I replaced the gun barrels with those of the RB Model sets 35B74 (75mm M2 L/31 and 37mm gun) and 35B82 (M1919 Browning machine gun). The upper hull, built up from many separate pieces, was not the nicest to put together, with a few gaps to fill. I think this should either come in fewer pieces or have an underlying frame onto which they are attached, such as is done for the turret in this Panther model.
“The Soviets … after one year of hard fighting realised it was hopelessly outdated. Surviving vehicles (infamously called “A grave for Seven Brothers”) were retired from front-line operations and shipped to quieter or less well-defended sectors, like the Arctic front.” 
Takom 1/35 kit .
Unknown unit, Uralmash, Sverdlovsk (Yekaterinburg), 1943.
SU-122 build – Part 1:Introduction
SU-122 build – Part 2:Assembly
SU-122 build – Part 3:Painting
SU-122 build – Part 4:Weathering (rust and chipping)
SU-122 build – Part 5:Weathering (wash)
SU-122 build – Part 6:Weathering (streaks)
SU-122 build – Part 7:Weathering (dust and rain marks)
SU-122 build – Part 8:Tracks
SU-122 build – Part 9:Weathering (dirt and mud)
SU-122 build – Part 10:Weathering (oil, fuel and damp stains)
SU-122 build – Part 11:Stowage
- The plastic, resin or balsa wood items were sprayed with Tamiya “Fine Surface Primer” (light grey).
- The stowage items were first painted with Mr.Color “Dark Green (2)” (23) or “German Grey” (40) or “Wood Brown” (43) or “Khaki” (55) or some of the paints of the Mr.Color “Russian Green” modulation set. All mixtures were in the ratio of 1 :2 in Mr.Color leveling thinner.
- The wooden beams, once painted a wood colour, were treated with several layers of AK Interactive “Heavy Chipping” fluid. Once dry, Mr.Color “Character Blue” was sprayed over it. Thirty minutes later, I selectively removed the blue paint with a stiff brush and water.
- Details were painted with Vallejo Model Color “Black Grey” (70862) or “Russian Uniform WWII” (70924) or Vallejo Panzer Aces “Leather Belt” (312).
- Some of the items were drybrushed with Vallejo Model Color “Khaki” (70988).
- The fuel drum was chipped with Vallejo Model Color “German Camouflage Black Brown” (70822).
- A 1:2 mixture of Mr.Color “Clear Gloss” (46) and Mr.Color Leveling Thinner was sprayed over the items.
- The items were washed with Wilder “Brown Shadow” (LS25) oil paint in enamel thinners.
- A 1:2 mixture of Mr.Color “Flat Clear” (182) and Mr.Color Leveling Thinner was sprayed over the items.
- The spade was brushed with AK Interactive “Dark Steel” (AK086) pigment.
- The same pigments used on the vehicle were used in various places on the items.
- Abteilung 502 “Engine Grease” (ABT160) and “Bitumen” (ABT004) oil paint in enamel thinners were used in various places.
- Following real pictures (here and here) I had left the fuel tanks and holding straps off on one side, replaced by an improvised unditching beam. I did put a spare fuel drum (perhaps containing oil instead) stacked against the other two on the opposite side.
- Tamiya “Soot” weathering powder and Vallejo “Carbon Black” pigment was added to the end of the exhausts and the surrounding area.
- The gun barrel end was lightly brushed with Vallejo “Carbon Black” pigment.
- Dilute mixtures of Abteilung 502 “Engine Grease” (ABT160) and “Bitumen” (ABT004) oil paint in enamel thinners were either painted in small patches or flicked from a brush onto the surfaces of the hull and running gear, to represent the subtlest stains or patches.
- “Engine Grease” oil paint – dissolved in enamel thinners to a much higher concentration – was added to parts of the running gear, certain wheels (to represent leakage from a seal) and parts of the engine deck to represent older oil stains.
- The same oil paint, in similar concentration but with added Humbrol “Gloss Cote”, was added to certain parts to represent newer oil stains.
- A dilute mixture of “Bitumen” oil paint and Humbrol “Gloss Cote” in enamel thinners was added to various parts of the engine deck and hull to represent diesel stains. In some places, such as around the fuel filling hatches, this was repeated later.