# How to solder



## Newtown Joe (Jan 30, 2013)

OK, now that everything is fixed I need to ask for advice on how to solder. I manage with great difficulty. Sometimes I get lucky, other times I struggle to make it work. 

Solder won't melt even when iron is very hot. 

Can't keep wire in place and solder at the same time.

Is flux needed in this type of electrical soldering?

Can anyone give me some tips to make it easier?

What is the best type of solder to use?

What is the best soldering gun?


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## JerryH (Nov 18, 2012)

One important thing that some miss is preparing the items to be soldered. The metal must be bright and clean. Rosin core small diameter is generally used for rail joints. A low wattage pencil point iron and maybe some heat sink clips to keep the plastic from melting. Keep the tip clean by wiping it with a wet sponge.


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## Newtown Joe (Jan 30, 2013)

What about tinning? The tip seems to get discolored real fast and that prevents heat transfer.
Should I just wire brush the tip to clean it before soldering?


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## JerryH (Nov 18, 2012)

Tinning helps. It sounds like you are getting some crud on the tip. Wipe it with a wet sponge while it is hot and it will be clean for the current task.


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## sjm9911 (Dec 20, 2012)

Wish I knew!! I suck at it. But ill tell you what works for me. I use a butane fueled iron , 30$ online. It heats up fast and melts the soldier instead of me melting the surounding stuff. Ive only soldered wires, clean an tin them. Tinning is melting solder on the wires before finally joining them. Use the better solder rated for wireing. Its thin. I use flux. , and I use the wet spong a lot.


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## Newtown Joe (Jan 30, 2013)

*Soldering*

Shouldn't it melt the solder right away? Seems like I have to wait and hope most of the time.


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## JerryH (Nov 18, 2012)

Make sure the tip is tightened. They will loosen up over time. Yes, if the tip is hot enough, the solder will melt right away.


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## tooter (Feb 26, 2010)

The wet sponge tip helps me the most. If the tip is not clean and bright, nothing else is going to work.

Greg


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## Newtown Joe (Jan 30, 2013)

OK, thanks for the tips.


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## SNNRail (Aug 31, 2014)

I feel your pain, some make it look so easy. What are heat sink clips?


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## wvgca (Jan 21, 2013)

getting rid of surface oxidation is important, pieces to be soldered should be sanded or similar to get them shiny clean, and the iron tip should be wiped clean and fluxed / retinned on a regular basis, a little flux on the work piece helps also, use only rosin core solder for hobby and electronics, either 60/40 or 63/37 will work well ...if your solder station is adjustable start around 550 f, for track and similar size work i use a weller gun 100/140 watt rated with ordinary household copper wire for a tip, fast heat up and very low cost, for electronics i use a hakko 936 station, very dependable for decades now


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## Big Ed (Jun 16, 2009)

T-Man just added some threads in his sticky thread on soldering if anyone cares to look,

http://www.modeltrainforum.com/showthread.php?t=24522


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## sjm9911 (Dec 20, 2012)

The t man just put some links in his sticky thread on soldering . Check them out. O scale fourm.


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## sjm9911 (Dec 20, 2012)

Guess I type to slow!


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## Big Ed (Jun 16, 2009)

sjm9911 said:


> The t man just put some links in his sticky thread on soldering . Check them out. O scale fourm.


You Polly the parrot?


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## SNNRail (Aug 31, 2014)

Thanks guys I'll definitely check that out.


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## fcwilt (Sep 27, 2013)

If were talking soldering rail joints:

- Wipe the tip before soldering each joint - a wet sponge is good - and cheap.
- Apply a small amount of solder directly to the tip to "wet" it - this helps heat transfer to the rail.
- Apply the tip to the joint with a bit of pressure - you need to get good heat transfer.
- Apply the solder to the rail joint - when the rail gets to the required temp the solder should melt and flow.
- If you just apply the solder to the tip it will of course melt but the rail may not be at the required temp and the solder will not flow into the joint.
- Don't use too low a wattage iron - you want to be able to heat the joint quickly to temp, apply solder and stop - if the wattage is too low the rail will suck heat away and the joint will heat slowly (if ever) to the required temp - but it can still get hot enough to melt plastic ties.
- If you can afford it get a temperature controlled soldering station.

- Rosin code solder is fine for soldering rail.
- Applying paste or liquid rosin flux can help - sort of belt and suspenders approach.

