[Aaronmnwelder]

Hey guys so I have to build 4 of these parts made them before a few times but always kinda struggled through this piece of the project. The part is a top cap to a 3 tier hydraulic actuated display. One of the problems I am having is keep the distortion down on the base plate. The base is .080 material tube is .125 wall and gussets are .062. the tube gets welded all the way around on fillet side and opposite side. The gussets get stitched in and they added slot and tabs this run to help with locating. I get some distortion when doing the the fillet and opposite side but it's not horrible, usually tack the tube in then do the opposite side weld to prebend the material then flip it over and lay heavy block on the base and do the fillet then shoot it with air to speed cool it. Does any one have a better process for doing that step? The real problem comes in when I do the stiches on the gussets. I usually weld the gusset to the tube first after its all tacked vertical up then do the fillets. This time they added the slot tabs so I was just going to tack n the fillet side and weld the slot and tabs on the opposite side but they only made tabs .020 high so when I tried to use enough heat to actually catch the tab tacks all popped and the 1 part got wrecked. Any advice?? Unfortunately the tabs for outer wrap are the same height.

[cj737]

Is it possible to weld or tack the tabs in first, then tack the fillets? You might need to lay 4-5 tack dabs for the strength before you weld the tabs to prevent cracking or popping. Also, make sure you don't snap off your arc with the tacks but taper them on and off. Run some post flow over the tack to help cool it instead of air.

And you could certainly place more tacks along the length of that gusset (if I'm understanding the assembly sequence correctly?)

[Aaronmnwelder]

Is it possible to weld or tack the tabs in first, then tack the fillets? You might need to lay 4-5 tack dabs for the strength before you weld the tabs to prevent cracking or popping. Also, make sure you don't snap off your arc with the tacks but taper them on and off. Run some post flow over the tack to help cool it instead of air.

And you could certainly place more tacks along the length of that gusset (if I'm understanding the assembly sequence correctly?)

cj I cant really tack the tabs first casuse with the little distortion I got from welding the tube to the base plate the tabs weren't even catching the slots. I had to tack then re heat the tacks and push down to get the tabs to lock in the slots. ya I think I will have to just weld the fillet on the backside of the tabs and then flip it over and fill the slot. I was just trying to avoind putting a lot of tacks or longer tacks on the fillet side cause in the past that is where I have seen the most distortion.

[cj737]

Gotcha. Is it possible to use chunky blocks for chilling and clamping while you tack up?

[Aaronmnwelder]

Gotcha. Is it possible to use chunky blocks for chilling and clamping while you tack up?

that's kinda what I did. I used three big squaring blocks to hold the base down while doing and the tacking and welding. Problem is my table at work run 1/4 plus inch off the ends so its exactly the ideal flat table. I wish could figure out a way to weigh the base down with 1 of those squaring blocks while welding the slot and tab but with the tube sticking out the opposite side cant think of a good way to do that.

[Arclight Ironworks]

@ Aaronmnwelder - recommend you build 2ea of these assemblies “back to back”. Think symmetry.

Mechanically affix the base plates to one another via fasteners in the bolt holes. Use additional clamps to achieve a flat/flat geometry. Now, you will be welding an 1/8” tube to a sandwiched base plate of 2 x 0.80” (~5/32”) thickness.

The back to back approach should aid in taming Mr Shrink. No amount of weight placed onto a single base plate will prevent warpage. Aluminum’s high solidification shrinkage rate (6%), coupled to the high thermal heat of conduction, drive you towards “skip welding” tactics while ALTERNATING between the Right and Left bolted assemblies.

You want to get it and get out. Arc light, fuse, then stop. Minimize the volume of weld.

And chill blocks have no use in this activity. If your assemblies were stainless steel, then Yes the use of Al/Cu backers would aid the process.

Focusing on the correct “attack plan” is your best remedy for success.

[Aaronmnwelder]

@ Aaronmnwelder - recommend you build 2ea of these assemblies “back to back”. Think symmetry.

Mechanically affix the base plates to one another via fasteners in the bolt holes. Use additional clamps to achieve a flat/flat geometry. Now, you will be welding an 1/8” tube to a sandwiched base plate of 2 x 0.80” (~5/32”) thickness.

The back to back approach should aid in taming Mr Shrink. No amount of weight placed onto a single base plate will prevent warpage. Aluminum’s high solidification shrinkage rate (6%), coupled to the high thermal heat of conduction, drive you towards “skip welding” tactics while ALTERNATING between the Right and Left bolted assemblies.

You want to get it and get out. Arc light, fuse, then stop. Minimize the volume of weld.

And chill blocks have no use in this activity. If your assemblies were stainless steel, then Yes the use of Al/Cu backers would aid the process.
Focusing on the correct “attack plan” is your best remedy for success.

I actually forgot about trying this. I do it a lot on stainless and steel base plate and tube stuff but have never tried on aluminum. Should I just tack them up normal then clamp them together and bounce between assemblies as I would do on steel and stainless. I have seen the 1 video Jody did where after welding he heated the part back up to I believe 400 degress to relieve the stress. Would you recommend that as well or is that just for thicker aluminmum? worried about putting that much heat to this thin of material. Thanks for the advice!

[Arclight Ironworks]

....I have seen the 1 video Jody did where after welding he heated the part back up to I believe 400 degress to relieve the stress. Would you recommend that as well or is that just for thicker aluminmum?....

No need to PWHT. Unless specified by code/specs. This ain’t CERN. You aren’t splitting atoms. Employ your known tactics with welding MS/SS and apply to Aluminum.

Fixture, then tack/weld. Skipping. Left to Right, Front to Back, Top to Bottom. Exercise patience. No rush.

[Aaronmnwelder]

....I have seen the 1 video Jody did where after welding he heated the part back up to I believe 400 degress to relieve the stress. Would you recommend that as well or is that just for thicker aluminmum?....

No need to PWHT. Unless specified by code/specs. This ain’t CERN. You aren’t splitting atoms. Employ your known tactics with welding MS/SS and apply to Aluminum.

Fixture, then tack/weld. Skipping. Left to Right, Front to Back, Top to Bottom. Exercise patience. No rush.

ok thanks for the advice. would you advise any air cooling to speed up the cooling or will that make it shrink worse? ya this stuff isn't code just need to look nice when done. Haha tell that to my boss, Only get 2 hour to build this piece with tacking the wrap, spotwelding the wrap and then piecing it all together and metal finishing it lol. Production life can suck sometimes lol

[Aaronmnwelder]

Got the project done and shipped 2 weeks aho. Thanks for all the help! Here is a few pics from the center section.