In my quest to improve Battlefront's T-72 and get my NVA army ready for painting, I've gone to great lengths to get the lower front glacis plate correct. Unlike the newer T-64 kit that has the lower front glacis plate detail molded in, the early T-72 kit is flat with no detail. Soviet T-72 tanks would have had the distinctive toothed plate with eight engineering attachment points above it, whereas the Czech and Polish produced varieties (like those received by the East Germans) would have only had four.
Step one in getting the miniatures ready for upgrading was to fill the seam on the front glacis. I've seen some photos where there is a clear weld line in roughly that area, but the gap seems overly large in scale and its placement wasn't perfect, so I decided discretion was the better part of valor and I filled it.
I used Mr. Surfacer 1200 to fill the gap because it is a nice liquid that can be easily brushed on and controlled. Once the Mr Surfacer had dried (nominally 2 hours, but longer is better), I sanded down the front to make it ready for detailing.
So... the elephant in the room... how to make the detailed toothed front plate? Well, I could use styrene, and that would take a long time, and be nearly impossible to replicate easily and consistently. Or I could throw the Hail Mary and dig out a technique I last used in graduate school - photoetching.
I used the Micromark photo-etch system, and for a hobbyist system it ended up working pretty well. I had a little over-etch which spoiled about 3 of the 12 possible parts, but I think I can fix that next time with a longer exposure. The system requires you to clean the brass, ad a film-based resist to it, expose, and then develop the resist. Once the resist is developed (which uses a sodium hydroxide solution), the brass itself is etched in ferric chloride (and yes, the whole thing does the chemist in me proud!).
One side finished etching before the other, so I had to pull half of the parts out of the bath while the rest were still etching. Once I was done etching, the remaining resist has to be removed in a concentrated sodium hydroxide bath.
All told I was able to get what I think will be nine functional parts (see above). As I currently have fifteen T-72 to finish up, I'm going to have to do another batch of twelve parts, so I may not end up using some of the more over-etched examples above.
Once the T-72 had been sanded, I added the photo-etched part to the lower front glacis and then added the engineering points and other details with strip styrene. I have a great tool called The Chopper that allows you to make multiple replicates of a piece that is a constant length. I'm using Evergreen styrene for the details.
So soon I should have my bevvy of T-72 tanks for my NVA force ready to prime and paint, and they'll not have a naked lower glacis!!! I'm hoping to get one more run through the photo-etcher done this weekend so I'll have enough to finish the lot.