Possibilities

I wet ballast using water with some isopropyl alcohol added, then apply white glue (PVA) diluted 50:50 with water.  I haven't encountered the problem you describe from that method.   I'm not sure any of these ideas help:

• Normally complaints of white residue come from using matte medium for adhesive, and are the result of talc that hasn't settled out of the medium.
• I tried off-brand cheap PVA glue from the dollar store once, and found it didn't fully dissolve.  Maybe you have a lower quality brand of glue?
• I found that alcohol can cause clumping when mixed with PVA glue.  After discovering that, I only dilute with water.
• Alcohol can cause Dullcote or other flat finish lacquers to turn white.  If you had any of that on the track, another application of Dullcote should eliminate the spots.

Alcohol problem...

PVA suspect...

Thanks gents, the odd thing is that I have the same outcome when I use only water as the wetting agent. 

The stretch that is now drying out actually looks worse then the previous stretch whilst I added a bit more water for the setting mix, somewhere in the region of 40/60 glue/water.

I reckon Rob is on the right track and the PVA is the suspect here. 
Will buy different PVA to see if that makes a difference. 

To remove the residue, I very carefully touched the areas up with a very fine oil, normally used for the spindle and bearing of my turntables. It actually really bring out the detail a bit more too whilst it does not seem to affect the glue holding down the ballast. 

Thanks again!

Henk

Hey- maybe...

you could try what I did... and let me know if it improves results.  Last ballasting I tried included Rain-X as the wetting agent- good results!

I think the white is PVA... and will wash off.  But what a drag!  Perhaps using a thin application of paint to color the ties for an 'alternate age' appearance (the RR's don't install All at Once, ya know! - except on New routes.)

Hard water dries with white

Hi Bruce, You know, that

Hi Bruce,

You know, that could be a reason too.

Here in the South East of the UK the water is very hard and we are continiously descaling taps, shower heads, coffee machines etc.

Since I have distilled water for cleaning vinyl, this is worth a shot too!

Thanks for the tip!

Henk

White ballast

Henk

Anytime you want to buy ANY liquid products, especially white glue, don't go for the el cheapo brands and always buy from the most popular hardware store in town because they are more likely to have the highest product turnover rate.

These white spots are likely to have a weaker bond but try picking at the spot with something sharp after about one week of drying.  If it still is a strong bond, visit your local art supply shop and buy a dark grey pastel stick and using the finest grade of wet and dry paper to create your own dust which you then apply on the ballast between the rails to cover the white spots using a make-up brush.

While you are at the art shop, see what sort of a deal you can get on buying a few 500ml bottles of Matt Medium which looks like white glue and is used to paint over paintings or drawings to protect them.  This product is by far the best to use to glue down your ballast and guarantee no white spots.

I have been using this method for many many years and the results have always been excellent.

It the drinking water from your water supply is suspect, buy a four litre bottle of water at your supermarket for use in an electric iron which has been de-ionised so that the steam holes don't clog up.

A better ballast adhesive

A problem with white glue and detergent is that under high humidity conditions (a dozen or so guys in for an operating session) it can create enough leakage current between the rails that it triggers some occupancy detectors.  To avoid this I started using "deep" base latex paint.  These base paints have no white pigment and are intended for making dark colors.  They also contain none of the ionic materials that can generate electrical conductivity.  Still there is some talc that can cause a blush.  I recently tried Minwax Polycrylic clear satin wood finish.  This is an acrylic paint base intended to dry clear.  I don't like it as a wood finish, but it makes a great ballast  and general scenery adhesive.  There is no talc to cause a white deposit.  I make a ballast mix using 50% Polycrylic, 25% water and 25% isopropanol.  The dilute mixture has remained stable for over a year in the plastic bottle the IPA came in.

matt medium

Another vote for Matt Medium

I use a good quality of matt medium, it takes forever to dry, usually overnight, but it dries perfectly clear and will not yellow over time, as I've heard can happen with some white glue mixtures. Dries hard as a rock too! Wetting with distilled water, or even just filtered water if you have a filter on your faucet, can help a lot with your wetting agent. Alcohol is cheap enough, but I prefer to just use filtered or distilled water and a drop or two of dish soap for a wetting agent. It doesn't smell so strongly as the alcohol, and works just as well.

And as for your present issues...

I forgot to mention, you could just paint the ballast with an airbrush. To deal with the white ballast you already have.  I've done this with good results, if you don't get perfectly close to each tie or the rails, no big deal, just free hand it, or use a card to block overspray from the rails. if it's really bad near the rails or ties, touch up with a small brush. I used some sand on a model that I was not particularly happy with the color, so I airbrushed it, and you could not tell it had been painted. It looked great!

White Residue After Ballasting - An Alternative

Many years ago when I was modeling in HO there was a wood glue product that my father used in his workshop.  I used it to ballast my track then.  That product was Weldwood dry wood glue.  I'd dump some ballast into a plastic container that had a cover, drop in a spoonful of the dry glue component put on the cover and shake well.     I would then apply the mixture to the track followed by a mist of water + dish soap.  Worked quite well.

I've moved on to N-scale and tried to find Weldwood dry wood glue at the local home improvement store.  The clerk I spoke with didn't know what I was asking for so I came away empty handed.  I did a Google search (today 12/31/12) and found the DAP products site.  It seems that the product is still available under the name Weldwood Plastic Resin Glue by DAP.  I do not know if this is the exact same stuff that I used ten - twenty years ago but...

According to the DAP website the stuff is still available and seems to be found more in the local type hardware stores (Ace, True Value and Family Farm and Home were the primary search returns when I searched for a local dealer on the DAP site.)

I'm not quite ready for ballast on my new layout (the West Huron and Toledo) but when I get to that point I'm going to test this old method - I worked quite well then and I'm hoping that it will work quite well now.

Bob Holmes

http://www.railheadphotography.com

White residue

Here is where you want wrong....................

3/ Glue it in place with the 50/50 mix of water and PVA glue, using a few drops of dish washing liquid

you only have to use dish liquid in the water!