Steel weld in sunroof delete panel discussion

[TRE Cup]

Hello to all and hope you are keeping safe distancing and healthy. With Chris in the UK no longer with us, and Rennline currently not providing these weld in panels
I had a discussion with a friend that has made plenty of metal shaped panels. Our talks have revealed some important details when it comes to closing off the opening in the roof
The existing opening has metal that is folded in a U shape, pinched shut. If you weld in a panel without grinding that edge open, then it is similar to over lap welding flares
You are unable to plenish hammer the welds to get a complete bond that is free from voids. So it may develop a rust location over time.
The right way is to grind off the edge, and butt weld the new closing panel in place, plenish hammer and then the usual prep , filler, to complete the job.



Bob is going to make a panel for us to evaluate in the next few weeks so we can decide if this will be a viable offering to you

Stay tuned

Stay tuned
Dave

[coomo]

Hi Dave.The panels that Chris at Fenn Lane supplied, used a recess to allow the edge of the panel to sit flush with the roof.I used them frequently.Still have one spare.

[TRE Cup]

Yep- we installed a couple of his pieces too. Its effective but "not right" in metal man parlance. I think for the most part, we will be okay with our past installs using Chris' panels w/o the removal of the lip. Just learning what is considered the better way that this should be done

thank you for your input

[911tracker85]

will be watching this.

I got one of the RL steel panels. after getting the sunroof/cassette cut out, got to looking at it and wondered about how to prep. talked to RL and they said you have to cut/grind off all the lip around the opening.

when I did the roof lost it's shape. another guy I communicate with is taking a different approach.

exchanged brief PMs with someone, dont recall who, that has done these. just brace it into shape and weld.....

looking for details on getting this right.

PS car on rotisserie.

[75 911s]

I just saw an ad on IG for the Rennline panel. Did you try to order one from them?

This is a better option imho:

Metal Roof skin (from our classifieds)

[pkabush]

I tried to order a Rennline panel a few weeks ago from our host. No dice. All out. I’m pretty sure these are Chris’s panels. Perhaps someone can confirm?
I ended up buying one from a seller on eBay who had five.
Dave makes a good point about the install. It never really occurred to me but, it is a lap weld.
My plan was to use a combination of panel glue and spot welds but I may rethink that.
Butt welding would definitely be better. I’m just not sure I can pull it off without significant shrinkage

[Trackrash]

Originally Posted by pkabush

I tried to order a Rennline panel a few weeks ago from our host. No dice. All out. I’m pretty sure these are Chris’s panels. Perhaps someone can confirm?
I ended up buying one from a seller on eBay who had five.
Dave makes a good point about the install. It never really occurred to me but, it is a lap weld.
My plan was to use a combination of panel glue and spot welds but I may rethink that.
Butt welding would definitely be better. I’m just not sure I can pull it off without significant shrinkage

Butt weld is really the way to go. Problem is the time and skill involved to do it right. First you have to cut and perfectly fit the panel both in gap and while preserving the curvature in both the panel and roof. Then the welds are going to warp the panel and you will have to hammer, dolly, and file the panel straight. Hammering the weld will flatten it and stretch out the shrinkage. Back in the day they called it a hammer weld, but that was with oxy-acetylene. There is supposed to be a "softer" mig wire, I have heard. The really skilled guys will TIG it.
Not for the faint of heart.

I cannot imagine panel adhesive will be a permanent solution, but I could be wrong. Also tack welding with a lip? Could work I guess.

[spyerx]

For those of you in Socal. reach out to SMC Metalcraft in Santa Ana. He did the panel for my 964. Absolutely perfect work, needed zero filler on the weld finish. He's done several others I know of. A real metal worker, if I recall used to work with Rod Emory.

You can find him on Instagram:
_salamanca_metalcraft_

[coomo]

This is how the roof looks like after the sunroof cassette and support is ground out.You can see the recess on the panel.It sits pretty flush.Prop it with curtain poles, and use the guide if you need too.Weld every few inches, then when seated you can fully weld in sections NOT continuosly.Chris told me to use filler(bondo) with metal constituents.normal type occassionally "moved around" and could be visible under extreme sunlight.

