Welding in Floorpans - Novice Welder - Need Advice, Please!

More of an art than a science - discuss metalworking and welding here.



Settled In
Posts: 29
Joined: Wed Jan 16, 2013 1:02 pm
Location: Naples
Country:
Italy
PostPosted: Tue Oct 04, 2016 12:00 am
Fellas -

I'm doing a nut and bolt restoration on a 1972 Alfa Romeo GT Junior (same body as GTV). I'm an inexperienced welder and could use some advice in welding in reproduction floorpans. FYI - using a Miller 211 MIG with .023 Lincoln wire, should be 75/25 mix of shielding gas (argon/CO2).

So, here's a picture of the floor. Looking from the top of the car towards the ground (you can see the back wall through the floor because the car is on a rotisserie tilted at a 90 degree angle). I cut the old metal out of the way so it would be easier to get to the spot welds to drill them out.

Image


And a view from the bottom looking up -- you can see the chassis legs that run underneath the floor pans.

Image


And the money shot -- that's the driver's front floorpan that's been cut out. I bought half floor pans new, and they are long enough to cover the area where the two front seat brackets are (the ones closest to the cut out metal). However, I'm trying to figure out the best way to fit and weld it up. I'm thinking that I can cut the old floor again between the two rows of spot welds. That way, the old floor would be secured by spot welds in that area and so would the new one. Then I could butt weld the two together, or I could also try to put a bit of a flange in the new piece and lap weld it over the original section. Suppose if I did that, I could do a bit of plug welding in the overlapped area, too, but that might be overkill. If I cut it in that spot, I would not have to mess with removing and re-welding the seat bracket mounts.

Curious to hear thoughts or recommendations!

Image


Thanks

Scott
72 Alfa Romeo GT 1300, Amaranth Red/Tan
66 Fairlane GT Convt, 428, 4 sp, Black/Black/Red
68 GTO Convt, Owner Built 455/TH400, Nordic Blue/White/Parchment
71 Javelin Road Race Project, Owner Built 401, T-10, 9"



Non-Lurker
Posts: 8
Joined: Wed Oct 12, 2016 6:42 am

Country:
USA
PostPosted: Wed Oct 12, 2016 6:48 pm
I would just cut it where you have the line posted, and then just drill and spot weld the new floor that you bought just like how the old one was attached. Is it a one or two piece floor? If you end up having to fabricate your own pieces it will depend how big of a break you have.
Attachments
image.jpeg



Top Contributor
Posts: 6213
Joined: Tue Sep 16, 2008 1:17 pm
Location: Pahrump NV.
Country:
USA
PostPosted: Sun Nov 06, 2016 10:53 am
Making that cut and removing that piece and all those spot welds then but welding them together and spot welding that all back down sounds like the way to go BUT Your sides on the Transmission tunnel and on the Rocker panel side are a problem too.

But welding in and grinding the weld bead down and plannishing the bead out is the ultimate repair with the main goal of having an invisible repair very hard to do as a Beginner but its also hard to maintain the original strength of the part which is more important? invisible or strength both! in my opinion.

If it were mine I would go with a Flange all the way around and do Plug welds then weld whole edges down Ya a lot more welding & heat and with it warping but in the end its a stronger repair that you can easily hammer and dolly and seal up afterward.
Its not going to be seen easily Better to make a stronger repair that can be fairly well hidden.

You should also try ESAB easy grind welding wire you'll be glad you did.
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

Return to Welding & Metal Fab

Who is online

Users browsing this forum: No registered users and 15 guests