Which solder/flux combination do you use for etched kit construction?

Discussion in 'Techniques' started by Mike Trice, 23 October 2019.

  1. adrian

    adrian Flying Squad

    I'm in "exactly" the same situation - I do hope Simon is okay. As for the Finney V2 - I'm not going to let it stop me opening the boxes - a new project is on it's way!
    chigley likes this.
  2. chigley

    chigley Active Member

    ditto regarding Simon, im still trying to finish the mok 4mt, many thanks to you and pad for the .photos etc. still got the 9f to build as well as just purchasing a hatchette scotsman kit off that well known site, Ken
  3. mickoo

    mickoo Western Thunderer

    ...and you were doing so well with the Finney and MOK kits :))

    I'd love a V2, but know I'd just end up making a whole new chassis for it, nowt wrong with the kit of course, far from it.

    I just like adding all the stays, middle cylinder block and niff naff that only the dead Beetle attitude reveals.
  4. chigley

    chigley Active Member

    i just like a challenge, like plumbing the injector bodies on the 4mt
  5. chigley

    chigley Active Member

    I like a challenge, like plumbing the injector bodies on 4mt:rant:
  6. neaston

    neaston Active Member

    I was under the impression that all fluxes are acidic to a greater or lesser degree and part of their action is to cleanse the metal immediately prior to soldering.

    I bought 2 x 500ml bottles of glacial phosphoric acid when I sold my business in 2000. I have just finished one. I use it diluted to about 15% with no other ingredients and apply it in very small quantities with a piece of wire. No brush it applies far too much. It helps solder steel, brass, nickel silver and white metal no problem. Wash it off at the end of each session under a hot tap.

    It does not rust steel loco wheels as many suggest but will blacken the tyres

    PS You may well find your dentist has used it on your teeth at some time in the past!
  7. Longbow

    Longbow Active Member

    Without a surfactant (eg IPA) the flux is probably less effective at carrying the solder into a joint.

    Phosphoric acid removes oxidised metal and is the active ingredient in some rust treatments - so it will clean rather than rust steel wheels. But left untreated the steel will simply re-oxidise.

    The blue-green deposits some have noted are the copper phosphates produced by the flux action. Wikipedia notes that these are insoluble in water and ethanol but soluble in ammonia, ammonium hydroxide (so presumably caustic soda too) and acetone. So your post-soldering cleaning regime needs the right chemicals. Detergent, white spirits or IPA will be ineffective.

    Acetone is the main solvent for cellulose and lacquer paints so presumably these are particularly prone to spoiling from residual phosphates.
    Last edited: 6 January 2021
  8. adrian

    adrian Flying Squad

    As my B.O.G. flux was getting extremely low I started looking at an alternative. I've tried a few alternatives - the citric acid and phosphoric acid versions above but I didn't like them as much as the B.O.G. Safety flux. I also tried a couple of the recommended no-clean fluxes recommended on the Guild forum - these were alcohol based but I couldn't get on with them either - the flux just seemed to flash off instantly before I could get the joint up to temperature.

    I then checked the Guild product directory for alternative suppliers and they also listed www.soldersandfluxes.co.uk . So I decided to give them a try. Note it is better to go to the Vehicle Restoration page Vehicle Restoration rather than the model engineering page - it seemed to have a wider range of fluxes. So I decided to try the Radsol 301 and the WL1 fluxes - I ordered online late Tuesday evening (midnight!) and they got delivered at lunchtime today - so excellent service.

    So initial tests on a few pieces of scrap and I do like the WL1 flux - it certainly seems on a par with the B.O.G. flux for soldering.

    The 2 photos below so from left to right 4 different tinning regimes - all using carrs solder cream.
    left - solder cream no flux
    then - B.O.G. flux
    then - WL1 flux
    right - red label phoshoric flux.

    flux - 1.jpeg

    flux - 2.jpeg

    The wetting with the WL1 seemed just as good as the B.O.G. that nice flat even silver flow like water. It seems to have less residue than the other fluxes and the edges have less of a meniscus than the other fluxes - the edges of the solder seems flatten out more than the other fluxes.

    So I tried a few other tests with joints, brass, castings etc. so far it I like it - I think it has a strong potential to be a worthy B.O.G. replacement. The test pieces above were washed and cleaned but the other pieces have been left as soldered to see what effect any flux residue has on the brass and nickel-silver over the next week.

    I will definitely be trying this on the next build and will report after a bit more time with it.

    flux - 3.jpeg
    Last edited: 8 January 2021
  9. ScottW

    ScottW Western Thunderer

    The datasheet provided on the B.O.G website for their water based safety flux would appear to point towards a similar product sold by Pearsons Glass.
    adrian and mickoo like this.
  10. Longbow

    Longbow Active Member

    Most industrial fluxes are intended for use in controlled environments, so I would be wary of using them in the home. And the active ingredient here - Hydrogen Bromide - is very unpleasant stuff. Do take precautions, especially proper ventilation.
    michl080 and adrian like this.
  11. Max Midnight

    Max Midnight Western Thunderer

    And even better news is that it is vegetarian!

    Nice to know that no animals suffered in the production of it......:rolleyes:
  12. adrian

    adrian Flying Squad

    Cheers - just ordered some for comparison.

