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PostPosted: Sun Dec 03, 2017 11:21 pm 
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stringy wrote:
I will also follow their prepping instructions using a mix of water and isopropyl alcohol to clean the hull, instead of the acetone I used.
If this doesn’t work long term, I’ll try Scotchweld DP8010 epoxy.
Great ideas here! I've been experimenting with bonding paint to a Hobie restoration project and tried a variety of processes. In all cases, bonding was improved by flame treating the PE. Here are some preliminary paint scrape tests showing various degrees of adhesion with different applications.

Image

If "flaming" can improve paint bonding, it should also improve adhesive bonding. In fact, It does (although not nearly as well as DP 8010).

The point is, flame treatment may improve the adhesion of the skegs.

Many of the plastic containers we use are flame treated to make the labels stick. It works well -- you don't see any paint flaking off that potato chip bag!

A word of caution -- flame treatment heats the surface only, not the body of your work. To succeed, the hot flame passes very quickly over the job -- when you're done it should look like nothing happened (not even any gloss on the surface). Here are a couple of links to give you an idea of just how fast this works.

This video is good, but I think he over heats by going back over his job. Seems to work though.
https://video.search.yahoo.com/yhs/sear ... ction=view

This video is better in that shows how quickly the process goes (and how close the flame is).
https://video.search.yahoo.com/yhs/sear ... ction=view

The method I used:
-- clean surface
-- wipe with common isopropyl alcohol (rubbing alcohol), Let dry completely!
-- flame
-- first coat (or glue, tack, tape)

It might be worth a try. 8)


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PostPosted: Mon Dec 04, 2017 2:11 am 
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Thanks for your input and results of your bonding tests Roadrunner.
What does AP stand for on your test samples? Is it alcohol prep?
I’ve watched a few of the clips you linked to and flame treatment looks to be another essential step in prepping PE. I’ll definitely be doing it. It’s not mentioned in 3M’s guides so thanks for the heads up!
The Primer 94 arrived today but I am still awaiting the improved VHB tape. The key to good bonding is all in the prep it appears. The couple of spots where the skegs lifted did so very soon after I stuck them down. The areas that didn’t lift have remained tightly bonded. So I’m guessing it was poor prepping or tape contamination/expired adhesive. The roll I used was a few years old!
I intend to prep as follows, being very careful to avoid contamination.
1-Clean area thoroughly using 50/50 mix water/Isopropyl alcohol, wiping in one direction only as recommended by 3M and dry thoroughly.
2- Flame treatment
3- Apply Primer 94 and let dry thoroughly.
4-Apply VHB taped skegs with uniform pressure ensuring no air bubbles.
5- Leave for 72 hours before on water testing
I am undecided about scuffing which is recommended for some surfaces but not for PE according to 3M’s guide.


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PostPosted: Mon Dec 04, 2017 8:06 pm 
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If a skeg makes a kayak track better when you're paddling, it will also make the kayak harder to maneuver with the rudder when using the Mirage Drive.


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PostPosted: Mon Dec 04, 2017 9:23 pm 
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pmmpete wrote:
If a skeg makes a kayak track better when you're paddling, it will also make the kayak harder to maneuver with the rudder when using the Mirage Drive.


That is what I thought as well but it was not the case. As part of my testing I did a 360degree turn while pedaling.
On the water it felt like I turned almost in a boat length. Here is what my GPS recorded. That is a 30’ yacht on the left.
I am using the original T&S Tandem Island rudder on my Adventure though!
Image


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PostPosted: Mon Dec 04, 2017 9:36 pm 
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stringy wrote:
What does AP stand for on your test samples? Is it alcohol prep?
Sorry I neglected to explain "AP". It stands for Adhesion Promotor. It's a primer that is supposedly good on plastics. This is the product I used:
Image
This particular product requires immediate application of the next product, as it is essentially a tack coat. I don't know if it works better than other primers, but apparently it's commonly used with plastics. Krylon makes a similar product but I'm told it is not flexible so I chose the DupliColor.

In my use, the ultimate goal was to apply a hydrophilic coating. This required a base (primer coat) and I used the AP to help stick the conventional primer. So it was a 3 coat process. In your case it might be interesting to pre-test whether or not to use a primer or go directly from flame treatment to adhesive. Using an intermediate coating may provide two ways for the bond to fail (surface to primer or primer to adhesive. Your application requires a better bond than just paint!

