Well as you know we in the UK have bee suffering a heatwave. As my friend Thomas noted that 40C was fairly common in the parts of the USofA where he has lived -here most summers are 20-25C. This put the kybosh om any printing as the bed needed to be about 30C for a good adhesion. After having printed lumps of chewing gum I waited for it to pass.
But this is the state we are at now.
The roof sections are complete, the side panels are bonded together and the pignoses assembled. The round vent for the radiator fan and the rectangular slot for the engine hoist doors.
This shows the start of the main assembly. The base board for the loco is 9mm ply. I use UHU glue as I find it sticks PLA to wood perfectly,
The other side panel is then glued to the assembly and the whole lot weighted with tins.
This is how it will stat for at least 36 hours then maximum strength is reached. The the smaller angles and louvres can be glued into position.
As you can tell by the shot below the only major part of the loco body to be produced is the front cab window. This I knew was going to be something that I only knew what it looked like once the other pieces were assembled.
Once everything is solid -it is down to the ruler and cardboard!
Ok, after some P38 and 60 grit wet and dry... This is the body after its first coat of "red oxide" primer. I notmally use red oxide as I find it to be a good high build and soft sand. There will be two coats of brushed on primer, two coats of green under coat and three coats top coat (BR Diesel Green).
Then it is back to tje keyboard and make all the louvres etc and stick them into place..
Yes.... It does look rather good in red!!! So, I will unlimber the tins of red undercoat and Crimson Lake.
I have an open day at my railway on the 18th - so the paint will have to wait. Keeping the paint "clean" in the detritus of gardening is impossible! As you can see the leaves are turning brown as autumn approaches. The other loco drying in the breeze is an EM2 this is pre WW2 designed C0-C0 electric 1500v OHL loco. The BR "Electric Blue" blue paint had to be specially mixed at £45 per litre. This is NOT the 70's 80's "Corporate Rail Blue" - which is far cheaper!!!
Well - before the next wave hits... The red primer coats are hardening off and in another three days will be hard enough to sand flat.
I thought I would give you an intro into the differences of wiring a G3 loco compared to that of a G1. The G1MRA standard is based on 24V fed track power. This is normally sufficent to get through dirt and give a reasonable long track run. However 24V track power in G3 is very rare and is normally limited to Exhibition layouts. The most famous of which is powered by twin 24V diesel cranking batteries -for reasons that will soon become obvious!!!
G3 normally uses 12V or 14.4V on board batteries. This means that it is a low voltage high current system. A typical G3 loco is circa 60W when cruising light engine. OK you say -so this if 5A @12V. This is correct but the heating effect is the square of the current by the resistance. Let us assume a 10 ohm motor. A typical three winding lobe motor value.
The heating factor is 5 x 5 x 10=250
The heating factor is 2.5 x 2.5 x 10=62.5
Thus the heating factor is four times for 12V as compared to that of 24V.
Hence most G3 locos have some form of assisted cooling!!! Either motors with coolant fans on the armature or external force cooling. Massive heatsinked ESCs are also common place as is fan cooling them.
My standard SLA battery is 12V 7.5 Ah which is mounted centrally for good weight transfer. My std ESC is the Viper series by Mtroniks and my std sound card is MyLocosound.
The latest thing that I am fitting is a steam/exhaust smoke generator this is the Seuther with the fan blaster. The oil heater is 5V and the fan couples to the motor feed off the ESC.
Each motor is fed from 10A cable from a 30A buss bar cable. The speakers are arranged in a cone to cone isobaric - hence wired with one in antiphase to the other This is my std for diesels, whilst cone in cone isobaric is my std for steam or electric traction locos.
Here are a couple of shots of a previously wired loco. The isobaric chamber is sealed with silicone bath sealant. It looks hideous but it works.
|Well -before the 2nd heat wave strikes... Here is the large radiator grill. The other grills can be produced from it. You will need; two @70x50, four @25x45, four @25x30 and four @25x20. simply altering the X Y and iteration (i) values will give you what you need.
As we cower under the trees... The first sets of louvres has come off the bed and been sprayed "Grey Pearl". The main loco body has been finished in "Crimson Lake". This is actual 1946 LMS lake! There are advantages to living here. Admittedly it did take the skill of a skilled paint chemist to restore the lake to usability. But now they can sell the exact formulation.
The loco now has a more modern feel than the era it is supposed to inhabit. But since "Westerns" are available in Blue, Maroon and (ugh!) "Sand", I don't really think it matters. It is my loco and I think it looks "right".
Now these should have attached to the last post(?)
