Learning to singe my fingers - HeavyDuty's brass kit odyssey

[HeavyDuty]

I build a fair number of radio kits, and in doing that I've found some braid is more effective than others. Unfortunately the kind I have on hand right now is barely usable.

[trisonic]

Ken, Yes, we tend to grab whatever is close to hand!

 

Btw I use Kester “Acid Paste Flux” formula SP-30 to make trackwork (it was recommended by Tim Warris but I do NOT use the Fast Tracks system) a tiny dab will do ya! I’ve probably got enough now for two lifetimes. It’s either Canadian or from the USA, so far as I’m aware.

It works well for me.

 

Trust this may help. Pete.

[PatB]

I agree that braids vary in effectiveness. I always dip the business end in flux before use, then apply braid to solder and iron to back of braid to draw the solder through the weave. Dunno if this is correct but it seems to work reasonably well.

[HeavyDuty]

A bit of a shock this morning - I never realized Slaters wheels rusted so quickly!  Five minutes work with a scratch brush cleared them up.  Wheels here tend to be either plated brass or solid stainless, so I never would have guessed this would happen.

 

Speaking of scratch brushes, I think I'm going to be going through these pretty quickly - I just ordered a new one with several refills.

[Kenton]

 

I'm still trying to come to terms with how much solder to carry on the tip. I did OK, but there is quite a bit extra solder to remove in places. In a few places I've managed to partially fill etched recesses

I'm afraid that I am completely against carrying solder to the work on the tip of the iron. For various reasons others on here seem to discount but one of them is that you have little control over where it goes.

 

We always use far too much solder when we start out and gradually learn that it is a waste, is not required and only needs to be removed afterwards. Try to get in the habit of using less. Solder (normal melt range) is no good as a filler. If you have big gaps between parts to be fitted yo have a grotty kit or you are being over zealous with the files. (This kit is far from grotty)

 

To clean up excess solder you require something harder than the solder but less than the brass. I would not suggest brass brush in a dremmel it goes everywhere and wears too quickly. The first tool should be a steel chisel or similar (you can buy a set but cheap enough to make) simply scrape away the worst of it taking care not to scrape the brass itself. Next up use a sanding block of Garyflex (sand set in a rubber block - different grades available) finally some emery cloth. I still think the glass fibre pen takes some beating in the final step. But you will soon start learning that too much solder is not required and is nothing but trouble and a waste of time. Only a very small amount of solder is required to make a join.

 

 

The rusty problem with Slaters wheels has been the subject on a couple of threads on RMWeb. You are lucky to be able to fix the problem with a glass fibre pen - sadly on some the rust is much worse. Also scratching the surface my simply induce more rust to form.

[HeavyDuty]

Thanks, Kenton - I'll look for a local equivalent to those abrasive blocks. And I agree - the best way is to not use too much solder to begin with!

 

All in all I'm satisfied with my progress to date - I'll get a pic up after I've cleaned it up a bit.

[buffalo]

 I'm afraid that I am completely against carrying solder to the work on the tip of the iron. For various reasons others on here seem to discount but one of them is that you have little control over where it goes...

 

Oh dear, here we go again   See past topics on soldering ad infinitum. The reason why we discount your objections is that they are just wrong! If you don't practice a technique, how can you possibly claim that we have little control over where it goes? With practice, both pre-loading the iron and using small chips at the joint work equally well and provide equal levels of control.

 

Otherwise, yes, practice using less solder. You'll soon know when you haven't used enough...

 

Nick

[HeavyDuty]

I tried using a steel bristled rotary tool brush on a hidden area, but I think it's too aggressive. I have a few brass brushes on the way that should help.

[Simond]

Returning to Powerflow flux - I find it to be superb, particularly on white metal with 70C solder (and for soldering lead)

 

Best

Simon

[HeavyDuty]

Simon, that's good to know. I don't have any experience with other flux, but the Powerflow is working fine for me so far - I'd just like to try a few others.

 

I did order a grit airbrush which is something I've been meaning to pick up for removing factory lettering using baking soda.  It should be useful for cleaning up brass, too.

[HeavyDuty]

The first grit airbrush ended up backordered, so I found another source; it should be here in a week or two.

