Low melt soldering irons

[Rob Rossington]

I'm looking for a soldering iron to build white metal kits.

 

I know they have to be variable with a low temperature setting.

 

Can anybody recommend one?

 

Cheers

 

Rob

[Sidecar Racer]

Worth a look , it's what I use .

 

http://www.finescale.org.uk/index.php?route=product/product&path=446_448_451&product_id=3811

[nzgresleyfan]

Antex is a popular brand, look for something around 25W.  It's not necessary to have a variable temperature setting, indeed it's helpful to have the iron at a temperature that will get the solder flowing quickly and efficiently.  I've never experienced the problem of melting parts.

 

Just make sure you have a good flux on hand and keep the tip of the iron clean.

 

Rob.

[Jol Wilkinson]

With white metal kits you need a lot of heat (watts) but a low temperature (degrees). The larger whitemetal parts absorb the heat taking it away from the joint you are soldering. High power means that you raise the temperature quickly, but you ideally want to restrict the operating temperature. W/M solder melts at 70 deg C. (although Carrs also do a 100 deg. version), most standard irons operate around 425 - 450 deg C.

 

You may well find a 25w Antex iron with a 3mm bit will do for starters. It's important the get the metal clean, well fluxed and get the iron tip in and out as quick as possible. Some people advocate using a standard 25w iron with a piece of thick copper wire wrapped around the standard bit several times with the end projecting out to create a bit. This is supposed to reduce the heat going into the joint and avoid meting the w/m.

 

The best and as usual most expensive solution is a temperature controlled soldering station (I use an Antex one), or you could try the Antex temperature controlled iron. The former is a control box on which you set the temperature linked to a thermostatically controlled 50W iron, the latter is an iron with a built in thermostat that you adjust with a small screwdriver. However, both of these are fairly expensive options, £60 plus for the Antex TC iron, around £150 for the Antex TCU.

[garethashenden]

It's not so much that you want a low-melt soldering iron as wanting low-melt solder.

[Coombe Barton]

There's a lot of difference between building white metal kits (lots of metal - large heat sink) and attaching white metal castings to brass. (Lower metal mass, lesser heat sink.

 

You have to be aware of the limitations of both equipment and skill. You need to raise the local temperature without necessarily raising the temperature of the whole, which is what people have said what they have done.

 

Before deciding may I suggest trialling with some scrap white metal first with a standard soldering iron. This way you'll prove what you need to know.

[Quarryscapes]

Trying to solder whitemetal with a standard Antex 25w iron in the same fashion as you'd solder brass is asking for trouble! You CAN build whitemetal kits with one, but you need to be freakishly fast and accurate at doing so. (I've done it, it does work, but it's not a method I'd recommend)

 

I've also got an ANtex TCS 50W iron and find it useless for anything, I do suspect it's a faulty unit though as the temperature adjuster has broken already (had it 2 months) so I shall reserve judgement till it's replaced. 

[Quarryscapes]

Forgot to add, there is a huge variety of whitemetals out there too, and melting points therefore vary wildly. My own castings are made from a grade with a melting point of 225, GEM kits for example however melt much lower. 

[Paul Cram]

I use an Antex 18w iron and the trick is not to touch the iron on the white metal. If soldering 2 white metal parts together I just touch the solder on the joint and lrt it flow down the joint. You can hold the iron there quite a long time without melting the casting. If soldering to brass make sure the brass is tinned and then only put the iron on the brass..

[Kenton]

Another vote for the Antex 25W (nothing added) but on the DJH (other casting lumps available) I have even used my 50W iron.

 

I hate temperature control with a vengeance and cannot abide them. I was taught to solder by getting as much heat in as fast as possible and to make use of heat sinks to take unwanted heat away from parts.

 

There is one hell of a load of scaremongering out there regarding melting white metal and the only way to avoid it being the use of feeble irons or dumbing down with temperature control units. The biggest risk is touching the side of your iron on adjacent castings. I'm sorry but that is similar to touching the iron on your fingers - well you just don't do that more than once!

