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Ron Heggs

Points Bridge, Hagg Bank, Wylam, Northumberland

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Hi Ron -

 

Been 'offline' for a while. Stunning progress! Two things - you say this model will go in a summerhouse? No danger of warping in the heat? Secondly - very early on it looked like you will building the intial structure over a plan. If so - how did you prevent the styrene sticking to the plan? I only ask because I've got to model the girder-work associated with the canopyof a platform at Brisol Temple Meads...

 

Regs

 

Ian

Hi, Ian

 

The summerhouse is a brick/concrete structure used in summer to keep us out of the heat on our pool terrace. The temperature rarely rises above 25 deg C inside

 

The paper template is used to hold the curved styrene pieces in place. As each successive piece is fixed I slip my modelling knife under the joint whilst brushing the PlasticWeld over the joint, then remove the knife. So the joint doesn't stick to the template

 

Then the first lot of braces are fixed on top of the curved arch. The arch is then removed, turned over and replaced and the second lot of braces fixed on top. So there is no possibilty of the structure sticking to the paper template

 

Once these braces are fixed the complete arch is removed and all successive braces, etc. are fixed off the template

 

If at any time a styrene joint becomes stuck to a template I slice through the paper to release the styrene, and gently file the offending paper off

 

Ron

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Ron -

 

Thanks for that - a somewhat simpler solution than I had envisaged! I was thinking along the lines of waxing the drawing - but my immediate counterthought was - styrene solvent... The knife approach is much simpler!

 

Regs

 

Ian

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One of the problems encountered, is the slightest difference in length in the suspension hanger and the actual distance between arch and deck beam will cause either a non-contact joint or a slight bending of the suspension hanger

 

So each hanger is made slightly longer than needed, and is successively shaved in length on a trial basis until the fit is exact

 

Some of the bending may be seen in these pictures

 

- latest progress

 

post-10633-0-42189000-1335554235_thumb.jpg

 

post-10633-0-47885100-1335554256_thumb.jpg

 

post-10633-0-10683400-1335554275_thumb.jpg

 

post-10633-0-42835100-1335554297_thumb.jpg

 

- eight more suspension/hangers to go

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- the first arch suspension/hangers completed

 

post-10633-0-90612100-1335640719_thumb.jpg

 

post-10633-0-70500900-1335640742_thumb.jpg

 

post-10633-0-62717900-1335640773_thumb.jpg

 

post-10633-0-96496300-1335640792_thumb.jpg

 

post-10633-0-05514600-1335640812_thumb.jpg

 

- just a couple of hangers to be trimmed to remove the slight bending, and one needs repositioning at its upper end

 

The next steps are to complete the deck plating, and fix the under arch strip to tie in the suspension hangers at their upper attachment points

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This will look really impressive when all three arches are together.

Is it not possible to fit the top and bottom anchours and the fix the tie with an overlap? this would then mean the cutting has to be less accurate.

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This will look really impressive when all three arches are together.

Is it not possible to fit the top and bottom anchours and the fix the tie with an overlap? this would then mean the cutting has to be less accurate.

Hi, Peter

 

This drawing shows the general arrangement of a suspension/hanger -

 

post-10633-0-45348100-1335648570_thumb.png

 

The only attachments are -

 

To the underside of the arch - an area of 0.5mm x 5mm

 

To the top of the deck beam - an area of 1.5mm x 2mm

 

Whilst the links overlap the suspension hanger any reduction in contact areas will reduce the effective load bearing

 

The only possibility to provide some adjustment would be to sandwich a short piece of 0.5 x 2mm strip (say 5mm long) inbetween the two lower links, and then cut the suspension hanger strip about 6mm shorter, so that it is still able to be set between same two lower links with sufficient room, and fixing area to allow the required adjustment without further cutting, etc.

 

I will trial this on the next arch

 

Cheers

 

Ron

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Ron - any updates on your extreme sports modelling masterpieces?

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Ron - any updates on your extreme sports modelling masterpieces?

Hi, Ian

 

Have been having a really busy time this last few weeks with demolishing walls for the villa reform, which has left me physically tired, and with aching wrists and arms - not really conducive to a plastic bashing

 

Hoping to have a break within the next couple weeks, when I could be back to a little PlasticWeld sniffing :sungum:

 

Cheers

 

Ron

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We are off again - trying to catch up after a long period reforming the villa

 

The latest pics. show the second arch ready to receive the legs of the outer 20thou x 60thou T bracing pieces -

 

post-10633-0-75307900-1347210827_thumb.jpg

The Guinness glass only holds water

 

post-10633-0-97825200-1347210845_thumb.jpg

The 40thou x 20thou strips - 28 off 41mm long & 44 off 42mm long ready to go

 

- more pics. later tonight

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Progress tonight -

 

post-10633-0-84813000-1347226143_thumb.jpg

T bracing legs fitted

 

post-10633-0-39154400-1347226162_thumb.jpg

 

post-10633-0-56497300-1347226181_thumb.jpg

A few cross braces for fitting between the T bracings

 

post-10633-0-96466800-1347226215_thumb.jpg

The first two pairs in situ

 

- completion tomorrow, then flat bracings to be added

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Hi Ron

 

I've only just heard about this thread and as usual it's absolutely stunning. Civil engineering in miniature it certainly is.

