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Posted by: McMark Jan 14 2018, 09:30 AM

Came down with a cold after my last video, so I was out of the shop for a couple days. Back at it today and made the promised 'real time' video of welding and grinding.

Ask any questions you have about the process.


https://www.youtube.com/watch?v=z5YEjjqgF_k

Posted by: bbrock Jan 14 2018, 10:50 AM

This is fantastic and I see a couple areas to improve my technique as I head out to the shop today. I wasn't appreciating how much adjustment is needed for edge matching AFTER the piece is fully tacked in place. Also, after the gap shrunk closed, I have been only reopening them if they interfered with the edge match and I think explains most of the little googes that have been left behind on my welds.

One thing I can't see well in the video is when you are using a dolly on the backside of the panel.

Thanks for posting this! I'll be trying to apply these lessons shortly.

Posted by: BeatNavy Jan 14 2018, 11:36 AM

Thanks for posting, Mark. Very helpful.

The sparks on the wheel go round and round, round and round, round and round...

Posted by: plays with cars Jan 14 2018, 11:48 AM

Thanks for the additional detail this video provides. It really makes one appreciate the effort and time that goes into good metal work.

Been hoping to become inspired to replace the FG flares on my car with the metal ones on the shelf. This video helps to demystify the process, but also highlights that its not a project to be taken lightly.

Posted by: Mueller Jan 14 2018, 12:04 PM

What? The shop owner cannot call in sick!

Thanks for making the video.

Posted by: worn Jan 14 2018, 12:36 PM

Thanks Mark!!
I had a whopper of a cold, but I caught it on the West Coast.
The thing I notice is that you are a pointillist welder. A lot of us, have the idea that you are supposed to be gracefully laying down 1 inch seams, or at least I did. But I can see how well the connect the dots works for you. It never occurred to me to control heat by controlling the dwell on the trigger finger. I always thought I should be able to dial it in.

Posted by: McMark Jan 14 2018, 01:13 PM

Definitely all spot welds. Each new spot weld is targeted on the edge of the last one. Basically 50% overlap from one weld to the next. I do it really quickly because I have 10+ years of muscle memory-- so my fingers and hands know exactly how far to move the gun/nozzle after each weld, and as I go along my subconscious is evaluating how the last tach weld went and what adjustments I need to make. For example, if I run into a bit of thin metal, it can blow through, so I instantaneously change from the normal stacking of tack welds to make a few smaller tacks to build up material in the 'weak' area and then a slightly larger tack to close everything up -- larger because the added material increases the thermal mass and it takes a bit more 'dwell' to heat up the thicker material. But all that is happening in less than a second. If you're starting out, your pace will/should NOT be as fast as mine.

Also, I run my welder at full heat and mid feed speed. I like my tack welds to go in hot and fast. Adjust the feed speed to minimize grinding as much as possible, while throwing enough material at it to build a nice tack weld. This will differ depending on your welder. The one I use most is an old Lincoln WeldPak 100, so full power on that is no where near full power on a 220v MIG.

Posted by: worn Jan 14 2018, 03:05 PM

Yeah, sounds familiar. It's just that you are much better at it. I have at times blown through and ended up tacking weld in a circle around the thin spot to make enough metal to build on. That often leads to cutting up the cardboard around a case of coke. They make great patch patterns. I used to have an old box where I tossed the old patterns in as souvenirs. Of course what beverage leads to the patch pattern depends on the user.

starting to snow here.

Posted by: Dck356 Jan 14 2018, 08:44 PM

Great video Mark! What grit paper are you using to grind and what wire do you recommend. Nice work for sure!!

Posted by: McMark Jan 15 2018, 10:34 AM

That's a 36g wheel. I thought it was 80g, but I just checked. In the spirit of 'do as I say, not as I do' -- I would recommend using a 36g to get most of the height removed, then switch to 80g for the more careful smoothing. Easy to make big grooves/gouges with 36g if you don't have a feather-touch.

Posted by: Dave_Darling Jan 15 2018, 12:57 PM

Random thoughts that occur to me as watch the video--

No audio, huh?

Interesting how that first section you welded popped upward as soon as you stopped.

How do you know how much of a gap needs to be left between the pieces of metal you are joining?

Sometimes when you pull the trigger, you don't get the same light-show that you do most of the time. Why is that? Did the wire not make proper contact or some such?

Damn, I could never do this kind of work!!!

--DD

Posted by: McMark Jan 15 2018, 04:55 PM

I didn't think there was much to be gained by the audio. Thought about adding music, but decided it wasn't worth the time. I gotz better things ta do.

I cut out all the 'dead time' where I'm switching (searching for) tools. So it looks like I have everything just ready to go. But really I cut out about 25% of the video of nothing.

Experience, but the important point I glossed over is that if the panels are hard up against each other they will 'pucker'. It's not an entirely accurate analogy, but think of tectonic plates pushing together -- they bump into each other and start moving upwards (mountain) or downward (valley). Same thing happens with the panels. If they're hard up against each other before you apply heat, then the heat expansion will cause a pucker. When I make a cut to relieve this (as in the video) I usually use an air saw which has a blade thickness similar to a hacksaw blade (very thin), but I didn't have room in this case for the tool. So I had to use the cutoff wheel. The cutoff wheel thickness is way overkill, but it's still a weldable gap.

Basically, yeah, it's a 'misfire'. Could be from a small section of rust preventing conductivity. Could be a bit of paint. Could be a piece of weld spatter that's bridging the electrode tip to the nozzle/shield, which is often touching the metal, causing a short and keeping the necessary spark from happening. Could be that I got 'lucky' and shot the wire right through the gap and missed the metal altogether. Lots of reasons, and it's all the stuff that is solved with proper prep and maintenance. Cleaning the metal well before welding. Replacing welder tips when they get spatter stuck in them. Cleaning the nozzle periodically. All the stuff we should do, but often skip to just keep going.

Sometimes I wonder myself. In fact I put off this patch panel for a bit because it's been a long time since I've done metalwork. I was really relieved and satisfied when it was all going right. Just like riding a bike...

Posted by: rick 918-S Jan 15 2018, 07:09 PM

It's like therapy from,a stressful day.

Posted by: burton73 Jan 16 2018, 02:56 PM

I got a hot splatter burn on my big toe today.

I was wearing tennis shoes.

Bob B