 

There are some odd grades on white metal to be seen in kits. Some of which will melt at 110 or thereabouts but there are also castings which will not melt until over 200. Like all soldering it is about understanding the process and practice.

 

BTW low melt "solder" technique is not really soldering at all - it should be approached as gluing and filling quite unlike brass or n/s which is more at the molecular level where less is a stronger bond.

[mike morley]

If at first you do not succeed, do not give up!

Soldering irons and their tips vary tremendously in style and nature and if your first attempt is a disaster it does not necessarily mean that either you or your soldering iron are ill-suited to the role. 

 

The first iron I used for white-metal kits was an already ancient 15watt Weller gifted to me by my father when he up-graded to something he regarded as better.  I got on with it like a house on fire and all of my better white-metal kits have been built with it.,  When it eventually succumbed to advanced old age I replaced it with the latest Weller equivalent and loathed it from the word go, mostly because of the awful shape of the tip - Weller describe as "chisel" but I'd call it an extremely blunt wedge, and it's the only type available for that iron.

 

Then my father died and I inherited the 18watt Antex he'd replaced the 15watt Weller he'd gifted to me.  The shape of the tip suits me far better but the iron itself does not.

 

I am now experimenting with the 15watt Weller and taking a file to tips intended for more powerful irons in order to make them fit.

 

One day soon I hope to find an iron and a tip that suits me as well as the iron given to me by my father

Edited April 5, 2014 by mike morley

[Baby Deltic]

I use a digital Antex with a large tip set at 115C for 70C solder. Using a non-temperature controlled iron is all well and good until you get it wrong and melt a hole through an expensive white metal kit. You can hold a temperature controlled iron tip against the component as long as you like to get a nice even heat and a good flow of solder into the joint without the fear of melting the part.

Edited April 6, 2014 by Baby Deltic

[t-b-g]

I am a little bit (soldering iron pun there folks!!) surprised to see people recommending soldering whitemetal with a normal temperature soldering iron.

 

If you are a highly experienced soldering expert and get everything right first time, then it is quite possible to assemble whitemetal using such an iron. I have seen kits assembled in that way and I used to do them that way myself but my modelling improved 100% when I started using a temperature controlled iron.

 

Soldering a metal that melts at around 200 degrees C with an iron that has a tip temperature of over 400 degrees C is full of possibilities for problems.

 

To get a good strong soldered joint, you really don't want to be depositing a lump of molten solder onto a cold metal surface. That can lead to brittle and weak joints. You need to warm the whole job up and let the solder run.

 

As has been mentioned, soldering is more about heat than temperature. A high wattage, low temperature iron allows you to solder whitemetal just like brass or nickel silver. You can warm the job up, take all the time you need to move bits around to the right place and you can solder tiny casings to big lumps of metal with no risk of melting either. Also, if you get something not quite straight, you can easily move it afterwards. This is the one I currently have, after the other (now discontinued) model expired after being dropped!

 

http://www.maplin.co.uk/p/60w-professional-lcd-solder-station-with-esd-protection-a55kj

 

The digital tip temperature read out makes it a bit more fail safe than those irons where you set it to high low or medium but don't know how the tip has responded.

 

With it set at about 185 degrees, I can solder the main whitemetal parts together with 145 degree solder, then I can turn it down to 150 degrees (which makes it just not hot enough to melt the 145 degree solder when it is attached to a big whitemetal heat sink!) to add detail parts with 90 or 70 degree.

 

As Kenton says, soldering whitemetal with a normal iron isn't really like soldering. It is a technique that can work but you need to develop a certain level of skill in knowing how long to keep the iron on the job. You need to get in, make the joint and get out before anything else melts. I used to struggle with the "get out before anything else melts" bit. I prefer to "play" the iron along a joint and to see the solder run along the joint nicely and that got me into trouble.

