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NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 7:50 am
by RobM
9 members attended this meeting.

David was drilling out the crankpin holes on the wheels for his LNWR Webb Coal Tank;
John was building a society lever frame;
Peter was building a Southern Guards Van;
Bevis asked for help with Templot and Howard and Tony W were helping him;
Martin was building a High Level kit for a Robert Stephenson and Hawthorns 14’
0-4-0 Tank.
Unfortunately he found that he had soldered a part the wrong way around, which was in an awkward place for unsoldering. Howard showed how to unsolder the made up unit using the hall’s hotplate!

hot-plate.jpeg
hot-plate.jpeg (124.02 KiB) Viewed 3252 times


Next week is another modelling night.

Brian Slater 25th May 2018

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 7:54 am
by Le Corbusier
RobM wrote:9 members attended this meeting.

David was drilling out the crankpin holes on the wheels for his LNWR Webb Coal Tank;
John was building a society lever frame;
Peter was building a Southern Guards Van;
Bevis asked for help with Templot and Howard and Tony W were helping him;
Martin was building a High Level kit for a Robert Stephenson and Hawthorns 14’
0-4-0 Tank.
Unfortunately he found that he had soldered a part the wrong way around, which was in an awkward place for unsoldering. Howard showed how to unsolder the made up unit using the hall’s hotplate!

hot-plate.jpeg

Next week is another modelling night.

Brian Slater 25th May 2018

Any chance of a more detailed explanation of the unsoldering operation?

Tim

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 10:33 am
by billbedford
You could also use a hot air paint stripper to unsolder, and solder for that matter.

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 11:03 am
by Le Corbusier
billbedford wrote:You could also use a hot air paint stripper to unsolder, and solder for that matter.


I ask because I stupidly soldered the solebar overlay on one of your midland wagons upside down in an absent moment .... couldn't work out how to unsolder without trashing all the work to date and potentially causing far more problems than it solved. I run the wagon with that face away from the viewer :?

Just wondered if there was a clever way of removing a soldered overlay in a targeted way :?:

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 11:12 am
by David B
Le Corbusier wrote: . . . soldered the solebar overlay on . . . . upside down in an absent moment ....


I have done the same and used the RSU. Hold the wok in a vice or similar, apply the probe to one end and gently separate the two parts with a scalpel. Move the probe along . . . repeat . . .. The solder does not (usually) stick to the steel blade.

The RSU can be used to unsolder as well as solder close to other items because the heating is quick and local, providing you don't keep your foot down too long. You need to have your workpiece held in something to keep both hands free, one for the probe and the other for the tweezers or scalpel.

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 11:19 am
by Le Corbusier
David B wrote:I have done the same and used the RSU. Hold the wok in a vice or similar, apply the probe to one end and gently separate the two parts with a scalpel. Move the probe along . . . repeat . . .. The solder does not (usually) stick to the steel blade.

The RSU can be used to unsolder as well as solder close to other items because the heating is quick and local, providing you don't keep your foot down too long. You need to have your workpiece held in something to keep both hands free, one for the probe and the other for the tweezers or scalpel.

David,

I have been enjoying your RSU articles in the Snooze, but have yet to take the plunge ..... the cost is too eye watering at present but eventually I hope to have a bash.

Tim

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 11:44 am
by Clive Impey
David B's method also works using a miniature gas flame instead of an RSU. It is reassuring to learn that I am not the only one who gets overlays on upside down.

Clive.

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 1:14 pm
by David B
Le Corbusier wrote: . . . have yet to take the plunge ..... the cost is too eye watering at present but eventually I hope to have a bash.


Thank you, Tim. There was loud silence after the second article so it is good to know they have been read and appreciated.

You say the price I eye-watering and it may appear high, but consider it a life-long investment in your hobby. Once you have one and use it, you will appreciate it's worth. I spoke with John Redrup (London Road Models) at Railex and he suggested the price may rise further, not to boost his profit but because the parts are costing more. Forewarned. I know a lot of people have bought RSUs recently, so I hope we will hear more about how they get on in the appropriate part of this Forum.

If you make it to the AGM next week, I will be demonstrating with a second unit for people to use.

Re: NAG Meeting 24th May 2018

Posted: Sat Jun 02, 2018 5:55 pm
by bevis
Tim,

As one of the on-lookers at the unsoldering ceremony I can assure you it is as simple as, heat up hot plate, place offending bits on, wait for slump, repeat as necessary until correct bit falls off, clean up plate, clean all denatured solder off parts of kit and start again with putting item back together.

If all you have is a gas ring them put a steel plate over it and treat as above.

Please note though this is a very unselective way of taking things apart so if you only have one overlay to take off then other methods may allow you to keep the rest of the model intact

Hope that helps,

Bevis

Re: NAG Meeting 24th May 2018

Posted: Mon Jun 04, 2018 10:30 pm
by Flymo748
Clive Impey wrote:David B's method also works using a miniature gas flame instead of an RSU. It is reassuring to learn that I am not the only one who gets overlays on upside down.


If there is one near you, the closing down sale at Maplin may yield a suitable gas-powered soldering iron.

I picked one up for (I think) twenty quid in the branch at Canary Wharf. It comes with a couple of bits and a nozzle which means it can be used as a miniature gas burner. It's now gone into the garage toolchest for emergency repairs to motorbike wiring when I am far from mains electricity...

HTH
Flymo

Re: NAG Meeting 24th May 2018

Posted: Wed Jun 06, 2018 12:08 pm
by Hardwicke
Maplins went a few weeks ago ...