With the right tools and materials soldering is actually quite easy. 

Practice on some scrap pieces of track until it becomes second nature.


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## rkenney (Aug 10, 2013)

1.) clean tip - wipe tip on a wet sponge occasionally

2.) tight mechanical connection between parts to be soldered (electrical parts need to be in contact with one another).

3.) flow solder off tip into joint as you apply heat (the melted solder flows heat into the joint)

4.) continue heat to 'boil' flux off soldered joint after you stop solder application (short time)

A heat sink protects sensitive electronics. Placed on the lead between the soldered joint and the semiconductor device it absorbs heat during the soldering operation, protecting the device from overheating.


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## Newtown Joe (Jan 30, 2013)

*Soldering*

One last tip.
Keep that hot soldering iron away from all your plastic pieces. I learned this one the hard way.


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## Northern Route (May 12, 2014)

I personally use a rosin past flux. I apply it to the parts, I use my soldering iron to apply the solder. The flux makes the heat transfer immediate to the parts and draws the solder off of the tip of the iron. A touch of the soldering iron to the parts makes a quick solder flow and prevents overheating the parts. Just make sure to make the solder flow or it will not work.


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## CTValleyRR (Jul 26, 2014)

One tip I've definitely learned over the years: you need 3 hands to solder, 1 for the iron, one for the solder, and at least one to hold the items you intend to solder together. Solution: clamps or clips to hold your work. These can also help by serving as a heat sink, to keep heat away from things you don't want to heat up too much.


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## SNNRail (Aug 31, 2014)

Northern Route said:


> I personally use a rosin past flux. I apply it to the parts, I use my soldering iron to apply the solder. The flux makes the heat transfer immediate to the parts and draws the solder off of the tip of the iron. A touch of the soldering iron to the parts makes a quick solder flow and prevents overheating the parts. Just make sure to make the solder flow or it will not work.


Great tips really here. I'm glad I found this community. This advice alone seems to make more sense to me than what I have tried to learn previously about soldering. I used to weld on car exhaust systems and the welding sticks had the flux and "solder" together, you would get the pipe up red hot (unlike electrical soldering) then place the weld stick in between the torch and the joint. The metal would just flow nice around the spot. 

So far electrical soldering hasn't been as intuitive for myself. I'm going to grab me something to test on and use these new tips, wet sponge, getting a little solder on the tip, and using clamps to hold and transfer heat.


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## fcwilt (Sep 27, 2013)

SNNRail said:


> about soldering. I used to weld on car exhaust systems and the welding sticks had the flux and "solder" together, you would get the pipe up red hot (unlike electrical soldering) then place the weld stick in between the torch and the joint.
> 
> So far electrical soldering hasn't been as intuitive for myself. I'm going to grab me something to test on and use these new tips, wet sponge, getting a little solder on the tip, and using clamps to hold and transfer heat.


Solder is available with cores of flux much like your welding sticks.

Others posts mentioned Rosin Core Solder which is quite commonly used for electronics work and usually works well for soldering rail joints.

The issue is the same in welding or soldering - you need to get the materials hot enough but not too hot.

Welding involves melting the metals being joined - soldering does not.

If while trying to solder a rail joint the rails start to melt - you crossed over from soldering to welding - and you really don't want to do this.


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## DonR (Oct 18, 2012)

Fcwilt mentioned my favorite soldering method.

I like a dab of solder on the tip of my iron. But first,
each part you are soldering must be 'tinned'. for most
model soldering I use a toothpick to apply a dab of flux,
then carry the dab of solder to each part and let the
heat quickly transfer the solder. When both parts have
the solder where they are to connect, clamp them together
then bring a 3rd dab of solder to the joint and the heat will
quickly 'weld' them together. 

Practice on scrap wire and rails and you'll quickly get the
hang of it.

Don


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## Newtown Joe (Jan 30, 2013)

From the answers here it's obvious that soldering involves a combination of knowledge, technique, art and a steady hand. All of which I posses to a limited degree.


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## fcwilt (Sep 27, 2013)

Newtown Joe said:


> From the answers here it's obvious that soldering involves a combination of knowledge, technique, art and a steady hand. All of which I posses to a limited degree.


It really is not difficult - start with the right tools and materials - practice - in just a short time you should be more then proficient.

Hands on I could teach you to solder rail joints in less then an hour - absolute max.


