Loco Kit Assembly

simon wrote:

The first kit I put together with 'Superglue' fell apart inside 18
months.
The ones I soldered are still complete.
One advantage of superglue is you can have all the fun of assembly at
regular intervals without buying a new kit! ;-)

Greg.P.

I had that problem when first tried to use araldite only it was 18 hours.
Then realised mix thoroughly and casually introduce were not quite the same.

Cheers,
Simon

simon wrote:

Been there, done that too :-(
One sign you've got it mixed properly is the constant colour throughout.
Trouble with the 5 minute stuff is it takes 6 minutes to mix it
properly.

Greg.

Incidently did soldering with cheap 30w iron without problems but some
concern about the temp, however asked trader about minmum wattage for Antex
iron and was told use temp controlled one as 18W may not deliver enough heat
to the joins. However, I dont want to pay that price, would prefer basic 15
or 18W - anyone know if they would be powerful enough ?

Cheers,
Simon

simon wrote:

Temperature and power are not the same things at all.

Wattage is the amount of power an iron can sink into a piece of work.  A
bigger 100W iron can sink 100W of power into a big-ish lump of metal.
Whereas a 15W iron can only sink 15W, and then its temperature plummets as
the big piece of metal can absorb all that heat and more.

Temperature is degrees C at the tip.  A temperature controlled iron lets you
decide what value that should be. Different types of solder melt at
different temperatures, typically "low melt" for whitemetal kits can be
below 100 degree C, whereas the old lead-based plumbing and electrical
solder is 188 degrees C.


With a lump of metal on a whitemetal kit, you may find that the 18W (or 15W)
iron will drop to about the right temperature.  Or you may find it drops too
low (and nothing melts), or you may find you touch a small detail and it
delivers 15W at 300 degrees C into a detail and destroys the detail.


You can get a crude, though effective, form of temperature control with an
old light dimmer powering a small iron. One or two makers used to sell
similar devices in a little plug brick.   Or, sometimes, discounters such as
Maplin have cheap temperature controlled irons on sale.



- Nigel


--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/

Thanks for the full answer, suppose it comes down to trying it out.
Has anyone tried to solder the major parts of a whitemetal loco kit using an
antex 18W iron ?

Cheers,
Simon

Yes, and I now had a Weller temperature controlled 40W soldering
station. http://www.brewstersbatteries.co.uk/catalog/weller-whs40lt -
solder-station-special-edition-p-49.html

Although I got mine from Expo tools - always get exceptional service
from them but thier site's a bit "sh 1 T" http://www.expotools.com
(Looks like their currently the victim of "passing off" as the ".co.uk"
diverts to someone else.

I'd echo everything Nigel says, it makes such a difference to have
constant power at the right temperature - regardless of what you're
doing, brass, NS, white metal.

--

All the best,

Chris

I've had an Antex temperature controller for about 20 years like:
http://peats.com/cgi-bin/catalog_v2.cgi?id=1383&type=product
but it was only about 10pounds. There is a newer model at a more
reasonable price at:
http://www.rapidonline.com/1/1/2816-energy-regulator.html

Alan

--
alan.dawes@argonet.co.uk
alan.dawes@riscos.org
Using an Acorn RiscPC

On 17/01/2011 4:59 AM, simon wrote:
[...]

No. Problem with a low-power soldering iron is that heat is not
transferred fast enough, which in turn means that the heat has plenty of
time to migrate away from the joint, which means it takes even longer to
heat it up, and so on. On large parts, you'll never get the joint hot
enough. Low-power irons are made for fine electronic work, where the
mass of the parts to be joined is very small. That's not the case with
white-metal locos.

Even 30W can be problematic on larger parts. I use a 50W/100W gun, and
heat sinks on either side of the joint. If there's no room to clamp them
in place, a wet rag as close as possible to the joint will work.

All this implies that you can hold joints securely in position for
soldering. A tip I learned years ago was to keep a lump of plasticine
handy. You can make all kinds of ad-hoc supports with it.

HTH
Wolf K.

Good point about holding parts, was doing that - great warning mechanism.
Will stick to current iron then - it works for me.

Cheers,
Simon

On 17/01/2011 15:20, Wolf K wrote:


I was about to say the same, but Wolf beat me to it.  I have a 50W
adjustable temperature iron, and that works really well.


Nah - singed fingers are part of the fun :-)

Incidentally, Simon, which solder are you using?  Hopefully 70degree
stuff.  That's quite a "lumpy" solder so it's particularly good to use
as a filler.  I do also use 188degree, but you need to be quick and have
chunky castings!

--
Paul Boyd
http://www.paul-boyd.me.uk /

Yep its Carrs's 70degree along with thier red flux. Have used as filler on
part built kit where boiler jooin was a bit prominent - saved splitting and
refixing, had to make sure fresh surface available though.
One time accidently used 140 degree and lingered there was slight damage to
white metal - best way to learn :-)

Thanks,
Simon

@unlimited.newshosting.com:


Blue tack for me :-)

--

All the best,

Chris

simon wrote:

short answer: NO.

Look at the quantity of metal attached to the bit of the iron.
Look at the quantity of metal attached to the join you want to solder.

Broadly speaking, if both are equal then the temperature is going to
average
between the two chunks of metal.

Little iron needs to be very hot to balance out at solder melting
temperature.
Big iron can be much cooler to balance out at solder melting
temperature.

Really hot bits tend to melt the whitemetal before they solder it. (Not
good)

The wattage needs to be sufficient to maintain the required heat over
the bit
and soldering object.
It's quite depressing to end up with a 20w iron soldered to a large loco
casting!

Adjusting the temperature of an iron can be achieved by putting a lamp
dimmer in
series with the iron, or even just a standard batten lamp holder in
series. Adjust
the iron temperature by varying the wattage of the light bulb you put
into the
bulb socket. A wattage equal to the iron's wattage is a good place to
start.
Get some whitemetal spruhe from the kit and adjust the temperature down
until it
is just below melting a small piece of spruhe.

Unfortunately every soldering task is different so there isn't one
standard answer.

Greg.P.