by Peik Borud

Tools:
I use a very hot gas torch for almost all my work now. This
thing is hot enough for brazing metal, so don't point it at one
spot of plastic for more than a few seconds! I used to use an
electric hot air gun, but this requires more patience, though
it may give a better result and less unsightly scorched plastic.

shows part of my arsenal: a cheap hot-air paint
stripper gun, the Professional "Leister" hot-air gun, my gas torch,
and a cheap gas torch made for waxing skis etc. The latter is
useless for serious plastic welding, though you may be able to do
some minor repairs.

Boats:
My first kayak was the Klepper K2, a fullbodied 4 metre design
which "evolved" into the "Flipper" in the mid 80's. This was
radical: I developed the idea of a flat low volume rear end at a
time when my friends where paddling Mirages and Dancers! It worked,
but later mods and brittle plastic (after repeated heat abuse)
left the wreck shown in pic

both ends open and an
unfortunate attempt at a  knee bump finally made me dump it in a
garbage container. This boat has a twin brother Klepper K3X with
identical hull doing flatwater duty at our sea-side cottage.
No mods on this one, and the plastic is still in pretty good shape
after more than 20 years, the last 10 of them with year-round
uncovered storage outside! Made it easier to sacrifice one of them.

Next was the Rotobat, which is x-link, so no big welding-job.
There's a web-site called Jack's Plastic Welding, they've got
some good welding tips that I've used for inspiration, but their
claim that cross-link can be welded with success is contrary to
my personal experience. So when a split developed inside the cockpit,
I repaired it using an aluminium strip and "pop" rivets .

This has held up just fine. I also replaced the useless thigh grips
with a carved-out piece of etha-foam that worked just fine

This old boat is still in good shape, but it's
getting harder to squeeze inside as years go by....

I found a 2nd-hand boat named "Freestyle" made by CSC (Canoe
Supply Company). The 3,7 metre hull was faster than the old Mirage,
because it had very little rocker. This made it pearl a bit too
easily, and made me a real ender-hero. An old picture from the play
spot "Bye-bye-baby" in river Sjoa:

shows me on the
way up with the boat basically in its present state, length reduced
to around 3,4 metres.


 shows the
chopped ends with red reinforcements that I added after cracking
the bow when hitting bed-rock under a drop (the CSC plastic is
probably even worse than past rumours about Pyranha; CSC has made
"economy" versions of Pyranha Boats.....).

shows a
necessary cockpit repair plus a small red strip over a crack in
the bottom of the hull....

Next project was the ACE "Flash" which I bought cheap from my
club with the intention of making a short playboat. This boat
was a plastic "slalom" design with pointed ends about 370 cm long.
After numerous chops it's now about 240 cms and fun for playing
in small holes and waves, especially in shallow spot where other
boat hit the bottom when going vertical. Some folks consider it
the ugliest boat in the club, but I admire it's compact "design"!
It's low volume and quite unstable, but I've paddled it in some
big water up to what I consider my personal limit around Grade 4.
Trying some modern playboats make you realise that modern designs
benefit from more volume around the centre and a flat bottom.
I may chop it a bit more some day to make it suitable for even
shallower water and vertical storage in my garage!

shows an overall view of the Flash,

highlights cockpit
details. The original stupid knee-grips have been replaced by a
pair of wooden child-size cross-country skis, screwed underneath
the cockpit rim, sculpted to fit and padded with tape and foam.
This works fine, although the deck of the boat is flat by today's
standards. I added some pieces of plastic breadboard to the tops
of the seatpillars to raise the deck a bit, see

which also shows that this is the only seat wide enough for me to
need padding! There's another ski going from the seat to the
homemade centerpillar to retain the hullshape which had a tendency
to oilcanning.

You can see my clubmate Martin
endering the Flash in the shallow playspot at Grettefoss near
Kongsberg, Norway.

The Enigma "cruising squirt" was next. I chopped it down in stages
from a pointy 300 cm to the present length of 220 cm, which was
reached quite recently (the desire to present the technique on the
Net was part of the motivation for this final cutting of the boat!).
I've also added some volume around the middle by "inverting" hollow
sections behind and in front of the cockpit to try to make it float
higher when on end. The boat now fits better in the local shallow
pool and can be stored vertically in a normal room. I've taken some
detail pics of this to show my present "method" of chopping boats:
I use a normal carpenter's saw. First cut halfway through the boat
from the top where you want the new end to be, plus cut right through
the hull a bit further out:

You may want to make the
first cut at an angle to create some local "rocker" in the new end
section:

shows a side view of the finished front of my
boat which illustrates the idea. Then cut horisontally from the end
to remove the top:


 shows the scary result!
Now heat the end flap and bend it up to close the hole:

should give you the general idea. You may need to heat and saw a
little bit to flatten this section so it fits, but the idea is to
close the end so that the bottom is one piece without weak spots since
this is the part of the boat that takes most abuse when you hit
something, and also needs to be absolutely watertight!


shows different views of the welding process.
Leave a lip of excess material around the edges, heat after the joint
is established, and bend it around the edges to make the result stronger.
The ends of whitewater boats get beaten and banged a lot, so I favour
strength rather than a neat look in this area. Resist the temptation
to file or grind off excess material; it may weaken the product!

shows the finished job,


- show details of the ends. They're not pretty, but they don't leak!

