guns fail to heat properly is a poor, high-resistance, connection between the copper soldering tip and the secondary terminals. The change to aluminum secondary terminals has guaranteed that the steel "set screws" will eventually "strip out" the threads in the aluminum, rendering the gun useless.

Historically, the Weller soldering gun was the "go to" tool for radio and television chassis-wired component replacement. Parts were mounted on solder terminals and it took a lot of heat to melt the solder securing them. Soldering irons of that era were large and unwieldly. Solder suckers hadn't been "invented" yet, although clever technicians learned to remove the outer shielding braid from coaxial cable, dip it in solder paste flux, and use it to remove solder by capillary attraction. Today you can buy solder wick in various sizes with flux pre-applied. No need to strip out the braid from coaxial cables. But the Weller Soldering Gun is pretty much obsolete and useless for serious electronics work, being replaced by the 40 to 60 watt "pencil" soldering iron or the newer temperature-controlled soldering stations. And for surface-mount devices (SMDs) you really need a hot-air work station.
One comment you made back in the early part of this thread leads me to believe you didn't know anything about inductance, inductive reactance, or for that matter, anything about reactance and how it affects AC circuits:


As you have (hopefully) learned by now, resistance and reactance bear only one thing in common: they are both measured in ohms. Reactance, unlike resistance, has an "imaginary" component that is either positive (inductors) or negative (capacitors). Don't get too wrapped around the axle about what this "means" because it is just the way mathematics is used to describe the physical observation of reactance and what distinguishes reactance from resistance.

So... how much "electronics theory" have you absorbed since this thread was started? Built anything yet? Let the "magic smoke" out of any components yet? Acquired a soldering pencil to allow you to do some serious, modern, electronic fabrication? All that is part of the experimental process. You learn by doing.
I have learned a good deal more since this post. This "repair" was a broken gun at work. Obviously it didnt work. As far as the set screws stripping. We usually just drill and tap a 1/4-20 hole in the other side. Works pretty good.
I am actually working on a motion alarm project right now. A small green led circuit to let me know the alarm is armed. A spdt relay is switched by current being triggered from the pir to a npn transistor.( did that make sense?) which trigger a red led and proceeds to a 556 timer ic. The ic outputs a tone to a speaker. ( still working on this part). I just need an enclosure and a board to build it on. Suggestions?
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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I would ditch the 556 and the speaker. Instead, use one of those really loud, really obnoxious, solid-state noise makers that the SPDT relay can energize directly, along with the red LED. You might also consider adding a rotating red (or yellow) alarm light for even greater effect. All that should really get the attention of whoever happens to enter the room and trip the PIR sensor.

BTW, which PIR sensor are you using? Can you post a link to it? I bought one from Radio Shack before I left Dayton last year, but haven't really had a chance to "fire it up" and see how well it works. I think it was in a display rack along with a bunch of Arduino Shields, so it may be a "plug and pray" fit for one of my Arduino Unos.

Some PIRs have an LED behind the multi-faceted Fresnel lens that you can use with a "walk about" test to see what areas the PIR will respond. Of course you can use the regular PIR output to light your own external LED, but I thought it clever that some models do this for you in an unobtrusive manner.

No suggestions on the enclosure and board, but try to keep it simple and inexpensive. I like Altoids cans for small projects, but check out the Dollar Tree stores and their ilk for plastic containers you can re-purpose. IIRC, two-part bath soap containers (for traveling with wet soap) make fair to decent project boxes.

Don't you already have another thread started for this project?
 

Electric-T

Jun 4, 2017
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I would ditch the 556 and the speaker. Instead, use one of those really loud, really obnoxious, solid-state noise makers that the SPDT relay can energize directly, along with the red LED. You might also consider adding a rotating red (or yellow) alarm light for even greater effect. All that should really get the attention of whoever happens to enter the room and trip the PIR sensor.

BTW, which PIR sensor are you using? Can you post a link to it? I bought one from Radio Shack before I left Dayton last year, but haven't really had a chance to "fire it up" and see how well it works. I think it was in a display rack along with a bunch of Arduino Shields, so it may be a "plug and pray" fit for one of my Arduino Unos.

Some PIRs have an LED behind the multi-faceted Fresnel lens that you can use with a "walk about" test to see what areas the PIR will respond. Of course you can use the regular PIR output to light your own external LED, but I thought it clever that some models do this for you in an unobtrusive manner.

No suggestions on the enclosure and board, but try to keep it simple and inexpensive. I like Altoids cans for small projects, but check out the Dollar Tree stores and their ilk for plastic containers you can re-purpose. IIRC, two-part bath soap containers (for traveling with wet soap) make fair to decent project boxes.

Don't you already have another thread started for this project?
Yes im sure i made another post about this project. I like the light idea. I may try that. As far as the noise maker. I already bought the ic. I would like to put it to use. Heres the pir sensor. Its cheap but effective.http://m.ebay.com/itm/HC-SR501-PIR-...3A9f7666ab15d0a9c9700575afffff0763%7Ciid%3A18
 

Electric-T

Jun 4, 2017
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So... how much "electronics theory" have you absorbed since this thread was started? Built anything yet? Let the "magic smoke" out of any components yet? Acquired a soldering pencil to allow you to do some serious said:
And if by "magic smoke" you mean burned out components then yes. Haha ive burned a couple 555 timers up. Leds are especially easy to burn up. Also a cr2032 battery when trying to solder legs onto a new cell for a nes game. Thank you safety glasses:)
 
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