S
Simon Dunkley
Guest
Plastikard Coaches for Banavie Road
Very impressive, Jim.
How long is it now taking per side?
Very impressive, Jim.
How long is it now taking per side?
Re: Rolling Stock for Banavie Road
- Thread starter JimG
- Start date
JimG
Western Thunderer
Plastikard Coaches for Banavie Road
I managed to do a bit of messing around over the weekend in between taking grandson sailing and doing maintenance on my own dinghy while the weather was good. But I got a floor cut on the mill from 60 thou Plastikard and also cut the partition strip from 40 thou to the same width. I had milled the coach ends but found that I had c*cked up on the thicknesses when I started putting things together so had to mill a new set to the correct thicknesses.
The ends fit inside the sides and the join is along a panelling line, so fairly easily disguised and a lot easier than attempting 45 degree mitre type joints. I did find one problem. The moulded sides and ends actually belly out a bit at the top of the tumble home. I had thought that might be the case when I took them out of the mould and my thoughts were confirmed when I started putting the sides and ends together. I suspect that I will have to extend the width of the upper clamp down to the top of the tumblehome to stop this happening. I suspect there is some differential heating going on due to the latent heat in the chunk of alloy and that the sides are springing off the mould. One side was worse than the other.
Here's a pic of the coach so far with all sides and partitions fitted...
There are also inner ends to support the milled ends - you can see them in the pic - at least the shadow of the one on the nearest end.
So I'll do the mods to the mould and start on doing something about the roofs. At least they are simple arc roofs, so no worries with complex ellipses.
[Simon]
I did speed up the milling processes, but with adding a surfacing cut in my new way of doing things, my speeds have gone back to where they were.
So it is still taking me about two hours to cut a pair of sides. I tried to get these times down by further increasing feed and speeds but started getting occasional problems of surface marking, probably due to the flexibility of the styrene sheet and also the low tack adhesive strength of the holding materials - both Multimat and the Letraset tape. So I've settled on my present speeds which seem to work well and it is a start and walk away operation so the longish times are not too much of a problem when I can do something else while the cutting is going on.
Apologies for the picture quality. You would expect that digital cameras would improve as time goes on, but my experiences don't agree. My old Fuji S5500 worked very well and gave good, sharp pictures but I decided to "upgrade" to an S2800 a year or so ago to give me a bigger pixel count. But the picture quality is really not good, except in bright sunny days exterior. The zoom lens is rubbish - witness the internal reflections on the above picture - and all manufacturers seem to be hell bent on getting the longest zoom possible and to hell with the picture quality. It's not only Fuji - I see from reviews that other manufacturers are going down the same road. I'm going to have to get another camera - I've had it up to here with this S2800 - but it seems like my choice is picking the best of a bad bunch.
Jim.
I managed to do a bit of messing around over the weekend in between taking grandson sailing and doing maintenance on my own dinghy while the weather was good. But I got a floor cut on the mill from 60 thou Plastikard and also cut the partition strip from 40 thou to the same width. I had milled the coach ends but found that I had c*cked up on the thicknesses when I started putting things together so had to mill a new set to the correct thicknesses.
The ends fit inside the sides and the join is along a panelling line, so fairly easily disguised and a lot easier than attempting 45 degree mitre type joints. I did find one problem. The moulded sides and ends actually belly out a bit at the top of the tumble home. I had thought that might be the case when I took them out of the mould and my thoughts were confirmed when I started putting the sides and ends together. I suspect that I will have to extend the width of the upper clamp down to the top of the tumblehome to stop this happening. I suspect there is some differential heating going on due to the latent heat in the chunk of alloy and that the sides are springing off the mould. One side was worse than the other.
Here's a pic of the coach so far with all sides and partitions fitted...
There are also inner ends to support the milled ends - you can see them in the pic - at least the shadow of the one on the nearest end.
So I'll do the mods to the mould and start on doing something about the roofs. At least they are simple arc roofs, so no worries with complex ellipses.
[Simon]
I did speed up the milling processes, but with adding a surfacing cut in my new way of doing things, my speeds have gone back to where they were.