Then I got the Hurricane, a 2nd-hand boat that had survived a severe
broaching thanks to the solid Prijon HTP plastic. I squashed and
reinflated the rear several times, and tried some hullshape mods.
No big deal. Then I squashed the bottom of the hollow seat and added
1 cm thick pieces of polyethylene on top of the seat pillars to
make more space for my thighs plus lower my center of gravity.
This was quite successful. and similar to what I did on the Flash.
I had a hard time finding a spray-deck that would stick to the
flimsy cockpit-rim of the Hurricane (this has been the subject of
several threads in the rec.boats.paddle news-group) and ended up
welding bits of plastic around the cockpit edge to improve this.
This was partly inspired by the cockpit repair on the Freestyle.
The end result isn't pretty:

I also tried to increase
the volume of the hull around the cockpit. This was almost(?)
catastrophic, and the lesson is: YOU CAN SQUASH OR INFLATE FLAT DECKS
AND MAKE SMALL BUMPS FOR KNEES AND TOES, BUT DON'T TRY TO STRETCH
THE MATERIAL IN KAYAK HULLS TO MAKE OLD SKINNY BOATS FATTER AROUND
THE MIDDLE! In addition I did some reshaping of the bottom, but
the end result is rather disappointing, and made paddling less
attractive until I got a new boat:

My newest boat is the Necky Jive 8'10" which I bought brand new in a
shop. This implies less need for modification, but after some months
I decided to add more rocker to the rear of the boat. It resisted
gentle attempts at heating and bending, but the method shown in

 plus gentle heating of the bottom did the trick.
Thule roofracks are useful for more than transporting boats.
The philosphy behind this mod is that the boat was hard to balance
front to back: It either tends to bury the bow, or moving the seat back,
it's hard to back-surf without rear endering.
So I lifted the tail to make the rear sink a bit deeper during normal
forward paddling, thus enabling me to move the seat forward, and the
added rear rocker should reduce the tendency to pearling while surfing
backwards. At the same time the back deck became more hollow (squashing
and increased rocker tend to go together, while inflating the hull will
often reduce rocker. This was certainly the case with the Hurricane).
The reduced rear volume will probably make the boat easier to squirt.
The centre pillar pushed out a slight "keel" in the bottom at the rear,
so I expect the boat to retain its good stable forward surfing ability.
When surfing small waves the tail is in the air anyway, so it makes no difference.
At the time of writing, I haven't testet this mod on the
water, but I like the new looks of the boat, and believe it's improved.

When squashing or bending hulls, take your time to let the heat "sink"
into the material. This is a risky process, because the hull will seem
stiff as long as there's some intact plastic on the inside surface.
Keep testing to see whether the surface is soft enough to be marked by
a slight touch of a finger-nail, let it cool a little, reheat to "sink"
the heat, and let it cool a little before applying force to change the
shape. Working on a molten surface makes some ugly marks. Also be aware
that the reaction to heat varies with the plastic and wall thickness.
The moment the heat gets all the way through to the inside, the plastic
will go soft very suddenly. This can cause bulges, holes and other nasty
surprises, and the scary thing is that this is very likely to happen when
you heat slowly.....
 

Other projects:
So what else have I done? Stainless steel rods that hold the mud guards
on many bikes are perfect raw material for face guards:

shows yours truly, well protected by a Wildwater Combi with homemade
hardware. A couple of nuts & bolts at the rear plus plastic "Panduit"
type strips through the ear holes at the sides hold the thing in place.
Basically faceguards consist of a bottom piece and a vertical piece
in front of your nose. The top of the latter I've bent through a hole
I drilled on the front of the helmet. I've done this job on 2 Combis,
the "Darth Vader" one on the pic plus another lighter version without
the additional "bomb-proof" cheek & eye protection wires for use on
deeper water. The choice of wrapping, soldering or brazing the wire
joints depends on what tools you have. The little white blob on the
picture is my noseclip parked on the grid. I find this quite handy
because I can hang it on a very short string.

may give
you some additional ideas! The blue and purple one with my name on it
towards the right is my first faceguard project which was made from a
piece of flat aluminium with some garden hose around it. This is an old
skiing helmet from a flea market. I ripped out the stuffing and covered
the inside with a 1cm layer of Ethafoam polyethylene mat that they sell
in the sports shops. This helmet is big enough to allow a neoprene
hood to be worn inside when playing in Norwegian winter water!

 shows some ideas of adding pockets and web reinforcement
to floatation aids.

are easy to make; the orange one is
a sleeve cut off a raincoat. You get floating polypropylene rope in
shops that sell sailing equipment. Put some foam in the bag to make it
float well.

shows a variety of spraydecks with added
straps to make them easy to pull off and prevent the loop from being
left inside the cockpit when they are put on.

Take me home