 

The design of the Lowmac is making cleanup with hand tools challenging.  I did find a sharpening stone to try making a chisel out of an old micro screwdriver - that should help a bit.  I want to clean up completely before I move on to adding finer details.

 

Bad pic of the current state of play:

[jamie92208]

Just found this thread and read that yu were going to start attaching the white metal castings.  i may be teaching my grandmother to suck eggs but this is the method I use.

 

1.  Clean then tin the area of brass that the casting needs to be attached to with normal solder.

 

2.  Cut a small piece of low melt off the string with a craft knife and put it onto the tinned area.

 

3.  Put some liquid flux on the area if you ahve sourced some.  I use 5 or 10% phosphoric acid that a friend mixes after buying from a pharmacy.  You may well be able to buy some from normal chemical suppliers.

 

4.  Take your smaller iron and place it behind the tinned area on the back of the brass.  This then lets the low melt solder melt.

 

5.  Place the casting into the melted solder and remove the iron and let the whole thing cool.  It takes longer than normal solder to go off.

 

6.  If it isn't quite in the correct place just re-apply the iron to the back of the brass till  the low melt goes liquid and then reposition the casting.  This can often be done after the iron is removed before the solder sets again.

 

I once did this when i was demonstrating at a show and every time I did it a crowd gathered.  At the end of the afternoon when i was using my 120w iron to do some coach sides it was the only orn available and hot and that worked very well as I only had to touch the back of the brass. 

 

 

Good fun and I look forward to seeing some pictures.

 

Jamie

[HeavyDuty]

Jamie, thank you - I was planning on following Jim's instructions including pre-tinning the brass with normal solder where the castings will be attached, but your method of heating the back of the work is something I would have never thought of on my own.

 

I'm still searching for a source of liquid flux, but to be honest the Powerflow is working well for me so far.

[jamie92208]

Jamie, thank you - I was planning on following Jim's instructions including pre-tinning the brass with normal solder where the castings will be attached, but your method of heating the back of the work is something I would have never thought of on my own.

 

I'm still searching for a source of liquid flux, but to be honest the Powerflow is working well for me so far.

If you can't get your iron to the back of the piece just place it  short way away from the tinned piece on the face.  That should work just as well.

 

Good luck and not too many burned fingers I hope.

 

Jamie

[hartleymartin]

On the steel tyres of wheels I've found that rubbing them with 6B or 9B graphite, even if there is light surface rust, tends to arrest the rusting process and gives a more realistic steel finish in model form. Regularly running the wagons on a circuit also surface-hardens the tyres and prevents rust build up - that's how the real railways did it!

[Matador]

Have you thought of using a resistance soldering unit , I,ve had mine for years. I also using Weller irons but the resistance unit performs miracles.

 

David

A Brit in the USA

[HeavyDuty]

I'd love a resistance kit, I've been looking at them but haven't jumped in as of yet. I haven't been able to get anything further done on the wagons, either - I'm hoping things will slow down in a few weeks.

 

I've been looking for something agricultural to load on this - a traction engine would be perfect.

[flexible_coupling]

I'd love a resistance kit, I've been looking at them but haven't jumped in as of yet. I haven't been able to get anything further done on the wagons, either - I'm hoping things will slow down in a few weeks.

 

I've been looking for something agricultural to load on this - a traction engine would be perfect.

 

If you fancy that you have any electronics skills, you can build a RSU yourself surprisingly cheaply, so long as you take the time to consider safe/protected operation electrically. I'm going to rebuild/alter the unit I made earlier in the year to have heavier-duty cable and to use thicker readily-available welders gouging rods that I can sharpen with a pencil sharpener. My unit has an automotive-intended high current 12V fused relay control with a small 'trigger' push-button inset into the handle with an LED (that's not really necessary) and I've been extremely pleased with the results.... game-changer for me as far as etched brass construction is concerned. Most commercial units utilize a foot-pedal control; I found the handle-mounted button works really well for me and it's a few less wires running around the bench. The learning curve for operation is short, and the singeing of the fingers can reduce significantly as you can, in certain situations, hold the work 'cold' with the RSU tip then momentarily apply localized heat. Hard to explain but it makes application of tiny laminated parts a hell of a lot easier!!