[coomo]

Originally Posted by pkabush

I tried to order a Rennline panel a few weeks ago from our host. No dice. All out. I’m pretty sure these are Chris’s panels. Perhaps someone can confirm?
I ended up buying one from a seller on eBay who had five.
Dave makes a good point about the install. It never really occurred to me but, it is a lap weld.
My plan was to use a combination of panel glue and spot welds but I may rethink that.
Butt welding would definitely be better. I’m just not sure I can pull it off without significant shrinkage

Yes, Rennline were panels from Fenn Lane.You probaly got yours from Stuggart Classica another UK reseller

[coomo]

Originally Posted by 911tracker85

will be watching this.

I got one of the RL steel panels. after getting the sunroof/cassette cut out, got to looking at it and wondered about how to prep. talked to RL and they said you have to cut/grind off all the lip around the opening.

when I did the roof lost it's shape. another guy I communicate with is taking a different approach.

exchanged brief PMs with someone, dont recall who, that has done these. just brace it into shape and weld.....

looking for details on getting this right.

PS car on rotisserie.

To be honest, it appears you may have stretched the roof as you removed the sunroof cassette.Never seen a wobbly roof like that before.You might have better luck shrinking the roof with shrinking disc/hammer.Use the new panel to maintain the shape.It has correct curve.minor tweaking will get it pretty much correct curve.

[Iciclehead]

I did mine a few years back, after I removed the cassette the roof held its shape quite well. I had a roof section from a wrecked non-sunroof car and I applied a little pressure to hold it in place, did the spot welding and then seam welded it.

I had a flange on my cut off piece, I also leaded the joint (very little required) as I would not trust any sort of plastic on that location.

Car is now painted, it looks perfect, there was a little fettling with the high build primer but other than that, it came out the way I wanted.

If I could do it again, I would butt weld instead of the flange using gas and then metal work any problems. It is a big, gently curved panel, so do not attempt until you are either foolish or skilled.....I initially qualified as the first kind, but was able to move int the second category by the time it was done.

Dennis

[911tracker85]

stretched the roof

and how would I have done that?

after getting info from rennline to grind off all the edges, when I ground off the folded edge, there was also a support brace that ran across the roof. it appears that it was held by the fold and was bonded, and the bonding let go as I ground off the folded edge.

will probably make another brace to get the panel in place correctly and my friend will tig weld it. also rebond the cross brace.

[Dpmulvan]

Overlapping metal will cause rust, if your not butt welding you want to use 3m panel adhesive to install. I wouldn’t worry about the panel adhesive it’s strong enough to tear the metal apart.
A good filler is upol D or evercoat metal2metal same stuff.

[Iciclehead]

Originally Posted by Dpmulvan

Overlapping metal will cause rust, if your not butt welding you want to use 3m panel adhesive to install. I wouldn’t worry about the panel adhesive it’s strong enough to tear the metal apart.
A good filler is upol D or evercoat metal2metal same stuff.

...well, time will tell...but I did the overlap but the weld on the outside completely seals the overlap, inside it is seam sealed, had weld through primer through it and of course is completely primed and painted.

I agree it is not ideal, but I think with the steps I mentioned above...plus the lead filler where needed....it will be fine.

I worry that an adhesive based solution would eventually ghost the seam as you'd need to use plastic filler for any voids and such, plus you'd not have the option for shrinking/stretching to maintain the curve with the bond agent holding it in place, so you'd need a perfect curvature to start.

Dennis

[TRE Cup]

modern panel adhesives are incredibly strong and with correct prep, won't shrink over time. They are not fillers, but glue between panels. You will damage the metal surrounding the panel adhesived pieces if you try to pry them apart
That being said, short weld beads spaced apart, as described above, minimize warping. Patience is the key

some great input here- thank you
Dave

[coomo]

Originally Posted by 911tracker85

and how would I have done that?

after getting info from rennline to grind off all the edges, when I ground off the folded edge, there was also a support brace that ran across the roof. it appears that it was held by the fold and was bonded, and the bonding let go as I ground off the folded edge.

will probably make another brace to get the panel in place correctly and my friend will tig weld it. also rebond the cross brace.

Perhaps you used a hammer too much?I dont know just throwing stuff out there.That brace isnt required.Once the panel is in place tortional rigidity should be returned