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Ballast Too Dark?

5396 Views 14 Replies 11 Participants Last post by  dwb
Anyone else have this problem?

I use the tried and tested method of laying ballast - lay dry, brush into place, water and drop of washing up liquid followed by PVA/water mix dripped on BUT ...

the ballast ALWAYS ends up going a dark shade and sometimes from grey to green.

I use fine and/or medium grey ballast (Jarvis and Woodland Scenics).

How do all the layouts in magazines and at exhibitions prevent ballast from looking dark grey/green? What, if anything, am I doing wrong?

Is there any way I can avoid this or will I either have to paint the ballast or use Woodlands Scenics light grey only?
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QUOTE (neil_s_wood @ 23 May 2008, 06:27) <{POST_SNAPBACK}>Hi Diesal, do you have any pictures to show us what it looks like? You can always add weathering to replicate oil leaks on top and rust near the tracks.

It seems strange that it's going green; is it near some flock or paint which would add pigment to the PVA water mix?

PVA usually sets clear so it shouldn't colour.

It's best to have a photo of what you're trying to replicate handy so that you can refer to it. While your ballast may not look like the layouts in the magazines you may be surprised that it looks more like real life ballast.

***PVA glues are mildly acidic so will certainly tint some ballasts. Strange reactions can happen especially on ballasts as they are made from strange stuff - some are various minerals but woodland scenics is actually crushed nut shells

An example - I used a cheap craft glue to fix real coal in a loco once, and the glue turned a bright almost flourescent green in places. The reaction died away as the glue dried but it was a stressful thing on a finished kitbuilt loco!

Actually I lay track on trackbed painted with neat undilued PVA and immediately add ballast OR if ballasting after laying I paint neat glue around the sleepers carefully and then add ballast onto it so I get no glue on the ballast at all but that method isn't for anyone impatient... (+ I use C&L track which has thin sleepers... if you are using the over-thick peco code 100 etc the ballast layer may be too thin for you)

back to conventional ballasting methods....

ballast will always be slightly changed if you drip glue on it - it will always darken for example, and in reality it will be less matt too which I think is not a good thing.

Try an experiment as follows: (don't try to do too much at once - a meter or so at a time - or in the case of this test, a length of track on any old board will do)

Don't use cheap glue. A branded PCA with a good "solids" content will be best when using the meths mix.

have good airflow as meths - alcohol and will smell a wee bit for an hour or so. ( at least its a clean smell though - your train room will smell likethe dentists :) )

Mix the glue 1 part glue to 2 parts water to 2 or 3 parts methylated spirits.
lay and tidy the ballast ready
use a fine squirt bottle and spray the ballast with methylated sprits + water in a 50 / 50 mix
shake the ballast glue mix then
drip on the ballast glue mix with a syringe (the kind used for filling printer cartridges - it doesn't need the needle really, but the 1mm needle they usually supply is big enough and gives better metering anyway)

You don't need to over soak it with glue - just give a good overall covering - with the meths in the mix it'll flow around the ballst much better than adding detergent and really soak in fast

after you have finished give it another light misting with the meths in the spray bottle, especially where its not totally flowed in.

the glue will hold the ballast gently but it'll not be like concrete...
any ballast on sleepers etc will come off easier...
the glue will have flowed over in a much thinner coat thanks to the meths so it'll look more like ballast not glossy rocks
the ballast will dry much quicker thanks to the meths which is alcohol so evaporates off fast.


use woodland scenics ballast glue with woodland scenics ballast - it will give U less grief!


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QUOTE (Brian Considine @ 23 May 2008, 16:17) <{POST_SNAPBACK}>Part of the problem is using ballast that is sand based which most of the cheaper ones are.

If you use a ballast that is actually granite you will not have this problem at all - it will darken slightly using PVA's but that's about it.

Try crushing a bit of the ballast - if it crushes easily it's not granite.

Don't skimp on the glues used - as Richard says, get a decent one.

*** An almost good test Brian - I have samples of three brands that respectively use walnut shells, olive stones and macadamia shells gound up and dyed. These are the three best ballasts I've ever used - and the stone ballasts actually crush much easier than the macadamia nut shell - that stuff is as hard as it comes (titbit of knowledge: Macadamias are actually native to Australia / queensland. Some bright spark took them to Hawaii and now its seen as a Hawaiian thing!).

I think the tinting comes from a combination of a cheap glue and the cheap dye used in making the ballasts.... (peco and horby ballasts for example colour a lot with some glues) and for stone ballasts the acid in the glue reacting with other elements or chemicals local to the areas where the ballast is sourced (it seems wrong to say "mined" when its small scale ballast :) )

John: I use meths as a wetting agent in many applications - I also mix it in acrylic paint when thinning and spraying it - its a really good (better than detergents) wetting agent that helps flow a lot. It is also quite a good paint stripper thats plastic safe - drop most brands of loco body in a dish of meths for 24 hours and the paint will be lifted totally.

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QUOTE (Brian @ 24 May 2008, 01:09) <{POST_SNAPBACK}>Hi Richard
The Meths you use in ballast gluing, is it the clear type or the tinted blue version which we have in the UK to stop us from enjoying its other benefits

***Either Brian - they are both the same alcohol. The blueish tint won't affect the result - there's not enough of it to matter :).

I started using it when it was tinted but something must have changed as over here its now clear once more.

Never tried its "other benefits" - I don't mind "getting blind" on rare occasions but actually going blind by drinking methyl alcohol doesn't appeal at all!

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QUOTE (alastairq @ 24 May 2008, 03:22) <{POST_SNAPBACK}>or is it even the same stuff we have in the UK?

Perhaps there is a reaction with the actual wetting agent?

often, a drop or two of washing up liquid is mentioned......but...which one?

there is a dutch firm who produce a specialised, flexible ballast fixative....which avoids the 'concrete wellie' effect of what is now our traditonal ballasting technique.

**Its the same stuff Alistair - Methyl Alcohol. As to the darkening or tinting of ballast it is almost certainly the acid in the glue which is the culprit, nit the one or two drops of detergant traditionally mentioned.

The stuff sold ex holland and the woodland scenics stuff are both derivatives of artists matte medium, which can be substituted for PVA with the meths and water mix for ecellent results.

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