Quote:
watched a few of the clips you linked to and flame treatment looks to be another essential step in prepping PE. I’ll definitely be doing it. It’s not mentioned in 3M’s guides so thanks for the heads up!
Sorry the intended videos didn't show up. There are a variety of philosophies (and wives tales) about how to go about bonding to PE, as you've probably seen. I've done two hulls now and applying the hottest part of the flame to the surface while moving your propane torch quickly seems to work well. For a larger job I used a weed burner (bigger flame).

Regarding the alcohol prep, I pre-clean and then use isopropyl 70% (= 30% water) right out of the bottle. I chose that over 91% and denatured because it was easiest to reach on the shelf. I don't think it makes any difference other than cost and how fast it evaporates. It's just a solvent that leaves no residue.

Quote:
intend to prep as follows, being very careful to avoid contamination.
1-Clean area thoroughly using 50/50 mix water/Isopropyl alcohol, wiping in one direction only as recommended by 3M and dry thoroughly.
2- Flame treatment
3- Apply Primer 94 and let dry thoroughly.
4-Apply VHB taped skegs with uniform pressure ensuring no air bubbles.
5- Leave for 72 hours before on water testing
I am undecided about scuffing which is recommended for some surfaces but not for PE according to 3M’s guide.
I used a scuff pad between primer and top coats -- don't know if it matters in your case. I had previously sanded one hull with 900 grit sandpaper but not the other. They both bonded well.

I'm excited to see how your project turns out. Finding alternative ways to bond to PE for different purposes is great to know! :D


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PostPosted: Mon Dec 04, 2017 9:48 pm 
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stringy wrote:
pmmpete wrote:
If a skeg makes a kayak track better when you're paddling, it will also make the kayak harder to maneuver with the rudder when using the Mirage Drive.
That is what I thought as well but it was not the case.
That's the beauty about trying things -- sometimes it defies conventional wisdom! :wink:


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PostPosted: Tue Dec 05, 2017 1:25 pm 
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Thanks for all that info Roadrunner! 8)
I've been practising flaming on an old hatch cutout from my original Oasis (remember that? :wink: ) and wetting the area to test the results. When it's done properly the water doesn't bead but spreads out uniformly. You can actually feel the difference as the flamed PE is not as slippery.
The VHB tape has arrived and I'll be refitting the skegs today. Although a couple of the edges had lifted slightly from the hull it still took a lot of force to remove the skegs. There was no tape lifting from the PVC skegs which could only be removed by roll peeling small sections at a time.

Roadrunner wrote:
stringy wrote:
pmmpete wrote:
If a skeg makes a kayak track better when you're paddling, it will also make the kayak harder to maneuver with the rudder when using the Mirage Drive.
That is what I thought as well but it was not the case.
That's the beauty about trying things -- sometimes it defies conventional wisdom! :wink:

Agreed!
I was sceptical that these small skegs would make any difference at all and was amazed at the tracking improvement. Then I was amazed that there was no noticeable difference in maneuvering when paddling or pedaling!


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PostPosted: Tue Dec 05, 2017 3:21 pm 
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Roadrunner wrote:
stringy wrote:
pmmpete wrote:
If a skeg makes a kayak track better when you're paddling, it will also make the kayak harder to maneuver with the rudder when using the Mirage Drive.
That is what I thought as well but it was not the case.
That's the beauty about trying things -- sometimes it defies conventional wisdom! :wink:


Skegs probably do add a resistance to the rear sliding around, but they probably help to put the kayak on edge which contributes to the turning as compensation. The adventure hull being shallow and flat by nature is hard to 'edge".

Putting a larger (necessary because its further forward) skeg in the daggerboard slot it actually causes it turn better than without


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PostPosted: Tue Dec 05, 2017 4:24 pm 
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Job done.
1- I cleaned skegs and hull with isopropyl alcohol/water 50/50 mix, then quick wipe with straight alcohol
2- Flamed both hull and skegs with butane torch
3-applied VHB tape to skegs
4-Applied Primer 94 to starboard side hull only. I’ll see if it makes a difference.
5-Fitted skegs to hull

Materials list
Gloves, Clean rags, Isopropyl Alcohol, 3M Primer 94, Gas Torch, Scissors, Tweezers for peeling VHB backing tape, 5952 VHB sheets x3 of 200mm x 100mm, 2x PVC skegs

Image


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PostPosted: Tue Dec 05, 2017 4:34 pm 
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WAVERIDER wrote:
Roadrunner wrote:
stringy wrote:
pmmpete wrote:
If a skeg makes a kayak track better when you're paddling, it will also make the kayak harder to maneuver with the rudder when using the Mirage Drive.
That is what I thought as well but it was not the case.
That's the beauty about trying things -- sometimes it defies conventional wisdom! :wink:


Skegs probably do add a resistance to the rear sliding around, but they probably help to put the kayak on edge which contributes to the turning as compensation. The adventure hull being shallow and flat by nature is hard to 'edge".

