navyman636
Thanks for the detailed explanation of efflorescence. I had it partly right in that it is moisture related but I didn't realize that the minerals did not come from the brick.
Dave
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
The white stains you mention appearing on the face of the brickwork very rarely have anything to do with the bricks themselves. When brick is fired correctly each brick ends up with a surprisingly tough 'skin' on all sides which is a huge part of the reason good bricks are so durable. (In some historic brickwork the skin has remained intact for many hundreds of years.) Its also the primary reason that sandblasting brick is always such a destructive act, generally leading to more rapid failure of the bricks, both in appearance and as structural components, than whatever may have been the original concern that prompted the decision to sandblast.
The white stains are the result of what we preservationists commonly call 'rising damp.' They result from excess moisture at the lower part of the wall, sometimes because of foundation failure but more often from allowing water to gather at the lowest part of the wall surface, by poor ground contouring and drainage. Over time the moisture wicks upward, drawing salts and other mineral compositions along with the moisture. As the rising moisture evaporates from the brick surfaces it results in a process called efflorescence, which can also take place on the surface of some stonework as well. The evaporating moisture leaves the mineral deposits behind when the water departs as vapor, and this salt deposit coats the outer surface. It also, because of the chemical composition of the salts deposited, accelerates the failure of the brick skin and then of the bricks themselves as the protective skin is dissolved by the salts. Again, the reason this shows up most often at the lower part of a brick wall is because the process is one of the moisture wicking up from below, not down from above.
Stains that appear to be coming from above can result from things like sheet metal cornices rusting, or wooden cornices and fascia dissolving because of bad maintenance, with the resulting moisture-carried stain being drawn down onto the brickwork by simple gravity. Another possible reason for stains coming down from above is because old (or sometimes poorly chosen and poorly applied new) paint powdering off the painted surface and being washed down in rain. Sometimes these stains can be washed off but washing brick should always be done gently to preserve its skin.
One other possible reason for what looks like stained brickwork is the failure of the mortar joints between the bricks, with the mortar dissolving in rain, usually, and the lime and other (perhaps unintended) mortar components washing down. Since the purposes of mortar include that it be sacrificial, this isn't unusual and will eventually appear on all brick walls, even those done by the best masons. This is part of the reason why repointing mortar demands knowledge and skill - the old, failing mortar is scraped out of the joint without damaging the brick, and good new mortar is inserted to restore the joint. The 'sacrificial' aspect of mortar is that it is specifically intended to fail before the bricks themselves will fail, which is why mortar, whether mixed for newly laid brick or for repointing old brickwork, should always be mixed to be weaker in strength than the bricks themselves. It's easier to repoint the brickwork than it is to replace the (often historic) brick, especially old brick of uncommon color and size. If you ever need brick repointed and you see your mason adding cement of any kind to the mortar mix, you need to fire that mason before s/he ever touches your wall, or you'll lose the entire wall decades before its expected lifespan is up.
When I'm assembling a brick structure I do whatever I can to make the mortar appear as unobtrusive as possible. There are no truly white mortars used in brickwork, although it is possible to get a white mortar by using a mix that's inappropriate for use as mortar. Sometimes too, when assembling a model of an old building with brickwork I'll revise some spots of the mortaring on the model to appear as a very badly done repair job, an occurrence those of us in historic preservation see all too often.
Thank you everyone for being so welcoming to the forum and hobby! I would post photos, but cannot seem to figure out how to do it correctly - any suggestions? All of the responses sound like great tricks, I am putting together a few DPM kits from woodland scenics and will be sure to try some of the new techniques I learned from everyone.Thanks Again,
ctrdylOn Another Note,Will I always have to wait for my posts to be approved or is that something that only happens to newcomers?
ctrdyl
Welcome to the forums!
Thanks for sharing your method. Posting a few pictures of your results would be great!
I have used a thinned grey acrylic wash to fill the mortar joints in my HO scale Walthers buildings. I apply the wash and let it dry for a couple of minutes, and then I use a damp cloth to scrub the mortar colour completely off of the brick face. I think that that is the most crucial step. Professional brick masons would never have left a trace of mortar on the face of the bricks. The result is rather subtle but I think this is a case where less is more. I have seen a lot of buildings where the mortar colour was left on the face of the bricks and they just do not look realistic.
