I needed to make a relatively large expanse of station yard and road on Valdieu-Lutran. I decided that chinchilla dust, a form of powdered clay, would be a good base. I initially tried to stick the dust to the baseboard using diluted PVA but this was unsuccessful because the clay did not stick well. After the glue had dried the dust easily rubbed off.

I therefore undertook some experiments to find the most effective method of sticking the chinchilla dust.

I tried wallpaper paste, Aleene’s Tacky Glue and 3M Spray Mount Adhesive on test strips. The best by far was the 3M Spray Mount Adhesive. This required extensive masking of the board to prevent contamination of the track etc. but was the only adhesive that gave a good finish. The chinchilla dust was sieved using a metal sieve to use only sub 1mm particles as the road surface.

To seal the surface ready for any paint or chalk effects to be added the dust was sprayed with a good coat of Testor’s Dullcote varnish.

I also added some static grass at the end of the embedded track in the station yard to add some variety.

From this trial this method will be used in future where stony ground cover is required.

I decided that I wanted in future to use chinchilla dust particles of less than 0.5mm size. I bought a cheap 0.5mm sieve off of eBay that fitted into my plastic funnel. I taped the vibrator I use for paint mixing onto the assembly. This is how it works

I now have 2 bottles of pre-sieved chinchilla dust ready for use.

p.s. 98% of the chinchilla dust I bought is <0.5mm in size.

I have just obtained a 0.25mm sieve and have re-sieved the 0.5mm sieved clay so that I now have <0.25mm sieved clay, >0.25 mm <0.5mm clay and >0.5mm clay particles. There was about 40% <0.25mm, 40% >0.25mm <0.5mm and 10% >0.5mm particle sizes in the sepiolite clay chinchilla dust from Pets at Home. I am presently trying to find out what thinners are used for Collall All Purpose spirit-based glue to experiment to see if a diluted spirit glue could be used to stick this sepiolite clay as ballast because PVA will just make the particles swell and will not stick this material.

I tried to dissolve Collall All Purpose spirit based glue in IPA but all you get is a slimy lump of glue in the jar. I tried adding 30% Acetone to the mix but it remained undesolved. Pure acetone dissolves the glue completely but when I tried to pour a 1:6 ratio glue/acetone mix onto sepiolite dust laid as track ballast it would not ‘wet’ the ballast. I tried wetting the dust with acetone then applying the glue mix and it was absorbed into the dust in a similar way to using water/IPA/washing up liquid to wet ballast before applying dilute PVA glue. Unfortunately my first attempt using diluted Collall glue resulted in a brittle ballast that easily flakes and so, unless I can find a different mix/method I don’t think Collall spirit based glue is a suitable medium to use for ballasting with sepiolite clay based chinchilla dust.