A Tale of Two Serpents
- Thread starter RichardG
- Start date
Dog Star
Western Thunderer
First, you need to use an organic cleaning agent to remove grease and fingerprints (cellulose thinners is recommended) and second an inorganic acid to remove the oxide layers (carrs acid etch).
Your description of the retaining tackle fits nicely with the origins of the CPL parts. I have a GWR dwg for the screw link adjuster and the title of the drawing includes the words "for binding chains". I provided a copy of that dwg to Pat Legg who arranged for the lost wax patternsto be masteredby the lat Tony Reynalds. So this detail of your model is beyond reproach.
Rgds, Graham
Your description of the retaining tackle fits nicely with the origins of the CPL parts. I have a GWR dwg for the screw link adjuster and the title of the drawing includes the words "for binding chains". I provided a copy of that dwg to Pat Legg who arranged for the lost wax patternsto be masteredby the lat Tony Reynalds. So this detail of your model is beyond reproach.
Rgds, Graham
magmouse
Western Thunderer
Thanks Graham. I just looked up the price of Carrs Acid Dip on the Precision Paints website - £7. Ouch. I then looked up the postage - £7.50. Double ouch. Then, I looked in the dusty drawer of modelling materials I inherited from my Dad - two bottles of acid dip, one hardly used, the other full. Nice. And as a bonus, a couple of bottles on Brass Black.
Thank you. You may have forgotten that it was your suggestion to use the CPL parts in the first place ....
Thanks, Richard - I might do a test with that as well. I've found the Birchwood Casey brass black to be rather unreliable, and never quite worked out if that's down to my technique or the product itself. I have the gun blue in stock also, so I can do a comparison.
Nick.
Rob Pulham
Western Thunderer
I find that gun blue works even better if the subject to be blackened, is warmed before you apply the gun blue. I just give the object a blast with an old hair dryer that I keep in the workshop for such things* I have only tried it with Birchwood casey but I suspect other brands may react better too on a warmed subject.
*Those who know me will know that I have no need of such a thing for my head
...
*Those who know me will know that I have no need of such a thing for my head
...
simond
Western Thunderer
Apropos the acid wash, Citric acid powder is cheap & easily available, you can use it for sterilising brewing equipment and it’s non toxic in limited quantity - it is Vitamin C.
You can also use it as a soldering flux. It washes off with water, and leaves no residue.
Indeed, it reminds me of the Wompon.
You can also use it as a soldering flux. It washes off with water, and leaves no residue.
Indeed, it reminds me of the Wompon.
magmouse
Western Thunderer
Thanks, Rob - warming makes sense to accelerate the chemical reaction.
New bump stops (Nick)
New
magmouse
Western Thunderer
Blackening the chain and shackle assemblies was mostly successful. I dunked them in some MEK, followed by an hour in Carr's Acid Dip. After a wash and dry, they went into Carr's Brass Black. The chain wanted to blacken more slowly than the cast brass parts, and by the time it was dark enough, the cast brass was a bit 'over cooked' and has flaked off a bit in places. It's good enough, though - once the load is attached and the chains are in position, I can touch up the odd glint of metal with paint.
I printed some bump stops for the bearing springs (is there a proper name for those?) with the Bambu A1 Mini printer, using the 0.2mm nozzle:
Fitted and painted:
With this level of magnification, a resin printed part would look slightly more refined, but they're fine with normal human vision!
The floor is attached - stuck down with a smear of epoxy resin. I did an initial weathering job on this with a wash of Indian ink, diluted in IPA. Some grey weathering powder will tone this down a little when the general weathering is done later. The two metal strips that protect the floor edge are 1mm x 0.2mm nickel silver strip, pre-painted and stuck on with 'tacky glue' - a white glue that is stickier than PVA, as its name implies. I wanted something that wouldn't set too fast, and which I stood a reasonable change of cleaning up if I made a hash of it. I've since added a spot of thin cyano at each end to add strength.
Next up - lettering. I've done a preparatory coat of acrylic satin varnish, just on the face of the solebars - hopefully enough to prevent any silvering.
Nick.
I printed some bump stops for the bearing springs (is there a proper name for those?) with the Bambu A1 Mini printer, using the 0.2mm nozzle:
Fitted and painted:
With this level of magnification, a resin printed part would look slightly more refined, but they're fine with normal human vision!
The floor is attached - stuck down with a smear of epoxy resin. I did an initial weathering job on this with a wash of Indian ink, diluted in IPA. Some grey weathering powder will tone this down a little when the general weathering is done later. The two metal strips that protect the floor edge are 1mm x 0.2mm nickel silver strip, pre-painted and stuck on with 'tacky glue' - a white glue that is stickier than PVA, as its name implies. I wanted something that wouldn't set too fast, and which I stood a reasonable change of cleaning up if I made a hash of it. I've since added a spot of thin cyano at each end to add strength.
