Garden Railway Forum

Trevor, that looks freaking amazing, I hope you are very proud of yourself.

As far as name plates go, it looks like your plates are lifting at each end the same as mine do. I am going to thicken up the base to try and avoid this but I am not sure if it's getting them off the build plate that causes it or whether it's the curing process under a UV lamp, I might try an outside natural dry to see if it's that. Let me know if you manage to overcome this.

EDIT: Another question, how high and how wide are your rivets as they look perfect, mine never come out as they look in CAD, lol.

Excellent work all round. Can't wait to see it in action

Rik

Nice lining!

Incidentally, (unless you get it right first time, of course!) what do you use to remove any mistakes while lining a plastic model? I use lighter fluid on metal locos, but want to line a tender I've made from plastic at some point and wonder how it would hold up?

Thanks,

Andrew.

-steves- wrote: ↑Tue Mar 02, 2021 8:16 am Trevor, that looks freaking amazing, I hope you are very proud of yourself.

As far as name plates go, it looks like your plates are lifting at each end the same as mine do. I am going to thicken up the base to try and avoid this but I am not sure if it's getting them off the build plate that causes it or whether it's the curing process under a UV lamp, I might try an outside natural dry to see if it's that. Let me know if you manage to overcome this.

EDIT: Another question, how high and how wide are your rivets as they look perfect, mine never come out as they look in CAD, lol.

Thanks for the complement!

I am quite pleased with it.

The rivets are 1mm diameter and 1mm high. Just rods - not actually rivet shaped. I don't think its obvious when they are printed - and even less so when painted.

The name plates were flat when I took them off the build plate - but warped under UV. I was planning to just glue them into place and expect the glue to hold them flat.

Trevor

Andrew wrote: ↑Tue Mar 02, 2021 4:59 pm Nice lining!

Incidentally, (unless you get it right first time, of course!) what do you use to remove any mistakes while lining a plastic model? I use lighter fluid on metal locos, but want to line a tender I've made from plastic at some point and wonder how it would hold up?

Thanks,

Andrew.

I do the same. I have been using lighter fuel on the plastic models as well. The underlying paint is Valejo acrylic airbrush paint and doesn't seem to be affected by the lighter fuel - which evaporates almost instantly.

Oh and I do make plenty of mistakes!

Trevor

Trevor Thompson wrote: ↑Tue Mar 02, 2021 6:58 pm

The name plates were flat when I took them off the build plate - but warped under UV. I was planning to just glue them into place and expect the glue to hold them flat.

I think I'd try to print them on supports with a plate on the build plate, and then trim the supports after curing. Doing it like that should hold it flat.

Yes I printed them with supports and a raft - but took them off the supports before exposing to UV. Will be interested to see it curing with supports in place has any effect

Trevor

I think natural drying on sunlight (when we get it) might improve this vastly as I have had other things go a little funny under UV that didn't in the sun. UV lights also make the resin change colour, again, the sun generally doesn't have such an effect on the resin.

Just to finish off this thread here are some photographs of the finished locomotive:
Trevor

You should be very proud of that. Well done indeed.

What a beauty!

Rik

Absolutely stunning.

I have been looking at Rick's videos - particularly with respect to sound cards.

Also after a season running this loco I became dissatisfied with the lack of detail - and the limitations of some of what I had done. So I have taken the opportunity presented by Christmas to get a sound card!

It would have been easier to incorporate the sound card and the speaker in particular when building it. The simple solution to fitting the speaker retrospectively seemed to be to make a new front panel for the water tank. I just hope it won't be too obvious! The other option the front of the tool box in the tender seemed more difficult to actually achieve. So I modified the drawing for the front of the water tank by adding a rectangular matrix of 1.5mm diameter holes. I created a backing box for the speaker at the same time, and printed both. This is the modified water tank:
The loco already had a bank of 8 AA rechargeable batteries - they were connected as 2 parallel banks. The sound card required more voltage so they were reconnected as one bank to double the voltage. The Micron radio receiver was able to cope with with the doubled voltage. It all fitted into the space under the water tank:
It seemed to me important to get the "Chuffing sounds" correctly synchronised with the motion, and I was a bit concerned that Rick had commented on not being able to get it to work using a reed switch and magnets.

Trevor

So to the magnets and reed switch.

Firstly I created a solid disc with 4 holes in its side, and printed it in two halves - so I could add it without dismantling anything. It is glued to the axle using "super glue" - and magnets are glued into the 4 holes. Not my favourite glue but the easy solution to the problem again:
I admit I have had lots of problems with reed switches. I have made a printed container to hold the reed switch , with holes for the wires to protrude upwards into the loco. Wires were soldered to the switch - without bending the switches leads.The reed switches seem really delicate - this is my sixth attempt and involved minimising the forces applied to the switch and its leads:
I cut the leads short and gently pulled the leads to lift the switch into its housing:
It is now glued to the bottom of the chassis, close to but clear of the magnet disk:
I have wired it to the sound card and the card programmed it to operate off the reed switch input.

So far that has survived the best part of a week of trials.

Trevor

Looks like a masterly solution to a problem... so lets hear it then!

While I have it in bits I have made some "improvements".

Firstly replacing the crossheads and their guides. I am now using an "engineering grade" or "ABS like" resin in the resin printer. The results seem significantly better. The components are more rigid, seem stronger, and cope with drilling tapping and filing. One wheel wasn't running true - so I sorted that. I also remade the coupling rods on the filament printer - the originals had worn journals. I have added brass bushes to the new ones:
Having created a passable model of the Ffestiniog loco lamp, and having the RC receiver that can control them it was an obvious addition:
Of course that chimney top isn't quite circular. So resin printed chimney top, safety valve cover, injectors, and tank handrails were obvious improvements. Since the sound card has the twin whistles for Welsh Pony - I had to make and fit whistles!

Trevor

So with all the "improvements" in place:
I suppose I need to video it running so that you can judge whether the sound card is an improvement!

Trevor

That is truly an amazing build Trevor. Brilliant solutions to a problem that is a bug bare to most people.
Looking forward to the video when the weather improves hopefully.

philipy wrote: ↑Tue Jan 10, 2023 4:08 pm Looks like a masterly solution to a problem... so lets hear it then!

Hmm? Not quite ready for that yet! The reed switch failed again. So its back to voltage dependant chuffing - which isn't quite right on this loco. The voltage which makes it start to move is load dependant which doesn't quite work. Part of the problem is that the reduction ratio on the worm and wheel is insufficient. So for example another loco with the same batteries, same motor and radio receiver will start a heavy test load but this one will not. It just causes the electronic fuse to cut the power. Not really satisfied with that - I know it could pull more and I think I am overloading the motor.

I modified the drive to incorporate a 3:1 reduction using plastic spur gears - but that was incredibly noisy - but it solved the other problems. I'm now trying metal gears with a 2:1 reduction to see how noisy they are.

So I am working to change the gear ratio to improve the starting. I think it will make starting less load dependant - and that looks to be important if I can't get the reed switch to work reliably.

I have also got reed switches from another source (not eBay!) which I hope will prove more reliable. That is about to be tried as well.

So I will try video when It works properly.

Trevor

I hope you manage to sort out the gearing, Trevor. It's such an attractive looking loco, it will be great to see it steaming through the garden scenery.

I'm impressed with the 3D printed motion. I did wonder about using the resin printer for the motion on my cardboard Hunslet but in the end I've gone for a mix of filament and brass. I was concerned that the resin might be too brittle.

Rik