As per title. Do I have to use PU sealant on exterior side panels, or can I rely on using pop rivets only?

What have others done here?

GRP cracks where there are stresses on holes. Rivets bend and crush and open up holes when forces pull them. PU adhesive is very sticky and cures quite rubbery. It takes the load off the rivets. The rivets stop the glue peeling. I'd use both. I did use both.

PS, I guess you needn't use much PU. A bead a couple of inches long here and there might be fine, and a bit easier to remove should you have to.

[Edited on 13-3-2009 by smart51]

I'd use a bead of PU as well as just the rivets for it's sealant properties as much as the adhesion.

If you get water between the panel and the chassis, and it can sit there, rusting into your rivets and the holes in the chassis it's not going to be pleasant in there after a while.

I put a bead of pu between the floor and the chassis rail. Then when I put the side panels on, they had a 90 degree return on the bottom, so they got bonded and riveted to the chassis rail. Finally I ran a bead of sealant around both sides of the join to exclude water.

HTH

Mike

Caterham doesn't, but I did. Can't hurt in the strength department. Also should form a barrier to slow rust occurring because of the ally/steel next to each other.

quote:

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Originally posted by RK
Caterham doesn't, but I did. C

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I used it at the base of my rear panel (ali). Unfortunately I wasn't happy with my first attempt, so I took it back off... which was a hell of a struggle!

So, if you use PU to seal/fasten a GRP panel, expect that panel to be trashed if you ever need to take it off again.

As said it will make it stronger and keep some wet out.

Once its gone off thats it, there is no moving the pannel at all.

Use both PU Adhesive and Rivets - but only use minimal PU to get a seal and fix.

PU Adhesive can be can using a sharp blade to part the components the residue can then be removed using a Petroleum Based Distillate i.e. Petrol, Diesel, Turpentine, White Spirit etc. It takes a while to begin to break down but perseverance will reward you...

Steve

Thanks to everybody for the advice. Both (PU and rivets) it is.

Hi

Best way to break the bond between two components joined with PU type sealants is with a stainless steel 'cheesewire' wherever possible.

As far as whether to use or not, I would say yes as it will reduce / eliminate fretting and subsequent corrosion.

It's the way I'll be going .............. eventually.

Regards Mick

The only thing thats stuck on with PU on my car is the floor and the infill panels behind the seats (both are also riveted)

My side panels are held on with two bolts at the rear which also hold on the rear wings, two bolts under the scuttle (also holding that on) and two bolts under the nose (again also hold that down). The there is one rivet underneath at the front. Super easy to get off if the need ever arises, and they certainly arent moving anywhere.

David