Osborn’s Models Exclusives, TT 1:120 “Arch Laser”

[luke_stevens]

Osborn's Models have started to produce a range TT120 parts and laser cut kits.

[luke_stevens]

Yesterday I ordered and today I received (v.impressive speed of service) one of their Syphon G kits

 

ALTT OCWW 080 TT Scale 1:120 GWR Siphon G.

 

First Thoughts:

 

This is a "serious" kit. It looks to be well designed and neatly produced. It comes in a flat box (pic 1) and has several laser cut frets, of different thicknesses to better capture the porotype (pic 2). There are also turned brass buffers and a rather natty painting mask. I'll be doing mine in BR blue so won't be using the mask which designed for the GW chocolate brown Freight livery.

 

I have attached a photo of the instructions (Pic 3). I hope Osborn's Models don't mind me posting this but I think it is a good indication of the thought and effort that has been put into the kit.

 

Pic 1

 

Pic 2


 

Pic 3

 

Edited March 25, 2023 by luke_stevens

[luke_stevens]

Some point in the early 80's I read a quote for an American Railroad modeller (I think it was John Olson) that said "No one was ever shot for not following the instructions, just for not reading them". So having read the instructions several times I decider to not follow them... My reasoning was that I haven't had much experience of this kind of laser cut kit before so I'd rather start with a piece that is less significant that the bogies: I began with the brake cylinder. The instructions suggest a strong PVA and / or superglue. As I'd already purchased a bottle of the Deluxe Materials Laser Cut Kit Glue I chose to use that. The brake cylinder went together ok and after a few minutes it had cured enough that I could gently smooth out the surface using a medium course sanding strip (Albion Alloys). I believe the prototype is metal so the banded wood grain wasn't going to be authentic. 

 

Pic 1
 

 

The rest of the chassis parts pretty much fell together as you'd expect. The truss rods fitted neatly as did the v-hangers. The holes for the battery boxes are too deep and they are loose so I backed them with a spare piece of fret to hold them a little more firmly. When gluing the bogie bolsters in place I supported them into the holes using a cocktail stick that was quickly removed so it didn't get stuck... 

 

Initially I'd been using the needle point applicator that came with the Deluxe Material glue. In pic 2 you can see the clearing pin became stuck and the complete applicator came loose. I continued by placing a large drop of glue on the packaging and using the pin embedded in the needle as an applicator. I applied glue to one surface of a part leaving the mating surface clear. It is important to make sure that nothing protrudes below the upside down floor level or the body won't sit flush to the floor.

 

Pic 2

 

 

I missed a trick with the bufferbeams. I should have checked the holes for the buffers to make sure they were the correct size for a push fit. That would have been easier to do _before_ I fitted the bufferbeam to the underframe. 

 

There are a couple of odd things I've noticed. The v-hangers have holes for a cross beam and the body fret has holes for door handles. Nothing is provided. I'm going to dig up some brass wire to do those jobs but I'm surprised no reference is made to these, beyond a cryptic reference in the initial painting to "pick out the handles"...

Edited March 25, 2023 by luke_stevens

[Ravenser]

Link to the website list of kits here:

 

Arch Laser kits

 

All GWR but good to see the first rolling stock kits available for this scale. There is an autocoach - all the other rolling stock kits are wagons

 

Wheels and turned brass buffers also available

 

Edited March 25, 2023 by Ravenser

[luke_stevens]

As I've kept going with the bogies I've been struggling to get things to go together smoothly. My first assumption was that i was getting it wrong, but then I went and found some actual photos and things became clearer.

 

Reference pic in picture below https://upload.wikimedia.org/wikipedia/commons/b/b2/GWR_"American"_type_equalised_bogie_(6901708506).jpg

 

The helical springs in the kit are the same length as the axle boxes and that is too long (pointed to with the cocktail stick)

 

 

For the 3rd and 4th bogie side frames I will trim them down.

 

And the wheels are just too wide to fit between the frames. Nothing that a sanding stick can't fix!

