Separating spot welds non-destructively?

[paredown]

I'm working on upgrading my old Delta dust collector, and have been reading about removing the constrictor plate on the intake. (Apparently Delta added these to the second gen versions to throttle the input, since people were running theirs without bags on them and burning out motors.)

It is a little hard to see, but the inner plate is set into the flange piece, and spot-welded (6 welds).

Since I need the outside plate to remain flat and undamaged, I can't just drill out the spot-welds (or if I did so, I would have no way to fill the holes...)

Any ideas from the metal guys about tools/procedure that would work? (I thought if I had a die grinder I could work from the side of the constrictor piece I want to get rid of and grind carefully--but I don't have one--just a 4" which seems a little big for the job.

 

[yatg]

If this was my project, I'd try a Dremel with a metal cutoff wheel.

 

[rustyjames]

I've done it successfully with a appropriate sized drill bit. There's also specialized dill bits, or annular cutters available.

 

[CJM8515]

drill out, fill with JB weld and smooth it out?

 

[Ole Slewfoot]

Spot weld bits are a little expensive, but made for the job...used carefully one of the DeWalt bits that are flat face with a centering point will do that job.

 

[gorilla]

The best way I've found for removing spot welds is a 3/8" pneumatic belt sander. Use the tip of the belt on the spot weld till you can break it loose.

 

[36truck]

best way is with a spot weld cutter. Body shops use these all the time to remove panels.

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[PCustoms]

Small grinder. Do it away from the sawdust

Drill just the weld.

Drill through and silicone the hole.

Many options.

 

[JonBoehman]

Harbor freight sells spot weld bits that are fairly cheap and they work very well.

 

[paredown]

Thanks guys--didn't know about annular cutters or spot weld cutters--I'll probably stop by our new Harbor Freight and use the 10% coupon!

 

[240sxguy]

Would you mind explaining what you mean by "people running without a bag installed"?

I have one of these dust collectors too, and I don't recall seeing that baffle.

 

[paredown]

Would you mind explaining what you mean by "people running without a bag installed"?

I have one of these dust collectors too, and I don't recall seeing that baffle.

I picked up the story from one of the woodworking forums--probably Lumberjocks--and apparently people were setting up these Delta 50-850 collectors outside without the catch bags (top and/or bottom?--not clear from the stories) and with no back pressure on the system, the motors would run at too high rpm, and were burning out. Second generation like mine had that restrictor plate installed, just behind the 4" Y connectors for the intake to throttle the intake just in case. Third generation--they reduced the size of the impeller instead, since people were removing the restrictor plate.

You can't really tell if it is there or not unless you take off the Y connector plate (although I suppose you may be able to get your hand into one of the 4" inlets and feel for its presence).

 

[240sxguy]

I picked up the story from one of the woodworking forums--probably Lumberjocks--and apparently people were setting up these Delta 50-850 collectors outside without the catch bags (top and/or bottom?--not clear from the stories) and with no back pressure on the system, the motors would run at too high rpm, and were burning out. Second generation like mine had that restrictor plate installed, just behind the 4" Y connectors for the intake to throttle the intake just in case. Third generation--they reduced the size of the impeller instead, since people were removing the restrictor plate.

You can't really tell if it is there or not unless you take off the Y connector plate (although I suppose you may be able to get your hand into one of the 4" inlets and feel for its presence).

Thank you for the heads up, I had considered running mine like this (outside, no bags) but if it's risking damage I will plan on utilizing the bags!

 

[Slednut]

1/2 x 18" air belt sander, takes seconds and doesn't leave a hole. One of the most versatile tools you can have.

​

 

[paredown]

Got it apart--could not find the spot weld drills at Harbor Freight, so I *****- punched (as best I could) to give me a center for a drill, and used a large-ish standard drill in my baby drill press (just went by feel, looking for one that still had a decent point; drilled nice dimples from the back side so as not to damage the piece I want to reuse).

Then I was able to start separating the two pieces with a cold chisel--broke the first weld and worked my way around. I had a scrap wood block with a slot cut in it that made a nice holder for the whole thing so I could bang away with it standing on edge.. Not quick, but it worked. I touched up the bumps with a file--good enough. I have to say--those were good welds!

Definite improvement in suction--now onto the next phase--adding a baffle and canister filter...

 

[Ohmthis]

I have this s dust collector. can I tell from the nameplate if it has a baffle or not?

 

[MBfreak]

Here is my take. I rebuilt a MB230 SL 1961 some 30 years ago. All welded steel body. Hood , doors, trunk lid, tonneau cover aluminum. These were the only parts not rusted out.
Family heirloom, very badly cared for. Had to replace wings, wheel arches, sills and lots of beams in the front and rear.
Cut parts of so that only a 15 mm strip with spot welds remained. Sandblasted to see exactly where the spot welds were, there was one every 25 mm in most places. Thank MB ! Bought a bunch of spot weld drills with a spring loaded centering pin. The trick for me was to drill out around the spot weld, and leaning the drill a bit for the last 0,1 mm and then stop. When all welds were done I used a hefty plier to roll off the strip , and breaking the last 0,1 mm around the welds in the process. That gave enough meat to rip off the dia 8 mm remaining "washer", the spot is only 1 mm in diameter. No distorsion in the flange. A ligt grinding gave an absolutely clean and straight surface when spotwelding on the new parts.
Took me around three months of evenings to replace front and rear wheel arches. Had access to a factory made body jig, so reasembly was fairly straightforward. And at the time MB body parts had not been priced out by the bean counters in Stuttgart.

Ola