I’m ballasting my N-scale layout with material from Arizona Rock & Mineral, using a diluted mix of matte medium after wetting with a water/alcohol soak. In a couple of spots I’ve gotten a two- or three-inch stretch of white residue between the ties. All my searches on the topic revealed ways to avoid the problem, but I haven’t seen any suggestions for fixing it after the fact. Paint over it? Plant weeds or have grain spillage on the spots? Permanently park a boxcar there? Fine, I guess, but how about a way to actually remove the white, short of starting over?
You have sucked up the un-diluted ‘scum’ at the bottom of the bottle. I had an area that this happened in as well. I removed/re-ballasted the ‘spots’ I had - Nithing like the 2-3" area you are describing. I would bite the bullet and revove the area and re-ballast the area.
I have had this happen with white glue in some scenery areas as well(working too late at night and not watching what I was doing). Those areas I let dry completely and they just add more ground foam.
I have enven had this happen with the pre-mixed W/S stuff - Do not shake up the bottle to get it all mexed - You will get the ‘scum’! Iy you must shake/stir it up, run it through a strainer into another container before using it!
Jim
What you’ve discovered is one reason why I ignore the cult of matte medium and use diluted white glue or yellow glue. Another reason is that matte medium isn’t water soluble when dry, so it’s harder to remove and reuse track after it’ ballasted. Weathering may be a solution, or adding weeds/dirt/spillage if that would be appropriate for the track in question. Otherwise you may just be stuck and have to start over.
There are a lot of reasons to prefer matte medium over white glue. A lot of us “cultists” know that matte medium contains talc as a dulling agent, and that you should let this settle out and decant the solution before using.
Before I learned this trick, though, I did get a couple of white spots. I made a wash of gray paint about 10% paint to 90% water and gently dribbled it over the white and the surrounding ballast. The ballast is a slightly different color there, because I didn’t do a very good job of matching the paint colors, but apparently I’m the only one who can tell (unless I call people’s attention to it).
There’s deprogramming for that you know.[swg]
In my experience, there are two reasons why the white film appears when using matte medium.
One, the undiluted matte medium has not been stirred. A brand new container of matte medium probably need not be stirred. But, after continued openings and closings, and as the container begins to be used up, stirring is required before each use to avoid settling. Otherwise, when you start to reach the bottom, the white film can begin to appear when the diluted matte medium dries.
Two, the diluted mixture is too strong. When ballasting, I use a 4:1 water:matte medium mix. Less diluted mixes such as 1:1 or 2:1 can result in the appearance of the white film when the diluted matte medium dries.
If I were you, I would remove the affected area of ballast and start over.
Rich
It’s been tried… didn’t take.
Welcome to the forums.
There was an article in an MR publication not too long ago about this subject. At the moment I can’t remember if it was a magazine or one of the special issues.
The recommendation was to mix the matte medium, then let it sit undisturbed for a week. The above mentioned talc, which causes the white residue, will settle out. Pour off the top into a clean container and discard the thick gunk at the bottom of the jar.
Good luck,
Richard