Welding a boat

[PAC]

I just picked up a Micro 250 that has a 3" crack in it under the butt seat. Any thoughts / ideas on welding? I've done some research but looking for as much info as possible before I attempt to fix!

Also after welding what type of saddle set up is suggested? I'm thinking Team etc do to the additional plastic. Thoughts?

Thanks!

[msims]

There was a pretty good thread on that not too long ago, lots of really good info. Someone even had info on a 'welder' for boats. I think that Sir Adam may have posted this info on the site somewhere... I had a look for the thread but couldn't find it.

[PAC]

Thanks... I looked for the thread to and couldn't find it.
Anyway Adam is looking into if the plastic is weld able for me. I have been researching too! I've been told piranhas (sp) are not weld able but I have to believe one of the innovative folks on this board has a solution - if only they would share (hint, hint,....) .
Again thanks!!!!

[Sir Adam]

As NZMatt currently has the welder, I can't tell you the exact items that actually happen, but basically there is a plastic material that wil bond VERY strongly to the boat, and you essentially weld THAT together with itself (after melting it on to the boat). It's actually made to fix car plastic, ATV plastic, etc..., but will apparently work on anything. If the welder won't touch it, let me know, and I'll either ship it to you to play with (when NZMatt is done) or you can pick it up when you get your Viper .

[NZMatt]

Hi PAC

I intend to sit down this weekend and learn how to operate the welder and have a go with it. How old is your boat? I believe Pyranha just uses regular PE in their boats, but if you can confirm the material, I could confirm for you this weekend if it should work. PE is notoriously difficult to surface bond to (my PhD research is actually focused on an aspect of that believe it or not), but if you heat the plastics up and get them to mix while melted, it is possible to creata a bond. You can do similar things by oxidising the surface. Regardless, I'll play this weekend and let you know how it goes (remind me if I get absentminded and forget to post )

Cheers

Matt

[PAC]

Thanks guys! Like I said before I'm not taking no for an answer, so along those lines I just received the attached email based on research and questions on an email I sent to these folks (one day turnaround verse the the manufacture - whom has yet to rely after a week (but then repairs are not their focus) relating to the welding / repair of High Density Polyethylene

"We sure do. We are about to introduce a new product called the KC Welder for repairing boats like yours. It sells for $49.95 and comes with the welder, special welding tip, 2 colored welding sticks (your choice of colors - enough to weld about 2 feet of damage - also available as a re-suppliable item once you run out - $6.00 for two sticks) a welder stand, and stainless steel reinforcing mesh. If you would like to order one of these, please give me a call and I can take your order over the phone as well as answer any technical questions you may have about the process. Welding Plastic is easier than you would think!
Sincerely,
Scott Bixler - Operations Manager
800-633-3047
Urethane Supply Company
1128 Kirk Rd
Rainsville, AL 35986-6038 USA
tel: 256-638-4103
fax: 256-638-8490"
There web site is Welding / repair of High Density Polyethylene

Take a look and see what you think! Also since I'm definately going to call this gentleman what type of questions so I ask? I have an engineering back ground but not in chems. so HELP - please!!!!!

NZMatt I look forward to hearing about your experiences!

[DanielHolzman]

I have a plastic welder also (Boston area) if it is more convenient. Despite a lot of rumors to the contrary, it is perfectly feasible to plastic weld either cross linked (the older style) or superlinear (the current fashionable plastic) polyethylene. As previously noted on this thread, it is very difficult to glue to polythylene (I wasted $25 on a special glue that did not work in cold weather, someday I will post the unfortunate results when my thigh brace connections disconnected in the middle of the Smith River one Spring), but plastic welding is relatively easy.

Since the crack is in a high stress area, I suggest reinforcing with stainless steel mesh. The crack is about three inches long, so I would cut two pieces of mesh about 4 inches long and 1 inch wide. First, V-groove the crack about 1/3 through the boat using a router or Dremel tool, then rout out an area the size of the mesh about 1/8 inch deep. Insert mesh, then weld right over the mesh. Do this on both sides, and you will be left with a patch which is stronger than the original boat.

Careful plastic preparation is essential prior to welding. The plastic needs to be very clean, which means scrubbing with soap and water first, then using either a commercial plastic cleaner or acetone (I prefer acetone). If you use the mesh, you will be routing out some plastic, so presumably the exposed plastic will be clean, but even minor amounts of surface grime can ruin a plastic welding job.

By the way, if you want to bring the boat to the Boston area, the only charge for using my welder is a quality six pack of beer....

[PAC]

I'm getting more confident which each post. Thanks guys.....
I also saw this posting on duct tape repair which as a last ditch effort I could do too - http://www.kayaking.peak.org/public_htm ... epair.html
As for the welding.... I figured acetone was the cleaner of choice so that confirmation is appreciated.
Couple quesitons - What size stainless mesh should I go with (assumption there are gauges) and where would I pick some up? Since the boat is not that thick - a little over 1/8 inch thick (well used but I couldn't say no since the cost was a case of beer) I'm going to assume that if the patch patrudes a bit from the hull (outside) that is not a reall issue other than some performance loss (but them I'm paddling it so that's not a real issue). As for the interior should the area be double meshed (two lairs - larger built over the inner, smaller lair?) or kept at one? Also do you need to drill out the ends of the crack to get it from expanding (spider cracks)? Thanks!
PS: I'm in Pittsburgh and I don't think I'll be heading up to Boston in the near future (even though my new Viper is with Sir Adam and needs picked up). However, if this works out for me when I do see you you'll definately get an adult beverage of your choice!