 

With a temperature controlled iron, soldering whitemetal ceases to be any problem at all and any risks of melting parts are removed completely. It is as easy as soldering anything else.

 

I wouldn't use anything else now but as I said, there are always many ways to approach these sorts of jobs. I am just a bit surprised that so many people get on so well soldering with normal irons because I used to really struggle, especially with small components and if I didn't get things 100% perfect first time.

 

I would never say to anybody that they should do things in a particular way. I will say that my own results improved dramatically when I got my temperature controlled iron.

 

Tony

[Baby Deltic]

I am a little bit (soldering iron pun there folks!!) surprised to see people recommending soldering whitemetal with a normal temperature soldering iron.

 

If you are a highly experienced soldering expert and get everything right first time, then it is quite possible to assemble whitemetal using such an iron. I have seen kits assembled in that way and I used to do them that way myself but my modelling improved 100% when I started using a temperature controlled iron.

 

Soldering a metal that melts at around 200 degrees C with an iron that has a tip temperature of over 400 degrees C is full of possibilities for problems.

 

To get a good strong soldered joint, you really don't want to be depositing a lump of molten solder onto a cold metal surface. That can lead to brittle and weak joints. You need to warm the whole job up and let the solder run.

 

As has been mentioned, soldering is more about heat than temperature. A high wattage, low temperature iron allows you to solder whitemetal just like brass or nickel silver. You can warm the job up, take all the time you need to move bits around to the right place and you can solder tiny casings to big lumps of metal with no risk of melting either. Also, if you get something not quite straight, you can easily move it afterwards. This is the one I currently have, after the other (now discontinued) model expired after being dropped!

 

http://www.maplin.co.uk/p/60w-professional-lcd-solder-station-with-esd-protection-a55kj

 

The digital tip temperature read out makes it a bit more fail safe than those irons where you set it to high low or medium but don't know how the tip has responded.

 

With it set at about 185 degrees, I can solder the main whitemetal parts together with 145 degree solder, then I can turn it down to 150 degrees (which makes it just not hot enough to melt the 145 degree solder when it is attached to a big whitemetal heat sink!) to add detail parts with 90 or 70 degree.

 

As Kenton says, soldering whitemetal with a normal iron isn't really like soldering. It is a technique that can work but you need to develop a certain level of skill in knowing how long to keep the iron on the job. You need to get in, make the joint and get out before anything else melts. I used to struggle with the "get out before anything else melts" bit. I prefer to "play" the iron along a joint and to see the solder run along the joint nicely and that got me into trouble.

 

With a temperature controlled iron, soldering whitemetal ceases to be any problem at all and any risks of melting parts are removed completely. It is as easy as soldering anything else.

 

I wouldn't use anything else now but as I said, there are always many ways to approach these sorts of jobs. I am just a bit surprised that so many people get on so well soldering with normal irons because I used to really struggle, especially with small components and if I didn't get things 100% perfect first time.

 

I would never say to anybody that they should do things in a particular way. I will say that my own results improved dramatically when I got my temperature controlled iron.

 

Tony

I use one of those Maplin LCD stations for general soldering, and very good they are too. For soldering droppers to track, or doing third rail, I use the big brother. It heats things extremely quickly so you don't melt the sleepers:

 

http://www.maplin.co.uk/p/60w-lcd-display-solder-station-n89cz

Edited April 6, 2014 by Baby Deltic

[John Tomlinson]

There used to be a Weller iron that worked off 12V DC, and could therefore be used via an old fashioned layout controller. By adjusting the dial on the controller you vary the power of the iron dependent on the size of the parts being soldered. If its still sold, and I think it is, an inexpensive and simple solution that has worked for me for years, although it obviously lacks the sophistication of modern techology. I've also used a Mains(240V) 18W Antex to solder big white metal castings, but as has been said you need to be careful not to melt them, by not lingering longer than necessary.

 

John.

