Laser cut track work.

Discussion in 'Permanent Way' started by paratom, 8 November 2020.

  1. paratom

    paratom Western Thunderer

    I have started researching the methods of track and point construction and hoping to embark on building an EM gauge layout. I have a large laser cutter and Templot on my computer and thinking of laser cutting all my track formations in .8mm ply sheet. The question is what is the best glue for sticking the C&L chairs to the ply sleepers. For the points which I imagine creates a bit more stress on the chairs would it be a good idea to have the odd C&L sleeper mixed in with the ply sleepers or even a copper clad sleeper, if they are available, soldered to the rails.
     
  2. richard carr

    richard carr Western Thunderer

    Butanone (MEK is another name) easily available on amazon in 1 litre quantities for £15 this will last you a long time.

    As for point work try to find some thin pcb that is the same thickness as the chair base, this can be super glued to the sleeper and then the rail soldered to the pcb.
    For example 0.5mm pcb is available which should be close enough to the chair base thickness, 0.6mm is available too but you might need to search a bit for it.

    Richard
     
    simond likes this.
  3. JimG

    JimG Western Thunderer

    Butanone - available in one litre and half litre quantites on Ebay - much cheaper than buying it as MEK in small bottles. I now use a syringe to apply the butanone. I find it much easier to apply than using a brush. 10 ml syringes and needles also available from Ebay - such as

    New Sterile Sealed Hypodermic Syringes + Non-sterile Blunt Needles | eBay

    I find the plastic to ply joint quite strong, especially if you apply a bit of pressure when the butanone is applied to force the plastic into the grain. The joint can also be broken quite easily using a scalpel blade or razor blade making adjustment quite easy.

    Jim.
     
  4. Dog Star

    Dog Star Western Thunderer

    I agree with Richard that Butanone is a good means of fixing C&L and Exactoscale rail chairs to plywood.

    MEK is shorthand for Methyl Ethyl Ketone which is "old-school organic chemistry" name for the solvent now known as Butanone. So beware of the Slater's Plastikard product known as MEK-PAK which is not MEK!

    I build S7 track using chairs and ply sleepers... and I do not find a need for using PCB sleepers / timbers.

    regards, Graham
     
    woolv likes this.
  5. paratom

    paratom Western Thunderer

    If your using Butanone in the syringes do they not have to be glass ones instead of plastic? Although the Butanone is delivered in plastic bottles or do they have to be a certain type of plastic.
     
  6. JimG

    JimG Western Thunderer

    I've been using butanone in plastic syringes for a few years now - even leaving butanone in the syringes for days between use and I haven't had a syringe adversely affected.

    Jim.
     
  7. Steph Dale

    Steph Dale Western Thunderer

    Bernard Weller of Exactoscale used to recommend applying solvent pipe glue to the areas of the sleepers you were going to be gluing on and leaving it to dry, then using MEK/Butanone to fix the chairs. The pipe glue will be a solvent with plastic dissolved in it, so it's effectively plasticising the wood sleeper, ready for a conventional joint.

    It's an added step, and the guys are comfortable without the need for it, but I'd be surprised if it didn't result in much stronger trackwork.

    Steph
     
    jonte likes this.
  8. Longbow

    Longbow Member

    Using Templot you could design laser-cut turnout sleeper bases as demonstrated here - note that no paper template is required, and that butanone is perfectly adequate to bond the chairs to ply, even in 7mm scale.

     
    jonte, S7BcSR, GrahameH and 1 other person like this.
  9. paratom

    paratom Western Thunderer

    While on the subject of ply sleepers it would be interesting to know what is the prefered method of painting the ply sleepers. I think a wood stain is the best method but do modellers stain the sleepers before adding the chairs or afterwards. I have heard that staining them before adding the chairs gives a weaker bond when it comes to glueing the chairs to the sleepers.
     
  10. paratom

    paratom Western Thunderer

    Interesting way of building points although I would be inclined to use ply rather than mdf. Not sure about the mdf track gauges but if you get a set with every point kit I presume you though them away and use a new set when you purchase another point kit. On the laser cutter you can half etch and I would be inclined in 7mm to half etch the webbing between the sleepers so that they could be hidden with ballast. Not sure if you get away with that in 4mm unless you used 1.5mm ply but then you would not be able to combine C&L sleepers with your track work. In 4mm once the sleepers are stuck down you could cut away the webbing but that would be quite a laborious job. Another way is to add them at the ends of the sleepers like I have done here, see illustration. The black lines are cut first then a second pass cuts the red lines.
     

    Attached Files:

  11. Longbow

    Longbow Member

    Greenwood use 3mm birch ply for their 7mm turnouts. The half etching idea is a good one, but I imagine it would add a fair bit to the lasering time and hence to the cost. Perhaps lasered half-cuts instead to facilitate webbing removal?
     
    woolv likes this.
  12. Boyblunder

    Boyblunder Western Thunderer

    The Greenwood kits are quite accurate and I think a relaxing way of spending a couple of hours. Mudhen built one for the Scale 7 newsheet and it worked straight from the bag with no modifications. Bob Godden has built several cutting back the webs with a scalpel. The first one I built didn’t work so well due to the common crossing jig not being quite symmetrical, Mike Greenwood has fixed this issue. I do cut back the webs by one ply with a scalpel and a cut down emery stick taking about 5 minutes for a whole turnout, but you can’t really see them anyway when ballasted. I think the excellent “Off the Rails” check rail chairs and JLRT stretcher bars look better than the standard kit offering. Greenwood turnout.jpg
     
    john lewsey, woolv, fenman and 3 others like this.
  13. paratom

    paratom Western Thunderer

    Looks good. Had not thought about removing one layer of ply from the webs, a good idea. I wonder if you could do this with .8mm ply? Of course I could be accused of being pedantic and some modellers would say you don't really notice the webs when the track is laid down and ballasted especially in 4mm.
     
  14. Phil O

    Phil O Western Thunderer

    I stained my plywood sleepers and timbering before use, I put them in an old butter tub and poured in Ronseal Jacobean Dark Oak and left it overnight, I then poured out the excess stain, finally I spread the sleepers out on sheets of newspaper to dry for a further 24 hours, turning occasionally. I have had no problems with the chairs coming adrift.
     
  15. paratom

    paratom Western Thunderer

    There is a good article in the MRJ on staining sleepers and gluing chairs to the sleepers.I have looked in the MRJ index but can't find it. I could look through my complete set of MRJ's but if someone can remember or knows which edition it's in that would be great.
     
  16. ICH60

    ICH60 Active Member

    When I built Highworth trackwork in S7 in the late seventies, I stained the sleepers with potassium permanganate. This was dissolved in water and the sleepers soaked overnight
     
  17. 3 LINK

    3 LINK Western Thunderer

    Sprayed with Halfords satin black before being used, then rubbed with white spirit to remove most of the colour.

    B0A433D8-6100-4988-A2FF-10F9032EF999.jpeg