Anyway, over the past few months I have been doing some research on HO scale brick sheets for my ATC building. After a preliminary bit of web searching, I decided to rule out milled wooden brick sheets and focused on styrene. From what I could gather, there are two popular products out there: Plastruct's brick sheets and The N Scale Architect's brick sheets.
N Scale Architects brick sheets also come in different brick patterns, you get two sheets to a package which are roughly 11" x 14" each, and they are about $20 a package. I purchased their #50001, which are referred to as "Modern Brick." These bricks are perfectly molded with much more relief, and look extremely uniform. The sheets are made in white plastic, and the lines are easy to see. The best part though is that the sheets are huge, and I can do any side of my building without having to splice. However, they must be ordered online as my local hobby store doesn't carry them. The cost per square inch works out to 0.06 cents.
To test out and compare the two brands, as well as hone my skills in using them, I built a small structure out of some styrene I had lying around. I laid it out so that each wall had a window, and the four corners would test joining the material to itself and to the other material.
One concern I had was that I had read applying too much cement would cause the sheets to melt. While I didn't pool it on, I used my normal liberal amount and the sheets came out fine. I even added more than necessary from the inside at the windows and nothing bad happened. I also had considered sanding the edges to 45-degrees so that they would join perfectly. This stuff was so thin though (about 0.020") that it would have been impossible.
1.) Trim the Factory Edges: always make sure to trim or cut all four edges, as the styrene brick lines were not always parallel to the edges. After you have done that, make sure to mark what is an established "straight" line. I used a black marker, which is why some of the pictures show this.
2.) Orientation: the brick sheets have a front and a back, and if you flip them around the grout lines will be reversed and look silly. The bricks are tiny, so I used a pencil to write "back" on the reverse sides to help me.
3.) Measure carefully and cut a little oversize: since the joints will not be hidden with angle trim, drain pipes, or vines, I cannot cheat and try for good enough. The joints need to be spot on. One of my cuts was about 0.015" too short and it doesn't look good. I guess I could fill it with putty and carve brick lines, but I think trying that might make those brick lines I scribe look too large. I am glad I tested this. I think I will add each side to overhang whatever other ones already exist, and then trim/sand/file down to size.
4.) Windows: because the styrene brick sheets are so thin, I can see the window openings by holding it up to the light. I don't think pre-cutting the windows in the brick sheets would be a good idea because trying to get it all measured and cut, and then glue it perfectly to the building core, would be difficult. When I went to cut the N Scale Architects' brick sheets I cut a bit on the inside and carved my way to the edges, finishing up with files. For the Plastruct, it acted like rubber and I was able to remove it by moving the blade along the edge. It wasn't bad, but it didn't act like the plastic I was used to . It's hard to explain, but both materials worked well.
Here are some pictures of my test structure, which clearly show the two different brick products. The first picture (with the Plastruct on the right, N Scale Architects on the left) shows a perfect joint. You can really see the textural differences in the molded bricks. I actually like the "sloppy" style of the Plastruct bricks more, but after painting I think the effect would be lost. Perhaps if I am going to model a more run down structure I can use them. They may be molded in the red so that they only require a matte finish without a paint coat, but I am not sure.
I had to be really careful when applying the cement because I couldn't use clamps. If I did, and some cement got between the clamp and the brick sheet, it could melt the bricks and make them look terrible. This isn't a concern on a regular styrene building because sanding and painting hide that problem. But not with bricks!