Copperclad handbuilt turnouts - what flux to use?

[Dan6470]

Hi,

 

I’ve recently completed my first turnout from a SMP kit, it took much longer than I expected but I am sure I will get faster. Of course I made a few mistakes that hopefully will not be repeat in my next attempt. However a couple, well at least one, thought came to mind as to whether it is necessary to use additional flux during the construction and if so what kind of flux is preferred?

 

I am currently using a mulicore solder used by electronic engineers that has flux included however I did add a little bit of additional plumbers flux (the flux used by plumbers during their joining of copper pipes) which allowed the solder to flow better but leaves residual that would need to be removed.

 

 

 

Your thoughts would be appreciated.

 

 

 

Dan

 

 

[RedgateModels]

I use traditional 188 deg tin lead solder with 9% phosphoric acid flux. All bought from Eilleen's Emporium. I tried electical solder (cored) but rapidly gave up on my first rail joint and went back to the old favourite combination. I only use the gastly lead free cored solder for what it is designed for now, that is wiring where it's difficult to wash off the flux afterwards.

 

Just make sure you wash the work thoroughly after using an acid flux

[PWSlack]

Carr's "red label" would be a useful addition to the toolbox (usual disclaimer).

[dymstocklr]

Dan. Never rely on the flux in multicore solder for anything other than what it was designed for - wiring. I use Powerflow flux for just about everything these days - or whatever equivalent your nearest plumbers supply sells. Just keep clear of all the lead free stuff!

Bill

[craigwelsh]

Phosphoric acid is nice and simple and can be washed off with water afterwards.

[Dan6470]

Hi Guys,

 

Thank you for your responses to my query. Clearly I should not rely on electrical multicore solder but what are the advantages/disadvantages of say the Phosphoric acid based flux over the powerflow flux from the local plumbers merchant?

 

Dan

[DerekEm8]

Dan. Never rely on the flux in multicore solder for anything other than what it was designed for - wiring.

Bill

 

I would'nt rely on any electronics that have been assembled with an acid flux. Acid fluxes are veboten in the electronics industry even citrus fruits/drinks amongst other things being totally banned.

 

Until the legislation changes (lead free solder) all printed circuits boards were assembled/serviced using 60/40 multicored tin/lead solder with the matching resin flux applied to the bare PCBs.

 

And what were they assembled on ? - copperclad paxolin/fibreglass boards. Copperclad sleepers are a spin off from the PCB industry.

I can't comment on lead free as it was introduced after I retired.

 

Yes- I worked in the military/aerospace industry for nearly 40 years.

[Jol Wilkinson]

I would'nt rely on any electronics that have been assembled with an acid flux. Acid fluxes are veboten in the electronics industry even citrus fruits/drinks amongst other things being totally banned.

 

Until the legislation changes (lead free solder) all printed circuits boards were assembled/serviced using 60/40 multicored tin/lead solder with the matching resin flux applied to the bare PCBs.

 

And what were they assembled on ? - copperclad paxolin/fibreglass boards. Copperclad sleepers are a spin off from the PCB industry.

I can't comment on lead free as it was introduced after I retired.

 

Yes- I worked in the military/aerospace industry for nearly 40 years.

But he isn't asking about assembling electronics

 

I would definitely go for 145 or 188 degree solder and 9% or 12% phosphoric acid flux. Any flux residue can be washed off with water (on a cotton bud if working in situ). I wouldn't use Powerflow under any circumstances as it isn't that easy to wash off.

[DerekEm8]

But he isn't asking about assembling electronics

 

I would definitely go for 145 or 188 degree solder and 9% or 12% phosphoric acid flux. Any flux residue can be washed off with water (on a cotton bud if working in situ). I wouldn't use Powerflow under any circumstances as it isn't that easy to wash off.

 

Jol,

I was'nt asking him to, I was pointing out the error of his statement regarding the use of resin cored solder. :rolleyes:

 

as below (more invisible ink??)

