CAMPER&BUS 83(^13)
Paint inner surfaces
Before you weld the
inner channel together, it’s
wise to paint the surfaces
that will be hidden from
view. Failure to do this will
result in them rusting from
the inside out in double
quick time. Everyone has
their preference on which
products to use and we
have experimented with a
lot of different paints over
the last 15 years, with the
conclusion that there’s
more than one good
product out there and
that any protection is better than none. On this occasion, we
decided to paint the inner surfaces with the Frost Zinc primer
mentioned earlier, as we’ve found that it etches well to the
base metal, goes on reasonably thick with just one application
and you don’t have to worry about brush marks, being that this
comes in aerosol cans. If you prefer other products, make sure
you follow the manufacturer’s guidelines and etch the surface
first – certain popular metal paints are great over rusted metal
but peel off clean metal depressingly easy. If using a brush-on
product, apply a minimum of two coats.
(^16)
Blast / clean up metal
Once we’d got the lower
sections back together, we
decided to have the inner parts
of our gate blasted – there was so
much surface rust that we figured
it’d be difficult to get at it all with
a wire wheel. Blasting is great for
finding thin and pinholed areas,
even better than a wire wheel in
fact, but it does give everything a
rough texture that will need to be
sanded with 120 grit paper before
the primer stage. A lot of people think that blasting makes life
easier, but it still creates a ton of work.
If you don’t want to go down the blasting route, you can go
over the area with a wire wheel and a series of wire brushes
attached to a drill, followed by some hand sanding prior to
rust conversion and primer. As a guide, it cost us only £20 have
our rear gate blasted, which really isn’t that expensive.
(^17)
Weld up
smaller holes
As we had
expected, our gate
came back from
blasting like Swiss
cheese, so we had
to make a decision
about which areas
we were going to
attempt to weld
up pinholes and
which areas we
were going to cut out and replace with fresh metal. As a rule,
if there are one or two pinholes in an area of around 30mm
then we chose to weld them up. More holes or bigger holes
than this and we decided to cut out and replace. One of the
inner side pieces on our gate was particularly bad and, as it
contained fairly complex curves, we formed several pieces of
flat steel to make up the tricky repair sections – these were
then butt-welded in place.
A tip for welding pinholes: Flick the trigger onto the metal
around the hole two to three times to put some metal blobs
on the area, then do a full tack. Doing this puts more metal
into the job and makes blowing a hole less likely. Practice
makes perfect and the more rust repair you do, the more you
get the hang of building up metal where there isn’t any. We
decided to form one of the lower outer corner pressings by
building up slowly with weld, as it would have been hard to cut
a piece small enough to weld in.
(^14)
Weld lower channel
You can now clamp
the inner channel into
position and plug weld
it into place. When plug
welding, we find it helps
if you clamp both sides of
each hole as you weld, this
also helps the panel to cool
between welds, as you have
to move the clamps. Work
slowly and move around a
lot to minimise the risk of
heat build-up.
(^15)
Weld lower channel (cont.)
When it comes to welding the centre supports to the
inner lower channel and welding the channel to the bottom
of the outer panel, we chose to stitch weld these areas,
even though this is now how it was done at the factory. Take
your time and weld in a series of tacks so as to minimise the
dreaded heat build-up.
(^18)
Grind
Once all the
welding is done, you
can grind back with
a few flap discs and
some finger grinder
belts in the corners and
tight areas. Take your
time and take regular
breaks, so you don’t get RSI, or my old favourite, tennis elbow.
Holding a grinder for long periods of time is no joke. It’s highly
likely you’ll find holes that still need welding on the first couple
of passes with the grinder. Usually, by the third grind you’ll be
pretty much there.