Friday, 27 April 2012

More silent running...

...Track and landscape contours

Getting there - The underlay will be trimmed flush with the end of the baseboard
when the glue has dried

Yesterday I built the frame and set the track bed in place. Before I could lay the track underlay the landscape contours needed to be cut and fitted. The internal parts are cut from expanded polystyrene foam 'rescued' from packing material. The outer contours are made from plywood and cut to shape using jigsaw. It is worth taking a bit of time at this stage. I have been a bit slap-dash in the past and it can never be corrected after the event. No matter how much effort is applied trimming and filling, it still looks like it has been trimmed and filled! Another little trick, that will save time later, is to cut two profiles for each end.

The end profile boards are cut in matched pairs. The second
one will be used on the adjacent board
The second profiles are used as the end of the adjacent baseboard frame ensuring a perfect match. Once the profiling was completed I laid some oversized strips of high density foam over the MDF track bed. These are deliberately cut over-width so that the hard shell landscaping can be fixed to this overhang creating yet another mechanical break. This is not a total isolation, as the hard surface will connect the shell to the track bed. I am hoping the very thin and light amount of material will transmit little or no vibration into the frame - time will tell. Staying on my recycling theme I found some old cork wall tiles in our loft and thought they would make perfect track underlay for the fine scale (SMP) OO flexible track. I am not sure if you can buy cork wall tiles any more (shows you how long we have lived in our house!) but a strip of the standard cork underlay would do the job if you have not got any old wall tiles kicking about - I knew they would come in handy one day!

Polystyrene intermediate formers and multi-layered
track underlay helps to keep noise transmission to a minimum
The whole lot will be weighted down overnight and left to dry. I have used a PVA glue (Original Titebond) to glue the wood together and the underlay down. I like Titebond and have been using it for a decade or more. it has plenty of 'grab' and cures quickly. Any PVA will do the job, white or yellow, it is a matter of personal choice. However, I would recommend buying it in bulk as it is much cheaper that way. I usually buy the odd small bottle and keep refilling it from the bulk container making it much easier to handle. For model railway use I would not recommend the 'permanent' or type II or III versions of PVA as they will not wash out of clothes and if, like me, you prefer to apply the stuff with a brush and mop up with a sponge it will ruin both if not washed out before it cures. When everything is dry, the ends of the underlay will be trimmed flush and the woodwork sanded ready for undercoating. The track will also be glued in place using PVA.

Ballasting will be carried out by laying it loose and 'solidified' it using diluted floor polish. When dry, the ballast will will hold the track in place, without the need to use track pins, thereby maintaining the mechanical separation. I will show you the section again, in a few days time, once I have laid the track and let you know if it runs any quieter.


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