Soldering confusion.

When I solder electronics for my model railroad, I generally tin the wire, then tin the soldering iron tip.

That tends to be all the solder I need. If you add more then you get the big blobs of solder which when working in n scale derails trains :/

Ye, thats what i found yesterday. I tinned the iron and then out that to the metal and then added the solder. But luckly it was on something with no detail and that was easy to clean up and it looks ok now, but took quite a bit of work with a file.

When you say you tin the wire, do you just cut a small piece od solder and place that where you want it?

I should have added adding some flux on the wire before, but yes then I put the solder to the wire.

The trick is to heat the wire from the tip and not so much the solder. The solder will melt when it contacts the wire.

As for tinnig the tip I just heat up the iron and put some solder to it.

Just make sure you work with a clean tip.

I also flux the rail before I put the wire to it, but depending on what you're doing I can't say if that would work.  I find it helps with the adhesion of the solder.

Bish

I've only just started soldering myself and have found that "Solder It" from Micro Mark works really well. It comes in a paste from an almost hyperdermic dispenser. I put a little between the pieces I want to join and just use the solder iron on one piece to heat it. as "Solder it" uses silver it melts at a lot lower temperature and the joins are really good.

Not saying this is the perfect way but its working for me as it keeps my solder iron clean and I don't have to worry about tinning etc

Phil

Hello!

You should generally keep the tip of the soldering iron tinned, to keep it in a good operating order. Otherwise the tip might get "dull", which means the solder won't stick to it at all. To "undull" it you have to take a damp sponge, rub the tip on it as if you were cleaning it (you actually want to remove some metal oxides from the tip), and then tin the tip immediately. It's OK to use paste, but the other way to go would be to buy thinner soldering wire - when you already have it, you can make excellent wiring or ruber hoses in your model out of it. Hope it helps, have a nice day

Paweł

Tinning means putting solder on anything- iron tip, parts to be soldered, whatever.  Once a  tip has been tinned, it will probably retain the solder for quite awhile, and does not normally need to be retinned every session unless you get it really cruddy.

As far as flux is concerned, ordinarily folks recommend acid flux. I do NOT recommend that for model work where you are working with fresh, clean brass.  Brass solders very easily, rosin core flux is perfectly adequate.  You can get very fine rosin core electrical solder in 060, even thinner spools.

The problem with acid core is that if you do not wash out the joint after soldering, and get ALL the acid flux out, it will cause paint in that area to degrade. So my philosophy is, never use acid core flux if you can avoid it.  Sometimes soldering some stainless (like music wire) does require acid core, but brass or copper certainly don't.

Thanks a lot for all the info guys.

Phil, is that Micro mark in the USA. I have a solder with silver in it, from radio Shack, but they don't have it in a paiste. And i have heard about soldering paiste, which does sound useful for PE.

Don, i have avoided acid flux and gone for a rosin core. The one i got was 062 but i have just ordered one half the size. But i will keep that in mind about the acid.

And thanks for all the other info guys, this has been great up and really cleared up the confusion.

Bish

yes its Micro mark USA

silver bearing solder 71 grams,7165.html

Phil

Phil, thanks for the link. That look ideal for PE. I'll get hold of some of that. I haven't bought from them before, but heard some good things.

Thanks again.

One last thing with soldering. You do not heat the solder- you heat the joint. A well tinned iron held to the parts being joined raises their temperature to a point where solder applied at the joint at a point opposite the iron melts and flows into it. Another necessary tool is a suction device such as an eye dropper designed for this, to remove excess solder from the joint.

Acid flux is a no-go.

Get a gun with a trigger, not a plug in iron.

GMorrison

One last thing with soldering. You do not heat the solder- you heat the joint. A well tinned iron held to the parts being joined raises their temperature to a point where solder applied at the joint at a point opposite the iron melts and flows into it.

Indeed. Don't make the beginner's mistake of putting a blob of solder on the tip of the iron and then trying to "wipe" it onto the part to be joined. The molten solder hitting the cold part will solidify instantly, making a mess and a bad joint.

Thanks for the advice guys. Got some more soldering to do this week, hopefully i can put some of this into practice.

Take it from  an old EE- tin the iron tip, heat the joint, and then apply resin core solder to the point where the iron and joint meet.  Never use acid cord flux/solder- that is for plumbing and iron pipes!

One more comment - CLEANLINESS is increadiblly important in slodering.  if you can, make sure everything (except the hot iron tip) gets a wipe down with acetone or alcohol just beftore applying heat.  Any grease, grime or oil (including from your hands) can affect the join.  If you can, it's best to use white cotton or latex/nitrile gloves when soldering to keep finger grease off.

When tinning the iron, I usually will wipe the tip with a bit of abrasive first.  If needed on a chisle tip, I'll use a file to touch it up.  Also, not all soldering jobs are equal, and a varitey of soldering implements can be usefull.  For most small hobby / electronic work, a 15-25 watt electric iron (NOT gun) is most useful.  If you get into larger things like RC landing gear, silver solder with a torch becomes necessary.  All "solder" is not created equal either.  While others have mentioned the rosin/acid flux issue, no one seems to have touched on the various solders themselves.  Make sure the solder (usually 60/40) for electronics is at hand.  I use a 50/50 mix at work, and there are vaious diameters of solder available too.  Make sure the size, and solder alloys make sense for the job.

Reid

After re-reading my post, let me add some stuff.  Most electronics solder is a 60/40 mix of tin & lead.  Plumbing solder used to have a higher lead content, but it's becomming almost impossible to get lead plumbing solder any more in the states.  Silver solder is another beast altogether, and is more used in brazing (a lower temp form of welding).  

Soldering is a bit of an art form, and needs practice to do well.  You will find you need heat sinks for some jobs, to protect delicate items close to the solder join.  Remember to always heat the part(s) evenly, and flow the solder into the join.  Remember - Clean, clean, clean!

R

Thanks R. I do have both silver solder and some 60/40 and have been practicing during the week. It wasn't pretty, but i have been able to clean it up. Its not looking to bad, well i don't think so.

Though i did have trouble with the method of applying the iron to the two parts to be joined and letting the solder flow into it. Nothing happened. So more practice i think. I found the best way was to put the solder onto the iron, then applying it to the part. It worked, but as some have pointed out, it leave a bit of a mess.

More practice i think.

The method of putting solder on the tip & trying to goop it onto the pieces is a disaster waiting to happen.  You are not really getting a good solder join, and it will be easy to seperate the parts.  You want to make sure you get the pieces hot & flow the solder onto them.  The solder should flow toward the heat.  you might look at one of these:   www.amazon.com/s    

I have both the weller, & portasol units, and they work well for medium sized units.  Some small stuff can be done but it can be tricky.  They are nice for out at the flying field or someplace you don't have power.

Reid

Ye, i was finding that out about the joints coming apart. Lukily it was some pieces of copper rod being made into a tower, so there was no detail on it and it was pretty easy to clean up with a file. I am going to practice some more before i start on any PE, and might well give the soldering paiste a try.

I bought the Weller SP25,  i'll give those other a look. Thanks for all the advice. I know i will get there in the end.

I solder quite a bit. Now , I tin the iron and the part ,then really hit the joint with heat.

RESULT smooth flowing solder and clean joints. I also recommend resin(rosin) core solder,NO acid. You would be surprised how well the "silver bearing" solder at RADIO SHACK" brand works.

Really great and you get NO heat distortion and successful solder joints very close to plastic and other soldered joints.      TANKER-builder

Thnaks Tanker. I did get both Rosin core and the silver from radio shack. I still need to practice some more, but the end result of my first attempts came out ok in the end.