Newbie - Straightening After Weld

[Papa]

It was suggested to me to actually use one long bead, that there is some disadvantage to starting and stopping along one long bead.

Then hand him the stinger and tell him to "show you". All too often, many, even experienced welders, think they need to completely tie the joint - when structurally speaking, there is no benefit or logical reason to do so. The more heat you apply to a joint, the greater the propensity for distortion. Yes, sometimes there is valid reason(s) to run a single, continuous bead, but preventative measures MUST be in place to avoid distortion and unwanted movement.

Just think about all the assemblies that are 'bolted' together... 'Tis nothing more than a large tack (spot) weld in the center of the pieces.

[Phil3]

Thanks. I got the impression a metal lathe table is preferred over a wood one, and managed to do that. Seems like I jumped out of one frying pan into another. - Phil

There is much to learn grasshopper.

I have been doing mechanical stuff for over a half century, and I'm still learning.
Dave J

I rather get the impression many here will forget more than I ever learn. That's OK, I always seem to get into things where the learning never stops...we just get better and better.

- Phil

[Rockmonton]

How can this be avoided,

Number 1 rule... do NOT make multiple passes in the same joint in rapid succession. Many first timers' think they need to 'fill' a burn-thru or cover an otherwise 'ugly' bead.... please don't. Finish up the structure, then go back after it's cooled to make adjustments.

On many multi-member structures, such as your table, I suggest you to tack the entire structure together before running any long beads. And when it's time to go back and finalize the welding, keep your beads short (perhaps 1" in length or less), and alternate your beads from side-to-side if the joints are open on both sides.

and more importantly for me right now, what measures (if any) can one take to straighten this, if even possible? It is not super critical, but would like it more flat.

Buy yourself an 4.5" angle grinder and a pack of thin cut-off disks. - even a budget Harbor Freight will do. And please don't forget the safety glasses.

AND HEARING PROTECTION! SERIOUSLY!

[PeteH]

This crossreferences another post...

If you do get a HF angle grinder, check that there's grease in the gearbox before you use it. Mine got burning hot after about 10 minutes, and when I opened it up I found about a teaspoonful of blackish crud that may once have been grease. Scraped it out, refilled halfway with synthetic grease (Superlube) and it's been fine ever since. Not the most powerful grinder you could want, but if you go easy with it it's surely worth the $15 (or $20, or $9.95, or whatever the current coupon price is).

[randyc]

Incredible - even as often as I've heard anecdotes like this one ! It's difficult to comprehend a country where labor is so cheap that cost-cutting measures consist of leaving out three tablespoons of grease !!!

[calgator]

I’ve done a lot of one-off welding in my day, mostly in my father’s shop and the rules were very simple:
1. All welds shrink when cooling creating tension, even in a jig.
2. Fully tack weld prior to fabrication.
3. If either metal is smaller than ¼” maximum weld bead should be ¾”. If both metals are at least ¼” thick welds can be 1” long.
4. Always make to welds in quick succession on opposite sides so that each weld will pull on the other. This will minimize, but not eliminate warping.
5. When working on a complicated part start at major structural joints, columns to beams then beams to struts and then cross bracing.
6. Make sure to measure for warp age during process like after welding the upper left leg to the beam and the lower right leg to the beam (looking down at a table assembly). It’s easier to make corrections with only a few welds and not the entire assembly.
7. If warp age appears think about which weld is pulling out of alignment. I’ve fixed many a project by heating up the right weld with a torch and releasing the energy and allow the part to resume the desired form.
8. And if you really mess things up just remember. Does not cost much to cut all the welds grind clean and tack back together. Unfortunately I’ve still had to do this even after steps 1 through 7.

Good luck,

Charles