Grinding down welds

[charles_darwin]

Hey, I've been making these SS tanks out of thin sheet metal using my TIG. One of the requirements are that the edges of the tanks are sharp 90degree angles, so I can't just run a weld and leave it like that, I end up running a few passes to build up some metal which I then grind down with a flap disc, and once the worst of it is gone I use my rotary sander to get it flat with the face of the sheet metal. The problem is the process of using the flap disc to get rid of the weld buildup creates deep scratches in the sheet metal, which I then have to sand out making the metal even thinner in those parts. Could anyone recommend a process or a tool to get rid of the weld buildup but not scratch the sheet metal while im doing it? Many thanks!

 

[Mark 2]

For me, Grinding disc on edge to get it close.

 

[Erie Fred]

Can you use that food grade solder to fill in the bad spots ?
I think Handy & Harmon makes it, used on kitchen sinks & similar.

 

[voipio]

A finer grade abrasive flap disc will give shallower scratches, though it will take longer to get the corners down to square.

 

[Seadog]

A finer grade of grit and come at the weld 90° anti-clockwise to the one position that you're showing in the photo.

 

[chrismac]

Interesting to know if the tanks need to hold anything...... or for decorative purposes, ie does the weld need to be on the outside and does it need to be fully welded, completely out the box but there could be other options,

 

[Gritineye]

I find flap discs tend to thin the metal either side of a weld due to them flexing, unless used as Seadog says.

I carefully use a nicely 'run in' grinding wheel to get close, then finish with a body file that doesn't scratch.

But I don't do stainless which may be harder to file.

 

[Hitch]

120g fibre discs, and backing pad, followed by a Klingspor interleaved combi mop.

SMT850 Plus combi-Abrasive Mop Discs Per/5

High quality combi non-woven mop disc - specially suited for machining of welding seams.

www.tgsindustrial.co.uk

Follow up with a bit of scotchbrite.

Also, looking at the way you're using that grinder, turn it 90 degrees and use a wider portion of the disc rather than the edge of it. Will help you no end with keeping it smooth rather than digging it away with the edge of the pad.
It will also allow you to keep the sanding marks much more localised.

 

[chip]

My preference on sheet metal is turn the grinder body so your coming in at the piece from side on so grinder bodies at say 3 o clock rather than the direction of the weld. this way you can use almost the full width of the pad and be flatter

 

[Munkul]

120g fibre discs, and backing pad, followed by a Klingspor interleaved combi mop.

SMT850 Plus combi-Abrasive Mop Discs Per/5

High quality combi non-woven mop disc - specially suited for machining of welding seams.

www.tgsindustrial.co.uk

Follow up with a bit of scotchbrite.

Also, looking at the way you're using that grinder, turn it 90 degrees and use a wider portion of the disc rather than the edge of it. Will help you no end with keeping it smooth rather than digging it away with the edge of the pad.
It will also allow you to keep the sanding marks much more localised.

bingo. But I'd start at 80 grit fibre discs cos I'm a bit rough

 

[Shedendman]

Those corners scare me,so begs the question,whats they're intended use?

 

[8ob]

Those corners scare me,so begs the question,whats they're intended use?

With all that grinding I would be worried about the integrity of what’s left, I would be getting a bit more creative with a pan folder to eliminate some of the welding.

Bob

 

[chrismac]

With all that grinding I would be worried about the integrity of what’s left, I would be getting a bit more creative with a pan folder to eliminate some of the welding.

Bob

Yes exactly, having the welds else where could help.

 

[Morris]

With all that grinding I would be worried about the integrity of what’s left, I would be getting a bit more creative with a pan folder to eliminate some of the welding.

Bob

A pan folder wouldn't give the required sharp corners though (not disagreeing, it's the best way imo).

 

[charles_darwin]

Thanks everyone for the replies - @Hitch definitely will look into the angle at which I approach the metal with my flapdisc and also some useful tips from other users. @Shedendman these are little artworks once polished up I submerge them 200meters underwater and the water pressure does the rest of the work for me. I did the first ones pre-titan submarine if anyone wants to ask hehe again thanks for the tips guys, looking forward to saving me a lot of time!

(@adam_tylicki) • Instagram photos and videos

583 Followers, 584 Following, 72 Posts - See Instagram photos and videos from (@adam_tylicki)

www.instagram.com

 

[Agroshield]

If there was some metalworking equivalent of this, it might do the job very controllably:

Charnwood 10 Inch Drum Sander with Floor Stand DS10

The Charnwood DS10/20 Drum Sander can work 10" in a single pass with a maximum working thickness of 3". 5 FREE sanding wraps and a 5 Year Warranty!

www.yandles.co.uk

Is there a way to suspend a belt or maybe finger sander in the air so its height can be adjusted in fine increments?

Another option could be a metal-cutting variation of this:

Paint remover | Wood processing | Metabo Power Tools

Paint remover from Metabo - High-quality, reliable and durable. Inform yourself now about the professional power tool range from Metabo.

www.metabo.com

 

[Shedendman]

Thanks everyone for the replies - @Hitch definitely will look into the angle at which I approach the metal with my flapdisc and also some useful tips from other users. @Shedendman these are little artworks once polished up I submerge them 200meters underwater and the water pressure does the rest of the work for me. I did the first ones pre-titan submarine if anyone wants to ask hehe again thanks for the tips guys, looking forward to saving me a lot of time!

(@adam_tylicki) • Instagram photos and videos

583 Followers, 584 Following, 72 Posts - See Instagram photos and videos from (@adam_tylicki)

www.instagram.com

View attachment 486417View attachment 486416 View attachment 486418

Now those are kool
what you could try is using a belt sander with app belt ie zirconia,and run it along the length of the joint this will get down any high spots but theres a knack to it

 

[Hitch]

If there was some metalworking equivalent of this, it might do the job very controllably:

Charnwood 10 Inch Drum Sander with Floor Stand DS10

The Charnwood DS10/20 Drum Sander can work 10" in a single pass with a maximum working thickness of 3". 5 FREE sanding wraps and a 5 Year Warranty!

www.yandles.co.uk

Is there a way to suspend a belt or maybe finger sander in the air so its height can be adjusted in fine increments?

Another option could be a metal-cutting variation of this:

Paint remover | Wood processing | Metabo Power Tools

Paint remover from Metabo - High-quality, reliable and durable. Inform yourself now about the professional power tool range from Metabo.

www.metabo.com

There is... Timesaver/Grindmaster.