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Soldering white metal





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#1 67A

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Posted 19 June 2011 - 22:25

Hi all,

I recently described my slight disaster (on help topics) with two white metal kits I had bought. I placed both of them in thinners to remove the poor paint finish, trouble was the araldite also failed and they fell apart. I would like to try soldering these back together but I only possess a 25w iron and I'm unsure of what grade solder I should use, any advice would be appreciated.


Cheers,
Mike



#2 bbishop

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Posted 19 June 2011 - 23:49

Mike,

I have two ways to solder whitemetal. The method used depends on the grade of whitemetal and the size of the parts. I think that hard whitemetal melts at a higher temperature than the soft variety but this is purely empirical.

1. A 50 watt variable temperature Antex with the heat turned right down. This is ok for large lumps of whitemetal but the temperature of the iron is probably higher than the melting point of the whitemetal so I'm depending on the latent heat of the metal and getting the iron away from the work quickly. I use this iron for anything in 7mm and for ABS kits in 4mm. With a Geen kit, I solderered the big bits ok but melted the brakegear.

2. A 25 watt Antex with a 25 watt light bulb in series. This reduces the temperature but also the heat so, whilst it is completely safe, it only works with small parts. Health and safety warning - the light bulb socket is live at 240 volts so don't use this method if there are children about. A dimmer switch is a safer option.

I only use Powerflow flux and Eileens low melt solder. I don't get on with liquid flux.

Bill

#3 John_Hughes

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Posted 20 June 2011 - 08:09

Good advice so far!

Can I just add that it's not usually regarded as a particularly good idea to use the same tip for whitemetal as for 'ordinary' soldering, in case the low-melt stuff (and the whitemetal itself) causes contamination.

#4 coachmann

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Posted 20 June 2011 - 08:37

Seeing as the whitemetal has been stripped of paint, it will likely need a good rubbibng down to remove any residuals from the paint and stripper before it wil readily accept low-melt solder.

I happen to use a Weller 25watt and 45watt irons and home-made flux. I tack major components together using ordinarry solder as used for brass and the bigger iron, the low-melt stuff being used purely as a filler between joints. This comes with experience though and I would not recomment the way I do things to a beginner. Best stick to low-melt solder.

#5 RedgateModels

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Posted 20 June 2011 - 08:55

Personally I take the cautious option. I have a Weller temperature controlled soldering station - one specially modified by the manufacturer for low melt solder. I started by getting a bit of whitemetal waste and wound up the temperature until it melted, then notched it down a bit. Once I had a setting that was just hot enough NOT to melt the W/M I was happy to use low melt solder and phosphoric acid flux.

The technique is a bit different frm normal soldering for me, I flux the joint, apply the solder to the iron then bring the two together. Once you get the hang of ot it's very satifying :)

#6 Kenton

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Posted 20 June 2011 - 09:13

I was taught to use a 25W iron, red liquid flux and 'low melt 70'C solder. No temperature control just good technique.

It has never failed me yet and with very few exceptions I have never had problems with "melting" the white metal.

As with all soldering the most important thing is to have clean metal.

The big lumps of whitemetal act as massive heat sinks and you need (as with all soldering) to get in quick, apply the heat, melt the solder and make the join, and get out fast, without moving the work until it has cooled - even if it means pain in your finger tips)

Rather than go to the lengths of purchasing a temperature controlled iron or faffing around with electrical mods. Try it out with the plain 25W iron.

Don't forget that all brass needs to be tinned with normal solder first and that includes your soldering iron tip.

Also remember that soldering whitemetal is more akin to hot gluing with liquid metal than it is to normal soldering. The solder has poor flow characteristics and can even be used to fill gaps in the join of whitemetal parts.

You should really keep a separate tip/iron for whitemetal work as the low melt solder "contaminates" the tip for normal soldering work.
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#7 67A

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Posted 20 June 2011 - 18:52

Hi all,

Many thanks for the above replies and the advice therein, I will have a go at it with my trusty 25w iron with a new tip as advised, will have to get some 70 deg. solder first though. If I find this too hot for my first attempts I will go for a variable temperature unit as advised.

Once again, many thanks for the advice.
Cheers

Mike.

#8 Kenton

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Posted 20 June 2011 - 19:45

with a new tip as advised

I would go with the old tip
1 - it is already tinned
2 - if you do fall back on the purchase of a temp controlled workstation then you can probably just replace it then.

if you enjoy the experience you simply buy another Antex for all brass normal solder work and keep the irons separate.
It is less hassle having 2 irons than keep changing tips on one iron, but then I guess it depends how much soldering work you do.