    As always with new sites (new to me anyway!) like this I like to see what else is on offer, especially on this one as my better half has done a few stained glass "windows" - actually framed pictures. So I was intrigued by the micro-wave kiln - just need to find a problem or a modelling task for it to solve! :cool:

    HotPot Microwave Kiln Medium 110mm
  13. ScottW

    ScottW Western Thunderer

    Keep us posted, it would be interesting to hear if it is in fact the same as that sold by B.O.G.
  14. Phil O

    Phil O Western Thunderer

    I spotted a thread on the other channel, that the owner of B.O.G, is currently incapacitated and out of stock and awaiting more supplies, but no delivery forecast.
  15. adrian

    adrian Flying Squad

    I wouldn't say exactly the same but it's certainly the closest I've found so far.

    So ordered Saturday afternoon and it turned up this morning - well packed so a thumbs up for good and prompt service.

    Initial impressions are it's very similar to B.O.G. flux in that it's blue! Although a slightly different blue - I would say more aqua blue rather than a cerulean blue of the B.O.G. The other difference is the smell - not technical in anyway but it is different. Not sure how to describe the B.O.G. flux but after consulting with my offspring the verdict was that the Pearsons flux smells just like those solid blue disinfectant blocks they put in the gents urinals!

    flux - 4.jpeg

    in use - I tried tinning my sample sheets used earlier - the Pearsons Safety flux used in the sample circled in red.

    This was on the brass sheet - very oxidised no cleaning.

    flux - 2 (1).jpeg

    and the nickel-silver sheet.

    flux - 1 (1).jpeg

    Again wetting and flow seemed on a par with B.O.G. and WL1.

    A couple of test joints, an overlap and a 90deg join.

    flux - 3 (1).jpeg

    Actually it flowed really nicely - the resultant solder joint was nice and smooth, the bead of solder in the corner of the joint was nice and tight if you know what I mean, also not too much spatter. The 90deg join it was soldered on the right hand side but it's not that clear on the photo but on the lefthand side it is possible to make out that the solder penetrated all through the join. So pretty good result as far as I'm concerned.

    A couple of other points - I'm not sure whether to describe it as viscosity or surface tension but again very similar to the B.O.G. flux. As shown in the first photo I decant the flux into a little dropper bottle to apply just a drop or two from the needle to the joint. With B.O.G. and Pearsons then the flux stays as a bead drop - much like a rain drop on a freshly waxed and polished car - whereas the WL1 flux seemed to have a much lower surface tension so that when you tried to place a drop or two it immediately flattened out and washed over the entire joint - like a rain drop on a car that hasn't been polished for a month or so. The one other small difference noted so far is that with the B.O.G. flux I found some of the ingredients tends to settle out of suspension and the bottle needed a good shake prior to use - now it might be because it's been in transit or that the flux is fresher but there were no such issues with the Pearsons flux.

    So there is the caveat that I need to use it few days and also see if there is any corrosion on the joints just test but overall the Pearson Safety Flux is not exactly the same as the B.O.G. flux but it's the nearest equivalent I've found so far. In some ways it slightly edges it so far as it doesn't appear to get a sediment. It is better than the WL1 flux in that it isn't plastered in hazard marking symbols and certainly the fumes were a lot less offensive.

    From my very limited testing so far I think if you have been using B.O.G. flux then this is the best equivalent and appears to be equally effective and useable and one I think I will be recommending. So many thanks for the link @ScottW a brilliant find. :thumbs: :thumbs: :thumbs:

    p.s. forgot to say total charge for 200ml incl p&p was £10.16 so it's not going to break the bank!
    AndyJEH, Len Cattley, ScottW and 6 others like this.
  16. mickoo

    mickoo Western Thunderer

    Good job sir, I've also noticed that B.O.G flux often fails to spread cleanly, maybe it needs a little drop of IPA to reduce it's surface tension, something I was going to try but haven't got around to.

    B.O.G flux used to be a clear colour with a hint of brown.....maybe it had gone off...it was the first bottle I had many years ago.

    Just ordered the Pearsons, whilst I have two bottles of B.O.G I'm going to make sure I've enough long term, I do tend to use it rather a lot (flux that is), I'm also from the wash the joint camp, rather than the dispense a drop form a pin needle or dispenser like yours.
    michl080 and Deano747 like this.
  17. simond

    simond Western Thunderer

    doesn’t that make it difficult to light?
    fenman, mickoo, Deano747 and 4 others like this.
  18. markjj

    markjj Western Thunderer

    I use this from Tempsford stained glass and have done for a few years now. You can buy it in a smaller bottle to if you want to try it.
    It works well on Brass, Copper or Nickel silver and washes off easily.
    Water-soluble Aquaflux 500mls
  19. markjj

    markjj Western Thunderer

    I forgot to add whitemetal to my list above it works fine with that with no problems as well.
  20. Focalplane

    Focalplane Western Thunderer

    Late to the party. I still have plenty of Carr’s yellow which works for me. That and the red stuff which is normally used in a separate location for health reasons though somehow I have got this far . . .

    Deano747 and Len Cattley like this.