Welding sequence confusion

Joined
Jan 25, 2021
Messages
1
I was reviewing my AZ Timberwolf plan to make sure I was welding the parts correctly so as to avoid distortion. The instructions on pages 79-80 seem to be opposite those on pages 116-117. These refer to welding cylindrical objects onto square tubing. Do sides (axial edges) or tops/bottoms (circumferential edges) get welded first? (I tried to include an Imgur image of these pages but was unsuccessful, sorry). I have correctly welded all these parts but want to clear up my confusion. Any suggestions?
 
Joined
Jan 14, 2019
Messages
28
Location
Great Mills, MD
Chuck,
I haven't done any welding yet, but looking at the Timberwolf and other AZ plans Brad is consistent in welding order: top, bottom, then sides. The only departure is when welding corner pieces cut at 45 degrees where Brad specifies welding the outside corners first as in pages 15-16 of the Timberwolf plans.

Pages 79-80 are for the pivot which is horizontal and pages 116-117 are for the head tube which is vertical. Applying the top, bottom, sides welding order to each of these cases yields what's in the plans.

I'll defer to the people with actual welding experience to provide a better explanation, but that's how I understand based on the plans.
 
Joined
Feb 20, 2013
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868
Location
Axedale, Victoria, Australia
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axerail.coffeecup.com
Welding expands metal. Weld all one side and you will have all that expansion, and potential misalignment as a result of it, on that side. The correct welding order is to spot weld opposite places so as to provide somewhat even heat around the object. Spot welding also helps to prevent burn-through by letting the heat dissipate more readily. Clamping things in place is also a wise move.

At least, that is my untrained, unscientific, take on it.
 
Joined
Oct 19, 2012
Messages
1,558
Location
Wakefield, UK
I would rather think welding shrinks the metal where you filled a gap. The molten metal has more volume than the cold metal.
Correct. As the weld cools it gets smaller and so pulls on both sides of the weld pool. Imagine if this weld was welded in a matter of an instant so the weld pool is all molten and then begins to cool. As the weld pool is largely on top of the sheet it tries to shorten the top in relation to the bottom. The beauty of steel is the fine adjustment hammer, pipe wrench or large lever is usually enough to correct any that creeps in.
 
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