Tuesday, February 17, 2015

First metal work - floor pan patch #1

1967 Ford Mustang Fastback floor patch welding Enough tearing it apart, let's start fixing stuff!

By this point I have found several areas of rust or damaged metal that needed to be fixed - a rotten section of toeboard in the passenger footwell, the rear transition pan where the shocks and rear seat mount, and the rusty apron panel overlaps in the engine bay. But I figured a newbie self-taught welder should start simple, and preferably, somewhere not easily visible.

Normally, one would start to learn welding on thick stock, like 14 gauge or thicker, and practice a lot on beads and joints. Then proceed to thinner metal and eventually work up to butt-welding (non-overlapped) patches in thin sheet metal (like 18 gauge or thinner). Eventually, you're good enough to fill holes in thin metal.  I decided to take the exact opposite approach, and of all the methods to learn how to weld, well, it's probably not the best way.  Like the saying goes, "a man who holds a cat by the tail learns a lesson he cannot learn any other way."

To be fair, I did spend a lot of time practicing lap- and butt-welds on scrap steel. But those are usually ideal conditions - the metal is clean, non-rusted, uniform thickness, easy to reach and see, etc. On the car, none of those assumptions are in place.

I worked on this little project off-and-on for nearly three months while doing other stuff in the meantime. Yeah - months. Don't forget, part of this blog is a confessional, where I show you what's not going perfectly well.

Remember this thingy? It's a non-stock electric fuel pump mounted under the rear seat floor pan by two bolts. My first task - fill those two holes.

So, with the welder set up for the right metal size, I fill the first hole no problem. The issue shows up when I try to fill the second hole. I get nothing but blowthru's and globby welds when I try to fill them. This quickly gets worse and worse. Eventually, I cut out the mess, cut and bend a patch and lap weld it in place (overlap welds). Grinding the welds down on top it looks fair, but the bottom is a mess.

Top view of patch.

Bottom view of lap-weld patch.

So I decide to do it right - first I practice a lot more for many nights, getting a feel for good and bad welds, poor grounding of the welder, etc., Then I go and get a dial micrometer from Communist Freight. This tool will show me the thickness of the metal on the car that I'm welding my patch to. What I learned is that the second hole was a little corroded - and the rust had thinned the metal. So I assumed that since the floor was 19 gauge metal, I should set my welding accordingly. As it turns out, that was too much power for the thin metal on the car, and it just blew through the metal, making a mess of things.

I cut out the bad metal patch (that's the rectangular hole there) and used the dial micrometer all around the opening to figure out where the metal stopped being thin and got back to the nominal 19 gauge thickness.

Then I marked where it was good again, an cut out all the thin metal - which left me with a hole like this:

Notice that ridge I cut right through? Well my patch would have to have to ridge as well in the same place or I'd have a gap - so I took one of my engine bay aprons that I wasn't going to use anyway (which also had the ridge in it), and cut my patch to fit around that ridge

Once it's cut to fit (5 hours later - maybe I'm just slow? Or maybe I should stop keeping track of elapsed time?), I hit the exposed metal underneath it with weld-through primer and placed the patch. Now I have good clean metal on both sides with a good ground and good settings on the welder.

Now, for butt welding thin sheet metal, you want your patch to be just smaller than your opening - like less than the welder wire diameter, which is 0.023" here. So, I carefully cut and sanded the edges of patch to fix exactly where I wanted it - knowing there was no second chance as I didn't have any more metal to use with the ridge in it. Backlighting helps see the width of the gap.

And presto, its' in. The top looks pretty good, the welds just need dressed up (ground down and blended into surrounding metal). I hit it with some primer just to see how well it looked after dressing the welds and making sure I didn't have any pinholes (missed welds that are  hard to fill in later).

The bottom shows good penetration in some places, not so great in others. This seam will need to be sealed after it's primed, but in the desert southwest, I'm not worried about moisture getting in there now.

If you look closely, you can see the first hole I filled with no issues just south of the patch. Oh well, one out of two, right?