[NZMatt]

Hi Guys

So I finally got the chance to test out the welder on Tuesday night. I was repairing a cracked seam (whcih looked like it had been welded previously) on a prototype plastic Pirouette S kayak that my club had. it's been lying there broken for about two years so I figured it was a good practise boat before trying my boat.

I started by trying to grind a bit of a "V-groove" around the crack but gave this up pretty early as I didn't really have an appropriate tool (I bought a grinding attachment for the drill, but you really need a fairly sharply pointed rotary rasp-type attachment as a grinder (a) gets choked up with PE and (b) creates a bit too much heat and (c) just isn't that effective. I'll try finding a different attachment before doing my boat. The other thing was that the plastic on this boat (being a prototype) was fairly thin and didn't leave much to create a groove into.

I then took the stainless steel mesh supplied with the welder and cut a small piece to fit over the crack. I used the welding tip to melt this into the plastic on either side of the crack and then filled the crack using the polyethylene welding rod. I didn't follow the exact instructions they gave as it'd been a couple of days since I'd read them (what they call method B), but it seemed to work OK, although I probably used more PE rod than I really needed to. I vaguely smoothed the surface with the welding tip, but wasn't overly concerned - function not form was my goal.

I then turned the boat and accessed the inside of the hull through the cockpit, having previously pulled the seat out (NB: the instructions actually suggest putting the mesh on the inside of the repair - probably would've been a better idea). I again applied the welding rod and vaguely smoothed it out afterwards. I filled the crack and went a little on either side (mainly melting the plastic already there) and on each end.

The result? Well two days later it appears pretty solid - more so in fact (when I flex that area of the boat) than slightly further along the seam. The mesh probably helps. It's not the prettiest thing in the world, but it seems to have been effective. Of course, I haven't actually put the boat back in the water yet (have to find time to put the seat back in and then let some kayaker be guinea pig ).

What would I do differently?...probably follow the directions a bit more carefully and create a better V-groove.

Pros: it seems to have worked.

Cons: the PE welding rod is clear/translucent white. Not problem for this boat since it is a vaguely translucent white, however very few kayaks are this colour. For visible repairs it'd be cool if there were colored rods to avoid glaringly calling attention to the repair. For this reason I might try method C on my boat (black in the repair area) which uses a black "fiberflex" rod and is the other method they recommend for PE. I'll probably try that sometime next week.

[PAC]

Well folks....
Last night i operated on the Micro and it looks like it was successful. Although at times I thought I had screwed it up.
The key is to take your time and work slow and do it over an extended period. The weld is in place and although not pretty it looks and feels extremely strong.
I too purchased a welder (ok another toy), which is basically a sodering rod with a large flat plate at the end (abut the size of a penny). As i was doing the work it was interesting to see the plastic from the rods melt into and mix with the boats material. It took more time an effort than I though it would but it did blend nicely.
One suggestion is to use a flash light shinning up from inside the boat to find where to drill the 2 very small holes (on either end of the large crack) to stop the "spider cracks" prior to welding. This two of us but the boy was really interested in helping, so......
The use of the reinforcing stainless steel mesh provided with welder was also a bonus in that i was able to completely submurge a nice sized piece of mesh into the existing plastic then cover it with a coating of new plastic on the inside. I did not do that on the out side - which has a cleaner more finished look.
I'm now going to work on outfitting the boat with a modified Team etc since I told J I would try it (I also think its a good set up).
I've taken some photos (talk about boring) and I'll try to post them and text on a site in the near future.
Thanks to NZMatt, Daniel, Adam, and others for tips and thoughts! I'll keep you posted on how things work out as this project progresses!

[Guest]

sounds like the micro is going to work out for you. i hope you like it as much as i like mine. lets go creeking some time soon. im headed to tullula in a couple weeks. you should try and make it down. --- joey

[pac as a guest]

Thanks Joey! I would love to go creek'n with you. But I don't think I'll be getting south soon. I can't even get out with Warren on the WV creeks (1 hr south). Family duties!
However, I plan on changing that in the spring. So stay in touch!
I did like your Micro (even though YOU dis'd your outfitting)!
I'l try to get photos out there in the near future.

[PAC]

Can you post your measurements on your saddle set up? Most importantly from the back rest of the seat to the back of the cockpit? If you have photos you can send that would be even better! paul at cline.net (just replace "at with "@").
Also anyone else with a Micro - please let me know. I'd like to get the set up done right the first time (I know - fat chance - but its worth a try)!
Thanks!
PAC

[PAC]

Here is a link to photos of "the project"! It's not very pretty but I hope it works. I'll let you know if my handy work was a failure or not over time.....
http://www.geocities.com/paulcline2002/