'Until the legislation changes (lead free solder) all printed circuits boards were assembled/serviced using 60/40 multicored tin/lead solder with the matching resin flux applied to the bare PCBs.

And what were they assembled on ? - copperclad paxolin/fibreglass boards. Copperclad sleepers are a spin off from the PCB industry.'

 

I might add that I use Multicore resin cored solder and resin flux on all my copperclad and etched brass soldering as I have done for the last 40+ years without any problems or corrosion as the residue from resin cored solder is inert.

[Jol Wilkinson]

I might add that I use Multicore resin cored solder and resin flux on all my copperclad and etched brass soldering as I have done for the last 40+ years without any problems or corrosion as the residue from resin cored solder is inert.

Derek,

 

You would therefore, in my experience, be unique in that you are succesful in using multicore for succesfully assembling etched kits.

 

I don't recommend multicore for kits (although I use it exclusively for wiring and electronics) not because it's flux residue is inert (a benefit) but because it doesn't work as well (again in my experience). An externally applied flux "cleans" the work before the solder is applied and also helps conduct heat from the soldering iron bit to the job. Combined with a good 145 degree solder (London Road Models) I find it's possible to get consistently good results.

 

I use the same solder and flux for pcb based model items - base board joint track ends (a pcb sleeper with C&L brass chairs), a twin track turntable for loco handling in the fiddle yard, etc. and find it works well.

 

Jol

[DerekEm8]

Derek,

 

You would therefore, in my experience, be unique in that you are succesful in using multicore for succesfully assembling etched kits.

 

Jol

 

Jol,

 

I've never been called 'unique' before (been called one or two others things) :lol:

I now NEVER use phosphoric acid flux (or any flux) on white metal I must have low melt soldered 2-300 kits without it.(doubly unique?)

I did try it once demo-ing at an exhibition, packed up in a hurry forgot it for a week - 1 kit ruined- never used it since.

 

But at the end of the day it's what you the modeller is happy and succesful working with.

 

(Sorry for going slightly OT)

[craigwelsh]

I now NEVER use phosphoric acid flux (or any flux) on white metal I must have low melt soldered 2-300 kits without it.(doubly unique?)

I did try it once demo-ing at an exhibition, packed up in a hurry forgot it for a week - 1 kit ruined- never used it since.

Fair enough choose a system that works for you, top advice. This bit about ruining a kit via phosphoric acid confuses me though. How?

 

The ability to remove the acid with a bit of water compared to the difficulty getting rid of plumbers stuff is the big benefit for me. Like Jol I find the separate flux does give a lot extra control to what goes where when building kits/track. I have used 188 cored though with a separate flux mind.

 

Sticking large lengths of n/s or steel to copperclad is different to attaching small electrical devices to it imho and with track especially you sometimes find you need to go back and some more flux helps!

[DerekEm8]

Fair enough choose a system that works for you, top advice. This bit about ruining a kit via phosphoric acid confuses me though. How?

 

The ability to remove the acid with a bit of water compared to the difficulty getting rid of plumbers stuff is the big benefit for me. Like Jol I find the separate flux does give a lot extra control to what goes where when building kits/track. I have used 188 cored though with a separate flux mind.

 

Sticking large lengths of n/s or steel to copperclad is different to attaching small electrical devices to it imho and with track especially you sometimes find you need to go back and some more flux helps!

 

Craig,

 

Have you ever seen etched through strapping ?? the effects of not scrubbing the kit quickly enough.

 

I don't use 'plumbers stuff', as I said in an earlier post, I use resin flux, so going back is not a problem.

[Godders]

Derek,

 

....... An externally applied flux ..................... also helps conduct heat from the soldering iron bit to the job.

Jol

 

I would be surprised if any liquid helped to conduct heat better than the metal that was in contact with the soldering iron! It is the metal that conducts the heat and the cleanliness that allows the solder to flow.

