Thread: Welding thin durogal tubing

I usually crank up the amps on the MIG, use the extra heat to burn through the gal and then speed up your pass once you get through to the metal. Of course do your welding in a well ventilated area to avoid breathing in the fumes.

Yes, I got the settings that seem to work OK, I think. However and this may be my lack of skills with a MIG, I seem to need to start and stop weld rather then continuous if I want to prevent holes.
Using canola oil spray as an anti spatter seems to help a tiny bit.
Interesting the "canola oil" smells badly as fish oil.

Duragal is designed to be welded without grinding the joint - it's a much thinner coating than batch-dipped gal.

Originally Posted by RustyArc

Duragal is designed to be welded without grinding the joint - it's a much thinner coating than batch-dipped gal.

What Rusty said, I've never cleaned Duragal prior to welding, suspect you may have settings a tad too high or the combination of grinding and canola oil is blowing holes.

You shouldn't need to use any anti spatter, just weld it as is and then clean afterwards with a rag or wire brush when you finished welding it all up.

If you like I'll weld a bit tomorrow to show you.

For more info download the Duragal welding guide from here
DuraGal® Easy Welding Guide (Technical Information)

Also have a look at Grahame Collins' info here
https://www.woodworkforums.com/f160/h...uragal-155607/

Keep the MIG torch angled right over too, go fast and hold your tongue just right.
Good luck with it.

Cheers.

Originally Posted by Marc

I am building a balustrade in 25x25x1.6 durogal. It is 20 meters of balustrade and at 110mm between balusters, it is a lot of welding.

Is there a trick to weld galvanized steel, short of burning it off before or grinding it off?

I found that grinding is not an option. Uneven steel from hammering, can not get to the galvo in the dimples, plus too thin, make it even thinner end up burning holes in it.

I can see burning with an oxi could work, but time consuming and don't have one.
Any suggestions very appreciated

You shouldn't need to burn or grind duragal prior to use, typically you will find that the clear coating on duragal rather than the zinc coating gives the greatest difficulty.
How are you applying your canola spray? If you are spraying the clean nozzle of the mig then thats fine although duragal is nowhere near as bad as true galv in this respect. If you are spraying the job then I would suggest that you probably shouldn't.
I notice that you mention hammering the joints. Are you using pipe top and bottom rails with 25x25 verticals? If so, a much neater solution would be to scallop the ends of the 25x25, you will get a tighter joint this way into the bargain.
As with all mig work on galv, CO2 is king of the shielding gasses, but if you have only Argon mix then it will also work albeit with a greater incidence of porosity and more spatter. It will also be of benefit if you direct the arc primarily on the thicker section, or that which does not have a raw cut edge and wash the weld metal onto the raw edge or thinner section, (we're talking "T" joint here).
Make sure that you tune your settings well, the better everything runs and is set up, the greater your productivity and success.

Originally Posted by Karl Robbers

You shouldn't need to burn or grind duragal prior to use, typically you will find that the clear coating on duragal rather than the zinc coating gives the greatest difficulty.
How are you applying your canola spray? If you are spraying the clean nozzle of the mig then thats fine although duragal is nowhere near as bad as true galv in this respect. If you are spraying the job then I would suggest that you probably shouldn't.
I notice that you mention hammering the joints. Are you using pipe top and bottom rails with 25x25 verticals? If so, a much neater solution would be to scallop the ends of the 25x25, you will get a tighter joint this way into the bargain.
As with all mig work on galv, CO2 is king of the shielding gasses, but if you have only Argon mix then it will also work albeit with a greater incidence of porosity and more spatter. It will also be of benefit if you direct the arc primarily on the thicker section, or that which does not have a raw cut edge and wash the weld metal onto the raw edge or thinner section, (we're talking "T" joint here).
Make sure that you tune your settings well, the better everything runs and is set up, the greater your productivity and success.

Thank you for the replies. I never thought of spraying the oil on the torch, I'll try that.
Spraying the job, keeps it free of spatter, not sure if it is because the spatter does not weld itself to the steel or because less is produced. The shield gas I have is argon/CO2 mix (general purpose I suppose)

After the third panel, and some 160 welds, I sort of got the result I need, yet still some are better than others and I don't know why.
I tack weld first, square it up, clamp it down to the welding table and then get going. I understand to start onto the tube that is sideways and go briefly to the one that is cut (T joint), however I can not go back and forth, I must stop and let cool down for a second. So it is a series of short weld.
When I get it right, the weld is relatively flat and requires little grinding. I find it difficult to weld flat when I hit the tack weld and usually end up with a bead that is too high at that point.
The worst part is to weld inside a mitre joint. The welding pool is erratic particularly at the beginning, once it is hot I can see the galvo going away in front to the pool, but then I have to stop to prevent melting a hole so its back to the start.
I only do one pass.
As for hammering, that is done before I even cut the material. Hammered tubing is horribly expensive so I do it myself setting the tube on a 40k anvil and a roller stand set at the same level. It gets easy once you get in the rhythm. Doing 200 mm at the time each side reduces bending. My texturing hammer is a 1.2k mallet that I have grinded to a half sphere. The ball pein hammers produce too small of a dimple.

When it comes to welding the 12mm square steel to the tube, (see photo, every 3 tubes there is a bar) I make sure to start and finish onto the steel bar, yet my brief "visit" onto the square tubing has to be long enough for the galvo to evaporate. I don't seem to blow any holes there yet I need to do some grinding afterwards. I can't get between the bars with the grinder properly so I use an air driven die grinder and a 10 mm burr. The weld material seems free of any porosity and the burr gives a nice round finish in no time.

The hammered bars with the upset center, are made hot on a machine and probably cooled down in water. Some are a slightly bent and twisted, but they are so hard that I find it impossible to straighten cold. If I have to forge them straight, that would defeat the purpose of buying them ready made.

Sorry I don't have any close up of my welding but will make sure to take them this weekend to post here.
Attached some of the panels I have finished. They will get powdercoated with Dulux Aztec black. A powdercoat that has a bit of texture to it.

In case someone is interested in modern Blacksmithing, have a look at this Hebo machine, probably used to produce the hammering on my square bars. The center was probably done with an air hammer and a die. At $7 each they are a steal even considering they are not perfect.
http://www.youtube.com/watch?v=8qGHW...feature=relmfu
Hebo STM5 Twisting & HPG2B Embosser - YouTube