73 240z restoration 904 White

[Patcon]

Look in wheees build thread. He did all of that. the results seem excellent

[DC871F]

New edition to the shop, plus some fire wall and battery tray area cutting and welding. New Kobalt compressor.

This is my first real attempt as being a fabricator, and I have to say it kind of man handled me, but I hope my grinding skills can overcome.

Frame rail has rust just right in this area, I plan on cutting a patch for it. Its all clean from the part I cut out forward, thank God. The other side still to be determined, its a little more crunchy.

Edited October 19, 2020 by DC871F

[grannyknot]

That battery area can be tricky for sure but you're going about it in the right way, have you checked the fresh air chimney just north of where you are working?  It is an area that gathers leaves and is very prone to rust.

I like that Lisle spot weld chisel, looks like you would get a cleaner cut but it's hard to beat an air hammer chisel for speed with multiple spot welds.

 

[DC871F]

5 hours ago, grannyknot said:

That battery area can be tricky for sure but you're going about it in the right way, have you checked the fresh air chimney just north of where you are working?  It is an area that gathers leaves and is very prone to rust.

I like that Lisle spot weld chisel, looks like you would get a cleaner cut but it's hard to beat an air hammer chisel for speed with multiple spot welds.

 

I have one of these. I made a new chimney and there are several pin holes on the shelf area that will need to be fixed. I plan on using a spot media blaster inside the cowl area to clean it all up and the make patch panels.

 

Along the firewall it looks like a pinch weld, just forward of the chimney. Plenty of rust on that seem, I'm contemplating cutting out the vertical area there on the firewall and patching, right where the negative battery terminal bolts on a welded nut. I'm not sure what the best way to correct this will be. Any thoughts?

Edited October 19, 2020 by DC871F

[grannyknot]

I tried to do most of my repairs through the shelf panel that the chimney attaches to, going in from the top entails a crazy amount of spotwelds to remove.  That seam on the firewall although it has easy access is a challenge because it is so visible, I have never had to repair that area so I'm not sure of the best way to tackle it.

[Patcon]

Are you welding your patch panels in with little 1" long segments of weld?

If you are, I have found that's too much heat. When I weld in panels, I make a small bead weld 1/8" to 3/16s diameter. Spaced about every 1" to 1 1/2". Let them cool, then add more. Keep adding beads until it's seamed up. Then grind and fill any pin holes that show up with more beads

[DC871F]

16 minutes ago, Patcon said:

Are you welding your patch panels in with little 1" long segments of weld?

If you are, I have found that's too much heat. When I weld in panels, I make a small bead weld 1/8" to 3/16s diameter. Spaced about every 1" to 1 1/2". Let them cool, then add more. Keep adding beads until it's seamed up. Then grind and fill any pin holes that show up with more beads

Yes. I tack weld the panel in, then start to fill in with a bunch of tack welds. But here is a problem I am having, and keep in mind I am no welder, this is all OJT after practicing on coupons. I am having issue with penetration, but if I up the current I start blowing holes. The first pic is the backside of the piece I grinded smooth. It looks good from the outside but on rear I cant get the welds to close up, too cold I'm guessing.

Back side.

Edited October 19, 2020 by DC871F

[Patcon]

I am not a pro welder and sometimes I struggle but I don't really judge my welds by the back side. For starters your seam of buttons looks pretty good. I have found though if the gap is too tight my welds aren't as good. I want a skinny 1/16 or so to bridge, not butted up tight.

Also your test piece has a lot of splatter. Are you running shield gas? are you close enough? Is thee flow high enough? Did you clean the test piece first?

[DC871F]

6 minutes ago, Patcon said:

I am not a pro welder and sometimes I struggle but I don't really judge my welds by the back side. For starters your seam of buttons looks pretty good. I have found though if the gap is too tight my welds aren't as good. I want a skinny 1/16 or so to bridge, not butted up tight.

Also your test piece has a lot of splatter. Are you running shield gas? are you close enough? Is thee flow high enough? Did you clean the test piece first?

The splatter only happened on the test piece. Running 75/25 at about 20-25psi in a closed shop, and it was clean. 

The firewall section I welded in I was able to come at it on both sides, so its in there good. I have my air hose close by to cool things off quickly, so it in there nice and flat.

[Patcon]

I have found that cooling with an air hose will cause excess shrinkage and warping.

It is a technique used by body men to remove dents and oil canning..

Don't get me wrong, I use to do it but I ruined several panels this way and simply let them air cool now. Sometimes I dolly them along the way to prevent the weld bead from warping the panel

[DC871F]

7 minutes ago, Patcon said:

I have found that cooling with an air hose will cause excess shrinkage and warping.

It is a technique used by body men to remove dents and oil canning..

Don't get me wrong, I use to do it but I ruined several panels this way and simply let them air cool now. Sometimes I dolly them along the way to prevent the weld bead from warping the panel

Oh wow, good to know.

I have done about 7-8 small patches so far, and all of them have ground out real nice. The firewall piece was the biggest to date. I sat and looked at for a long time before going after it. It wasnt too bad since the passenger floor pan is removed and I can get pretty good access to it.

Edited October 19, 2020 by DC871F

[Patcon]

I think the bigger the panel and the longer the seam the more chance for problems. Small patches are a great way to learn because they are reasonably forgiving