So it is still taking me about two hours to cut a pair of sides. I tried to get these times down by further increasing feed and speeds but started getting occasional problems of surface marking, probably due to the flexibility of the styrene sheet and also the low tack adhesive strength of the holding materials - both Multimat and the Letraset tape. So I've settled on my present speeds which seem to work well and it is a start and walk away operation so the longish times are not too much of a problem when I can do something else while the cutting is going on.Apologies for the picture quality. You would expect that digital cameras would improve as time goes on, but my experiences don't agree. My old Fuji S5500 worked very well and gave good, sharp pictures but I decided to "upgrade" to an S2800 a year or so ago to give me a bigger pixel count. But the picture quality is really not good, except in bright sunny days exterior.
The zoom lens is rubbish - witness the internal reflections on the above picture - and all manufacturers seem to be hell bent on getting the longest zoom possible and to hell with the picture quality. It's not only Fuji - I see from reviews that other manufacturers are going down the same road. I'm going to have to get another camera - I've had it up to here with this S2800 - but it seems like my choice is picking the best of a bad bunch. Jim.
JimG
Western Thunderer
Spurred on by the coach building thread, I've picked up on the Caledonian coaches again. I last worked on them in September when I used a trial underframe for one as a test bed for sprung axleguards for an article in the S scale Gazette. Just previous to that, I had had another go at making an arc roof to fit on the bodies. I had made one a month or two earlier and used the laminate method with thin Plastikard sheet but it had not been a success. With this second attempt, I reckoned to let the roof season for some months so that I know that it would not distort after time, and so far it has stayed the way it was built. I still used the laminate method, but just two sheets of thicker material rather than four sheets of thinner material. Here's the roof on the first class coach which is perched (not too squarely!!) on the trial underframe.
However, the real elephant in the room was the construction of the birdcage style brake ends on the brake thirds. I had also done some sides for Scott Willis who is is building the NBR versions of Drummond's design and we had an exchange of ideas as to how we could achieve a good result. It was Scott who came up with the idea of a Perspex inner structure to stick the Plastikard sides to which would also act as the glazing. So I started with a go at a frame using 2mm Perspex sheet.
The front and rear frames are in the middle with the spacers to the right. I re-cut the Plastikard sides for the test.
The Perspex bits made up into the former like so
However, I let Scott see this picture and we both reckoned that the two vertical spacers would be visible througn the windows so it was back to the drawing board to change to one vertical spacer.
With the new parts in the foreground which made up into this
with its "two former" predecessor in the background. I glued the Perspex with Butanone - my 35 year old MekPak wouldn't look at it. I then tried a test assembly with the sides with varied degrees of success.
The ducket sides are supposed to fit between the ends such that the thickness of the end pieces becomes the end panelling on the sides. This worked quite well on the upper panelling, but getting the compound curves correct on the lower rear edges was a bit of a fight and I'm going to have another think about improving that. I had also developed the 2D sides to account for the S curve of the duckets and over-cooked it such that they were about 0.75mm too long - hence the untidy tops and bottoms. I also got one glue stain on the windows but that was just due to a bit of clumsiness on my part. The Butanone wicked nicely under the Plastikard and didn't intrude into the glazing area. If I can't get brown or dark Plastikard, then I will have to find some way of disguising the inner side since it sticks out like a sore thumb when viewed through the rear windows.
Jim.
PS. Hoping to get another camera soon when I can, once again, take decent pictures.
However, the real elephant in the room was the construction of the birdcage style brake ends on the brake thirds. I had also done some sides for Scott Willis who is is building the NBR versions of Drummond's design and we had an exchange of ideas as to how we could achieve a good result. It was Scott who came up with the idea of a Perspex inner structure to stick the Plastikard sides to which would also act as the glazing. So I started with a go at a frame using 2mm Perspex sheet.
The front and rear frames are in the middle with the spacers to the right. I re-cut the Plastikard sides for the test.
The Perspex bits made up into the former like so
However, I let Scott see this picture and we both reckoned that the two vertical spacers would be visible througn the windows so it was back to the drawing board to change to one vertical spacer.
With the new parts in the foreground which made up into this
with its "two former" predecessor in the background. I glued the Perspex with Butanone - my 35 year old MekPak wouldn't look at it. I then tried a test assembly with the sides with varied degrees of success.