Good luck, start with the big bits (usually the way you put any kit together)

#9 djparkins

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Posted 20 June 2011 - 20:00

Hi all,

I recently described my slight disaster (on help topics) with two white metal kits I had bought. I placed both of them in thinners to remove the poor paint finish, trouble was the araldite also failed and they fell apart. I would like to try soldering these back together but I only possess a 25w iron and I'm unsure of what grade solder I should use, any advice would be appreciated.


Cheers,
Mike


This link should help - deals with brass & white metal - a 7mm site - but the advice will be applicable to other scales -

http://www.7mmlocomo...id=37&Itemid=45

Regards,

David Parkins

#10 D51

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Posted 20 June 2011 - 21:02

Hello,

I use a Skytronics dimmer switch built in to a 13A plug. This costs £7.39 from Amazon.
Have a separate bit for an Antex 25 watt iron and 70 degree solder. The combination works a treat!

Frank

#11 R A Watson

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Posted 20 June 2011 - 21:44

I am always wary of melting the white metal and therefore have developed the following method.

No doubt some one will say it is not correct but it works for me!

(1) clean both surfaces to be joined with a glass fibre brush or similar device.

(2) mate both parts in a clamp or with masking tape.

(3) flood the joint with flux (chosen to suit your prefferences)

(4) cut a small "pea" of low melt solder and place it on the joint in the flux

(5) apply the iron directly on the pea of solder,not the white metal, the solder will melt and run along the flux completeing the joint.

(6) clean up the job and move onto the next task!

Simple, but effective, although I have not had to join small components as I have not soldered much white metal since putting together K's kits and similar projects, smaller detail bits are best done with superglue or Araldite.
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#12 newbryford

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Posted 20 June 2011 - 22:04

I am always wary of melting the white metal and therefore have developed the following method.

No doubt some one will say it is not correct but it works for me!


I often use this method when soldering small white metal parts. Never carry any amount of solder on the iron to the joint, as the solder will be at the full temperature of the bit and could melt the workpiece.

My preference is for a large iron - say 50W - for large whitemetal joints because they act as a heat sink and will rapidly reduce the temperature of the bit. I will sometimes use a 50W iron with small bit for detail work.
My "secret" is not to let the iron be around the joint for too long, otherwise too much heat gets into the workpiece and it can take a relatively long time to cool and solidify, thus increasing the risk of a dry joint.

If soldering white metal to brass/copper/nickel-silver, pre-tin the b/c/n-s with normal solder first, before using low-melt to make th full joint.

Cheers,
Mick

#13 DLT

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Posted 20 June 2011 - 23:01

I often use this method when soldering small white metal parts. Never carry any amount of solder on the iron to the joint, as the solder will be at the full temperature of the bit and could melt the workpiece.

My preference is for a large iron - say 50W - for large whitemetal joints because they act as a heat sink and will rapidly reduce the temperature of the bit. I will sometimes use a 50W iron with small bit for detail work.
My "secret" is not to let the iron be around the joint for too long, otherwise too much heat gets into the workpiece and it can take a relatively long time to cool and solidify, thus increasing the risk of a dry joint.

If soldering white metal to brass/copper/nickel-silver, pre-tin the b/c/n-s with normal solder first, before using low-melt to make th full joint.

Cheers,
Mick

All very interesting, my advice is pretty much the opposite of Mick's!

I use a very old Weller 15watt iron that was never man enough for anything but the smallest bits of brass, but it turned out to be perfect for whitemental.
And I pick up blobs of solder on the tip of the iron and transfer them to the joint. Works perfectly for me!

I use liquid flux and Carrs 70-degree solder, and of course I emphasise all the advice about getting the joint clean and shiny.

This method works a treat, using a fairly small tip on the iron I can apply a largish blob of solder from the rear of the join, running the iron along helps the solder to flow along the join. Using plenty of flux I can carefully run the tip along the outside (visible) side of the join, and this helps to draw the solder through, and I stop when the tiniest shiny bead is visible, with no gaps.

Good luck!
Dave.
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#14 craigwelsh

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Posted 21 June 2011 - 10:08

I was taught to use a 25W iron, red liquid flux and 'low melt 70'C solder. No temperature control just good technique.