Putting a larger (necessary because its further forward) skeg in the daggerboard slot it actually causes it turn better than without

Agreed Waverider. Turning in my TI and Adventure with the daggerboard down is improved in all but slow speed, tight maneuvering.
I’m thinking the skegs sitting forward a bit have a similar effect. As they are so small they are more effective at speed whereas in slow speed, tight turns their effect is minimal, much like a stalling rudder?


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PostPosted: Sat Dec 09, 2017 1:08 pm 
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pmmpete wrote:
Hobie Mirage Drive kayaks have a bit of rocker so they will turn rapidly when using a rudder. As a result, when they are paddled, they don't track as well as most sea kayaks. However, All of the Hobie kayaks track way better than any whitewater kayak. If you spend more time paddling your Hobie, you'll realize that it is easy to keep it going in a straight line. A skeg is unnecessary, will make it harder to maneuver your kayak with a paddle, and eventually is going to get damaged or broken.

Sorry, but you are totally wrong. I have been paddling dozens of different kayaks for many years. The Revo 11 is the WORST handling kayake I've ever been in when the rudder is lifted. It is not a matter of getting used to the boat or knowing how to paddle. It's sad that a skeg is needed, but it is. IMO the Hobies are controlled by the bow position. Its like sitting in the front seat of a 2-man canoe and trying to steer it. You can't get the thing to turn. Once it starts turning, you can't stop it. In situations like surf landings and launches, where you can't use the rudder, it's really awful.


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PostPosted: Sat Dec 09, 2017 1:12 pm 
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Unfortunately, the attachment has proven too fragile for my use. Dragging the hull over beaches with the skegs attached, they don't last long. But they ARE great on the water.


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PostPosted: Sat Dec 09, 2017 2:49 pm 
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How was the skeg attached K57 and what hull prep did you do?
Did you use adhesive or VHB?
I’ve done two trips with the upgraded VHB tape and the skegs remain rock solid. Zero lifting of tape anywhere yet.
The skegs are more protected on my Adventure than on a Revo by the looks of it, but even so I can’t see dragging through sand being a problem as the bond is very strong ...so far!


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PostPosted: Sat Dec 09, 2017 7:41 pm 
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kross57 wrote:
pmmpete wrote:
Hobie Mirage Drive kayaks have a bit of rocker so they will turn rapidly when using a rudder. As a result, when they are paddled, they don't track as well as most sea kayaks. However, All of the Hobie kayaks track way better than any whitewater kayak. If you spend more time paddling your Hobie, you'll realize that it is easy to keep it going in a straight line. A skeg is unnecessary, will make it harder to maneuver your kayak with a paddle, and eventually is going to get damaged or broken.

Sorry, but you are totally wrong. I have been paddling dozens of different kayaks for many years. The Revo 11 is the WORST handling kayake I've ever been in when the rudder is lifted. It is not a matter of getting used to the boat or knowing how to paddle. It's sad that a skeg is needed, but it is. IMO the Hobies are controlled by the bow position. Its like sitting in the front seat of a 2-man canoe and trying to steer it. You can't get the thing to turn. Once it starts turning, you can't stop it. In situations like surf landings and launches, where you can't use the rudder, it's really awful.


The adventure/revo 16 hull is not like the other mirage kayaks as it has a keelson (unlike the revo 13 for example) and virtually nil rocker, which makes it track straight, but the issue is when it is affected by weathercocking and starts to veer that tracking works against you as it is hard to bring it back onto course with just paddle strokes. Hence the need for a skeg or rocker to reduce it veering in the first place.


That is to say a sit in kayak like a whitewater kayak or sea kayak is easier to manoeuvre back onto course using paddle strokes as you can also edge them more readily.


I think if you put a big skeg on the back it would make manoeuvering difficult, and in effect is the same as dropping the rudder and wedging it fixed. With a sailing rudder this makes it impossible to turn if its fixed. Small skegs within the depth of the existing keel probably dont have such a huge resistance


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PostPosted: Sun Dec 10, 2017 7:27 am 
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I have a Revo 13. Getting thru breakers is sometimes a challenge. Getting the rudder deployed is sometimes not possible or takes too long in surf. Keeping kayak straight thru breakers while paddling is difficult. Do you think this mod would help that situation?


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