The ducket sides are supposed to fit between the ends such that the thickness of the end pieces becomes the end panelling on the sides. This worked quite well on the upper panelling, but getting the compound curves correct on the lower rear edges was a bit of a fight and I'm going to have another think about improving that. I had also developed the 2D sides to account for the S curve of the duckets and over-cooked it such that they were about 0.75mm too long - hence the untidy tops and bottoms. I also got one glue stain on the windows but that was just due to a bit of clumsiness on my part. The Butanone wicked nicely under the Plastikard and didn't intrude into the glazing area. If I can't get brown or dark Plastikard, then I will have to find some way of disguising the inner side since it sticks out like a sore thumb when viewed through the rear windows.
Jim.
PS. Hoping to get another camera soon when I can, once again, take decent pictures.
Steve Cook
Flying Squad
Thats an interesting technique Jim / Scott Is there any advantage to doing what you have, rather than using 2mm platicard and just machining in a pocket for some glazing (outside of the fact that you don't need to add glazing obviously)?
Is there any advantage to doing what you have, rather than using 2mm platicard and just machining in a pocket for some glazing (outside of the fact that you don't need to add glazing obviously)?I can see that it works, but painting looks to be more difficult, and my (very limited) experience of thick glazing is that it creates a prismatic effect. This can apparently be reduced a little by coating both sides of the thick glazing with Kleer, but I've not yet tried this to see if it works. Putting something dark coloured behind the glazing certainly doesn't work, that I have tried (and disliked).
Steve
JimG
Western Thunderer
Thats an intersting technique Jim / Scott
Steve,
You might just have given me another idea. But the problem is that the corner posts on these brake ends are quite fine and there is not a lot of "meat" to allow a more complex construction to hold glazing sheet which does not, in itself, beef up the corner. I'll do a bit more doodling in CAD to see what might be possible. It could certainly be easier with my Caledonian coaches, but Scott's NBR coaches have more complex shaped ends which might not be amenable to other methods.
But the problem is that the corner posts on these brake ends are quite fine and there is not a lot of "meat" to allow a more complex construction to hold glazing sheet which does not, in itself, beef up the corner. I'll do a bit more doodling in CAD to see what might be possible. It could certainly be easier with my Caledonian coaches, but Scott's NBR coaches have more complex shaped ends which might not be amenable to other methods.
Points noted. I'm doing my tests to see what problems I might hit and I am a bit worried that the thick Perspex sheet might introduce optical problems which I haven't envisaged.
Watch this space.
Jim
Steve Cook
Flying Squad
I see what you mean Jim, its all getting a bit skinny around there especially with the ducket sides sitting inbetween the ends.
With pleasure, 'tis a very interesting threadWatch this space.
Steve
BrushType4
Western Thunderer
Awesome work JimG
JimG
Western Thunderer
I see what you mean Jim, its all getting a bit skinny around there especially with the ducket sides sitting inbetween the ends.
With pleasure, 'tis a very interesting thread
Well, in between getting used to a new(to me) dog - a Staffie cross rescue case - and getting the February S Scale Gazette out, I've managed to have another look at at these brake ends and thought I would try using much the same method as I have used for the coach sides with a Jenkinson style Plastikard inner support with cutouts for glazing. What follows is, I think, the third attempt since I got into a right mess with various versions of files and differing measurments that I went back to the beginning and started all over again.
An issue I have with DraftSight, which I have been using, is that is does not update a file's date and time stamp when you re-save it after alterations. I got into the habit of searching for files by date from my previous profession of digital sound handling, where the date and time stamp of a file could be the fastest way of finding it. So I was picking up the wrong versions of DraftSight files - and there are a lot - so I'm now back onto AutoCAD LT which does update file date and time stamps.
The inner frames were cut n a similar fashion to the perspex ones, with the same style of spacers. Here's the complete set with the outer sides on the left, the inner sides in the middle with the spacers, and the ducket sides on the right.
The inner parts have rebates milled for the glazing material - 12 thou deep in this case for 10 thou clear acrylic sheet.
The inner frame was built up.
And the inner outer face (IYSWIM) is stuck on. The ducket sides are designed to fit in between the sides, with the edges of the sides reproducing the edge panelling on the duckets, so the inner side has to project 0.35mm to achieve this.
And the ducket side fitted
You can just see about a one thou ridge on the left side and it is about the same on the right side (although it looks worse). I will wait until it has all hardened and then do a bit of light sanding to smooth things down.