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## jesteck (Apr 15, 2014)

Sorry I'm chiming in a little late here. I'm a retired plumber and know a bit about soldering, using everything from pencil irons through acetylene torches. Some basic principles:

1) Surfaces to be soldered must be clean and free of paint and oxidation. The purpose of flux is to prevent reoxidation when heating the components.
2) Overheating can and will cause the flux material to boil off and allow the components to re-oxidize, defeating your purpose.
3) For electrical work on a model RR of ANY scale, you do NOT want to try to use a roll of 1/8" plumber's solder from Home Depot. You'll melt everything in sight before the solder even thinks about melting. Instead, you'll want the smallest diameter resin-core or multi-core solder you can find; try Radio Shack, Walthers, or your local hobby shop.
4) If you're afraid the wet-sponge might leave some plastic or rubber residue on the tip of your iron or gun, use a wet paper towel.
5) Heat sinks can be as simple as alligator clips. All you want to do is keep the heat away from where it's not supposed to be.

Using the smallest diameter resin core solder you can find will let you see exactly when the solder flows into and around the joint, whether it's a rail joiner, a track feeder, or some other smaller contact. Apply the heat where you want the solder to flow to. Keep your tip clean and tinned, but don't overload it with solder. Practice!


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## trains galore (Jul 22, 2013)

Great tips!
I always use 60/40 rosin core solder, the trick is heat THEN apply, but be especially careful with soldering delicate components (transistors, ICs) as too much heat will destroy them!
Also really important to keep the tip clean, a little solder and then wipe it on the sponge. For some reason one of my irons keeps turning the tip a weird gold colour even though I keep tinning it. It was only a cheap one though, the soldering station is a lot better!

I learnt initially by getting old junk PCB's and practicing on them, then I built some electronics kits. Unfortunately I stopped doing it for a while and when I came back I was really messy and I still can't do it quite as well as before, my hand just keeps shaking, tried using the iron in different hands and all that but it is really annoyingGuess I just need to get some more practice
Clamps definitely help though!


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## tjcruiser (Jan 10, 2010)

Chiming in late on my part ... had a quick read above, but not sure if this has been suggested ...

When soldering track rails together (like on HO track), put a wadded-up damp paper towel (or sponge) a couple of inches away on either side of the intended solder joint. The water will act like a heat sink, and help prevent the plastic ties from melting / distorting during the hot soldering.

TJ


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## gunrunnerjohn (Nov 10, 2010)

Heat is all important when soldering heavier stuff. You'll do less melting with more heat than less heat in most cases, the heat isn't there nearly as long. As TJ says, blocking the heat from traveling down the rail is a good idea.

For finer work, the soldering iron is all important, as well as cleanliness. I have the Hakko soldering station, a worthwhile investment. It's a 70 watt station with adjustable temperature. The really nice thing about this one is you can calibrate the heat so the temperature on the dial is actually the temperature getting to the tip! I run it at 650 for PCB work, and it works great. The tip is important as well, when they get dull and you can't properly tin them, trash them!


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## trains galore (Jul 22, 2013)

I run my soldering station at about 320 degrees most of the time for pcb's.
How often should I replace my tip? I replaced it about a year or so ago but it isn't tinning quite as well as it used to, maybe I should replace it


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## DonR (Oct 18, 2012)

Sometimes it helps to file the tip and
re-tin it. 

I don't replace my tips until they have 
eroded to where they are no longer
usable.

Don


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## gunrunnerjohn (Nov 10, 2010)

Many of the new tips are plated, and when that wears off, they won't tin properly and will quickly need to be replaced. You need a good tip to work on SMT components on circuit boards.


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## thedoc (Oct 15, 2015)

A lot of good advice here, even the newer iron tips are plated with tin, and they can be filed down and re-tinned, but I prefer the old copper tips. Flux prevents the metal from re-oxidizing and some flux will clean the metal a little. If you need to use acid flux solder, you will need to carefully clean the items and neutralize the acid. N-S and brass rail are easy to solder, steel is a bit more difficult. Some provision should be made to keep the plastic ties from melting, but removing them, soldering the rails, and replacing the ties, might be the easiest.

FYI I used to try to teach this to Jr. HS boys, so I know a little about soldering.


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## Lee Willis (Jan 1, 2014)

I really have no problems soldering. I use a Weller 200/260 gun and file down the tip before use and tin it fresh. Works great.