The big lumps of whitemetal act as massive heat sinks and you need (as with all soldering) to get in quick, apply the heat, melt the solder and make the join, and get out fast, without moving the work until it has cooled - even if it means pain in your finger tips)

Rather than go to the lengths of purchasing a temperature controlled iron or faffing around with electrical mods. Try it out with the plain 25W iron.

Don't forget that all brass needs to be tinned with normal solder first and that includes your soldering iron tip.

Kenton i've always been curious to know how you deal with things like 4mm buffer bodies or brake shoes using a 25W iron. In my experience these things turn into a blob if they even get a sniff of a 25W iron in the vicinity. I agree it works for the big bits but not these smaller parts.

Many thanks for the above replies and the advice therein, I will have a go at it with my trusty 25w iron with a new tip as advised, will have to get some 70 deg. solder first though. If I find this too hot for my first attempts I will go for a variable temperature unit as advised.
Mike.

The snag with that approach is that unlike brass/NS if you get it wrong you end up with a blob of wm and no kit! Maplins temp controlled irons are only about £20 and perfect for wm. Most kits have a sprue of surplus material you can attempt melting to set the temperature and then you dont have to worry about what you're doing so much.

#15 Kenton

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Posted 21 June 2011 - 11:36

Kenton i've always been curious to know how you deal with things like 4mm buffer bodies or brake shoes using a 25W iron. In my experience these things turn into a blob if they even get a sniff of a 25W iron in the vicinity. I agree it works for the big bits but not these smaller parts.

Nerves of steelbrass. Although I admit my first choice would be to replace these two items with brass turned/etched equivalents - certainly in the case of buffers as I seem to have an issue with springing the white metal offerings that come with some kits.
The issue with temperature controlled irons is purely that they were not around when I leaned how to solder. So having always used a simple plain iron I can see no reason not to use it. The use of a temperature controlled iron probably does the job as well, but it does encourage sloppy technique of leaving the tipi engaged with the work for far too long.

I would also advise against carrying the low melt solder on the tip to the work. The main reason being that the alloy used for this degrades while being heated.

I would also not use superglue - the parts need to be a very perfect fit. Araldite is OK if you are desperate but I don't like the stuff and is the main reason I dismantle most kit built items. The join is always a weak one in comparison to a soldered join.

But as mentioned earlier there are different qualities of whitemetal - some certainly take much higher temperatures than others.

#16 multiprinter

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Posted 21 June 2011 - 12:29

I have in the past taken apart with my fingers supposedly soldered white metal kits. If you do not get enough heat to the joint you may as well use glue. If the solder doesn't run freely(and shiny) right through the joint then it isn't hot enough. I've never understood how a boiler, or any other larger part can be soldered properly with a 12v iron, there just isn't enough heat. A 30w iron was the normal tool I used but if I had the 75w on to do the brass bits on a mixed kit(such as DJH) then I just carried on using it on the white metal.
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#17 coachmann

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Posted 21 June 2011 - 15:19

i've always been curious to know how you deal with things like 4mm buffer bodies or brake shoes using a 25W iron. In my experience these things turn into a blob if they even get a sniff of a 25W iron in the vicinity. I agree it works for the big bits but not these smaller parts.

I routinely solder whitemetal buffers, in fact everything, to my coaches with the trusty Weller 45watt iron. I want heat there and then, not slowly sinking in as happens with a smaller iron. Of course experience counts but you only get this with bags of practice. A smaller iron is better suited to a job where very small whitemetal fittings are being soldered in place. My smallest is a 25watt!
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#18 67A

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Posted 21 June 2011 - 22:02

Hi guys,

Well a plethora of information for me to digest in the above posts, rest assured I will try a few of the methods out and let you all know, as there are no local exhibiions for a while I will wait for the RMWeb show to get the materials and have a go, once the kits are rebuilt and repainted they will adorn my Bermuda Road MPD layout which is coming along albeit slowly.

many thanks to all


Mike

#19 67A

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Posted 21 June 2011 - 22:10

Hi again,

Just spotted that there won't be much trade support at the members show so will mail order the items and get on with it, I have also remembered I have an old 25w iron lurking in a drawer which I will try out first.

#20 newbryford

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Posted 21 June 2011 - 22:25

But as mentioned earlier there are different qualities of whitemetal - some certainly take much higher temperatures than others.


I think Alan Gibson kits used a higher melting point alloy that was purported to be pewter. It was certainly more resilient when using large irons!

