Suggested Tool End Seam Weld

[Lionelgee]

Hello All,

What sort of tool would you recommend to cut through some lengths of weld that are on the end seam of at least two sheet metal panels?

The attached photograph shows the join between the plenum or cowl, the front door pillar and another piece of steel. The join or end seam is length of weld - not a spot weld.

I used a reciprocating saw after I had made space for the blade. This worked really well on the passenger side. However, due to the extent of the rust on the driver's side - instead of cutting through the weld, the blade started to track through a couple of layers of sheet metal. I would like to have more control the next time I face having to cut similar runs of weld on the end seam.

I have to remove the plenum because of extensive rust along the top length of the firewall and plenum joint. Plus, there is more rust where the plenum joins the front door pillar. The rust has eaten away the right angled ends of the plenum and along the bottom of the windscreen sill.

Decades ago the lower windscreen rubber must have started to leak. Water then found a home in the joint between the plenum and the front door pillar and it kept this area moist. This formed a breeding ground for lots and lots of rust.

Kind regards
Lionel

[Bruce Parker (RIP)]

No matter what you have to go back to the most solid metal. Welding rust thinned metal never goes well. If it were me I'd cut back to the best solid metal you've got, bust my butt forming a replacement part of the same gauge steel then weld top and bottom.

[Lionelgee]

Originally Posted by Bruce Parker

No matter what you have to go back to the most solid metal. Welding rust thinned metal never goes well. If it were me I'd cut back to the best solid metal you've got, bust my butt forming a replacement part of the same gauge steel then weld top and bottom.

Hello Bruce,

Thank you for your suggestion. It one I intend to follow to the letter, However, the first thing I have to do is to totally separate the panels. To do this I have to remove more welded end-seams.

Once each panel is removed I can work on it as an individual unit. Where I will cut the rust out and make rust repair sections.

After this work is done, I will also be using weld through primer and some form of heavy duty seam sealer.

The main target of my post was to find a tool that can do a better job cutting the welded seams than what quality the reciprocating saw provided on the driver's section.

My concern is that the reciprocating saw needs clearance for the full length of the blade's stroke. I was lucky with the position in the door space that I could get the required clearance for the blade. However, the part where the plenum joins with section that forms the lower windscreen channel may feature a dead-end. This means the reciprocating saw blade will not have clearance to operate in.

Perhaps, a small Dremel cut-off wheel or die grinder fitted with a cut-off wheel? Or is there another Dremel-based tool that could do the job of cutting/grinding through multiple seam welds?

Kind regards
Lionel

[rob love]

A dremel is for hobby stuff. I would not use it on a larger project like this. You will either use up way too many cut off discs (they cost more than full size discs) or you will burn the tool out.

Go with a pneumatic die grinder/cut-off tool, and use the 3" cut off wheels....the thinner the better. Around here you can usually find the tool for sale at around $15 or $20, and the cut off wheels have got more expensive so expect to pay about $1.50 each for those in packs of 5. I remember when I could get those for about $3 a pack, but the chinese seem to now want a living wage.


The cut off wheels will cut in a far more controlled manner than a reciprocating saw. You may have to finish the seams with an angle grinder and a sanding disc. Consider attaching the new panels with epoxy. It is as strong or stronger than a weld, and it has the bonus of sealing the seams.

[Lionelgee]

Hello Rob,

Thanks for the tip about the cut off wheel on a die grinder. Last night I found a mandrel online that fits the 3 inch cut off wheels and works with a die grinder - as you suggest. I also saw an online article - which I can of course no longer find - that warns against using cut-off wheels on die grinders. It might have been because of the lack of safety guard.

I tried one of the "Multiple Purpose" tools which has a plunge cut-blade and a flush cut blade. The result was pretty underwhelming. I reckon I should have collected some ants and put some honey on the welds. Their efforts would have been more effective in cutting through the welds.

Thanks for the suggestion about epoxy. I was thinking of some Sikaflex products when I previously typed in "Sealant".

Kind regards
Lionel

[Lionelgee]

Hello Rob & All,

I found that article again - it is from Norton Abrasives - Accessed 25th August 2020 from https://www.nortonabrasives.com/en-u...us-combination.

Yes, it was about how the die grinder with a cut-off wheel fitted does not include a safety guard.

Kind regards
Lionel