Plastic fabrication

As described elsewhere I've experienced some hull warp on my Hobie Revolution.  While dealing with warranty issues I am also thinking of fall-back positions if I get stiffed.

FishSniffer commented that perhaps "... they didn't spray enough plastic in that section".  This got me thinking that perhaps reinforcing the hull is a possibility.  Adding a couple pounds of plastic sure isn't going to make the boat too heavy.  A few internal cross-wise ribs or longitudinal stiffeners might do it.

- Does Hobie actually use spray technology to build up the hull? 
- What is the plastic used by Hobie?
- Can this be glued/welded?  Using ABS and/or PVC cement perhaps?
- Are there plastic fabricators in the Seattle area who might know how to do this?
- Will fiberglass mate to the Hobie plastic? 

As described elsewhere I've experienced some hull warp on my Hobie Revolution.  While dealing with warranty issues I am also thinking of fall-back positions if I get stiffed.

FishSniffer commented that perhaps "... they didn't spray enough plastic in that section".  This got me thinking that perhaps reinforcing the hull is a possibility.  Adding a couple pounds of plastic sure isn't going to make the boat too heavy.  A few internal cross-wise ribs or longitudinal stiffeners might do it.

- Does Hobie actually use spray technology to build up the hull? 
- What is the plastic used by Hobie?
- Can this be glued/welded?  Using ABS and/or PVC cement perhaps?
- Are there plastic fabricators in the Seattle area who might know how to do this?
- Will fiberglass mate to the Hobie plastic? 

No spray, it's just little beads or powder of plastic they throw in the rotating mold. It's linear polyethylene. It can be welded  and probably glued. I don't know about fiberglassed

Here's a how it's made video of basically how hobie would make there yaks

I'd say outside of welding with straight polyethylene, all other glues used will have various success rates. Initial adhesion, flex, expansion/contraction, heat/chill, water, etc... all play a huge part in whether anything will stay put for any length of time. 

Why not just use the hot water/black plastic bag method to unkink the hull, and then support it with a carved block of foam from the inside?  It won't add hardly any weight at all to the yak in doing so.   Marine Goop will hold it in there sufficiently and is probably the most use and cost effective glue that is easily available.

I'd say outside of welding with straight polyethylene, all other glues used will have various success rates. Initial adhesion, flex, expansion/contraction, heat/chill, water, etc... all play a huge part in whether anything will stay put for any length of time. 

Why not just use the hot water/black plastic bag method to unkink the hull, and then support it with a carved block of foam from the inside?  It won't add hardly any weight at all to the yak in doing so.   Marine Goop will hold it in there sufficiently and is probably the most use and cost effective glue that is easily available.

Damn! I like the way you think.

I've been to the Hobie factory in Oceanside, CA and seen their facilities.
The kayaks are rotomolded. The plastic, which looks very much like powder laundry detergent, is introduced into the two part mold that is heated and slowly spinning on a bow/stern axis. The spinning allows the plastic to get into all the nooks and crannies of the mold. The mold is cooled and the kayak taken out of the mold.
Fiberglas(polyester) resin will not adhere to polyethylene, nor will most epoxy resins like the kind used with carbon fiber. Most adhesives won't stick either because polyethylene is a mainly non-porous material, nowhere for the adhesive molecules to get a grip.
I use Lexel to stick stuff like gaskets and transducers to the kayak and have used tried and true JB Weld to fix a small crack around a hatch, but the only way to get real structural integrity with repairs is polyethylene welding.
As far as the warped hull, if you put it outside, warped side up, on a hot day, odds are it will pop back to it's original shape. I warped my hull leaving it strapped to my truck on hot days, when it happens I just take off the straps and give it the UV bake-off.

Should be warm enough today and/or Saturday to get it done   

CBY - thanks for the video link.  Pretty cool.

Why not just use the hot water/black plastic bag method to unkink the hull, and then support it with a carved block of foam from the inside?  It won't add hardly any weight at all to the yak in doing so.   Marine Goop will hold it in there sufficiently and is probably the most use and cost effective glue that is easily available.

I too like the way you think.  I was also thinking flotation bag or beach ball.  Okay, onto plan C!

I'll leave the boat out in the sun today or over the weekend.

Add a black plastic bag over it, and you'll see that it will attract the extra warmth.  If you have the kayak propped where the dent is at the lowest point, and just add a couple of gallons of hot water to the inside of the hull it will begin the transformation with the added weight of the water. 

I'd suggest using the dense foam rubber blocks that are available to carve kayak seats from, to use as your internal support vs. anything inflatable. 

If you are going to buy dense close celled foam like Insayn mentioned.  Don't buy it from a kayak shop.  They think its made of gold.

You can easily get about 6-8 times as much for the same price by purchasing one of these archery targets:


Cabela's has them and there are other brands as well.  I was in wholesale Sports (formerly Sportsman's Warehouse) and they had their store brand version for $38.99.

You can also carve a custom made butt pad with the left overs.

Your frugal shopper,

Craig

Dude, awesome info on the foam score.  It is amazing how much a price changes on a product, just based on what it's labeled use if for.  I love finding this kind of deal on multiuse products. Remind me sometime to tell ya the story about purchasing VW CV joints and stub axles for off road use. HUGE savings on that one. 

I'd suggest using the dense foam rubber blocks that are available to carve kayak seats from, to use as your internal support vs. anything inflatable. 

Why foam versus anything inflatable? 

I'd suggest using the dense foam rubber blocks that are available to carve kayak seats from, to use as your internal support vs. anything inflatable. 

Why foam versus anything inflatable? 

Foam can be formed to keep the boat from changing shape.  The inflatable could very well put pressure where you don't want it, as well as not put support where you do want it.   So, you could be chasing your tail on that one.

Oh, and foam rubber won't pop on ya in the event something sharp finds it's way in there. 

Just carve the foam rubber to the exact shape you want, wedge it between the top and bottom of the inside there, and just give it a touch of Marine Goop to keep it there.  Done annnnnd done!

 

If you are going to buy dense close celled foam like Insayn mentioned.  Don't buy it from a kayak shop.  They think its made of gold.

You can easily get about 6-8 times as much for the same price by purchasing one of these archery targets:


Cabela's has them and there are other brands as well.  I was in wholesale Sports (formerly Sportsman's Warehouse) and they had their store brand version for $38.99.

You can also carve a custom made butt pad with the left overs.

Your frugal shopper,

Craig

DAMHIK, but I can recommend against having a few to many 7&7's around the fire at elk camp and then tossing one of those into the flames....

My 8 year old managed to save up around $150 and we snuck down to Cabella's and purchased a bown and arrow set for her with a target. 

Her mom was pissed 

The kids however, were super excited, and occupied for hours, outside, away from the video games.  I was never more than 5 feet from them when they were shooting either.

Why foam versus anything inflatable?

Foam can be formed to keep the boat from changing shape.  The inflatable could very well put pressure where you don't want it, as well as not put support where you do want it.   So, you could be chasing your tail on that one.

Oh, and foam rubber won't pop on ya in the event something sharp finds it's way in there.  

Just carve the foam rubber to the exact shape you want, wedge it between the top and bottom of the inside there, and just give it a touch of Marine Goop to keep it there.  Done annnnnd done!

So we are discussing compressible foam?  And, the assumption is the rebound force is enough to keep the boat in shape?