122 Dmu

Discussion in 'WR Action' started by Simon, 8 June 2010.

  1. richard carr

    richard carr Western Thunderer

    Simon

    It's great to see this going again.

    Richard
     
  2. Simon

    Simon Flying Squad

    I have tonight been chivvying away at the epoxied pegs and ends of the sides and have achieved a pretty good fit between sides and castings.

    Profile2.jpg Profile1.jpg

    It would all be ready for gluing, but as I observed earlier in the thread I have managed to get a mismatch between the rainstrip on the sides and that moulded on to the cab end castings. A further compilation is that on the side pictured above, the rainstrip actually "runs off" across the coach side and finishes in different relative heights at each end.

    I'm going to ponder this, I think the answer will probably be to cut the rainstrip off the top of the sides and replace it so that it lines up at either end, although the newly epoxied brass angles make this difficult:rolleyes:. The gap between the top door shut lines and the strip will also then vary slightly from end to end on the side pictured, although I don't think this will notice very much.

    Then there is the floor to think of, the "foot" formed by the solvented strip of styrene sheet at the base of each side is actually sitting at slightly less than 90 degrees to the "mean perpendicular" of the sides, but I don't think this matters as the plastikard facing that will be going on to the solebar frame faces will cover any slight gap and also fix the sides along their length. Current thinking is that I will solvent in a floor strip between the two "feet" running along the coach length (which will correct a slight inward bow on one side in particular), and then epoxy a sheet metal floor in on top of this assembly to make a good solid job. This will probably need to go in as several pieces I think as the epoxy will go off if I try to do this in one operation - I suspect aluminium sheet will be the material to use.

    It does look pretty impressive though and I feel fairly motivated to try and get it through to the completed body shell stage, if not further:p

    Plenty to think about….

    Simon
     
  3. Simon

    Simon Flying Squad

    I decided that the way forward was to remove the rainstrip from the body sides. After an hour and a half of tedious work with a sharp knife I have managed to remove them from both sides, with a minimum of damage to the body surfaces along the way.

    In for a penny in for a pound, I have now "tack superglued" the sides and ends together, deciding that the new rainstrips will be better applied to an assembled shell so that I can align them properly with their cast counterparts.

    Tacked.jpg

    I'm going to leave it until the morning now, the next stage is to check the whole thing for squareness and general alignment across the panel faces before completing the joints by running epoxy into the rear faces and around the brass pins.

    In the above picture you can see the slight inward bow of the side nearest the camera, the insertion of a centre floor section will sort this out I think.

    Simon
     
  4. Simon

    Simon Flying Squad

    I cut out a floor section last night and glued along one side length with poly cement. I also noticed that one side/cab casting joint was a bit "off", the lower side being a bit too proud near its base and the whole thing at a slight angle. So this morning I unglued it, which was messy and difficult, although looking on the bright side I don't envisage the body coming apart at these joints in service(!) I then chivvied everything and have just stuck it back together and also run poly cement along the base of the side, there is a slightly larger gap between casting and side than there was but that can be filled.

    Here it all is with various weights in place to hold the sides as tightly as possible to the floor while the poly cement goes off, hopefully safe to handle by tonight.

    Gluing .jpg

    The mark on the side is where superglue ran between the side and a piece of plastikard that I was using when I clamped it together, thank Gawd I thought about the possibility and removed it before the glue had fully cured:rolleyes:

    I'm pretty confident about cleaning this up. In any event all four of these joints will need filling and finishing and it may well be that there will be some evidence of a joint when it is finished but I figure that'll be a small price to pay for having created the monster in the first place.

    So assuming I'm happy with the overall shape etc I reckon that tonight will see the start of flooding the joints with epoxy from the inside, which will strengthen the joint and firm up the thin side sections to avoid flexing when I start filling and sanding.

    It will also make sense to try and make a roof section in the fairly near future, which will need to support the body side top edges along their lengths. This will hopefully ensure the whole thing stays the right shape as all the glues dry off and I tack other bits on to to it.

    So still travelling hopefully, roof challenge looming...

    Simon
     
  5. Dan Randall

    Dan Randall Western Thunderer

    Looking good. :thumbs: It's great to see this back on your workbench Simon. :)


    Regards

    Dan
     
  6. Simon

    Simon Flying Squad

    Thanks Dan, I'll try and keep going this time…

    To which end, I have now run epoxy resin behind all four joints and the basic shell is now complete.