Cheers,
Mick

#21 Removed a/c_Natalie Graham

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Posted 21 June 2011 - 22:57

I routinely solder whitemetal buffers, in fact everything, to my coaches with the trusty Weller 45watt iron. I want heat there and then, not slowly sinking in as happens with a smaller iron. Of course experience counts but you only get this with bags of practice. A smaller iron is better suited to a job where very small whitemetal fittings are being soldered in place. My smallest is a 25watt!



That's the key, getting the heat on the joint quickly and not leaving the iron there too long. If the joint doesn't go right straight away, allow the parts to cool and try again, don't keep trying. It is the accumulation of heat that will melt the whitemetal parts, not the size of the iron. I have a temperature controlled iron but never bother to change the setting.

#22 armchair modeler

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Posted 12 July 2011 - 00:48



I may be too late in replying to this but for the record:-

If the white metal has been previously glued with Araldite or any other epoxy resin, it will fall apart if dunked in Nitromorse or similar agent. In fact it is a good way to dismantle a kit previously constructed this way.

HOWEVER

when you try to solder the bits back together the chances are that the "mating faces" are still contaminated with microscopic traces of the glue. This will stop the solder from "taking" as the molten metal , solder, forms a molecular bond with the "host" metal of the kit. The golden rule with white metal is to clean it and when you consider it clean, clean it again. Do not fall into the trap of thinking that because the surfaces won't bond and the joint wont hold is because the iron was not hot enough and turn up the heat. There will be tears before bedtime. I know I've done it!!:cray_mini:

The glue leaves a microscopic film which stops the bonding process, a film that is not likely to be removed by flux, no matter how good. The best way is fine abrasive and a small quantity of a substance called elbow grease with a large quantity of patience to achieve a good smooth shiney surface that the solder can bond to, again with the assistance of suitable flux to acid clean the hopefully chemically clean faces and help the solder flowi nto the joints. It is the solder that should melt not the whitemetal of the body.

There are plenty of soldering tips on this site. Have a search. There are people more expert than I on this subject . My advice is based only upon bitter experience :(

Armchair




#23 Bruciethefish

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Posted 12 July 2011 - 18:24

I've always used an Antex 15w iron for whitemetal, the solder being 'Wood's metal' (I have a couple of plastic cup shaped lumps, which should see me out..), & the flux being watered-down Jenolite rust remover. (1 part Jenolite to 2 or 3 of water) I make sure the joint lines are clean, flood the joint with the flux using a cheap plastic brush, then lift a blob of solder on the tip of the iron & place it on the joint, running the tip along the join until the solder is all in the joint. This is repeated as neccessary.
The trick here is to keep the iron moving, so you don't apply heat to the same spot for too long. I've used this method for over 30 years on thousands of jobs, & it works pretty well...

#24 LesG

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Posted 25 January 2012 - 16:25

One tip I picked up 30 to 40 years ago from an article in a magazine by I think Dudley Dimmock is to listen to the flux.
When the iron is on the joint the flux boils and can be heard sizzling, the boiling flux keeps the temperature below the melting point of the whitemetal. As long as you can hear the sizzling the metal should not melt, when the sizzling stops remove the iron immediately as the temperature will then rise.
I used this technique about 30 years ago the solder together an Anbrico mechanical horse & trailer (4mm) with Eames low melt solder & flux using an ordinary iron that I used for electronic work. the only thing I melted was the steering wheel which was very fine.
It works in the same way that a lead container can be used to boil water in that the water keeps the metal to atemperature slightly above waters boiling point, when the water boils away the metal temperature will rise to the point when the metal will melt.
I have used this myself and it works as long as you remove the iron when the flux stops boiling.
Regards,
Les.

#25 hayfield

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Posted 25 January 2012 - 18:01

Hi all,

I recently described my slight disaster (on help topics) with two white metal kits I had bought. I placed both of them in thinners to remove the poor paint finish, trouble was the araldite also failed and they fell apart. I would like to try soldering these back together but I only possess a 25w iron and I'm unsure of what grade solder I should use, any advice would be appreciated.


Cheers,
Mike

Mike

I buy cheap whitemetal kits to rebuild, they get dunked in caustic soda which not only removes the paint but has a good go at glue as well. After they get a good wash and I give them a good burnish with a wire brush in a mini drill.

I am just rebuilding a Wills E2 which went through this process. I used an Antex 25 watt iron, London Road Models Phosflux 12 (12% solution) which works (plenty of it) better than their Phosflux 6 which was sold to me as a whitemetal flux and Carrs No 70 solder

I cannot better the advice given about soldering, only to report the items that worked on a kit which had been stripped of paint. Good luck