Weld repair

I have just purchased a Prijon barracuda kayak (my first),and note there is a scrape along the bottom that I would like to repair.I asked the question of Paddling .net, and was asked to register and ask the question to the membership. I was given the advice that polyethylene boats can be repaired using patch’n go. So I suppose it asks another question of what material Prijon kayaks are made of? I think I better ask Prijon the question as well. I trust I have openned a topic that is useful to the membership, and if I get to know from Prijon I will post it.

HTP repair stick
available in various colors

http://www.rutabaga.com/Plastic-Repair-Stick_p_287.html



supposedly it can be used with a hot glue gun. a soldering iron might also do the trick, or an actual plastic welder iron. (obviously you’ll need some knowledge of how to do plastic welding without burning a hole in your hull.)



I presume it’s a pretty deep gouge? I wouldn’t worry about attempting to repair shallow scratches from normal wear.

Prijon contact in the States used to be

– Last Updated: Jul-10-12 5:25 PM EST –

wildnet.com

I have a Prijon. It’s not a poly and not
a rotomold. They call it High Performance Thermoplastic HTP. You’ll notice your boat is made from two pieces joined together. If they can join the whole boat together, it should be easy to make repairs. Wildwasser is the main dealer for Prijon and would have the sticks your looking for.

Weld repair
Before I made my choice of a Prijon kayak I looked at reviews and have seen a video of the manufacture of the kayak.It is manufactured in Australia although it is German. The plastic is in tube form fed vertical which is heated to plasticise it and stops at a predetermined depth to fit the die. The dies close to cocoon the plastic and a hole is punctured to the inside of the plastic. A gas is injected at pressure( inert gas I suggest) to allow the plastic to form in the mould. The mark you are suggesting will be the half joint of the mould.Once the mould is formed and the die is split the flashing is cut off the half joint.The cockpit and other shapings are routed which takes no time at all.Worth looking for this video which only lasts for min’utes.I will go back to see where I saw it as it is worth a look.

welding
On e-bay England there is a company called Avoncraft who sell Prijon kayaks direct from Prijon. I asked the question of them to have this reply: HTP have repair sticks which are melted in a glue gun.It is suggested it is not a proper repair as the parent material(kayak) will be cold. Now I have been collecting plastic bottles, milk bottle tops,and others well before I purchased this kayak(I think I like all the bonny colours). I intend to make a rudder using this plastic(of my design),and will experiment with various options. One is to place some fibreglass resin in the parent body to plastercise it and in fill with some plasercised polyethylene.I am a retired Engineer so I will enjoy the activity. If successful I will post it onto the forum.In the mean while the repair on the kayak will be left alone as it is more cosmetic than a major repair.

link to info on plastic welding a kayak
http://www.oceankayak.com/customer_support/kayak_repair/welding/



I’ve repaired a hole in my Perception kayak, and it has been water tight now for over 5 years. I used plastic repair rods the manufacturer sent me and a heat gun (paint stripper). Just be careful not to ge the boat too hot or you will melt right through it!

In ww circles, word is that HTP does
not weld, and crosslink doesn’t weld. Linear and superlinear poly, like that used in most ww kayaks, welds properly in skilled hands.



But we’re only talking about a “scrape” here. Why weld a scrape?

Wildwasser sells plastic sticks
I bought one in Boulder, where Wildwasser has an office. I never used it on the Twister, though, and later I sold the boat. But if they sell their own repair sticks (color-matched, to boot), it appears as though plastic welding is possible.



I would not bother patching up a scrape.

That’s not the same as plastic welding.
It may work for a while, but real plastic welding uses the boat’s material, and any added material is also the same material. I have no idea what they’re using in those repair sticks, but it may not bond very strongly.

What are they used for?

– Last Updated: Jul-17-12 12:23 AM EST –

Filling in scratches?

You drizzle the stuff on a crack, and it
sort of binds it together.



West G-flex epoxy is getting a fairly good record for repairs on linear poly, but I haven’t heard reports about crosslink or HTP. Usually, though, the flaming procedure makes G-flex stick well enough to hold, and it will also hold glass or Kevlar cloth reinforcement over the repair, to spread future stress.

Interesting
Whoever drizzled the same-color plastic goo to try to cover up a broken area where a rudder part went into the stern on my first sea kayak (a CD Squall) must’ve thought it could still pass as a new, first-quality boat. Too bad I assumed that sea kayaks were like bikes or cars, that damage and/or repairs had to be divulged to prospective buyers.



Based on that botched “repair,” I tend not to believe that melted plastic can adequately repair a crack or hole. Maybe if the boat only gets hung up instead of actually being paddled!