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Discussion Starter #1 (Edited)
I have been wanting to learn to plastic weld for some time now and was just given an EZG 60 (thanks, Badazws6!). With it's past history, it should give me plenty of practice! Anyhow, I was wondering if anyone out there has any suggestions/tips for me before I get melting my new broken boat away, please feel free to critique the following.

From what I have gathered, here is the idea:

  1. heat up the plastic to the melting point by incrementally increasing temperature of your heat source and giving each increased temp setting some time to see it's effect before you crank it up to the next level (once the setting is learned, I assume you can just go to it from the start for the next welding session). Once plastic darkens a bit/ gets a bit shiny, it is melted.
  2. Add/melt welding rod material into crack and mix melted boat + melted rod material so they bond to one another (don't just melt the welding rod into the crack)
  3. Let cool
  4. Sand to desired finish
Somewhere I had read that some people actually add in a piece of metal screen into the weld to increase strength, any feelings on that?

Also, I know the plastic blend is important as well. As I understand it, only linear plastics can be welded. I believe that the EZG60 is made of linear plastic, but can anyone confirm it?

If so, will any linear plastic welding rod from a kayak shop do, or do I need to get the exact blend from Wavesport?

Thanks a million, everyone! Cheers,
-Tony
 

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How big is the crack? The standard method is to drill the ends to stop propagation, and then tape the inside with vycor.

The one time i tried welding (an'01 pyranha) the weld held great, but the plastic cracked badly about an inch away from the weld on day one.

I know some folks have succeeded in welding, but it is very finicky, and can easily render a boat useless.
 

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Discussion Starter #3
There are multiple cracks; one is an inch long near the bolts that adjust the seat near the cockpit lip, and then there are 2 U-shaped cracks, one near each of the thigh braces on the cockpit lip.

Honestly, if the boat doesn't make it out alive, it is alright because it was free and it will be a learning process for when my main boat gets a crack. I will get some pics up before long (I actually haven't seen any pics amidst the slews of posts on EZG problems anyhow).
 

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Get ahold of xacker or [email protected] Far and away the best plastic welders I've met. I don't think either one of them has had a proper boat this summer. Alex Kilyk is good too, but I'm not sure he reads the buzz since he hit the PNW.
Joe
 

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Plastic Welding

We do a lot of polypropylene welding at work, and while I have never welded on a kayak, I think that most of the principles hold true. I agree with all of the above, and would just add that I believe resin is VERY important, to the extent that I would get welding plastic right from the boat manufacturer or from a donor boat of same make and color. At work we have also had problems with welds being contaminated because the surfaces were not cleaned properly prior to welding. Surfaces really need to be as clean as possible, and weld contamination will weaken even the best weld. While welding (I would use a forced hot air wellder on a boat) If you see smoke, you are too hot, and contaminating your weld. Lastly, in our buisness, we fill out finished tanks with water and beat all of our weld seams with a rubber mallet to stress test... If I had a welded boat, I would want to make damn sure it was strong before I relied on it in water of any consequence...
My 2 cents... Best of luck!
Tim
 

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Discussion Starter #7
Right on. I will definitely make sure the area is good and clean before I go at it. I am also getting plastic directly from Wave Sport for welding. Thanks for the tips. Keep the tips coming if you have any more for me!
 

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We do a lot of polypropylene welding at work, and while I have never welded on a kayak, I think that most of the principles hold true. I agree with all of the above, and would just add that I believe resin is VERY important, to the extent that I would get welding plastic right from the boat manufacturer or from a donor boat of same make and color. At work we have also had problems with welds being contaminated because the surfaces were not cleaned properly prior to welding. Surfaces really need to be as clean as possible, and weld contamination will weaken even the best weld. While welding (I would use a forced hot air wellder on a boat) If you see smoke, you are too hot, and contaminating your weld. Lastly, in our buisness, we fill out finished tanks with water and beat all of our weld seams with a rubber mallet to stress test... If I had a welded boat, I would want to make damn sure it was strong before I relied on it in water of any consequence...
My 2 cents... Best of luck!
Tim
That's good tech information. I've been wanting to try this for sometime so I've been following this thread.
 

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Right on. I will definitely make sure the area is good and clean before I go at it. I am also getting plastic directly from Wave Sport for welding. Thanks for the tips. Keep the tips coming if you have any more for me!
I'll be interested to hear your results. Keep us posted.
 

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Here is my plastic welder. I bought it about 20 years ago from an industrial supply house so it was not cheap. I got it for welding my motorcycle fairings and have only welded ABS plastic with it. You will find the better welders have a lot better temperature control and you will have better control of the weld quality.

 

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Discussion Starter #13
after welding round 1

So I went through and welded all the cracked spots. I haven't sanded anything yet to a finished product (and don't know if I will to be honest), but here are the pix of welding round 1. I know I know, it's sloppy.

I ended up using a variable temp heat gun ($35 @ Ace) for the heat supply and a set of tips for the heat gun ($6) which reduced the diameter of the tip of the heat gun for better accuracy. A crappy old spoon + fork were my only other tools necessary. This worked pretty well.

Since the EZG issue is that the cockpit rim flexes too much near the thigh braces, I came up with the idea to go ahead and weld a brace in the gap on the inside of the cockpit rim, as pictured. This really stiffened up the cockpit rim when you push where the thigh braces attach. I think this may help the issue of cracking on the EZG rim.

I just wanted to say thanks to Scott @ Confluence for the extra welding plastic from another boat--- it is really easy to go through a lot of plastic for a beginner at plastic welding. Thanks, Scott!
-Tony
 

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If you want to fix the cracks right, talk to the pros at Boulder Boat Works 720-565-0789 (Andy or Chris). These guys weld up co-polymer dories every day. They have fixed four cracked kayaks for me and they know more about temperature specifics and how to do bomber welds than anyone else I've ever found or even heard of.
I crushed the stern on a boat and cracked it in three places. Not only did they reform the stern, but the welds done on the cracks are now the strongest parts of the boats (three years afterward still holding strong).
Tell Andy that Craig sent you.
The $ you spend on the repairs with Boulder Boat works will resolve the cracks, strengthen the integrity of the boat and help to lengthen the life of the boat.

Buenos suertes!

-Craig
 
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