Lessons learned:
- know the thickness of the metal you're welding to. Don't assume, measure it and know.
- weld-thru primer is of limited usefulness. You should still remove it from wherever an actual weld is happening, as it interferes with the arc on a MIG welder. It's good for protecting sealed layers of metal, though.
- MIG welds without the gas turned on look really bad. If you see a bad weld, STOP and figure out why before plowing ahead.
- Lap welds look like they'd be really good at trapping water and causing rust to start again. A butt weld is better, even if you have to run seam sealer over it afterwards.
- Welding is not like soldering or brazing. Take time to learn how the process works. I can tell from here I'll never be a great welder, but I want to work at it and become a better welder.
- dressing welds with an 80-grit flap disc on an angle grinder is a great way to thin metal. Use a cutting wheel or dremel instead and remove weld material down till it's just proud of the base metal.

"Are we learning yet?" - John Connor to the Terminator in T2

Monday, February 16, 2015

Windshield Removal

1967 Ford Mustang Fastback windshield removal The car is pretty well stripped down at this point, but there are still some major assemblies left to come off:
  1. Front Windshield, which is already broken
  2. Rear glass, which is not already broken, and really expensive to replace
  3. Wiring harnesses, front and rear
While all these didn't come off on the same day, some of them don't warrant their own post. I'll likely regret this later when I'm slacking off from the car and want to make it look like I'm actually doing something. Again, I find myself short of good pictures. My camera skills are great at taking shots that are both too close and out of focus, but that's what shop manuals are for.

First, the windshield. It's cracked top to bottom and a little sideways as well. As I heard from Brett, he says the dents on the roof and the cracked windshield are all from the same event - namely, some joker walking around on the roof. I've had cars I hated and wouldn't even do that to them. 

Anyway, the windshield is shot. Good news is this glass is fairly easy to get and is reasonably priced assuming you don't need that concours factory-perfect stuff. And then the challenge is finding a glass shop that will install it without breaking it. Add to this the gooey, gloopy, hocus-pocus way both pieces of glass are installed, and you have a recipe for trouble.

Here's the upshot: in order to remove the glass you first have to remove the windshield trim. So you have to SHOVE this little hook tool between the glass and the shiny chrome trim (that is both easily ruined by this process and impossible to find good reproductions for) and then LOCATE about two dozen little clips buried in the gooey glass sealant, then TWIST/PULL the clip to unhook it from the trim while not damaging it or the glass - and all by feel since you can't see what you're doing. Check out this 2 minute video that someone else made to see the horror that awaits you.

Since the front glass is already shot, I used it as a learning experience for the process so I can do it for the back glass. 

So, here's how it went...shove in the hook tool, fish around for a clip, twist the hook around to catch the clip, slip off and start over.  Fish, twist, slip, fish, hook, twist, slip, FRACK! Repeat as needed. It took me 4 hours to finally get all the clips pulled out and managed to save the 5 pieces of chrome trim from a bunch of perforations or bends.  

Once the trim is out, I ran a boxcutter around the inner and outer perimeter of the gasket that holds the glass in the window frame. Then, with two helpers, gently shoved it out and threw it away.

And now we just have to clean this mess up...there are two kinds of glass sealant in there, and cleaning it out took another couple hours. But, as a friend of mine told me when I dragged the car home, "Well, it's cheaper than a twenty year-old."

And remove the clips from the frame...

And toss them - these are single use items in my book.

Next up is the rear glass, and the same drill: find and unhook about 24 clips without damaging the trim, this time with the added challenge of not breaking good rear glass (oooh, and you better believe that original glass with that little stripe that runs the length of it from top to bottom is internal-organ expensive!)

I was so excited this worked I forgot to take pics of the trim off the car. And there's no action shot because, for us, you can have either the shot, or the unbroken glass, but not both. Again, it took hours to get this done - you simply can't rush it or you'll break something.

I needed a way to safely store the glass in long-term storage as well as just move it. I worried that just carrying it wrong could cause it to break. So we built a little glass stand out of a pallet and some wood and pipe foam we picked up at Lowes Automotive.

Also around this time I extricated the engine bay wire harness now that the engine was out of the way, and the rear wire harness. The harnesses are crispy and the connectors are not exactly flight-ready, so they'll be replaced.

The engine bay harness - shockingly simple compared to a modern car.

The rear harness - even easier. I'm looking forward to wiring this car up after paint and body work.

The electrical plan isn't fully formed in my head yet, but it'll be near-stock with some upgrades for high-power lights, a modern charging circuit, extra circuits for whatever accessories I see fit, and a 'good-enough' stereo - because the real soundtrack for this car isn't supposed to come from the dashboard. Quite honestly, the more I hear about the future with driverless cars, the more retro I want to make this one.