Brick mortar color and dirty washes

Mike,

I have been experimenting with the same weathering techniques. The answer I have is Chalks. Try using them here is a link that has a good step by step procedure on a HO building:

http://www.google.de/imgres?start=89&sa=X&biw=1366&bih=673&tbm=isch&tbnid=_AbgBDG74YXNPM:&imgrefurl=http://www.gatewaynmra.org/2003/building-smalltown-usa-helens-country-kitchen-assembly-tips-techniques/&docid=OgyszSfD89dD1M&imgurl=http://www.gatewaynmra.org/wp-content/uploads/2003/10/rix-helens-kitchen-07.jpg&w=613&h=555&ei=PuyUUuCyCOWyywO2iIHgBA&zoom=1&iact=rc&dur=381&page=4&tbnh=142&tbnw=153&ndsp=33&ved=1t:429,r:5,s:100,i:19&tx=72&ty=50

There's really no need to strip the mortar. You can "paint" the entire structure with an alcohol/india ink mix and it really won't change the brick color very much, if at all. I start with a very small amount of india ink added to the alcohol, then brush a small area. It it's too light I add another drop or two of ink, then brush again. Repeat until you get the desired effect.

You'll be happier with the results if you wash, prime, and paint the ice house first before applying the alcohol/ink wash. Use cheap primer and paint, preferably flat. I use the Walmart dollar cans. Use the same method as above to make the dirty wash. Don't use the same batch you mixed for the switch tower except as perhaps a trial. It may be darker than you want to weather the ice house.

There are many different ways you can weather a building. Peeling paint, rotted wood, and on and on. Here's a picture of a Bar Mills kit I did using only alcohol/india ink and chalk on the roof to weather:

do like brr does, but you are not limited to inda ink. You can choose a bunch of different colors..Check out hunterline weathering mixes.

BRR's approach is what I typically do.  I wash the entire building with the India ink wash.

If you want a darker look, you can make a second coat.