 

 

But that is a job for tomorrow...

 

Final pic, all the bits of the bogie before I realised what was wrong...

 

 

[natterjack]

Thanks for the introduction to this range.

 

I use a fair bit of laser cut ply and usually use sanding sealer to fill the grain while still on the fret (HMG or home brew of non shrink dope and tac- Halfords filler primer also works well but avoid anything water based).

 

 

[luke_stevens]

8 minutes ago, natterjack said:

 

I use a fair bit of laser cut ply and usually use sanding sealer to fill the grain while still on the fret (HMG or home brew of non shrink dope and tac- Halfords filler primer also works well but avoid anything water based).

 

 

I was wondering about the grain. My concern with things like the Halfords primer is how fine the laser cut parts are: the bogie is scarcely an inch long. 

 

I'll keep people informed :)

 

Luke

[britishcolumbian]

Thanks for these informative posts. I found out about these kits a few days ago and have been eyeing them, looks like I'll order some once I'm back home from Hungary. Just need to figure out which cars A) lasted the longest post-nationalisation, and B) are likeliest to have been seen around Yeovil.

[natterjack]

58 minutes ago, luke_stevens said:

My concern with things like the Halfords primer is how fine the laser cut parts are: the bogie is scarcely an inch long. 

Many of my laser cut ply parts are smaller. I sand the  frets  after grain filling - just lay the fret on a flat hard surface and use something like the cheap sanding sponge blocks (dry, not wet) in a gentle circular motion . In fact any well filled paint will do the trick and one of my fall-backs is blackboard enamel-(but it takes an age to dry).  Just avoid anything  water based on the finished surfaces or the grain will instantly reappear.

 

A little trick I use in my drawing for laser cutting is an extra 0.05mm all round, that is an addition to all outer lines and what amounts to a reduction to inner holes; much like metal etching, laser cutting will reduce  outer dimensions and enlarge any holes. The 'extra' results in snug fitting joints regardless of material thickness for this sort of application.

[nick_bastable]

I would refer you to this  https://www.rmweb.co.uk/topic/52798-bath-queen-square/page/25/#comment-3380792   about half way down the point been

 

Next up is priming and rubbing down before attaching the overlays, this is crucial as painting lifts the grain on the ply leaving a furry, grainy surface.I didn't do this on the original one I built and rubbing down the grain with the overlays in place was a real pain. I drilled a hole in the middle of the floor and mounted the body on a cocktail stick. Quick spray with Halfords primer, allow to dry, rub down with fine wet and dry and repeat.

 

25mm bogie I have laser cut and used them in n6.5 @ 12mm  although I did add bearings

[Moxy]

4 hours ago, britishcolumbian said:

Thanks for these informative posts. I found out about these kits a few days ago and have been eyeing them, looks like I'll order some once I'm back home from Hungary. Just need to figure out which cars A) lasted the longest post-nationalisation, and B) are likeliest to have been seen around Yeovil.

 

I can't answer part B, because I know nothing about the Yeovil area, but I might be able help with part A.

 

Fruit D & Siphon G lasted into at least the 1960's in general traffic, and even into the 1980's in departmental use.

 

Some of Paul Bartlett's photos here

 

Fruit D

Siphon G

[Ravenser]

9 hours ago, Moxy said:

 

I can't answer part B, because I know nothing about the Yeovil area, but I might be able help with part A.

 

Fruit D & Siphon G lasted into at least the 1960's in general traffic, and even into the 1980's in departmental use.

 

Some of Paul Bartlett's photos here

 

Fruit D

Siphon G

 

All but one of the Siphon G photos are inside framed/matchboarded vehicles. Just one outside framed Siphon - noted as condemned in 1957

 

A few GW brake vans survived in Engineers use  into the mid 80s

Edited March 26, 2023 by Ravenser

[luke_stevens]

On going progress...

