To weld or "glass"

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To weld or "glass"

Post by friedman » Sat Aug 10, 2019 9:11 am

This thread is for the average spider (or other Fiat) owner, not the Brad A. and other serious types although I respect responses from such gentleman.

You have a spider that will just be a nice driver, not a show winner and not a "I want it just like it came out of the factory" car. You have a MIG but have no real metal bending skills with the 22ga metal you get from Lowes or Home Depot. Your floor looks like this:
IMG_1059[1].JPG (87.9 KiB) Viewed 3917 times
The floor looked perfect until you realized someone had laid down and expertly applied layer of fiberglass. The driver side looks the same. I wonder if I should have left the glass in. I wonder if I should just reglass it. There is lots of compound curves here. A friend told me a POR-15 and glass matt layer would be just fine. I'm not getting replacement floors as that's a whole other layer of complexity to the repair and I am certainly not paying someone else to do it. I don't think the floor is that structural and it will never be seen with insulation and carpet on top.

Current plan is to deal with my depression and just weld in lots of home made patch panels and try to minimize all the burn throughs I will create, maybe a layer of glass on top of the repair patches.

I kept looking for terminal rot that would cause me to abandon the car but can't find any. For an east coast 75, I bought this spider because the front suspension towers are perfect (how weird is that) and the rear arches are original and not rusted.

Anyway, just curious on what the rest of you think.
Carl in Virginia
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Re: To weld or "glass"

Post by miker » Sat Aug 10, 2019 9:45 am


It turns out that someone asked and got a great set of answers on this long ago for a different project. ... 8&start=10
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Re: To weld or "glass"

Post by cgranju » Sat Aug 10, 2019 10:41 am

That is funny. Having the MIG & all, I think patching + seam sealer/whatever is simple. It could be done meticulously in a fashion of which even Brad would approve, or it could be done time/function-efficiently and my guess is that either fashion would be adequate. The only thing I would (personally, I mean if it were my car) is do it in a manner that would likely lead to future issues or make it more difficult later for someone to do a complete floor plan if such were desired. The reason for the last part is that these days of you have a 124 Spider that is solid/original in the ways you describe, it’s worth (to me) being sure it’s preserved so the option is always there to be “driver” or a full on restoration.
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Re: To weld or "glass"

Post by friedman » Sat Aug 10, 2019 12:10 pm

OK, Chris, when I have decided what to do I'll get your approval since you will eventually buy it from me! Or you can tell me know what you want me to do to fix "your" spider.

Not too worried about future value, a real restoration shop will just laugh and cut out all the floors from sill to tunnel.

Mike, nice find, I had forgotten about that post although that was a rivet v weld post. This is a fiberglass v weld post that I will probably ask again in three years because I forgot I had already asked I usually do.
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Re: To weld or "glass"

Post by MikeGreer » Sat Aug 10, 2019 4:53 pm

Carl, if you decide on glass, and this is in no way an endorsement for glassing the floor, use epoxy resin, not polyester. Eons ago I glassed some rust on my XK140 roadster, I'm sure the guy that bought it imeadiately cut it out and welded in new metal, but I didn't have a welder.
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Re: To weld or "glass"

Post by rridge » Sat Aug 10, 2019 6:26 pm

If you are "restoring" a car for your own use or to sell at top dollar, you weld. If you are trying to get an orphan back on the road at a price a young enthusiast can afford you glass it. But you knew that already. I endorse Mike's recommendation of epoxy resin. I use the
West System thickeners that make it less messy and less expensive to work with.
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Re: To weld or "glass"

Post by bartigue » Sat Aug 10, 2019 11:07 pm

My welding skills are comically bad. The last thing I welded I was glad a tire fit over it.
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Re: To weld or "glass"

Post by davedecker4 » Mon Aug 12, 2019 1:10 pm

If you have a welder...
I live on the west coast and I cannot endorse glassing over this. If it were just a hole in middle of the floor and you can glass to solid steel on either side that will support it, that would be one thing. If you get crappy, too thin metal at home depot, get it from somewhere else. There should be some type of metal or welding supply shop in your area. Get a couple sheets or pieces of slightly thicker stuff. Use some old scrap fender or sheetmetal if you have to, and grind it clean (both sides especially where your welding it). Throw a couple bead roll lines down the middle or around the edge for strength if you're worried about it. If you don't have the bead roller, see if somebody you know does or if they have one at the metal store. If you can't do that, skip it. You can always pound a dimple on the edge you have to match, over an anvil, vice, rock or what have you, with a hammer, so the pieces line up before you weld em. You can bevel the edge with the grinder to be real trick. Like paint, prep work makes most of the difference. If you don't have a job you have to get to, you can probably spend 10 or 20 min practicing welding stop signs together or whatever scraps you have handy, before you start welding on the floor. Start with settings listed on, or inside the door of your welder. Do a little at a time so things don't twist up. Grind off the boogers and see how its going. Clean strong power to the welder, clean strong ground, clean strong edges that line up with the right gap.
Should be beauty. Or at least functional. You'll throw the carpet over it anyway.
Glassing takes quite a bit of learning to get right anyway.
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Re: To weld or "glass"

Post by paulc » Mon Aug 12, 2019 4:09 pm

Ours didn't look quite that bad, just a few holes with solid metal around.
Not having a welder, I glassed :o with several layers of fiberglass mat (not cloth) out to the good metal. Also used epoxy resin not polyester, epoxy is much stronger.

Good book on fiberglassing is : How to fabricate automotive fiberglass & carbon fiber parts / by Daniel Burrill with Jeffrey Zurschmeide.

Useful to duplicate/repair that air dam when you ran over that speed bump. :?
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Re: To weld or "glass"

Post by atruscott » Mon Aug 12, 2019 5:35 pm

They say that a poor welder is a great grinder.... :)

Take a look at what panels you can get. It might be that cutting back the rust to the edges of the panels you can find, will get you to some nice firm metal. Tack weld with the MIG, with plenty of space between each tack.... and keep going until all the racks fill the spaces. Then go to work with the grinder to smooth it all out. I think you’ll be astonished how good it can look if you take your time. Same with underneath. Tidy up the welds. Then coat the whole lot with POR15. There’s something about that nice glossy hard coating that makes everything look good!

If you really don’t want to do any welding... then grinding out the worst of the rust thinned metal, POR15 and fiberglass, will probably work pretty well. I’d probably install some rivets so I know there’s no chance of lift if the fiber doesn’t fully adhere, and I’d also want to clean up underneath and fiber there too. I think underneath is the problem.... if debris causes some rust pockets to start forming, could easily get in between a lifting fiber floor and the old floor.

Thinking on it - probably a similar amount of time for both approaches. Keep us informed!
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