To seal or not to seal - fender to body joint

[Cloggie]

Guys, my project is getting to the last strokes and one of the areas I wonder about is the bolted on front fenders.

When I painted them I did UPOL Raptor over the whole underside (after plastic bead blasting) but did not put Raptor where the front fender mounts to the shell nor on the bolt strip where the clips/bolts fit to fasten the fender.

Now, when I disassembled the car, Porsche had globbed on a ton of underseal everywhere in that joint, mine is well coated with good primer, good paint (all Glasurit) and I have the proper Terostat ribbon in the seam.

Part of me wants to leave the joint as it is so I can get in there with a pressure washer and clean out road grime and check that no rust is forming, the other side of me wants to get some good chip guard and spray the seam as much as I can to make an impervious barrier and protect that joint.

Thoughts?

The car was completely rust free before rebuild, zinc layer intact all good all over....so in theory it ought to be pretty durable.

Thanks

D.

[2.7RS]

How are you planning to use the car?

Garage queen?

Fair weather driver?

Track car?

Show car?

Safari car?

Winter driving?

[Cloggie]

Originally Posted by 2.7RS

How are you planning to use the car?

Garage queen?

Fair weather driver?

Track car?

Show car?

Safari car?

Winter driving?

It will be driven on generally good days, not winter but most definitely in the rain and likely some less than perfect roads from time to time.

I suspect your line of thinking is like mine, if it is only "wet" from time to time without a lot of road sludge and mud in there, then leaving it as it is means the wet can get out as it is all open to the air...and in theory with galvanizing, very good Glasurit primer, raptor almost everywhere and good Glasurit top and clear coats - well, ought to be OK?

But certainly appreciate your thoughts on the matter...

D.

[Dpmulvan]

The tape was put there for a reason and not just to keep crud out of the joint.

[Cloggie]

Originally Posted by Dpmulvan

The tape was put there for a reason and not just to keep crud out of the joint.

Very true and my previous 911 - which I also built myself - did not have any undercoat there and so far it has not rusted to the best of my knowledge.

Just the authorities are increasing the use of road chemicals as vehicles become more rust resistant hence my increased worry...

Thanks!

D.l

[Bill Douglas]

I replaced both fenders and didn't have the seal. I live in a seaside location and I didn't want salt building up in there because of a seal.

[962porsche]

if your referring to the tape used between the fender lip and the cars apron where the fender bolts up to it then I would highly recommend using it.
some may say or think it promotes rust but in fact it does just the opposite!
as the car will twist and move the matting surface of the two panels will also twist. it's to stop or help prevent the two panels from grinding against each other it also stops water / moisture from invading between the two panels that could leak mounter into the cars trunk area.
I have restored god knows how many 911's and have seen on every one when the strip caulk tape was not used that the area on the apron has rust on it. in most every case by the time you see the rust creeping from under the edge of the fender / apron area the apron is totally shot.
the porsche engineers put it there for a reason if your smarter than they are the choice is yours to use it or not.

[Cloggie]

Originally Posted by 962porsche

if your referring to the tape used between the fender lip and the cars apron where the fender bolts up to it then I would highly recommend using it.
some may say or think it promotes rust but in fact it does just the opposite!
as the car will twist and move the matting surface of the two panels will also twist. it's to stop or help prevent the two panels from grinding against each other it also stops water / moisture from invading between the two panels that could leak mounter into the cars trunk area.
I have restored god knows how many 911's and have seen on every one when the strip caulk tape was not used that the area on the apron has rust on it. in most every case by the time you see the rust creeping from under the edge of the fender / apron area the apron is totally shot.
the porsche engineers put it there for a reason if your smarter than they are the choice is yours to use it or not.

I most definitely have used the terostat ribbon and would not dream of not using that part.

There has been pretty good squish out of that ribbon which encourages me to just leave it as is rather than dealing with the relatively open seam as shown in these photos






Please note there are a couple of fender bolts not yet in.....they will of course go in prior to the car going on the road.

D.