[Andy Reichert]

I have the ultra-fine grain solder paste used in surface mount PCB assembly available in small quantities here in the US. Because of all the frog assembly we do, I have a temp controlled hot air gun and a 250 W resistance soldering unit. I hardly ever use an iron at all now, even though I have the original German made Weller station.

 

The key for us is use the solder pasted and flux from small syringes fitted with 0.010" diameter stainless steel needles. You can place a spot of solder down to only the size a scale rivet and just heat it to make a perfect joint, all without any excess flowing out.  Or use a solder paste "printing" pad and solder a whole area absolutely evenly.

 

 

 

Andy

[Simond]

Andy

 

I'm pleased to hear that there is solder paste that will go through a syringe, as my experiment suggested that this didn't really work - it was/is near impossible to press the syringe. I think it is a different paste.

 

What paste are you using please?

 

Thx

Simon

[HeavyDuty]

One of the RSU options I've considered is something home made - I have an article on how to build one using an old PC power supply.  I used a friend's RSU years ago and really liked it. 

 

A SMT hot air gun isn't something I've thought about before.  Andy, are they available at non-nosebleed prices for hobbyists?

[Matador]

I have the ultra-fine grain solder paste used in surface mount PCB assembly available in small quantities here in the US. Because of all the frog assembly we do, I have a temp controlled hot air gun and a 250 W resistance soldering unit. I hardly ever use an iron at all now, even though I have the original German made Weller station.

 

The key for us is use the solder pasted and flux from small syringes fitted with 0.010" diameter stainless steel needles. You can place a spot of solder down to only the size a scale rivet and just heat it to make a perfect joint, all without any excess flowing out.  Or use a solder paste "printing" pad and solder a whole area absolutely evenly.

 

 

 

Andy

Where are you getting your SYRINGES I tried to buy some and nobody would sell them to me.

 

David

A Brit in the USA

[Simond]

I built my RSU using a transformer "kit" from Maplin, and some very thick (over 1mm) varnish-coated copper wire. I can't remember how many turns I put on in the secondary, but it gives about 4V open circuit. There's a button on top of the box which energises the primary I usually have it on the floor and rest my foot on it using a toe to operate it.

 

One thing I have seen both in reality, and in an old MRJ is a pair of tweezers that can be connected in place of the more usual carbon rod and earthing plate. I think this would be useful, and will try to get a pair at some point.

 

I have found handy to have a small modelling "G" clamp with a 4mm hole in it - I can then easily clamp it to the workpiece if the ground plate isn't convenient. Otherwise a short length of wire with a 4mm socket at the end - the other end can be temporarily soldered to the thing you are assembling.

 

Whilst I wouldn't choose to be without the RSU. the Maplin temp controlled iron, a couple of small Wellers, a whacking great 100W iron and a cook's blow lamp pretty much complete the armoury. Horses for courses!

 

Friends in the right place regarding syringes. Ideally the ones whose needles lock on. Take the grinder to the needle, you won't improve your health by injecting yourself with solder & flux! (Or oil, or Powerflow)

 

Best

Simon

[Andy Reichert]

One of the RSU options I've considered is something home made - I have an article on how to build one using an old PC power supply.  I used a friend's RSU years ago and really liked it. 

 

A SMT hot air gun isn't something I've thought about before.  Andy, are they available at non-nosebleed prices for hobbyists?

 

Where are you getting your SYRINGES I tried to buy some and nobody would sell them to me.

 

David

A Brit in the USA

 

My own Heat gun is a bit fancy, but I found one from Harbor Freight for under $50 that seems to have the same high watts and features.  (12 setting heat gun Part # 69343 if it's still available). However I have not tested the HF version (yet) .  The only difference visually is that it does not come with a narrowed output nozzle, which concentrates the heat to a smaller area. There is however an extra parts kit which appears to include one.

 

My RSU is an American Beauty 250 W, with a set of clamping tweezers, which IMHO, are almost essential if you want to build self guarding frogs.

 

I buy syringes, twist-on needles and solder paste in bulk, then put economic amounts in the small syringes and add a needle to supply for other modellers use.  BTW, Using them with glue instead is the way I build track so easily. And the syringes and needles are availble separately. But you'd have to go to my web site to check the details.