    One side is distinctly bowed in along its top edge, the other much less so, but it/they happily straighten when supported and will at least mean that the sides sit firmly "into" the roofline. I need to stick on a couple of bits of brass angle at one end to give a continuous edge of brass along the top of the sides and then there is the filling and sanding of the external joint to be done.

    Bowed.jpg

    In addition I need to work out and make fixings to attach the chassis frame to the completed body so that the two will be detachable from each other. I envisage four nuts running on to two threaded rods secured into the resin cab floors at each end, each protruding through holes in brass sheet soldered between the frames sitting under the resin cabs.

    The roof wants sorting sooner rather than later too, as it will protect the fragile body sides and keep everything in shape. I have a few ideas floating around, mostly revolving around forming aluminium sheet over a wood former, possibly in several sections which would then be epoxied together.

    The sort of thing that I might put off for years:oops:

    Down the shed tomorrow then…..

    Simon
     
  7. Neil

    Neil Western Thunderer

    Resin cast in sections to match the sections on the prototype?
     
  8. Simon

    Simon Flying Squad

    That is a good thought that would work really well, but I'm after a "quicker fix" as the construction of moulds etc would take quite a while.

    I wouldn't rule it out though, depending upon how well or otherwise my aluminum bashing efforts go.

    Given the "mission criticality" of the roof and my current do or die state of mind I'm going to have a go at it today, so by tonight I may be making another mould.

    Another option would be to plane up the whole roof from wood, although this would mean the "ceiling" would be very low precluding interior illumination etc.

    "Interior illumination" - who am I kidding:rolleyes:

    Just seen "Tornado" go through and drinking tea at the moment:)

    Simon
     
  9. Simon

    Simon Flying Squad

    Former for roof profile made up this morning, I will plane and sand it to shape tomorrow.

    Formerfame1.jpg

    First piece of brass sheet soldered into frame end under cast cab floor.

    Formerframe2.jpg

    Both ends now with brass sheet soldered in place and two more soldered into central section for additional location of the body. Holes drilled through in relevant places, 8BA bolts run into holes in resin floor attaching frame to body assembly, two pieces of brass sheet cut out and drilled to sit above plastikard body over the two central soldered brass sheets, holes drilled in more or less matching places.

    Fileframe3.jpg

    I have a plan for all these holes, I'm just thinking I ought to cut out and solder the buffer planks to the frame ends before bolting it all together, even though it will all be unboltable.

    Still quite fired up by it all:thumbs:

    Simon
     
  10. Simon

    Simon Flying Squad

    The chassis frame is now attached to the body, all seems square and in alignment.

    Floored.jpg

    I have also planed the roof former, although I think it is a bit too domed and will adjust it tomorrow.
     
  11. Ressaldar

    Ressaldar Western Thunderer

    Hi Simon,

    you're making excellent progress again, you will be getting the primer paint ready in no time:thumbs:.

    regards

    Mike
     
  12. Simon

    Simon Flying Squad

    I haven't won yet, but here's the third section of formed aluminium roof being glued to the first two sections. The sections are joined by lap joints of shaped aluminium sheets epoxied across each joint on the underside of the roof. The whole ghastly business has occupied me for most of today:rolleyes:

    Roofed.jpg

    It fits between the cab ends fine, but requires a bit of work to get a proper "line" along the edges. The next challenge will be making up and successfully attaching a strip to go along the roof sides, with its lower edge dropping vertically down so that it sits behind and supports the top edge of the sides.

    I think it is going to work, this method is certainly viable for wagon roof making. I intend to use the previously made SR profile former to make up a two part roof suitable for a "van C" - 0ops, another project:oops: - better finish this one first, maybe….

    Simon
     
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  13. Simon

    Simon Flying Squad

    After a session at the club tonight I have moved a bit closer to a viable roof, it also got a blow over with Halfords grey primer earlier this evening:

    Issues.jpg

    Two main issues.

    1.) Achieving a good edge between bodyside top and roof arc, the solution will involve the use of epoxy filler and the filing off of some "low spots" along the roof edge I think.

    2.) Achieving a good line along the top of the bodysides, avoiding bulging and bowing. This is an issue despite gluing a strip of brass along and under the edge of the roof, sitting behind (and supporting) the bodyside top edge. This will involve the construction of some lateral struts between the sides at cantrail height I think.