Edited April 6, 2014 by John Tomlinson

[Jol Wilkinson]

John,

 

that reduces the temp by reducing the power, unlike a TCU which reduces the temp but maintains the power/heat.

 

Jol

[Thane of Fife]

_{I used to use a Weller 40w connected to a light dimmer switch. It was Ok but a but chunky.}

_{I upgraded to a Weller WHS40 and am very happy with it. It}

_{There are the clever people who can use a ordinary soldering iron to solder white metal parts. This will tend to slightly melt the castings into each other, forming a very permanent joint.}

 

_{Thane of fife}

[RedgateModels]

Another vote for the Weller WHS40, mine is a specially modified version that goes down lower than the standard model (which is 200 deg C I think) - make sure you get the LT version like this :

 

http://www.soldering-shop.co.uk/catalog/weller-whs40lt-40-watt-soldering-station-special-edition-p-49.html

[Kenton]

 

You can hold a temperature controlled iron tip against the component as long as you like to get a nice even heat and a good flow of solder into the joint without the fear of melting the part.

The flow characteristics of low melt solder does not improve with temperature. The very poor flow characteristic is due to the alloy used. It can only be improved by the use of a suitable flux. As explained before it acts very much like a hot glue and nothing like higher temperature solders.

Even heating the white metal parts to melting point will not form a true soldered join at the interface - you will have to heat them beyond that point until all you have is a blob of molten metal. One of the main reasons is that white metal forms an oxidised surface which resists bonding at the molecular level - quite the opposite of brass and n/s.

 

 

Soldering a metal that melts at around 200 degrees C with an iron that has a tip temperature of over 400 degrees C is full of possibilities for problems.

 

Continuing the misunderstanding of temperature and heat - they are not the same.

 

 

To get a good strong soldered joint, you really don't want to be depositing a lump of molten solder onto a cold metal surface.

I never deposit a lump of molten solder - that is because I NEVER carry solder on the tip of the iron to the work, I simply cannot see the point of boiling the solder in such a way, potentially dropping molten solder over the bench or worse, and it just goes against all that I know. The heat sink properties of the metals you are going to join are considerable, so that molten solder (small mass, very conductive) will crystalise immediately then wait for more heat to pushed out by the iron. Far better to place small chips of sf solder at the point of the join and then apply the heat from the iron to the solder. The solder melts as it heats up and flows into the join the surrounding metal has very little time to take up enough heat to ever reach 200'C unless you leave the iron tip wallowing on the job.

 

 

There are the clever people who can use a ordinary soldering iron to solder white metal parts. This will tend to slightly melt the castings into each other, forming a very permanent joint.

It has nothing to do with 'clever' and everything to do with experience and confidence in what you are doing.

 

As explained above the castings do not melt and even if they did they would not bond. Sure you would get a puddle if you left the iron in contact for too long - but that is no bond. I have never had issues with brittle joins (except where I have neglected cleaning parts - another issue altogether) and have had no problem in dismantling mistakes (yes we all make the occasional one or two) simply by the boiling water method. So the 'very permanent join' is another myth.

[Arthur]

I have ridden these many leagues for there is work for me here, Devilry and False Witness I say. Give them up, give them up and save your mortal souls. Who here has spoken of 'NEVER carrying solder on the tip.......'

 

 

Ah, Kenton!

 

I never deposit a lump of molten solder - that is because I NEVER carry solder on the tip of the iron to the work, I simply cannot see the point of boiling the solder in such a way, potentially dropping molten solder over the bench or worse, and it just goes against all that I know. The heat sink properties of the metals you are going to join are considerable, so that molten solder (small mass, very conductive) will crystalise immediately then wait for more heat to pushed out by the iron. NFar better to place small chips of sf solder at the point of the join and then apply the heat from the iron to the solder.