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## MattR (Oct 30, 2015)

I too kind of stink at it. I get it done, but there are definitely better people for the job.
Please explain a bit about tinning and proper flux use. I would love to get better also.

Thanks,
Matt


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## higgsbosonman (Nov 17, 2014)

I've worked very hard to get good at soldering, and most of it comes down to the tools. What I've learned is that flux is magic, and lead free solder is garbage without enough magic (with the exception of silver solder). Lead solder is the best, hands down. Guns are nice for wires, but can't do much else like soldering to electrical boards. Also, some lead free solders have both a minimum and a maximum working temperature, and sometimes they are not seperated by much (less than 50C in a lot of cases), so that a digitally controlled soldering iron is required for them. A set of helping hands helps for keeping wires in their place; I paid $4 for mine at menards. I put heat-shrink or electrical tape around the alligator clips because they'll bite right through wire insulation. I'm eventually going to track down a scrapbooking heat gun, because they are the perfect size for shrinking heat-shrink and not melting anything else.
What I currently use to solder is a Hakko FX888D. If you're going to do any amount of soldering, it is a lovely piece of engineering that I drooled to have for years. Weller makes an equivalent if you want an american brand, although I don't know the exact make and model. I can assemble PCBs with it, and I have a friend who can do surface mount soldering with his, although he has much more practice than me.
This is overkill for people who just want to bond wires to wires. If you ever need to assemble electrical boards or do precision soldering in the confines of an unusally frustrating locomotive, then having the ability to get a good joint in two or three seconds is fantastic. Otherwise, I don't mind using a weller gun. It's what I learned with.


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## MattR (Oct 30, 2015)

So " tinning" is applying a coating of solder to something. Be it the gun tip,or wires. 

So wires are then simply put where they need to be and then just re heated? 

How come the solder applied to the gun tip for thinning doesn't wipe off when cleaning the hot tip on the sponge?

How often should one re tin the tip?

Should flux be applied to the tip or smeared on at the connection location?


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## ED-RRR (Jun 4, 2015)

*Warning; Soldering Gun*



Lee Willis said:


> I really have no problems soldering. I use a Weller 200/260 gun and file down the tip before use and tin it fresh. Works great.


There is nothing wrong with a Weller 200/260 gun..

- BUT - 

Warning: 
Soldering Guns release a "magnetic field" ..
This may/will damage electronic components..
This especially applies to [DCC] electronic components..
......


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## trains galore (Jul 22, 2013)

Interesting to hear! 
I have only ever had an iron/station, though I do have an old desoldering gun around somewhere. 

Why is it then that the guns produce this magnetic field but standard irons do not?
There must be a difference in how the heat is generated, I know most irons these days use a ceramic heating element.


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## trains galore (Jul 22, 2013)

MattR said:


> So " tinning" is applying a coating of solder to something. Be it the gun tip,or wires.
> 
> So wires are then simply put where they need to be and then just re heated?
> 
> ...



I'm no expert but the idea is to tin the end of the tip so that the solder flows easily when trying to make a connection. Keeping the iron clean is very important, I wipe the tip on a wet sponge after making each connection, and tin the tip again. 
Even though you are effectively wiping off the excess solder, you will find that the tip is still nice and clean if you wipe it after tinning.
Flux is used at the connection location to assist the solder to ''take'' especially if the connection is a little dirty or tarnished from age (for example an old switch may have slighly tarnished contacts.) I have never really needed to use it much as the solder I buy has a flux integrated into it, but I know many people who still use a seperate flux. I simply use 60/40 solder and it works fine for me, just keep the tip clean and try to avoid burning insulation on the wires as it is tough to remove from the tip, smells awful and looks messy! 

It is also good to tin any wires you want to put into screw terminal blocks as it stops the strands from poking out all over the place, although you can just twist them neatly.


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## ED-RRR (Jun 4, 2015)

*Track Rails*



tjcruiser said:


> When soldering track rails together (like on HO track), put a wadded-up damp paper towel (or sponge) a couple of inches away on either side of the intended solder joint. The water will act like a heat sink, and help prevent the plastic ties from melting / distorting during the hot soldering..TJ


There is a special "soldering tool" that has been proven and tested for decades..
[HO] #MLR-5005 Soldering Tool (Highly Recommended To Have)..
Also insures perfect track alignment.. 
--> "Only" soldering the (x2) "Outside" track rail faces..








......