 

 

It looks good, though there are a couple of issues I had to deal with. Drawings to follow :)

 

Luke

[luke_stevens]

15 hours ago, natterjack said:

Many of my laser cut ply parts are smaller. I sand the  frets  after grain filling - just lay the fret on a flat hard surface and use something like the cheap sanding sponge blocks (dry, not wet) in a gentle circular motion . In fact any well filled paint will do the trick and one of my fall-backs is blackboard enamel-(but it takes an age to dry).  Just avoid anything  water based on the finished surfaces or the grain will instantly reappear.

 

Do you prime both sides of the piece? If so what do you use to glue things together. I assume wood glue will no longer be any use.

 

15 hours ago, natterjack said:

A little trick I use in my drawing for laser cutting is an extra 0.05mm all round, that is an addition to all outer lines and what amounts to a reduction to inner holes; much like metal etching, laser cutting will reduce  outer dimensions and enlarge any holes. The 'extra' results in snug fitting joints regardless of material thickness for this sort of application.

 

Yes, I've found that the "cuts" are not vertical. All the pieces seem to be trapezoid! 

[luke_stevens]

13 hours ago, nick_bastable said:

 

25mm bogie I have laser cut and used them in n6.5 @ 12mm  although I did add bearings

 

 

Which bearings did you use and where did you get them from?

[nick_bastable]

42 minutes ago, luke_stevens said:

 

Which bearings did you use and where did you get them from?

standard 2mm top hat bearings from  the 2mm Association  

[natterjack]

46 minutes ago, luke_stevens said:

Do you prime both sides of the piece? If so what do you use to glue things together. I assume wood glue will no longer be any use.

Depends what you use; acrylics and shrinking dope (of course) will both contract on drying so would need to be both sides; those I've suggested above I get away with one side. Wood glue will still work after rubbing down but I tend to use either aliphatic glue , Gorilla Crystal Clear (for convenience) or twin pack epoxy. Super glues also work very well but for some reason I have found the usual pva wood glues prone to delamination with laser grade ply and also pretty useless with mdf.

 

57 minutes ago, luke_stevens said:

Yes, I've found that the "cuts" are not vertical. All the pieces seem to be trapezoid! 

Laser cuts are focused on the bottom of the sheet to be cut and that produces a slight but appreciable cone and chamfered edge up to the top surface. For that reason, I design my frets with the required outer finishes on the bottom. this is especially noticeable in the 2 and 3mm sheet I regularly use.

[Porfuera]

19 hours ago, luke_stevens said:

And the wheels are just too wide to fit between the frames. Nothing that a sanding stick can't fix!

 

 

 

That looks like quite a tight fit, even with sanding.

 

I was wondering whether the wheelsets are overwidth or maybe the back-to-backs are correct but the tyres are too wide (obviously the tyres are not to scale), something like that.

 

Is it possible for you to check the wheelsets against other TT:120 rolling stock to see how they compare? Failing that, maybe against some track?

 

Maybe the bogies are the correct scale width but need to be slightly overscale to allow for the out-of-scale tyre width.

[natterjack]

2 minutes ago, Porfuera said:

I was wondering whether the wheelsets are overwidth or maybe the back-to-backs are correct but the tyres are too wide (obviously the tyres are not to scale), something like that.

FWIW the Romford 4mm scale wheels (EM profile?) i am using in my TT120 GG-1 conversion are narrower and with slightly shallower flanges than the Tillig wheels they replace. I think the makers of this kit indicate the wheels are from Europe, so Tillig seems a fair bet.

[luke_stevens]

59 minutes ago, Porfuera said:

 

Is it possible for you to check the wheelsets against other TT:120 rolling stock to see how they compare? Failing that, maybe against some track?

 

 

Will do when I'm home.

[luke_stevens]

2 hours ago, Porfuera said:

 

I was wondering whether the wheelsets are overwidth or maybe the back-to-backs are correct but the tyres are too wide (obviously the tyres are not to scale), something like that.