 

 

I'd agree with pretty much everything else you say Kenton but we've had this discussion on carrying solder before. I virtually ALWAYS carry solder on the tip, and have never had a problem. Both methods work, I find my way quicker but would never gainsay the other. As for the solder freezing when hitting the brass, potentially, but I never see it. And one argument for carrying the solder, molten on the tip, is that as the solder is already hot, you are carrying more heat into the joint.

 

Both ways work, it's a matter of personal choice.

 

Anyway, can't hang about, more devilry to root out.

[LNWR lives on]

I have no idea on current irons as I am using my dads old copper tipped iron which is not tempreature variable etc

 

The best advice i got which I will give to you is to get a copper tipped iron reasonable cost within your budget, use plenty of flux and have a go, start with a kit that if you make a mess of it your not going to be too upset and start by assembling the heavier parts first to get a feel of it and then you can move onto the thinner parts where you are more liable to melt the thin castings

 

Just get stuck into it, look at other techniques by all means but develop your own method. Mine most people would have a kitten at but for now its working for me, even though it needs refining

 

Aside from the iron a block of wood with some softwood nailed to it to form a 90 degree corner can be a very helpful 3rd hand

 

David

[buffalo]

Well said, Arthur! As you say, both methods work and it's all down to personal preference. Sometimes I use one, sometimes the other. Whilst I agree with much of what Kenton has to say about soldering, I do wish he would stop repeating this nonsense about 'boiling' solder. Soldering irons are just not hot enough to boil off any of the constituents of any modelling solder.

 

As I've said more than once before, the idea that you shouldn't carry solder to a joint is only appropriate with flux-cored solders and we should only be using them for electrical work.

 

Nick

Edited April 8, 2014 by buffalo

[Kenton]

 

I'd agree with pretty much everything else you say Kenton but we've had this discussion on carrying solder before. I virtually ALWAYS carry solder on the tip, and have never had a problem. Both methods work, I find my way quicker but would never gainsay the other. As for the solder freezing when hitting the brass, potentially, but I never see it. And one argument for carrying the solder, molten on the tip, is that as the solder is already hot, you are carrying more heat into the joint.

 

When both ways work that is fine for you.

 

But my post was specifically countering the argument proposal/claim that was being made where the blob of solder allegedly being carried would freeze on contact with a big lump of whitemetal. Something I do not disagree with as white metal has pretty poor conductivity properties. So though I do not disagree with it, it would not happen to me (or anyone following my soldering technique) as the blob is never carried in the first place.

 

Of course soldering brass is quite a different matter altogether and do not quite see the relevance of brass in this context?

 

I don't have too much of a problem with different techniques working except when the reasons for doing one over another are outnumbering. Although I can see several reasons for not carrying molten low melt solder on the tip of an iron, I can find no reason in its favour.

Edited April 8, 2014 by Kenton

[mozzer models]

I just use a Antex XS25 25wat iron for soldering white metal

[buffalo]

...But my post was specifically countering the argument proposal/claim that was being made where the blob of solder allegedly being carried would freeze on contact with a big lump of whitemetal. Something I do not disagree with as white metal has pretty poor conductivity properties. So though I do not disagree with it, it would not happen to me (or anyone following my soldering technique) as the blob is never carried in the first place...

But, if you had tried it, you would know that it was nonsense, unless you use an underpowered iron or too small a tip. The molten solder boils the flux on contact and that starts the local heating necessary for the solder to bond. Provided the iron can maintain the tip temperature well above the solder melting point, there's no chance of 'freezing'.

 

...Of course soldering brass is quite a different matter altogether and do not quite see the relevance of brass in this context?...

Oh come on, they aren't really that different

 

I don't have too much of a problem with different techniques working except when the reasons for doing one over another are outnumbering. Although I can see several reasons for not carrying molten low melt solder on the tip of an iron, I can find no reason in its favour.

I wish you'd tell us some believable reasons for not carrying solder on the iron! As to reasons in it's favour, how about speed, convenience, not needing to spend time cutting up and placing small pieces of solder, and being able to solder at any angle without the solder fragments moving from where you want them.

 

Nick