Welding Tips and Tricks

Just started a new job TIG welding aluminum....since it is manufacturing, time is money. As a matter of practice and as something I always do, I began stainless steel wire brushing all of my joints after fit up but prior to welding, and was told to skip that obviously because it takes too much time. Needless to say the welds turn out so/so but not as good as they could be. I increased my cleaning action on AC but I find it odd they do not want me to brush the area. Keep in mind the surfaces are not wiped with acetone or any other pre-cleaner. It is just straight 6061-T6 aluminum which has been kept indoors but still has a bunch of oils, oxide, and scale on it. So my question is, has anyone else dealt with this in the workplace? Just seems a manufacturer would want contamination-free welds as well as a nice looking bead. It is harder to accomplish without at least brushing before welding. Right now I'm just doing what I'm told and skipping the wire brushing but am a perfectionist and want the best beads possible. Thoughts/ideas? Thanks.

Demonoid.

The welding technologist or engineer should state within the procedure the degree of cleaning the base material before welding. That procedure, written or verbal, is given to the supervisor who in turns gives the welders their instructions. One reason of many for 'written' welding procedures is to ensure that the welders get clear instructions. Usually if a supervisor orders the welder to shortcut the procedure, the supervisor should also sign-off and take the responsibility for the decision.

There is also an 'acceptance criteria' for what makes the weld acceptable. If the procedure does not require brushing of the base material, and if that finished weld conforms to the acceptance criteria, then that weld is okay from the point of view of the fabricator.

It is helpful when a welder makes suggestions to the supervision and welding engineering to improve the welding process and welding productivity. The management if wise, will evaluate the suggestion and make a decision. A suggestion is usually accepted by management if the suggestion will both optimize the welding process and increase productivity.

Alexa

Alexa gives a great techincal description.

However, you have to weld it. Ask for a copy of the WPS for the weld, and refuse to work outside it's specifications. Every last detail should be there, right down to what tungsten you should use.

If they don't have a WPS for the weld, you're off the hook, and can burn it in any 'ol way, but I would HATE that.

6061 ain't cheap, and the customer who's paying for it will expect a certain standard of weld.

Steve S

Also depends on what treatment the part gets afterwards. Many things are treated further after they are welded, say, media blasting and protective coatings. I weld a lot of things that get powder coated. After they are finished, it's difficult to tell that there is actual welds there with even the dime edges being almost indistinguishable from a smooth fillet.

ETA: I rarely clean or brush anything these days and make up for it in other ways. I also notice that a lot of the things I build end up being overbuilt by default with addition of other members that make the structural importance of weld strength moot, collectively.

This is something that I just don't understand. Cleaning is one of the most important things on TIG as we all know. Even if the weld won't be under stress etc.
It seems that certain people just care about money and time.... It's sad sometimes.

Markus.

True, money and time are important variables.

It is also important to understand the acceptance criteria.
The buyer of the products from the fabricator should agree to that acceptance criteria.
If the level of the quality can be reached with less work (money and time), then there is little use in making a product more expensive.
For example, the butt joint welded between to pipe lengths of a pipe line, will have an acceptance criteria that states among other things, a maximum quantity of slag inclusions. With a fast moving pipeliner team, the welder and/or the grinder often clean those welds 'just' enough to reach the acceptance criteria of the slag. This moves things alone faster, and the Client is getting the agreed upon weld quality.

Tanks.
Alexa

Personally, I don't clean aluminium unless it is visibly dirty. If there is obvious oil, grease, cutting fluid etc. I go for the acetone, but with new stock I've found that pretty rare (just wipe dry before tacking). Usually I tack it straight up and would only clean/brush if something untoward happened during tacking. I only wire brush if the aluminum is obviously crusty (say parts that have been on my boat). I like the idea of the spray bottle with weak detergent though. My projects aren't really sensitive to the width of cathodic etching, so I tend to run a little bit more on the AC balance than is strictly necessary.

I suppose my "anal" predisposition for cleaning aluminum comes from the repair work I sometimes do. I have to grind paint and road grime off.

I also did a job that was 100% x-ray with extremely strict standards. That was a "clean your rod, too" kind of job.

To support the topic, though, I've welded stuff that still had paint in pitting that blew up at me, even puked on my tungsten, and got acceptable results.

Steve S

I agree that sometimes it is just better to clean it than to find out after the fact. But, we also have to realize that many of the school ingrained procedures were adopted before we were competing with countries that pay their workers 3.00/day or .75/hr.

I weld in such a way that contaminants are strictly superficial and at most 'might' be a little aesthetically unpleasing, but do not weaken the integrity of the weld. If I see that it might get into the lower structure of the weld, I merely float them higher with a slightly taller bead, As long as the throat of the weld is pure, there will be no issue.

Wire brushing on plate is one thing, but on pipe, it is often more unattractive than the weld done without it. I typically grain the brush marks accordingly so that it's not noticeable once the pipe oxidizes over time.

I did experience this in my first welding shop. Now I never tried to wire brush anything because it was kept indoors and usually did not have a lot oxides but there was a lot f oils, grinding dust on the material. How I handled it was how many parts there were and what the weld criteria was. Some of the stuff was simple .063 corner to corner joints so I didn't do any cleaning. Some of the small run more critical parts like .030 no bleed through boxes I would give a,quick wipe down with a cleaner. Usually would only get a order of 30 to 40 so would only take 5 minutes of my time to clean. Some of our thicker stuff that got bevels ground in them I would clean as well because they had to air tight and hold pressure and we were having porosity issues. if it causing issues talk to someone about it, your welding inspector, supervisor etc. if it's not causing issues a trick I found helpful when welding dirty material was to weld a little slower. There were parts we did that were just to big to clean in a timely manner,.so dropping your balance a little and slowing down should help. If you are really fast and exceeding you hourly numbers I would ask someone if you can clean the material as long as you hit your hourly numbers they probly would not have a issue with it.