Technique:

The restoration of rare and costly gun parts mandates the use of TIG welding  for it’s superb heat control and atmospheric shielding. However, other factors must be considered to attain the level of craftsmanship such parts demand. Our primary goal is an invisible repair. Below are some considerations toward attaining that goal.

Surface Integrity ... The weld deposition must smoothly transition into sharp edges, corners, flat surfaces, and contours without erosion or undercutting.

DENSITY ... The weld deposition and the parent metal must posses a similar density. the weld must be homogeneous and free from cold shuts and porosity.

FIRE SCALE ... Side and bottom surfaces of the parent metal adjacent to the weld must be protected from atmospheric scaling at high heat.  Auxiliary argon gas shielding must be applied to these areas, as well as to polished shotgun bores, rifle bores and chambers.

METALLIC LUSTER ... All of our filler rods have been tested and verified for their capability to match the metallic luster of the parent metal. Luster must match for bright polishing, niter bluing, and charcoal bluing. 

COLORATION ... All of our filler rods rods have been tested and verified for their capability to to accept, browning, rust bluing, and color case hardening in the same way as the parent metal to which they are applied. Grain refinement techniques are also employed to enhance color blending. 

HARDNESS ... A large number of gun parts are hardened. Soft wrought iron lock parts, set triggers, and malleable iron receivers and mechanisms are case hardened.  Carbon steel components are quench hardened and tempered, generally to spring temper. “V” springs, hammer notches, extractors, sears, rifle bolts and sword blades are but a few examples. In some cases we can preserve hardness and temper by employing heat sinks, other times we can apply a hard carbon steel weld where it is practical to reduce the weld in a hardened state. We have also been successful TIG welding and re tempering “V” and Flat springs, with only a slight loss in strength.  

HEAT TREATMENT ... Heat treatment consists of pre heating prior to welding, followed by post heating, drawing, tempering, normalizing, or annealing after welding. The purpose of heat treatment is to relieve the internal stresses resulting from welding, refine the grain structure, and improve the strength of the bond. The amount of heat employed differs with the metals being welded, and even the decision to heat treat, or not, is affected by appearance requirements, as much as by technical necessity. Think of the challenge in welding brightly blued shotgun barrels, with polished bores, lead soldered rib, and silver brazed bytes. The method, amount, and location of applied heating requires the utmost in control to achieve satisfactory results.

Provenance ... The history of a gun is extremely important. By knowing the name of the maker or manufacturer, and when the gun was made we can draw much more accurate conclusions about the metals and heat treatment used in the manufacture of the gun.

MACHINING ... Although files continue to be a mainstay of custom gun making, and repair, many shops employ a variety of conventional, and CNC machine tools as well. We  do not perform machining but freely consult with our clients , on fixture design and finish machining, when requested. Our background includes a forty year career in machining, both conventional, and CNC. Unusual restoration jobs do exist where multiple machining operations are interspersed with multiple TIG welding operations. Such jobs must be identified, and carefully planned, to avoid difficulty. 

RESTORATIVE WELDING 401 South Ninth Street, Oregon, Illinois 61061 815-732-1249 Peter.R.Nagel@gmail.com   © 2013 Peter Nagel