[Dave at Honley Tank]

Hi,

 

I’ve recently completed my first turnout from a SMP kit, it took much longer than I expected but I am sure I will get faster. Of course I made a few mistakes that hopefully will not be repeat in my next attempt. However a couple, well at least one, thought came to mind as to whether it is necessary to use additional flux during the construction and if so what kind of flux is preferred?

 

I am currently using a mulicore solder used by electronic engineers that has flux included however I did add a little bit of additional plumbers flux (the flux used by plumbers during their joining of copper pipes) which allowed the solder to flow better but leaves residual that would need to be removed.

 

 

 

Your thoughts would be appreciated.

 

 

 

Dan

 

 

 

From what Dan says above, he's fairly new to this soldering lark.

Derek you're cheating! but you are my friend so I must dilute that statement. What I mean is that your soldering experience, in an industrial setting and for employment, probably out-weighs the rest of us put together.

My industrial soldering experience involved solder pots and blow torches and has little to commend it in our hobby. My dad taught me to solder with an iron but it was a coal fired soldering iron and I was about 10 years old. Again not really transferable to our hobby.

Early in the hobby I was introduced to electric soldering irons and cored flux, but for use on kit and track building I had very limited success. However when I was taken under the wing of the likes of Sid Stubbs, John Langan and Norman Whitnall, I was introduced to phosphoric acid flux and 145 degree solder and from then my success has been pretty close to 100%. I had met Powerflow flux through DIY plumbing and when I applied it for modelling jobs found that it was as good as phosphoric acid.

Craig has expressed a dislike for Powerflow due to problems with after-cleaning. Try a 50:50 mix of meths and water and an old toothbrush. As yet that's not failed me in the last fifteen years of modelling.

While both these fluxes seem to perform equally well, my experience is that phosphoric acid fumes are difficult not to breath in and, at least to me, an irritant. On the other hand Powerflow does not so irritate me.

Some of you know that one of the members courses I run at Manchester MRS is actually Introduction to Soldering. From these I have realised that those modellers who are convinced that they cannot solder can within about an hour become confident that they can indeed solder. The difference is that they learn about differing types of solder and flux and that the soldering iron power rating and contact area of the tip are the things that count.

My advise to Dan:

For electric wiring joints stick to the cored solder you now use but where it is possible make the work melt the solder rather than taking a blob of solder to the work. For other modelling use one of the fluxes mentioned on here and stock differing melt levels of solder BUT SCRUB CLEAN AS SOON AS YOU HAVE FINISHED THAT SOLDERING SESSION AND SCRUB AGAIN BEFORE PAINTING!!

Use at least a 25 watt iron with a 3mm diameter tip and keep that tip bright and shiny clean. For track making; 145 solder and either phosphoric acid flux applied by paint brush or Powerflow applied by large bore hypodermic syringe. If you go to the trouble of tinning the underside of the rail and the sleeper then you will have difficulty on not getting 100% good joints, but it should not be necessary to always go to such lengths. With either of these fluxes, immediately at the close of your soldering session, use an old toothbrush to vigorously scrub away any possible remnant of flux. I use that 50:50 mix with Powerflow and a mix of water and household soda (tablespoon to about a pint) for phosphoric acid. When I'm in 'belt & braces mode', I use both!

That's what works for me Dan.

[R A Watson]

On the track building side I have always used Multicore solder with P C B sleepers with no problems, but over the years I have found the easy way is to apply the iron on one side of the rail and the solder on the other, once the joint is hot enough the solder flows under the rail with minimum showing when the joint is completed. But that is just my way and no doubt others will insist this method cannot work, once again "horses for courses" rules.

 

With regard to cleaning up Powerflow flux I am surprised that no one has suggested cleaning up with I P A (Isopropyl alcohol, not best bitter) applied with a cotton bud this dissolves the residue and can be mopped up with a paper towel with no scrubbing or getting the work wet.