 

I take it that drinking water from a Guinness glass is only a temporary set back. :jester:

 

Cheers SS

Edited by Siberian Snooper

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Hi Ron

 

I've only just heard about this thread and as usual it's absolutely stunning. Civil engineering in miniature it certainly is.

 

I take it that drinking water from a Guinness glass is only a temporary set back. https://www.rmweb.co.uk/community/uploads/emoticons/default_jester.gif

 

Cheers SS

Thanks for your comments and your numerous 'likes'

 

With only two weeks to go - my long period 'off modelling' means that I will not complete this bridge before the deadline. However, I will continue with the build and keep all informed of my progress

 

Cheers

 

Ron

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Although the Challenge End Date has passed the build continues -

 

post-10633-0-83446600-1350672195_thumb.jpg

The cross-bracings between the outer bracings

 

post-10633-0-07070200-1350672121_thumb.jpg

The arch now awaiting the cross-bracings between the inner bracings

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Started on the internal cross-bracings -

 

post-10633-0-53039200-1350852707_thumb.jpg

80 strips cut ready for the next 10 sets of bracings

 

The jig is used to set the three differing sizes of cross-braces -

The larger one is used for the external (two set) cross-bracings (36 sets)

The upper right is used for the internal (four set) cross-bracings (26 sets)

The lower right is used for the internal (five set) cross-bracings (10 sets)

 

post-10633-0-75384100-1350852745_thumb.jpg

First four in place - another 22 four cross-brace sets, and 10 five cross-brace sets to go

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Progress update -

 

post-10633-0-97968500-1352243769_thumb.jpg

The 10 sets of internal bracings fixed to one half of the arch

 

post-10633-0-18302200-1352244006_thumb.jpg

The remaining set of the 4 set of cross-bracings and 5 sets of 5 cross-bracings ready to be fixed into the internal braces

 

post-10633-0-81275900-1352243965_thumb.jpg

Comparison of 4 & 5 sets of cross braces

 

- next step is to construct the 6 sets of internal bracings and fix into the arch

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Dear Ron,

I am a Chartered Structural Engineer for my sins, now retired, and I am hugely impressed by your model "structural engineering" - just like the real thing but no welding, bolting or rivets! Whilst I have worked on many 12 inch to the foot scale structures, I don't think I could come anywhere close to acheiving what you have in 1:76 scale. Fantastic modelling.

I have just a couple of queries - are you using Evergreen styrene and what make of adhesive are you using? I am having some difficulty making some signal box window frames out of Evergreen strips which refuce to stick together with the solvent I am using. I would appreciate you advice.

Also, just a warning that all arch structures tend to spread under load so the deck needs to tie the feet of each arch together or, as in a masonry structure, the abutments must be able to resist this lateral force which may be significant under the load of a model loco and train passing over it. I suspect the real bridge relies on massive masonry abutments to resist these horizontal forces.

I can't wait to see the finished structure in all its glory.

Regards,

Brian.

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Dear Ron,

I am a Chartered Structural Engineer for my sins, now retired, and I am hugely impressed by your model "structural engineering" - just like the real thing but no welding, bolting or rivets! Whilst I have worked on many 12 inch to the foot scale structures, I don't think I could come anywhere close to acheiving what you have in 1:76 scale. Fantastic modelling.

I have just a couple of queries - are you using Evergreen styrene and what make of adhesive are you using? I am having some difficulty making some signal box window frames out of Evergreen strips which refuce to stick together with the solvent I am using. I would appreciate you advice.

Also, just a warning that all arch structures tend to spread under load so the deck needs to tie the feet of each arch together or, as in a masonry structure, the abutments must be able to resist this lateral force which may be significant under the load of a model loco and train passing over it. I suspect the real bridge relies on massive masonry abutments to resist these horizontal forces.

I can't wait to see the finished structure in all its glory.

Regards,

Brian.

Hi, Brian

Thanks for your comments

 

With regard to the styrene which I use for all my structures - most is stripped from Javis sheets and occasionally specific extrusions from Evergreen

Joints all made using PlasWeld. Butt the two pieces together tightly and stroke the joint with a small brush dipped in PlasWeld, the joint is solid in seconds

 

Originally, I was going to tie the arches via an underbuilt wire system to prevent spreading, but thought that a better option would be a temporary baseboard 1200mm x 400mm with two large wood blocks which will act as the masonry abutments, and prevent spreading of the arches. (The bridge will eventually be placed in a suitable location in our pool summerhouse where the tracks run from the rest of the layout)

 

Cheers

 

Ron

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Finally managed to complete this half of the arch -

 

post-10633-0-32095800-1352916506_thumb.jpg

 

post-10633-0-22270900-1352916468_thumb.jpg

 

- the other half of the arch is now waiting for the delicate touch of solvent on styrene

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post-10633-0-44729100-1353008716_thumb.jpg

96 strips for the 12 (4 sets) of cross braces, and 50 strips cut for the 5 (5 sets) of cross braces

 

Ready to construct the remaining cros-bracings for this arch

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Hi Ron.

 

Only just discovered this thread. Your use of plastic strip/card is stunning. Not content with Manchester Central you hare building this as well. Once this is finished are you moving on to a scale Forth Bridge? :jester: I think in 4mm it is about 9 metres long :O.

 

Regards

 

Steve

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