Hi Paul,
Those frame rails were unfinished inside, right from the factory and
over time condensation and other moisture gets in there causing a
surface scale. Any area that isn't well ventilated and given
opportunity to dry out is particularly prone to rust. But, after all,
Triumph was probably thinking of a useful life of about 10 or 20
years, not the 40 to 50 years we're getting out of the cars!
After cleaning out the round outriggers and frame tubes as best
possible with compressed air, I used a foam pad, stripped off the tip
of one of those "foam brushes" you find in most hardware stores,
attached to the end of a long, stiff piece of wire (actually brazing
rod, if I recall correctly). That makeshift tool was dipped in POR15
and pushed into each tube from the side. A couple coats were applied
to try to get as thorough coverage as possible. POR15 works
particularly well to encapsulate old rust and help prevent it
spreading. One key thing is that it actually sets up more in the
presence of moisture, and forms a hard, waterproof barrier.
By the way, I also reinforced the body-attachment outrigger tubes
using the same techniques, with 1" pipe driven inside and then spot
welded. A similar reinforcement could be done to the straight sections
of the two round, full-width tubes at the rear of the frame if you
feel it's needed.
Probably the worst single area for internal rust on the TR frame is
the diagonal braces behind the front spring/shock towers. The reason
is there is no drain hole in these. So, moisture gathers at the bottom
and is trapped, eventually rusting out from the inside. Check yours
carefully around the base, where they are welded to the main
rail. Even if okay, it's a good idea to drill a 1/4" drain hole on the
inside, to allow the inside of that strut to dry better in the future.
Yes, there are tools to spray Waxoyl or similar inside of frame
rails. These are simple siphon guns with flexible tubing attached and
spray tips that are pushed into the frame rail, then backed out as the
spraying is done. It's usually necessary to drill a number of 1/2"
holes as access to push the tubing and tip well up inside the
rail. The holes need to be done carefully, so that they don't weaken
the frame in any way. There are some existing holes on TR frames that
help, but more must be drilled. The holes are plugged up afterwards.
Waxoyl would be my choice. It goes in as a mist and settles onto all
surfaces, where it creates a self-healing layer of protection. In
fact, any holes, gaps or openings other than the one used to insert
the spray wand need to be taped or blocked off, while the mist settles
on the inner surfaces.
Siphon guns can be purchased a number of places, including Eastwood
Co. or J.C. Whitney. (Whitney's paint is more of an undercoating,
though, not a Waxoyl like product.)
Yes, Waxoyl should be repeated occasionally, but probably every 3 to 5
years at most, unless the car is driven a lot in an extremely
"British" climate. However, careful planning and drilling of holes
while the frame is out from under the car and stripped can make it a
relatively easy job to repeat even when the car is all back together.
Powder coating really won't work. It's not possible to direct the powder into
all the internal areas of the frame with any assurance it will cover well.
Dipping in some sort of high-zinc content solution would probably be
best, but would also need all existing rust removed first. Probably
that would require a stripping dip, which leads to concerns if all the
chemicals have been removed and won't seep out to ruin the final
finish.
That's why I would choose Waxoyl or similar as the most practical
compromise way to reduce rust inside these old frames to a minimum. By
the way, it can also be used inside rocker panels or other trapped
areas of the body, which can cause concerns similar to the frame
rails.
Cheers!
Alan Myers
San Jose, Calif.
AMfoto1@aol.com
http://hometown.aol.com/amfoto1/amfoto1.htm
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