 

 

Hope ths helps someone,

 

Wally

[Dave at Honley Tank]

On the track building side I have always used Multicore solder with P C B sleepers with no problems, but over the years I have found the easy way is to apply the iron on one side of the rail and the solder on the other, once the joint is hot enough the solder flows under the rail with minimum showing when the joint is completed. But that is just my way and no doubt others will insist this method cannot work, once again "horses for courses" rules.

 

With regard to cleaning up Powerflow flux I am surprised that no one has suggested cleaning up with I P A (Isopropyl alcohol, not best bitter) applied with a cotton bud this dissolves the residue and can be mopped up with a paper towel with no scrubbing or getting the work wet.

 

 

Hope ths helps someone,

 

Wally

 

Hi Wally,

Yes indeed IPA is a good solvent to have around the workshop. However it is only a solvent, and you used the description - "...this dissolves the residue..." . Very true, but does it negate the acid?

I'm not too sure it will. Perhaps some one with chemical knowledge can tell us on here.

There seems also some reluctance to go to the trouble of (& I quote my own words here) "...use an old toothbrush to vigorously scrub ....". That vigorous scrubbing will not only clean away any flux residue but it is also likely to show up any poor joint. Better to find that at the soldering stage than some time later when the model is complete and painted. Perhaps not so important with track but for etched brass kits etc!????

[R A Watson]

Dave,

 

I must admit that I have only used the I P A on brass and it does indeed leave a very shiny surface, that does not discolour, and I have not suffered any reaction after use including some joints done a considerable time ago. The tip to try this method was given to me by someone who used it for cleaning up etched P C B's on an industrial scale (using 5 litre cans of the stuff) and was therefore using it to clean up etching acid, so it seems to be O K.

 

As an alternative to the good old toothbrush I use a version of "Scotchbrite" pan scouring pads which is supplied to motor vehicle body repairers as a gentle abrasive for finishing touches on newly sprayed vehicles, this is normally obtainable in three different grades so it is extremely adaptable.

 

Wally

[Dave at Honley Tank]

Dave,

 

I must admit that I have only used the I P A on brass and it does indeed leave a very shiny surface, that does not discolour, and I have not suffered any reaction after use including some joints done a considerable time ago. The tip to try this method was given to me by someone who used it for cleaning up etched P C B's on an industrial scale (using 5 litre cans of the stuff) and was therefore using it to clean up etching acid, so it seems to be O K.

 

As an alternative to the good old toothbrush I use a version of "Scotchbrite" pan scouring pads which is supplied to motor vehicle body repairers as a gentle abrasive for finishing touches on newly sprayed vehicles, this is normally obtainable in three different grades so it is extremely adaptable.

 

Wally

 

Thanks for that info Wally, I'll give it a try. Mind you my water based mixes are probably much less expensive than IPA!?!

Dave

[Brian Harrap]

Hi,

 

I’ve recently completed my first turnout from a SMP kit, it took much longer than I expected but I am sure I will get faster. Of course I made a few mistakes that hopefully will not be repeat in my next attempt. However a couple, well at least one, thought came to mind as to whether it is necessary to use additional flux during the construction and if so what kind of flux is preferred?

 

I am currently using a mulicore solder used by electronic engineers that has flux included however I did add a little bit of additional plumbers flux (the flux used by plumbers during their joining of copper pipes) which allowed the solder to flow better but leaves residual that would need to be removed.

 

 

 

Your thoughts would be appreciated.

 

 

 

Dan

[Brian Harrap]

Hello Dan, and anyone else who's listening. Ever tried AQUAFLUX as used by the stained glass people and available from their usual suppliers. NO acid, NO residue, NO smell and no washing off so no Brillo pads/toothbrushes etc. (how one is supposed to do that (washing off) after repairs or alterations to in situ trackwork I don't know). Brilliant stuff for glasswok and copperclad construction, been using it for years-no problems.

Regards, Brian.