 

Wheel face to wheel face = 14.6mm

Inside frame unsmoothed 14.5mm

Once I've squared up the edges it closer to 14.3mm.

 

I can work with that though it will require the side frames to be perfectly vertical with little available slop which isn't great.

 

2 hours ago, Porfuera said:

Is it possible for you to check the wheelsets against other TT:120 rolling stock to see how they compare? Failing that, maybe against some track?

 

 

Tillig wheel face to wheel face = 15.0mm

Piko wheel face to wheel face = 15.0mm

 

Visually the wheels provided with the kit are finer looking than the Tillig or Piko wheels (I can't find my Roco TT120 wagon at the moment)

 

[luke_stevens]

2 hours ago, natterjack said:

Depends what you use; acrylics and shrinking dope (of course) will both contract on drying so would need to be both sides; those I've suggested above I get away with one side. Wood glue will still work after rubbing down but I tend to use either aliphatic glue , Gorilla Crystal Clear (for convenience) or twin pack epoxy. Super glues also work very well but for some reason I have found the usual pva wood glues prone to delamination with laser grade ply and also pretty useless with mdf.

 

I have aliphatic glue to hand.

 

So planned line of attack:

Spray the frets with Tamiya lacquer,  via an airbrush to control the spray fineness. Both sides of the side frets.

When dry fine sand a respray

Repeat the process for the coach ends.

Glue the inner sides to the body carcass.

Glue the outersides to the body carcass

 

Make sense? 

 

2 hours ago, natterjack said:

 

Laser cuts are focused on the bottom of the sheet to be cut and that produces a slight but appreciable cone and chamfered edge up to the top surface. For that reason, I design my frets with the required outer finishes on the bottom. this is especially noticeable in the 2 and 3mm sheet I regularly use.

 

Thanks for info. This becomes very clear with parts this small!

 

Luke

[natterjack]

21 minutes ago, luke_stevens said:

When dry fine sand a respray

If there is any further laminating to do I would miss the respray at this stage as the alphatic  needs some porosity for a bond. If you have any to hand, a touch of thin superglue around exposed bonded edges is useful belt and braces security and helps in the final paint finish- those edges can really soak up paint, probably as they are something akin to charcoal after the laser treatment.

[luke_stevens]

4 hours ago, Porfuera said:

 

That looks like quite a tight fit, even with sanding.

 

 

There is, of course, a much easier option: cut away that part of the brake shoe frame. In the centre it still supports the sideframes, at the far end attach the brake shoe to the subframe and brace. Result: no rubbing, tight clearance or binding. And no need for delicate filing!

 

Luke  

Edited March 26, 2023 by luke_stevens

[Porfuera]

14 hours ago, luke_stevens said:

 

Wheel face to wheel face = 14.6mm

Inside frame unsmoothed 14.5mm

Once I've squared up the edges it closer to 14.3mm.

 

I can work with that though it will require the side frames to be perfectly vertical with little available slop which isn't great.

 

 

Tillig wheel face to wheel face = 15.0mm

Piko wheel face to wheel face = 15.0mm

 

Visually the wheels provided with the kit are finer looking than the Tillig or Piko wheels (I can't find my Roco TT120 wagon at the moment)

 

 

I measured the wheels of one of my Hornby tank wagons this morning and the face-to-face measurement was also 14.5-14.6mm which is the same as those you have in the kit.

 

13 hours ago, luke_stevens said:

 

There is, of course, a much easier option: cut away that part of the brake shoe frame. In the centre it still supports the sideframes, at the far end attach the brake shoe to the subframe and brace. Result: no rubbing, tight clearance or binding. And no need for delicate filing!

 

Luke  

 

Sounds like you have found a good solution.

 

I was wondering about the coupling height since it appears to be mounted on the bogie rather than the body but from your photo it looks like it will be more or less at axle height, which is where they are on the Hornby wagons so that should work well.

 

It is all looking very good and I'm looking forward to seeing more of your progress. I'm tempted to buy a Fruit C or a Fruit D!