There is one case where white stains do appear on the face of the brick, and that is where weather conditions and poor construction cause minerals to be leached out of the bricks. These stains generally appear lower on the walls and have a sort of cloud like appearance with the top of the stains standing out clearly and the lower parts fading into the brick. They are common here in Ontario. I am not sure if they are related to the freeze/thaw climate or if they appear in the south as well.
sschnabl I built the Walthers roundhouse kit a few years ago. I spray painted all the bricks the mortar color, in this case a grey primer. Then I dry-brushed the brick color on the tops of the bricks, being careful not to get any of the brick-colored paint in the mortar lines.
I built the Walthers roundhouse kit a few years ago. I spray painted all the bricks the mortar color, in this case a grey primer. Then I dry-brushed the brick color on the tops of the bricks, being careful not to get any of the brick-colored paint in the mortar lines.
I do something similar, only instead of a brush I use an art marker. It's not like a felt-tip marker, it has a hard point so the color only goes on the raised bricks. I don't remember the brand, but my favorite is called "English Red" and I get it at the local Michaels' art/craft store.
This is one of my better mortar jobs:
It's one of the Walthers "Merchants Row" kits. The front wall is a single piece, but it models a group of adjoining buildings, so I did a lot of masking to make each storefront distinct.
The left side was sprayed with primer and the mortar was applied by "flowing" an acrylic paint wash into the grooves. The weird thing, though, is the center section. I sprayed the white paint over the original tan base color, working with the rattle-can at a low angle because I had the model surface in a cardboard box on top of my gas grill. The paint settled preferentially on the brick, and didn't flow into the mortar lines, leaving me with the best brick wall on my layout.
It takes an iron man to play with a toy iron horse.
For the last N scale engine house I've put together I had used wet water with a bit of black acrylic paint to do my dirt and grime wash. Once dried, much to my surprise the soap in the wet water had settled as white residue in the mortar grooves, while the faces of the bricks had the expected grimy look to them.Who new! Worked out great for me.
I built the Walthers roundhouse kit a few years ago. I spray painted all the bricks the mortar color, in this case a grey primer. Then I dry-brushed the brick color on the tops of the bricks, being careful not to get any of the brick-colored paint in the mortar lines. There is a company out of the Milwaukee area, Roberts, I think, and they have a mortar product that you apply over the painted surface and then wipe off the tops of the bricks. I haven't tried it yet, though.
Scott
A minor technical correction:
Mortar is used to secure brick and concrete blocks. Grout is used in the gaps between ceramic tile. They are two distinctly separate products.
You can't use grout to lay concrete blocks or brick, and you can't use mortar to seal the gaps in ceramic tile.
I've used the same "powder" technique, first with common baking flour and then with Hydrocal. Both work OK. I set the Hydrocal with a water mist, so it remains plaster-like and will take an India Ink wash to tone it down.
Now, though, I'm using a thin wash of acrylic paint, mostly white with a bit of gray added for color. I find that it flows into the grooves much better if I first spray the building with cheap rattle-can rust or brown primer. I'm modeling in HO, which may make a difference on which technique is better, as the mortar lines are larger than they should be in N. This takes several applications, but I find it easier as I don't have to do any spraying.
Thanks for the suggestion! I used diluted white paint and it was very messy - too much time and effort. I have white weathering powder that I think has an adhesive in it.
Terry
The Problem: I have been assembling some of the Walthers cornerstone n scale kits for my layout and noticed that many modelers were frustrated with their kits because the pictures on the box presented the model with grout between the bricks, a detail not molded into the kit.The Solution: After a little tinkering I found that by using white pastel powder (I made mine by scraping a white pastel so that a powder formed in a small container) one could brush the white powder onto the model and that the white powder would naturally gather in the gaps between the bricks creating quite a realistic and fast way to add "grout" to the model. Many modelers are use to using pastel powders to weather buildings, and the technique is very similar. If you are looking for a darker or more grey grout effect multiple pastel powders can be mixed to create the ideal color of grout for your taste. After the desired grout affect is achieved I used a clear flat enamel spray to seal my "grout" in place.
I thought I would share this since I have found it to be a very helpful technique on anything I model, and I hope you find it very helpful too!!! Does anyone else have any thoughts on how to detail the Walther's kits?All the best,ctrdyl