But this time it looks like they have. The louvre tiles fit into their cavities after a once over with a file to clean up the louvre edges. The motor hoist doors are now stuck down and the main painting can commence.
I have decided to go with a 70's full face yellow rather than the 60's "warpaint" stripe. This makes it more visable as it runs through the orchard.
The next major part is the steel work. This will be made from steel angle or U section bronze welded together. Then there is the laser cutting of the bogie frames to take the motor units.
I am not sure how this software will react to a DXF - so a PNG might have to be used to show you the part(?)
Once this heatwave has passed I can return to printing...
Another day cowering in the shade ... So, I decided to experiment with the smoke/steam generators. Examination showed a heating coil, a cotton wad .
I grabbed my apprentice who "vapes" and the experiments began. I had previously bought a vial of "root beer" scented smoke as I had never tasted or smelt it.
We coupled the fan to a 6V SLA and dripped oil onto the fluff. Sealing the box - we then applied power from a VariStat PSU. The fan turned and at 4V some
smoke began to appear out of the exhaust ports. At 6V it was noticable but at 8V it was deemed to be"perfect"!!! Consumption was thought to be a little high at 1.8A continuous.
The only proynlem was that neither of us were really that happy with the number of time we had to syringe liquid into the container. We then tried commercial "Vape" liquid -which was absolutely superb. I am going to duplicate the recipie of 70% Propalyne Glycol and 30% Glycerine -but without the Nicotine and flavourings. I do have to admit that the "Cherry Pie" scent blasted out the exhaust was mouth watering.
The next step is to jack up the base of a 5V VREG with a 3V Zener diode to the correct feed voltage and then attach it to the main12V buss bar.
This is the last piece of code. This is the emergency external engine and electrics cutoff. There was some debate in the early days of what would happen if a loco derailed tipping or caught fire. The solution was called "the bottle". This is (I suppose) the worlds largest Mercury "tilt" switch,, As the glass capsule would break in a collision or derailment -thus the Mercury would not make the connection to main buss bar. The red handle beside it was a simple "gas tap" lever and the Mercury drained away. As both sides were linked in series, one cut off the other.
I don't know if this is the origin of "bottling it" (losing your confidence) or the reverse -but either would fit.
AFTER HAVING PICKED MYSELF OFF THE FLOOR LAUGHING!!! The forum software DOES accept DXF files directly -however the resulting image seems to be about 2 pixels square at normal resolution. So, here is the screenshot. I use LibreCAD -as my system used Debian 11 - that will come as no surprise.
You may be puzzled at the hole specifications i.e. m10 rather than 10mm. This is because the hole will be tapped to take an M10 thread thus requiring a hole that is smaller than 10mm.
The m10 take the axles, the m6 is the compensator bar,, the M4 are the fitting holes to the pivot and finally the m2 are the troque/reaction bar for the power axles.
In three days it will be the third of the four open days that I have every year. I normally allow young guests to use some of my models and locos. Now that I have shifted from carving wood and abs sheet to printing- it means that young potential members can now afford Gauge '3' locos and borrow the track or rolling stock!!!
I have produced four designs for "pocket money projects". These are "the wonder engine" , "sparkie", "tobias" and "two little ducks".
It requires less than a 1Kg reel of PLA to print any of them the main cost are the running componants. The skill level required for assembly is classed as (1).
This means a kitchen table, some sandpaper and a tube of glue. A hand brace and a soldering iron or a cable crimp.
Making the chassis is level (2) as it requires a butane/propane gas torch and some knowledge of silver soldering. But you could use pop rivits.to keep it at level (1).
If all goes well the class 22 should be running around at Flitwick in September.
No it wasn't!!! But eventually the bogie plates did drop through the letterbox. As I have said these are 3mm thick BMS (bright mild steel) and have the axle bearing holes and other things cut into the steel with a laser. from left to right... spring connection, bearing hole (10mm), lazy susan mount 4mm and bogie compensation pivot (6mm).
This shows the motor units that will sit between the bogie plates. The wooden spacing piece simply holds them at the correct distance to slide the plates over the axles. Some people may ask -"why is he using compensation rather then a sprung axle"? The answer has to do with the supply of suitable springs! I need springs with a Hookes coefficient of about 500 grammes per millimetrewith a coil diameter of not more than 8mm. YES they do exist -but at "wallet heart attack" prices...
The motors are the Italian SME 1620 series -which have recently gone out of production. However I do have a good stock of them to keep me going. They seem to be a 9 Volt motor but operate quite happily at 6 Volts thus allowing to use two in series off the 12 Volt buss bar from the ESC.