Roger,
A lot of cracks are caused by "too hot" of a mixture when hardener is
applied. The stuff hardens too fast and at an uneven rate throughout.
This allows the filler to have pockets that are not of the same
consistancy anc can crack due to changes in temperature and stress.
Joe Curry
Roger Helman wrote:
>
> I heard, that the cracks which appear in plastic fillers are because the
> filler expands and contracts at a different rate then the metal underneath.
> It's because of this expansion and contraction that cracks appear in time.
>
> Roger Helman
>
> Egil Kvaleberg wrote:
>
> > On 8 May 1998, Dr T. Dafforn wrote:
> >
> > > I've seen, during the restoration how water seems to get under filler
> > > somehow and rots the metal from the inside...
> >
> > Correct.
> >
> > Applying filler to bare metal will make it stick, but small cracks in the
> > paint on top may easliy cause havoc - filler is in fact quite a
> > hygroscopic material.
> >
> > > I don't want this to happen..
> > > So I was wondering wether its is worth painting zinc rich primer over the
> > > area before the filler was added, to protect the metal..
> > > Will this prevent the filler from sticking???
> >
> > To a certain extent, yes. It will not stick as good as to bare metal.
> >
> > > or am i just being too paranoid about rot?
> >
> > No - that is simply not possible.
> >
> > Using filler is something of a loose-loose situation. It really only works
> > for in very thin layers on panels that aren't suspect to rust anyway.
> > There are fillers with am imherent high content of zinc, they may perhaps
> > help a bit.
> >
> > The best way of handling this is old fashioned lead. Not as difficult as
> > it might look, either.
> >
> > Egil
> > --
> > Email: egil@kvaleberg.no Voice: +47 22523641, 92022780 Fax: +47 22525899
> > Snail: Egil Kvaleberg, Husebybakken 14A, 0379 Oslo, Norway
> > URL: http://www.kvaleberg.com/ PGP: finger:egil@kvaleberg.com
>
> --
> Roger Helman 71 TR6 CC67866L
> Digimation Inc. http://deepthought.digimation.com/rogerh/
> New Orleans La.
> www.digimation.com
> Voice. 504.468.7898
> Fax. 504.468.5494
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