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## ED-RRR (Jun 4, 2015)

*Soldering Gun*



trains galore said:


> Why is it then that the guns produce this magnetic field but standard irons do not?
> There must be a difference in how the heat is generated, I know most irons these days use a ceramic heating element.


Soldering Iron:
Electrical soldering irons usually have a resistance heating unit, similar to what you would find in a hair dryer or a toaster. 
Electrical current passes through the heating unit, and electrical resistance causes the unit to get hot..

Soldering Gun:
Has a large AC-->DC "Transformer..








......


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## thedoc (Oct 15, 2015)

ED-RRR said:


> There is nothing wrong with a Weller 200/260 gun..
> 
> - BUT -
> 
> ...


Will this "Magnetic field" effect a defibrillator, there's a lot of electronics in one of these, and I know there are a few members who might have one.


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## ED-RRR (Jun 4, 2015)

*"Magnetic Field"..*



thedoc said:


> Will this "Magnetic field" effect a defibrillator, there's a lot of electronics in one of these, and I know there are a few members who might have one.


Sorry, but I can "Not" help you with your question..:dunno:
Search the "Internet" --> Defibrillator Magnetic Field
You will find some information..

Fact:
- Transformers do release a "Magnetic Field"
- A "Soldering Gun" uses a "Transformer"
- Electricity flowing through a wound up coil produces this kind of magnetic field







......


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## ED-RRR (Jun 4, 2015)

*Tip Cleaning Station..*

I never liked using that wet sponge procedure..
- messy
- cools off the tip

I use a wire sponge, contained in a special container..
- Specially made steel wire sponge
- Polishes the soldering tip removing "old" solder

Caution:
I have seen the sponges in (x3) "Different" colors..
- Brass
- Copper
- Silver
But they are all made from "Steel"..







......


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## gunrunnerjohn (Nov 10, 2010)

ED-RRR said:


> Warning:
> Soldering Guns release a "magnetic field" ..
> This may/will damage electronic components..
> This especially applies to [DCC] electronic components..
> ......


I'm curious where this idea comes from. In general, magnetic fields will have no averse effects on electronics. The only exceptions might be magnetic sensors, but I've never seen any ill effects working on many magnetic encoders for model trains. Have you actually experienced such damage your self? If so, can you be specific as to what was damaged?


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## ED-RRR (Jun 4, 2015)

*"Magnetic Fields"*



gunrunnerjohn said:


> I'm curious where this idea comes from. In general, magnetic fields will have no averse effects on electronics..


Question: 
What will happen if you wipe a magnet over a "Credit Card" ??

Answer: 
Demagnetization will strip out the data on the "Internal" circuit board.. 

Conclusion: :dunno:
At your "Own" risk use a "Magnetic Field" soldering "Gun" for your electronic circuits !!
......


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## gunrunnerjohn (Nov 10, 2010)

ED-RRR said:


> Question:
> What will happen if you wipe a magnet over a "Credit Card" ??
> 
> Answer:
> ...


Apples and oranges my friend. The magnet strip on the credit card is NOT electronics, it's a magnetic strip. FWIW, a strong magnetic field will have NO effect on the internal circuit board in the new chip equipped credit cards. They use FLASH memory, and magnetic fields have no effect on it.

I won't argue the point farther, suffice to say I've been designing electronics most of my life, including a lot of avionics that are critical to flight safety. Magnetic effects are so low on the list of hazards that it was never a defining factor when we worked on a design.


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## Mr.Buchholz (Dec 30, 2011)

Newtown Joe said:


> Solder won't melt even when iron is very hot.


Try replacing the tip. I had the same problem a little while back, until I noticed everything but the tip was hot. They do stop heating up after a period of time.



Newtown Joe said:


> What is the best soldering gun?


I have a Weller 8200 pistol grip soldering gun. Awesome thing. I recommend these over the iron any day. If you don't have one, GET ONE.

If you need more help with soldering, send me a PM and I'll see what I can do.

-J.


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## gunrunnerjohn (Nov 10, 2010)

It really depends on what you're soldering as to what tool would be best. Finer work around circuit boards, LEDs, and fine wiring is better done with a small iron, I prefer a temperature controlled model. For my fine work, I use the Hakko FX888D soldering station. For track work and heavy wiring, the gun is great, I have the Weller 100/140 that I've had for years, still going strong. Between the two, I have most soldering covered. 

If I need more heat, I also have a propane Turbo Torch.


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