Re: NAG Meeting 24th May 2018

Posted: Wed Jun 06, 2018 12:12 pm
by Hardwicke
You can make your own RSU. I have one that the Dukeries Group (precursor to NAG) made for me. GPO transformer with two leads. Length/thickness varies to alter the resistance. Coaxal fitting at the end and a carbon rod. It was £20 thirty years ago.

Re: NAG Meeting 24th May 2018

Posted: Wed Jun 06, 2018 12:26 pm
by Hardwicke
I made the leads and holders so no one else was responsible. I'm not making any suggestions or recommendations. I am liable only to myself.
20180606_131540.jpg


20180606_131620.jpg


20180606_131708_Burst01.jpg


20180606_131754_Burst01.jpg
Well used. Rusty after 25 years in a garage/workshop


20180606_131824.jpg
Fine use of an old berol pen until I trod on it a few weeks ago. Needs glueing.

Re: NAG Meeting 24th May 2018

Posted: Wed Jun 06, 2018 12:27 pm
by Hardwicke
Oh yes. It's heavy as well !

Re: NAG Meeting 24th May 2018

Posted: Wed Jun 06, 2018 1:40 pm
by Alan Woodard
Is it for arch welding ? :-)

Al.

Re: NAG Meeting 24th May 2018

Posted: Wed Jun 06, 2018 5:17 pm
by Hardwicke
I have done low melt 70 degree but I did try repairing my bike rack before the bike was stolen. Not hot enough !

Re: NAG Meeting 24th May 2018

Posted: Wed Jun 06, 2018 10:46 pm
by Flymo748
Hardwicke wrote:Maplins went a few weeks ago ...


Depends where in the country you are...

At Canary Wharf, it is closing at the end of this week, the one atLiverpool Street still seems to be going strong for a few days yet.

At 70-80% off everything, it must be worth a root around...

Cheers
Flymo

Re: NAG Meeting 24th May 2018

Posted: Thu Jun 07, 2018 6:34 am
by JFS
David B wrote:
Le Corbusier wrote: . . . soldered the solebar overlay on . . . . upside down in an absent moment ....


I have done the same and used the RSU. Hold the wok in a vice or similar, apply the probe to one end and gently separate the two parts with a scalpel. Move the probe along . . . repeat . . .. The solder does not (usually) stick to the steel blade.

The RSU can be used to unsolder as well as solder close to other items because the heating is quick and local, providing you don't keep your foot down too long. You need to have your workpiece held in something to keep both hands free, one for the probe and the other for the tweezers or scalpel.



Just to mention that the whole point about "unsoldering" in the way described above is NOT to use any kind of implement - any kind of "separate the two parts with a salpel" implies the potential for distortion. Against that, a hotplate is not very discriminating - the whole job is "start-again"

As for the method:-

1. Place item on hotplate until the solder runs
2. Remove item, tap on hard surface and watch it all fall to bits.
3. Repeat, as the bit you want unsoldering will be the last to come to bits.

Then very carefully and thoroughly clean all the parts to remove all tarnish and solder, re-read the instructions (if there are any - otherwise, do some more second guessing of the designer's mindset) before restarting the whole job afresh.

This is the first time I have used an electric cooker - we have gas at home which is a bit more controllable. Not that I have ever needed to use such methods for myself ... ...

Poor old Martin - I had been trying to do this particular bit of re-work discretely. Next thing, not only was there a full-house audience to watch, there was a photographer capturing the moment for publication! Good job Martin does not frequent these pages!

I see we are discussing RSUs again. I can't imagine how I ever got to my 50(odd)th year in modelling without ever finding a need for one! Personally, I would find a small and controllable gas torch a much better investment - especially for unsoldering... and silver soldering ... and doing larger jobs in brass...

Can I ask Michael (Hardwicke) - does your home made RSU have a CE mark? Looks a little bit lethal to me! And isn't 10v a bit on the high side

Best wishes,

Re: NAG Meeting 24th May 2018

Posted: Thu Jun 07, 2018 6:34 pm
by Hardwicke
Flymo748 wrote:
Hardwicke wrote:Maplins went a few weeks ago ...


Depends where in the country you are...

At Canary Wharf, it is closing at the end of this week, the one atLiverpool Street still seems to be going strong for a few days yet.

At 70-80% off everything, it must be worth a root around...

Cheers
Flymo

Interesting !
There was a lot of junk at Nottingham, but I got some things I wanted.

Re: NAG Meeting 24th May 2018

Posted: Thu Jun 07, 2018 6:45 pm
by grovenor-2685
Can I ask Michael (Hardwicke) - does your home made RSU have a CE mark?

I think that was built long before CE marks existed :)
Regards

Re: NAG Meeting 24th May 2018

Posted: Thu Jun 07, 2018 8:40 pm
by Flymo748
Hardwicke wrote:
Flymo748 wrote:
Hardwicke wrote:Maplins went a few weeks ago ...


Depends where in the country you are...

At Canary Wharf, it is closing at the end of this week, the one atLiverpool Street still seems to be going strong for a few days yet.

At 70-80% off everything, it must be worth a root around...

Cheers
Flymo

Interesting !
There was a lot of junk at Nottingham, but I got some things I wanted.


Well, I had time to pop into the one in Liverpool Street and picked up a load of heatshrink (always useful for insulating DCC chips, and for keeping wiring tidy) at the rate of four packs for a pound.

And a few other useful household and garage bits and pieces for not-a-lot of money. So in with all the endless cables and PC components, you can find some real bargains.

Happy hunting!
Flymo

Re: NAG Meeting 24th May 2018

Posted: Fri Jun 08, 2018 12:32 am
by Hardwicke
:D
grovenor-2685 wrote:
Can I ask Michael (Hardwicke) - does your home made RSU have a CE mark?

I think that was built long before CE marks existed :)
Regards