My Tuning Tips for the Aster Precedent Class 2-4-0 'Jumbo' proved
very useful for kit builders and owners of that particular model and so I
thought it might be useful for customers to have something similar for the new
These notes will be updated from time to time as more information
and experience comes to hand. You are invited to add your tips and ideas for the
benefit of all.
Please keep in mind that tips for both kit builders and for
owners of ready to run models are included below.
As supplied the wicks may not be entirely suitable for supplies of the poor
quality ‘Meths’ supplied to the UK market. Generally wick replacement with
either traditional material or the newer carbon fiber or mineral wool materials
may be desirable. With the right wick, the boiler should steam like fury.
Ultimately some reduction to the height of the wick tube maybe be
desirable – your comments appreciated.
I have found that the use of the oil pressuriser is only required, if at all,
very occasionally if a medium grade of oil is used. If the loco sounds a little
‘hoarse’ then a quick on – off application of the pressuriser gets oil
moving again. Remember to close the regulator when using the oil pressuriser.
3. Loco /
The coupling bar between loco
and tender is very rigid and may, on a bumpy track, cause the tender to lift. To
correct this I suggest the careful enlargement of the slot in the tender draw
beam by 2 mm. Only the top edge needs to be filed carefully. Alternatively fit a
new drawbar made of a thinner material.
freeze. Experienced runners will know this but the tyro may not,
so let me remind you that it is a good idea to slightly crack open the loco’s
regulator and blower controls as the machine cools down after a run. If you
don’t do this then the controls may ‘freeze’. If you try to loosen them
when they have ‘frozen’ then you may unscrew the regulator (or blower) body
in the boiler.. Should you forget this ‘tip’ then don’t panic, relight the
fire (ensuring there is water in the boiler) and the controls will magically
‘unfreeze’ when temperature is up to operating levels. This effect is all to
do with the differential expansion of brass and stainless steel but can lead to
a very irritating strip-down and rebuild if forgotten!
beats. My own production example and other production models I have seen
working clearly demonstrate the ‘six beats to the bar’ of a three-cylinder loco.
If you can only hear four and two ‘whooshes’ of steam then perhaps the valve on
the inside cylinder may have dropped-off the port face. Too much boiler priming
may push the valve off but it should snap back quickly.
6. Water feed
union. I like to run my Aster A3 close coupled to the tender. However,
the water feed union part 10-11 may foul the tender. I suggest exchanging part
10-11 for LN5 on the water return pipe 10-38 in the tender tank. Reference to
the drawings makes this clear.
Where this pipe crosses the
smoke box it should be painted black. A small point but worth doing.
In reality the
wheel rims and hubs are black with a fine white line separating green from
black. Please refer to a photograph of an A3 in LNER livery. Aster Hobby Co Inc
are very proud of their polished rims etc. I leave it to you to decide if you
make this adjustment. Tender wheel rims are plain black.
A number of runners (including myself) have found that the Aster A3 works best
with the reverser about three full turns back from full forward gear. Clearly
some experimentation with your model is required but having seen when building a
kit how much valve travel occurs in full gear, some reduction seems very
sensible and gives more even beats and a smoother performance.
Several kits have been successfully built and the following
points should be noted
1. Drawing two is
drawing three and vice-versa. Labels
will be found in the back of the instruction book to correct this.
2. When fitting
the crosshead to the piston rod, be sure to fit the slide bars to the crosshead
first. If you follow the instructions you will find it difficult to do this
after you have ‘lock-tighted’ crosshead to piston rod.
3. Extra care
taken on getting the valve timing right will be rewarded by a great running
loco. The part of the construction
is the most challenging but the drawings and instructions are quite clear. Near
enough is good enough does not apply to this section. Get it right from day one!
4. To help in this regard, make yourself a small protractor from card (or
clear plastic) with an angle of 34 degrees. Place the chassis on a flat surface
and using your protractor get the return crank angle set precisely. Time taken
here will be rewarded later.
5. Boiler. Having
fitted the regulator and blower into the boiler, be sure to fit the dummy back
head in place before adding the various back head fittings. A dry run with parts
will establish the correct order of assembly.
6. From Jerry Reshew of Diamondhead USA. In order to get a mirror finish on both the cylinder
port faces and valves themselves, I switch to 1500 grit paper after doing the
requisite polishing with the supplied 1000 grit paper. About 100 strokes of wet
and light pressure should really give you a superb finish. The absolute mirror
finish really does make the locomotive run beautifully in the case of the Mikado
and the Jumbo.
7. When assembling the exhaust steam pipe from inside cylinder
3-24, to exhaust steam pipe 3-9, it may appear that the blast nozzle 3-25 will
be out of alignment. Do not worry; this will be corrected in Section 5 when part
5-31 is fitted.
8. The lengths of the flexible tube (BT5) is reported to be reversed in
the drawing. The feed should be 180mm and the return 160mm, please check this
9. Most kit builders will agree that the Aster A3 is one of the best
Aster kits for ease of construction and accurate fit of parts. However the
tender axle guards can be very frustrating. Small spigots attacked to the dummy springs may not
locate properly in the holes provided in the tender frame. Either file of the
spigots or enlarge the tender frame holes (3.5mm drill).
10. Let me re-emphasize the important note on page on page 24 of the
Aster A3 Operating & Instruction Manual. The operating of any small model
under compressed air is for valve setting as described in the manual and should
be applied for the minimum time possible. The
use of compressed air for other proposes is positively discouraged. Unlike
steam, which has a lubricating effect and will draw oil into the flow,
compressed air will blow out any lubricants in the steam ways, valve chests and
cylinders. Damage caused by over use of compressed air will not be covered under
for permission to reproduce Aster Tuning Tips for the A3 on SouthernSteamTrains.com is expressed to
Andrew Pullen, author © 2002 Aster Hobbies Ltd.