I'm happy with the lower side with the complex curve. Here the edge of the outer body side should be flush with the body with the lower panelling on the ducket side protruding. The join is well disguised by the panelling and I'm pleased with it.
And the final part is the glazing. I cleaned the slot out with a strip of 10 thou phosphor bronze which I keep handy for these kinds of jobs, then slipped the 10 thou glazing in.
All that is left now is to trim off the glazing.
So it has worked out quite well and it will be a bit easier to deal with the interior as far as what can be seen through these large windows. The system will also work with the NB coaches I have also been milling for another modeller not a million miles away from this forum.
Jim.
Attachments
Steve Cook
Flying Squad
Excellent work Jim 
I can see the advantage of being able to accurately mill a slot for the windows on the ducket (inner outer face ), I would be unable to be able to generate that level of crispness with hand tools.
Looking forward to seing an entire coach stuck together
Steve
I can see the advantage of being able to accurately mill a slot for the windows on the ducket (inner outer face
), I would be unable to be able to generate that level of crispness with hand tools.Looking forward to seing an entire coach stuck together
Steve
JimG
Western Thunderer
Excellent work Jim
I can see the advantage of being able to accurately mill a slot for the windows on the ducket (inner outer face
The only thing I will probably do is to add 10 thou or 15 thou sheet as backing to the upper parts of the ducket sides. These have been milled, literally, paper thin to get the lower panel thickness thin enough to bend easily into the "S" shape without any form of heat moulding. I suspect that I could poke a hole in them quite easily with a misplaced finger nail.
Looking forward to seing an entire coach stuck together
I'm going to try and get a complete set of five bodies - one first, two third and two brake third - built up for the AGM at the end of next month. I think I've got a good method for the roofs so they should all be complete - apart from chassis, lamp covers, door handles, grab irons, brake gear, buffers, couplings. I sometimes think that making the body of a coach is the easiest, and quickest, part.
Jim.
JimG
Western Thunderer
That looks pretty nifty
Cynric,
I've been using DraftSight regularly for the past four or five months and, in general, I have got on very well with it. But the file date/time stamp thing was becoming a real problem for me. I also had several swearing sessions when doing relative movements with ESNAP on when the program would use a snap point as a reference for the wrong direction rather than the direction the mouse pointer was indicating. I either had to switch ESNAP off or choose how I indicated the direction quite carefully. AutoCAD is a lot more forgiving with this and goes the right way 99 times out of a 100.
Jim.
28ten
Guv'nor
Draftsite is very good for a free program, but I work quicker in Autocad. I have been taking a long look at my workflow and as you say the building part is quick and easy compared to some of the computer traumas 
like you i sometimes find it easier just to restart from scratch rather than trying to chase little bugs in the drawing.
like you i sometimes find it easier just to restart from scratch rather than trying to chase little bugs in the drawing.
JimG
Western Thunderer
I've been experimenting with making the arc roofs for the coaches since way back in the middle of last year. I had thought about using heat forming but experiments with that did not turn out well - the main problem being the edges of the Plastikard which produced frilly edges. I then tried laminating thin section sheet, using 3 x 10 thou and 1 x 5 thou to get the 35 thou thick roof I was looking for, but that experiment didn't turn out too well since the thin sheet reacted differently to how much MekPak was used to do the bonding and the finished result started looking a bit like the surface of the moon. I then tried using thicker sheet - 20 thou and 15 thou - and got a result which seemed good. So I left the first prototype for a few months to see if any problems developed, and none have so far - fingers crossed.
I had decided to have the roofs removable on the stock therefore the roofs had to be free standing and retain their shape with no other help. So I went for the former style of construction which I have used before with success. I drew up the shapes in CAD and milled them out of 40thou sheet on the CNC mill - and got end results which reminded me of Keil Kraft kits of many years ago.
The formers were then built up to provide the framework
with some completed roof frames behind.
I then stuck the frame onto the 15 thou roof sheet down the central longitudinal former.
I then placed the frame and sheet in the roof former and pressed down to get full contact with all the lateral formers and applied MekPak to the lot.
I then applied a weight and left the lot for about 24 hours to set properly
The 8" file was a handy weight spreader. But I found that the weight was a bit uncontrollable and have now started using a clamp which is more adjustable. The 20 thou sheet is also in there although not glued just to give the correct radius for the 15 thou sheet.
