First published in the August 2009 AMMS Brisbane newsletter
One of the enhancements one can apply to a WW2 AFV model is to model the weld lines on the vehicle. There are innumerable techniques for doing this using solvents, soldering irons, etc. However, there seems to have been little consideration of exactly what the original weld beads looked like on the original vehicles. For example, the welded hulls of the Russian KV-1s used a welding process which produces no external weld beads yet I have seen a number of KV-1 models complete with prominent weld beads
It’s worth surveying the welding techniques used in the production of WW2 tanks and the appearance of the weld lines associated with those techniques. I’ll restrict my comments to the welds between the main armour plates of the hull and turret. Many small components were welded onto the hull/turret but the thickness of these means that the weld beads are quite narrow and can’t be easily modelled.
In the early part of WW2 weld lines weren’t noticeable on tanks because the plate was fairly thin and it seems to have been standard practice in most countries to grind the welds flush with the plates. This practice continued in Britain and the US throughout the war. Modeling welds in these vehicles should be limited to modeling scuff marks from the grinding process. In Germany and Russia however, the need to maximise production volumes and the need to increase the armour thickness meant that welds were left in a rough state when the tank was delivered.
German tanks from 1942 onward were notable for the practice of using interlocking armour plates with prominent weld lines along the plate joints. At this time the Germans knew of no technique to weld thick plates in a small number of welding passes so the welding practice used appears to have been open arc welding which produces a rippled surface from the multiple passes of the arc. The image is from the side of the frontal plate of a Tiger I. The classic modeling techniques using hot wires or fine soldering irons can be applied to models of these vehicles.
Russian practice is more complicated because of the different capabilities of the competing Kirov (Leningrad) and Kharkov plants. The Kharkov factories had access to the advanced welding technologies pioneered by the Paton welding institute in Kiev whereas the Kirov factory initially used older and more expensive techniques.
The main product of the Kirov plant early in the war was the KV series of tanks. The armour plates were joined by an expensive process of bolting the plates together and then welding the interior angles of the plates. This means that there usually aren’t visible weld beads on the exterior of the tank but the cut off bolt heads are noticeable. The image is from the rear of a turret of a KV-2 the row of dimples corresponds to the bolts used to join the plates – note the minimal weld bead on the plate join.
From early 1942 T-34s were welded by a submerged arc (electroslag) technique which gave good weld depths and could be done in a few passes. This was so successful that the Russians claimed that they could replace 10 or so skilled welders with a semi-skilled operator. The appearance of the weld done with electroslag welding is quite different from classic arc welding. The weld bead stands proud of the surface and usually is quite smooth. The image is the weld of the glacis plate to the side plate of a T-34 Model 1942. This welding process was so successful that the relocated Kirov factories at Chelyabinsk (Tankograd) adopted it for the IS-2 series of tanks. Modeling welds on these vehicles is more difficult than for German vehicles since the weld line must be built up to emulate the raised beads of the electroslag welding process.
Details were taken from images on www.ammsbrisbane.com (Tiger), www.jagdtiger.de (KV-2) and www.thetankmaster.com (T-34)