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Another bridge too far

Discussion in 'Members Personal Layouts' started by paul_l, Feb 8, 2018.

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  1. Apr 24, 2018 #101
    paul_l

    paul_l Staff Member Administrator

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    Just got them out of the molds

    Facet Rock Mold G1244


    This casting is approx 240mm wide

    Random Rock mold G1234 only 2 of the 3 castings done as I ran out of plaster.


    The larger casting is approx 100mm wide

    Paul
     
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  2. Apr 24, 2018 #102
    York Paul

    York Paul Staff Member Moderator

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    Is it casting plaster of paris you use Paul?
     
  3. Apr 25, 2018 #103
    paul_l

    paul_l Staff Member Administrator

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    Hi Paul

    Yes I'm using Hobbycraft plaster of paris

    https://www.hobbycraft.co.uk/plaster-of-paris-25-kg/566824-1000

    the first cast I made I used Polyfilla, and found air bubbles and not as clean detail. Now that may have been because the mold was dry, since that first cast, I've wetted the mold first befroe adding the plaster, I also add some tissue paper strips in the middle of the larger castings.

    Paul
     
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  4. Apr 25, 2018 #104
    Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    We'l done Rocky :facepalm:
     
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  5. Apr 25, 2018 #105
    jakesdad13

    jakesdad13 Staff Member Moderator

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    They look good mate. Any bubble holes just fill with ready mix filler. Once painted and weathered you will not see them.

    Pete.
     
  6. Apr 25, 2018 #106
    paul_l

    paul_l Staff Member Administrator

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    I must admit, wetting the mold first seems to have got rid of the air bubbles

    Paul
     
  7. Apr 25, 2018 #107
    paul_l

    paul_l Staff Member Administrator

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    Well my gamble / long shot didn't pay off.

    At the Glasgow show I ordered some laser cut sides from Torri Laser Ltd.

    Adrian said he would scale up a Lattice Bridge side to give me a almost 2ft long side.

    They arrived today and look the bee'e knee's


    Only drawback is they arn't high enough


    I will contact Adrian to see if he can double the height, without having to redraw the sides, otherwise, its back to plan A and make them out of wire.

    These won't be wasted as I reckon they will make an impressive O gauge foot bridge or an OO lattice bridge.

    Paul
     
  8. Apr 25, 2018 #108
    Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    I thought he was aware that it was to be scaled up to O Gauge. All that wait as well. They look great but he's obviously not been listening. I' try again and emphasise the size. He should give you a discount for messing up the first order as well. They are very useable but not what you ordered.
     
  9. Apr 25, 2018 #109
    York Paul

    York Paul Staff Member Moderator

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  10. Apr 25, 2018 #110
    York Paul

    York Paul Staff Member Moderator

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    Ha try again... think I lost a bracket off your post reply... so here it is again.
    I read once Windowlean sprayed into the mold before pouring in the cast acted as a good releasing agent... dunno but maybe worth a try. Anyway your casts look great.:thumbs:
     
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  11. Apr 26, 2018 #111
    paul_l

    paul_l Staff Member Administrator

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    Cheers Paul, I'll give that a try.

    I've been impressed with the Woodland Scenic mold results, and I'm getting some interesting results just part filling a mold.

    Not sure whether to have a road bridge in front of the rail bridge - stone built multi arch single lane with pedestrian passing points, and a small waterfall feeding into the river behind the rail bridge, or if that may be a bit too much.

    Paul
     
  12. Apr 26, 2018 #112
    jakesdad13

    jakesdad13 Staff Member Moderator

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    Or, not tried it but it may work, a quick spray of oil of the type you use on a frying pan.
    I used sunflower oil on my mould when I cast some brake shoes for my Andrew Barclay.

    Cheer's, Pete.
     
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  13. Apr 26, 2018 #113
    paul_l

    paul_l Staff Member Administrator

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    The clay strips were ready to continue

    Cuts made all the way through, and chamfers applied to each corner of the support Pier.
    Glued together with Mod Podge, then a polystyrene backer added - glued again with Mod Podge, then the gaps between the styrene block and sides filled with plaster.
    Clay worked into any gaps in the external joint and the courses re-established.
    Once dried two coats of slate grey applied


    Two hours later a black wash applied (two drops of Acrylic black thinned with water)


    Wait another two hours and dry brushed with light grey (2 drops white + 1 drop Slate grey), followed by another drybrushing of the above light grey + 2 more drops of white.


    And in place should look like this


    Paul
     
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  14. Apr 26, 2018 #114
    Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    Like the rusty bridge. Coming together.
     
  15. Apr 28, 2018 #115
    paul_l

    paul_l Staff Member Administrator

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    Plan B started for the bridge sides

    In 123D Design I knocked up a panel approx 170 x 103 mm, with Angle sections at 45 degrees, with straps top, bottom ends and across the middle.
    The idea is to print 2 sections per panel and glue them back to back to give a diamond pattern.

    upload_2018-4-28_13-23-40.png

    So the design looks like above, and took approx 1.5 hours to print the first panel.

    It still needs the second panel for the full effect, but looks like this



    You'll have to wait another couple of hours for the second panel to print.

    If this looks good, then I will need to print 7 full panels per side, giving 28 in total - boy my printer is going to be busy :whatever:

    Paul
     
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  16. Apr 28, 2018 #116
    paul_l

    paul_l Staff Member Administrator

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    And with the second layer


    Paul
     
  17. Apr 28, 2018 #117
    Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    I must admit Paul ..... the jury is still out on this. I think ( as you suggested earlier ) the pattern may be a bit tight. I think I would have made the gaps about four times the size and increased the size of the steel members by at least two. It looks very good but too close together. Maybe try making a card lattice and overlaying that first to get a better idea of the steel section sizes and the gaps. Especially given the print time.

    it is good though.:thumbs:
     
  18. Apr 28, 2018 #118
    jakesdad13

    jakesdad13 Staff Member Moderator

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    Personally I would reduce the height by around half and make the lattice work with bigger openings.
    A couple of examples.

    Lattice bridge side 1.jpg

    Lattice bridge side 2.jpg

    However, rule 1 applies here mate. If you are happy then that is all that matters.

    Cheer's, Pete.
     
  19. Apr 28, 2018 #119
    paul_l

    paul_l Staff Member Administrator

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    Will have to see if I can print that fine.

    [​IMG]

    Will have another go
     
  20. Apr 28, 2018 #120
    paul_l

    paul_l Staff Member Administrator

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    How about this then - its a flat grid tho

    upload_2018-4-28_22-27-9.png

    Paul
     
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