Once the 15 thou sheet has set, the 20 thou sheet is stuck to the 15 thou sheet and the whole lot goes in the former again to set for 24 hours. This last operation has to be done a bit quickly. I stick one edge of the 20 thou to the edge of the 15 thou and let it set for a minute or two, then do a wash of MekPak across the rest of the sheet and get it into the former immediately and get the clamp on. It generally works OK. Sometimes I get an edge not quite stuck properly, but I can just re-apply MekPak and clamp it back in the former and it turns out fine.
The former is a piece of alloy sheet which was formed in a 3 in 1 chopping and forming machine in my outside workshop. I milled a shape to the correct radius and used this to get the alloy to that radius.
The end results have been pretty good, with nice straight edges to the sheet and no sign of any major distortions. The original roof made last summer is still as square as it was when made and others made in the last few weeks have retained their shape so far. Here's the first built roof mounted on the all first body, taken at an angle to show that it looks quite smooth.
If you look at the roof very closely with the naked eye you can just see very faint ridging where the formers are but this will become invisible when it gets a paper covering to represent canvas. This is the reason that I have changed to using the clamp so that I can control the pressure better when clamping the roofs in the former and maybe get rid of this very slight ridging. The next job for the former will be Caledonian 45ft arc roof stock so I'm hoping that the same methods will work on the longer roofs.
Jim.
I then tried using thicker sheet - 20 thou and 15 thou - and got a result which seemed good. So I left the first prototype for a few months to see if any problems developed, and none have so far - fingers crossed. I had decided to have the roofs removable on the stock therefore the roofs had to be free standing and retain their shape with no other help. So I went for the former style of construction which I have used before with success. I drew up the shapes in CAD and milled them out of 40thou sheet on the CNC mill - and got end results which reminded me of Keil Kraft kits of many years ago.
The formers were then built up to provide the framework
with some completed roof frames behind.
I then stuck the frame onto the 15 thou roof sheet down the central longitudinal former.
I then placed the frame and sheet in the roof former and pressed down to get full contact with all the lateral formers and applied MekPak to the lot.
I then applied a weight and left the lot for about 24 hours to set properly
The 8" file was a handy weight spreader.
But I found that the weight was a bit uncontrollable and have now started using a clamp which is more adjustable. The 20 thou sheet is also in there although not glued just to give the correct radius for the 15 thou sheet. Once the 15 thou sheet has set, the 20 thou sheet is stuck to the 15 thou sheet and the whole lot goes in the former again to set for 24 hours. This last operation has to be done a bit quickly. I stick one edge of the 20 thou to the edge of the 15 thou and let it set for a minute or two, then do a wash of MekPak across the rest of the sheet and get it into the former immediately and get the clamp on. It generally works OK. Sometimes I get an edge not quite stuck properly, but I can just re-apply MekPak and clamp it back in the former and it turns out fine. The former is a piece of alloy sheet which was formed in a 3 in 1 chopping and forming machine in my outside workshop. I milled a shape to the correct radius and used this to get the alloy to that radius.
The end results have been pretty good, with nice straight edges to the sheet and no sign of any major distortions. The original roof made last summer is still as square as it was when made and others made in the last few weeks have retained their shape so far. Here's the first built roof mounted on the all first body, taken at an angle to show that it looks quite smooth.
If you look at the roof very closely with the naked eye you can just see very faint ridging where the formers are but this will become invisible when it gets a paper covering to represent canvas. This is the reason that I have changed to using the clamp so that I can control the pressure better when clamping the roofs in the former and maybe get rid of this very slight ridging. The next job for the former will be Caledonian 45ft arc roof stock so I'm hoping that the same methods will work on the longer roofs.
Jim.
ScottW
Western Thunderer
The coaches are coming along nicely Jim
I had to pinch myself there, for a minute I thought I had jumped sites to an aero modelling news group. Those roofs remind of my childhood days building Balsa airplanes.
By the way how are you getting on with the brake coach?
Regards,
Scott
I had to pinch myself there, for a minute I thought I had jumped sites to an aero modelling news group. Those roofs remind of my childhood days building Balsa airplanes.
By the way how are you getting on with the brake coach?
Regards,
Scott