Removing Spot Welds

[Tom '74 911]

Originally Posted by frankc

Another thought; when the seam is accessible from both sides, should one take into consideration which side of the panel is visible after assembly?

I would say absolutely yes to this. Think ahead to the final product and what method, or weld location and type, will require the least amount of clean up before paint etc...

One additional thought - if there is an option on which side to drill out the spot weld from, I typically chose to drill from the side of the panel to be removed/replaced and try to leave as much of the panel that's staying as possible (w/out drilling a bunch of holes through it).

As you mentioned earlier in the thread, the holes you'll end up with from drilling out spot welds will be bigger and messier than what is actually required for plug welding in the new panel. I think it's better, where possible, to go back and use a punch for the holes to plug weld through. they will be cleaner and more accurately placed.

Just my thoughts.

Tom

[Jonny042]

Adding my vote for the blair tools rotabroach. They work great. Make sure you get enough spare cutters, they can (and do) break occasionally.

[Puma]

I've been trying to drill through some spot welds and so far I'm having no luck. It's difficult for me to see the welds accurately and I've punched through several times, seems like it happens so fast.

Any advice on "seeing" the welds accurately?

How do you keep from punching through?

[Tom '74 911]

Originally Posted by Puma

I've been trying to drill through some spot welds and so far I'm having no luck. It's difficult for me to see the welds accurately and I've punched through several times, seems like it happens so fast.

Any advice on "seeing" the welds accurately?

How do you keep from punching through?

To have the best shot at seeing the spot welds, I typically use a grinder with a wire wheel to remove all the undercoating and paint before I start drilling. You can use a center punch to keep the bit from walking as you start too.

What tool are you using to drill? One of the nice things about the spot weld drill I posted a photo of earlier in the thread is that it has an adjustable depth limit which can be set to "just enough"... If you don't have that option, just go slowly and keep your eyes on it - usually when you drill through the top layer, it will separate and then you know to stop...

It's tedious!

Best,
Tom

[Puma]

Originally Posted by Tom '74 911

To have the best shot at seeing the spot welds, I typically use a grinder with a wire wheel to remove all the undercoating and paint before I start drilling. You can use a center punch to keep the bit from walking as you start too.

What tool are you using to drill? One of the nice things about the spot weld drill I posted a photo of earlier in the thread is that it has an adjustable depth limit which can be set to "just enough"... If you don't have that option, just go slowly and keep your eyes on it - usually when you drill through the top layer, it will separate and then you know to stop...

It's tedious!

Best,
Tom

I've used cobalt drill bits and a harbor freight spot weld bit. Note, I just wanted to try the HF bit before I bought a set from Wurth.

I've tried a paint remover wheel only angle grinder to get to the spot welds. Where it reaches it does a decent job.

Tonight I got what's left of the right side gas tank support out. I plunged through several times no matter how careful I tried.

Thanks for the tip on the dedicated drill. I may have to buy one, I've got a lot of spots to drill. Hope they aren't too expensive.

[Tom '74 911]

I wire wheel the entire length of the seam and the spot welded flange to bare metal. That way, the spots are easy to locate.

That tool is not cheap unfortunately and you need a big compressor to run it... but if you've got a lot of welds to drill through, it's worth it I think. There are a ton of spot welds to drill if you have to remove an entire floor!

Lots of people (including myself) have had success with much simpler, less costly spot weld drill bits used in a regular drill too... sounds like you're on the right track.

Sometimes I simply use a grinder to grind through one side of the weld. You have to be careful and it does introduce a lot of heat to the area, but sometimes it's the fastest, easiest method.

Bottom line is there is no easy way to do it - it's slow, hard work!

[Puma]

Thanks Tom!

I'm first going to try the Blair skip-proof cutter setup in a drill and see how that works for me and if I decide the specialized drill is worth it.