    Feeling moderately positive about it, maybe do some more tomorrow…

    Simon
     
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  14. Peter Insole

    Peter Insole Western Thunderer

    Simon, will you not be adding a couple of substantial bulkheads (brake compartment wall and smoking section - with door) in that super beastie? They might significantly help to keep everything in line!

    The body side doors can be thickened up as well, the droplights should be set back rather than flush like the rest - that might add a bit of extra rigidity into the bargain? I would think that if you beefed up the insides and firmly attached them to the top and bottom rails, they would not be that obvious when viewed sideways through the windows and between the seats?

    A very naughty, non scale dodge I admit, but needs must and all that...!

    Pete.
     
  15. Simon

    Simon Flying Squad

    That's a good idea Pete, although the bulkheads aren't in terribly useful places and the way that I've arranged for the glazing to "slot in" means that bulkheads can't be fitted until the glazing is fitted, unless they don't quite reach the sides above waist height.

    As regards the droplights, hmmm, food for thought. As currently designed the drop lights in the main sides are going to be at the same "depth" as the main windows, maybe I ought to change this for appearances sake if nothing else…. The driver's window droplights are set further back in the resin casting.

    Since last night I have deployed a "high tech" epoxy filler which I have run along the roof edges to get them to follow the tops of the sides exactly. I masked the sides with masking tape and ran silicon grease into the edge that the filler was "run against" to avoid it sticking to the sides.

    I have just been down the shed and removed all the masking tape and it has mostly worked, although the filler is still a bit "rubbery" not having yet fully cured. I've just blasted the roof with another witness coat of primer, in the shed as its raining - very smelly.

    As regards holding the sides on the right alignment, the lateral strut idea was pants as everything moves. I think that by epoxying plastikard along my brass "down stands" (so that they actually meet the inside faces of the sides, which the current pieces of brass strip don't) I can effectively hold the sides out into their proper alignment, maybe.

    Off to pick up the roof from the shed and then make a brew, I haven't given up yet…

    I'll post a picture when I've packed the strips out with plastikard and if/when it looks credible.

    Simon
     
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  16. Yorkshire Dave

    Yorkshire Dave Western Thunderer

    Just rout a channel down the centre of the 'ceiling' deep enough for a LED strip.

    - Edit thought you were using the wood roof... DOH. Should have read more clearly.

    And 'fogged' windows....? :oops:
     
  17. Simon

    Simon Flying Squad

    Well it's better and with a bit of luck may be the basis for a finished job.

    Better1.jpg Better2.jpg

    It needs more filler along the edge, I'm toying with the idea of using squadron filler as it'll be easier and quick drying, but I suspect I ought to use the two part epoxy filler. I did and here's a second pass with it later on.

    Filling.jpg

    The trouble with it is that it slumps out of the joint. I think I'll try running some knife stopper over it tomorrow before I de-mask the body to try and get a better shape along the edge of the roof.

    Simon
     
    Last edited: 12 September 2017
  18. Simon

    Simon Flying Squad

    Still progressing, I have just made a third pass with the epoxy filler along both roof edges to improve the line and shape, no picture but it looks encouraging:)
     
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  19. Simon

    Simon Flying Squad

    A quick fourth application of epoxy filler to both sides this morning, the aim now being to get the roof's edge to follow a straight line between cab ends. On the first image the roof appears to go too far out in the middle, this is because the body on that side is still slightly bowed in. My cunning plan is that when the bodyside is "straightened" by more packing behind its top edge, the roof edge will be in the "right place".

    Filled1.jpg Filled2.jpg

    With the roof in place the whole structure feels nice and rigid and I intend to make fixings for each end of the roof to secure it before moving on to other aspects of the build as this will make the whole thing easier to handle and work on. Fair bit more chivvying and sanding of the roof to go before its finished though. On the positive side this roof construction is definitely good enough to be used on the finished model:)

    Simon
     
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  20. Simon

    Simon Flying Squad

    Not much time tonight, but I have removed the roof and done a bit of sanding of the filled surfaces. I'm pleased with the regularity of the resulting roof section, it may yet need a little more epoxy filler in odd places but before adding any I will first spend some time rubbing everything down with wet and dry to achieve a more finished surface.

    Roof.jpg

    The roof section is satisfyingly rigid and strong feeling and when placed on the body the whole think looks quite convincing (from a distance:p)

    Simon