Titanium will tolerate almost nothing on its surface when it is hot. Oxygen, nitrogen, carbon, moisture and shop oils are all absorbed into the metal rather than sitting on top of it, and the result is a hard, brittle zone that behaves quite differently from the parent material around it.
Because the contamination is absorbed rather than deposited, it cannot be removed afterwards. A joint that picked up oxygen during welding carries that weakness permanently, which is why nearly all the effort in titanium work goes into preparation before the arc rather than correction after it.
The first contamination usually arrives before the weld does. Cutting fluid, saw swarf, grinding dust and oxide from abrasive cutting all sit on the cut edge and in the joint gap, and they will burn into the puddle the moment it forms.
Machined edges are the worst offenders because the debris is fine and gets into places a wipe will not reach. Hand-finished and formed parts carry their own residue too, from lubricants used in forming and from any steel tooling the metal has been dragged across.
The first cleaning step is mechanical, using a dedicated stainless brush or an abrasive that has only ever been used on titanium. Sharing a brush with steel deposits iron particles that contaminate the weld, and the discolouration that follows is often blamed on the gas when the tooling was the cause.
Cleaning should cover the joint faces and a margin either side, plus the area the arc will pass through. Only the surfaces that will be hot need attention, but on a small part that is nearly all of it, and it is worth doing properly rather than quickly.
After mechanical cleaning comes a solvent wipe to lift oils and handling residue. The order matters: wiping first and brushing afterwards simply pushes contamination back into the surface, and the part then looks clean while being worse than before.
Solvent should be fresh, applied with a clean cloth dedicated to titanium, and allowed to evaporate fully. Trapped solvent in a joint gap turns to gas under the arc and shows up as porosity that has nothing to do with the shielding.
Clean titanium should leave the bench only as a finished part. Bare hands leave oils, gloves used for steel leave iron, and a clean surface left out in a workshop collects airborne dust and grinding debris in minutes. Cleaned parts are best covered or bagged if there is any wait before welding.
Storage follows the same logic. Tube and sheet kept clean, separated from steel stock, and handled with dedicated gloves avoids redoing work. Preparation is the part of titanium welding with no shortcut, and it is where the outcome is decided on parts such as our TIG titanium welding parts.
Multi-pass work needs cleaning between passes, not just at the start. Each pass leaves a heat-tinted surface, and that oxide is both a contamination risk and a barrier to the next pass fusing properly. On titanium the tint should be addressed before the next run rather than welded over.
The same discipline carries into finishing. Any part that has to be uniform in appearance is cleaned mechanically and the surface restored rather than polished over the top, which is the working rule for the titanium fabrication components produced on this side of the shop.