Next up - lettering. I've done a preparatory coat of acrylic satin varnish, just on the face of the solebars - hopefully enough to prevent any silvering.
Nick.
magmouse
Western Thunderer
I'm going to wait until tomorrow before doing lettering, to let the varnish harden. It occurred to me it would be good to be able to position the chocks correctly, to them do the securing pins, before weathering. This means knowing where the wheels of the planned load will come.
I dug this out of the Cupboard of Possibilities - the planned load:
The first step is to build up the main body - this is a single etched part, which folds to make the rectangular shape:
Looks okay, doesn't it?
Except - the fold lines are partly half etched, and partly etched through, in a 'dotted line' pattern. You can see an unfolded line at the top, and a folded and soldered one at the bottom of the side:
So you get a weird dotted edge. Am I expected to fill that? How? Or file it to an unprototypical chamfer?
The same on the corners:
And the back corner:
And what are those chain-dotted lines running across the doors?
While we are at it - there's a huge gap in the two panels that make up the front:
The instructions say "if there's a gap, fill it with a piece of wire". If? IF???? Clearly the designer knew perfectly well there would be a gap, and instead of modifying the artwork, wrote a line in the instructions.
And one other thing - the foot steps fold from an inner end and go through slots in the outer face of the end - a familiar way of designing these:
Seriously - how am I expected to fill all that space around the steps and make a decent job of it?
So - plan B. I'll use the supplied castings and perhaps one or two of the etched parts, but do the main build from plasticard. It's pretty much a box, with the slight complication of the wheel arches, but really a straightforward thing to make in styrene. I can use the kit etches as a template.
Another £35 badly spent!
Anyway, I'm slowly regaining my equanimity, and there are many worse things in the world than a shoddy kit, especially right now, so onwards and upwards.
I'll make enough of the kit to work out where the wheels will land on the wagon, and stick it back in the cupboard for another day.
It seems the Serpent has allies....
Nick.
I dug this out of the Cupboard of Possibilities - the planned load:
The first step is to build up the main body - this is a single etched part, which folds to make the rectangular shape:
Looks okay, doesn't it?
Except - the fold lines are partly half etched, and partly etched through, in a 'dotted line' pattern. You can see an unfolded line at the top, and a folded and soldered one at the bottom of the side:
So you get a weird dotted edge. Am I expected to fill that? How? Or file it to an unprototypical chamfer?
The same on the corners:
And the back corner:
And what are those chain-dotted lines running across the doors?
While we are at it - there's a huge gap in the two panels that make up the front:
The instructions say "if there's a gap, fill it with a piece of wire". If? IF???? Clearly the designer knew perfectly well there would be a gap, and instead of modifying the artwork, wrote a line in the instructions.
And one other thing - the foot steps fold from an inner end and go through slots in the outer face of the end - a familiar way of designing these:
Seriously - how am I expected to fill all that space around the steps and make a decent job of it?
So - plan B. I'll use the supplied castings and perhaps one or two of the etched parts, but do the main build from plasticard. It's pretty much a box, with the slight complication of the wheel arches, but really a straightforward thing to make in styrene. I can use the kit etches as a template.
Another £35 badly spent!
Anyway, I'm slowly regaining my equanimity, and there are many worse things in the world than a shoddy kit, especially right now, so onwards and upwards.
I'll make enough of the kit to work out where the wheels will land on the wagon, and stick it back in the cupboard for another day.It seems the Serpent has allies....
Nick.
Tony Overton
Western Thunderer
Mmmmm, I'm depressed now. I've one of those kits in my stash. Looks like the etches might as well stay there......... I look forward to seeing Nick's replacement body.
Tony
Dog Star
Western Thunderer
And if you are thinking of a styrene body.... then so do we. Model Railway Journal, issue 7, 1986, has a relevant article by Essery, Twells and Peascod. This is about building a 7mm pantechnicon and MR open carriage truck.
Rgds, Graham
magmouse
Western Thunderer
Overseer
Western Thunderer
Milliput would be my go to to fill the holes and all the corner joints. Shouldn’t take too long.
magmouse
Western Thunderer
For the corners, that might work. Around the steps - tricky to smooth that back, because of the raised panel mouldings - you can't get a file to the panel surface. And that's even worse with the gap between the two halves of the front end.
I've decided to prepare the castings for the wheels and undercarriage parts, and do a temporary assembly. That will allow me to get the wagon chocks in the right place. I can decide how to finish the pantechnicon after that.
Nick.
magmouse
Western Thunderer
No progress on the lettering - but I have done enough of the underpinnings of the pantechnicon to use the wheel spacing to position the chocks:
I was also able to determine two other things:
Nick.
I was also able to determine two other things:
- The pantechnicon is within the GWR 1899 loading gauge (Historical Loading Gauges on british railways), though only just, and
- there's a hole missing on the top of the sides (top right in the above picture). Good grief...
Nick.