Scratchbuilding trial, using aluminium
Posted 12 April 2018 - 22:28
Usually, it won’t bond, because the aluminium carries an oxide layer on the surface, but if you break that layer, it will. The trick is to scratch-brush it using a brass brush (a cheap suede shoe brush is perfect) then tin both surfaces that are to be mated, while continuing to scratch-brush through the wet solder, so that the solder gets into direct contact with fresh, unoxidised, metal. Once the surfaces are tinned, you can then solder the parts together normally. Needs a fair bit of heat to keep the tinning solder wet while you scratch-brush.
Try it on some scrap.
Posted 13 April 2018 - 01:15
Many moons ago I worked in a tin can factory, and had access to as many sheets of plate as I wanted. Never took the opportunity, but your thread has reminded me.
The 'tinplate' came in various forms depending on the food or beverage that it was destined for. Long time ago now but as I recall, different types of plate served different uses.
Most of it was steel (sometimes plated, sometimes not) and there was also aluminium.
What all these had in common was that at least one side was lacquered, I think the norm was both sides but the lacquer varied. Again, depending on its intended use. For example, Coke would presumably be more acidic than baked beans, thus a different lacquer was used.
I'm intrigued to find out if the plate you have access to is lacquered or sealed in some way.
Obviously if it is, this would affect soldering and perhaps paint and adhesives, although clearly it also offers corrosion protection (and especially so if it were steel).
Hope that's of use.
Posted 13 April 2018 - 10:22
Yes one side is clean shiny metal, which doesn't seem to oxidise, although being aluminium it undoubtedly is. The other side an interesting photo-reactive agent; when exposed to a UV light the surface becomes pale grey and water adherent, when not exposed it becomes deep blue and oil adherent, thus picking up oil-based ink to transfer it onto the paper. Or, as we call it in the trade, witchcraft.
So far the coated side seems to stick to the superglue better than the bare metal, and also accepts acrylic paint nicely too, but ultimately I am going to spray with car-primer anyway. Although I am also going to try printing paper labels to stick onto the flat surface as an interesting trial (see Nearholmers' post further up).
Posted 14 April 2018 - 21:13
I’ve cut ... things (W-irons?) out of ali and folded them round to make brackets for the brass axle-boxes.
I’m really paranoid about losing the little brass ends, but I don’t want to glue them in as this is just a trial.
Then tack the both of them, carefully measured distance apart. 63mm between axles centres, right guys?
It occurred to me AFTER I’d done all this that I should use a single piece, joined together for a fixed distance AND to ensure it’s all parallel.
And carefully I rest it upwise on the track... and it wobbles! Well not too badly, but room for improvement haha!
Posted 14 April 2018 - 22:29
Finally I was worrying about the couplings I’ve made, being folded aluminium filed into a hook shape and glued on the front. Too much tension and the glue might fail. So I got a bit of iron wire and bent it into shape, hammered flat and filed a bit, through a hole in the buffer beam, a sharp angle and glued to the subframe. It’s a lot stronger but a bit overscale. Maybe I’ll use thinner wire on the next one?
Or try soldering the ali hooks in place?
Edited by Thunderforge, 14 April 2018 - 22:46 .
Posted 15 April 2018 - 20:18
It’s not often these days that someone has a bash at something in a truly original way, and you have.
Whether, in the fullness of time, aluminium will, in sheet form, prove to be a good material for railway modelling, I rather have my doubts, but ‘hats off to you’.
Cast aluminium is a good material for commercial models, of course, with zillions of Hornby Dublo stations continuing to prove that point.
Posted 15 April 2018 - 22:41
I never have any money and 7mm looks impossibly expensive at first glance, especially compared to what you can pick up in OO scale! But I thought I’d see how much I can do myself and I’m doing good so far. Ideas include making resin cast wheels and pinching smoke units out of cheap toy trains.
I’m drawing the pattern pieces up on the computer so I can print out these aluminium plates with the templates already on them. Initially to help myself by not having to redraw them, but if anyone is interested I could probably do a copy for a couple of quid.
Posted 17 April 2018 - 21:04
A signal happened today. I tried to use aluminium for the post, but it split when I tried to crease it, so I used card. Then glued a large nail up the bottom (!) and glued that to a two pence piece. The signal itself is two layers of aluminium with a layer of clear plastic sandwiched between them. I’ll paint the circles green and red (or whatever the correct colours are). The signal arm is glued onto a thin nail which pokes through the post. A trip to the charity shop tomorrow will hopefully result in some round beads so I can finish the top.
The question is, do I hang it with washing?!
Edit: it does look rather small compared to my wagons, but it’s roughly 21feet, which would have had a four foot signal arm. Maybe next time I’ll make a bigger one. Although if I make too many signals I’ll need to make a turnout to justify having them- eeek! Scary!
Edited by Thunderforge, 17 April 2018 - 21:15 .
Posted 05 May 2018 - 21:43
Painted using acrylics and washes, then weathered with hairspray ‘n’ chalk pastels, something I’ve never tried before.
The canvas covered load is just bits of wood under some tissue paper coated in PVA and paint.
I think I’ll file the coupling hook rounder, it looks worse on this wagon because there’s less wagon there to hide it.
But I’m jolly happy with a wagon which has only cost me the wheels! :-)
Posted 06 May 2018 - 21:39
I’ve never been very neat with hand lettering, so I spent an hour carefully cutting a stencil for the arc, which bled so much that 90% of it is repainted anyway. You live and learn...
Posted 06 May 2018 - 21:53
A tip I was given many years ago by the late Malcolm Parker of the Model Railway Club was to use flattened toothpaste tube metal for angle iron and strapping on O gauge wagons. It is sof enough to bend round corners and punch rivet detail into. The only trouble is I don't know if anyone still makes toothpaste in metal tubes.
It seems like you have a niche in producing replica tinplate style wagons. Good luck with the aluminium modelling!
Posted 16 May 2018 - 22:19
So I switch the wheels back to the first wagon and they sit perfectly on the rails!
I assume Richard Trevithick never suffered from problems like this. Also he wasn’t using a material which has the structural integrity of damp cardboard.
Still, at least I have two wagons which sit flat and run smoothly, even if one of them isn’t the nicely painted box van.
On a more positive note I have hit upon the idea of removable loads with the aid of a magnet hidden in the top. I can use my uncoupling device to hoik out the load quickly and easily. The magnets came from an old phone case, the coal load is styrene and bits of gravel.
I’ve started making a load of covered hay (painted fur wrapped around a styrene block), I’ll take some more photos when I get round to it.
Jim Read has kindly let me have instructions for his home-made locomotive and controller, I’ve ordered some parts so watch this space! :-)
Edit: horn blocks probably wouldn’t work on a wagon, I think the axle boxes would be too small to hide them. I thought about increasing the height of the holes the wheel bearing sit in, to give them some vertical play, but I can’t help thinking that it’s a Bad Idea.
Edited by Thunderforge, 16 May 2018 - 22:38 .