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PostPosted: August 31st, 2014, 10:40 am 
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pblanc wrote:
I have used G Flex epoxy to wet out the plain weave S fiberglass sold by Sweet Composites in both 4 oz/sq yd (style 6522) and 6 oz/sq yd (style 6533) without any problems. In fact, I have not noted any significant difference when wetting out these cloths compared to plain weave E 'glass variants of the same weight. But I never try to wet out more than one layer at a time.


My experience using straight G/flex has been much the same. It helps if the G/flex is warm and so less viscous. I just seat the bottles in a shallow tub of warm water, or put them in my truck is if is sunny and warm out (my shop is well insulated, on a slab and stays relatively cool).

I believe that using peel ply helps as well, so that the glass/resin can be lightly compressed. The glass isn’t “floating” on the epoxy and the saturation/distribution is better.

pblanc wrote:
It is also worth noting that G Flex epoxy can be mixed with West 105 resin and hardener in any proportion desired. Just stir the two together and apply. The properties of the mixed and cured epoxy will then be between those of G Flex and 105 epoxy and the exact properties will depend on the proportions mixed together.


I use straight Gflex for some smaller patches and outfitting, but usually go with a mix of G/flex and 105/206 for larger jobs, for no other reason than that I’m cheap and have West 105 by the gallon with pumps and the costlier Gflex in 118ml bottles.

The mix is usually about 50/50, but working with small batches I can adjust the ratio for more Gflex in heavy wear or impact areas.

When mixing Gflex and 105/206 I use the same pot, mix the Gflex first so it is easier to eyeball a proper proportion of A/B, and then pump in the 105/205, add any thickeners, graphite, pigment, etc and remix everything together.

One thing I have a harder time remembering to do is clean and prep some other small repair or project, so that I have a use for any resin mix remaining. I hate to waste resin, but I also hate to put on more than needed just because I have some left in the last pot.

A testimonial to G/flex I mentioned a few years ago – I repaired the ceramic lid on a decorative humidifier pot that lives atop the wood stove in winter using some leftover G/flex. That ceramic lid had been dropped and broken in 3 or 4 pieces.

Thousands of hours atop a woodstove covering a cast iron pot of boiling water and steam and that lid is still sound and sturdy. If G/flex will stand up to that it’ll do for most things, and the ability to mix teeny pencil eraser amounts has made it my go-to epoxy for small repairs or difficult materials.


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PostPosted: September 4th, 2014, 12:12 pm 
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I've patched my royalex canoe's cracks several times with Legos dissolved in acetone. Leave the legos overnight in a glass jar. The resulting paste should be the consistency of tooth paste. It dries quickly, so you have to work fast when applying. Sand smooth after a day or so.

Paint scratches get covered with Krylon Fusion for Plastic spray paint. Yours looks in a lot worse shape than mine, and probably not safe in rapids now, but if you just want it to float, this approach is a lot cheaper and probably less work.

I stole my grankids' Legos.

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"A dead thing can go with the stream. But only a living thing can go against it." G.K. Chesterton



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PostPosted: September 4th, 2014, 5:27 pm 
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I've dabbled in acetone + ABS paste. In the end it worked, but I had a scare with how melty it initially made the whole repair area. Should've supported the area first with some glass or ABS sheet on the inside. Instead I now use the plastic repair putty over a homebrew ABS paste. I'd try the the ABS paste again the a small repair, but I'd be hesitant to use a bunch of it all over the bottom of this boat.

If you do use it, apply the thick paste in thin layers - you don't want to use a thick, goopey layer! Another reason I think the 2-part repair putties are better/easiest to work with.

Let us know how it works out! Hey, try some different approaches to different cracks - you've got several of both to choose from!

P.

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PostPosted: September 4th, 2014, 6:43 pm 
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The ABS slurry idea is fine replacement for paint to cover the boat where vinyl has worn off but will noy do structural repairs. That boat needs glass. A lot of glass. I suspect this boat will see water again...


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PostPosted: September 5th, 2014, 7:39 am 
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Yeah, that has been my experience as well. I had an old Encore that had hull bottom wear and damage beneath the pedestal not unlike the boat in the picture, although perhaps not quite as extensive. The exposed ABS was worn thin and had a rippled texture with small areas of exposed foam core.

I tried applying an ABS slurry to it twice, once using acetone as the solvent and once using MEK. The initial results looked pretty good but both times after a single low water run, significant portions of the ABS scratched off or came off in chips where the slurry had been applied to the "valleys" of the rippled hull surface. The areas of the underlying hull to which the slurry had been applied looked unaffected, suggesting that the slurry had not physically or chemically melded with the hull, as some have suggested.

I finally removed all the applied ABS slurry (which was pretty easy to do), smoothed the hull with thickened G Flex epoxy, applied three layers of 'glass, and painted the hull bottom and the boat has held up extremely well.

I do know of some experienced white water boaters, one of whom is Jim Michaud, who advocate the ABS slurry technique so I will allow that I might have done it wrong, perhaps by trying to apply too thick a layer at a time, but based on my experience, I would not suggest that technique to repair this type of damage.

A word of caution: both acetone and MEK dissolve ABS. You can get away with applying these solvents briefly to the solid ABS elements of Royalex because they flash off so quickly (acetone quicker than MEK) but either will dissolve the foam core of Royalex pretty quickly.


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PostPosted: September 10th, 2014, 10:58 am 
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pblanc wrote:

I tried applying an ABS slurry to it twice, once using acetone as the solvent and once using MEK. The initial results looked pretty good but both times after a single low water run, significant portions of the ABS scratched off or came off in chips where the slurry had been applied to the "valleys" of the rippled hull surface. The areas of the underlying hull to which the slurry had been applied looked unaffected, suggesting that the slurry had not physically or chemically melded with the hull, as some have suggested.

A word of caution: both acetone and MEK dissolve ABS. You can get away with applying these solvents briefly to the solid ABS elements of Royalex because they flash off so quickly (acetone quicker than MEK) but either will dissolve the foam core of Royalex pretty quickly.


Pete, that ABS slurry repair technique was greeted with great fanfare a few years ago, but the enthusiasm seemed to die off quickly as folks had various degrees of success. The lack of specifics, especially in DIYing the slurry mixture (which solvent, what scrap plastic to dissolve, solvent-to-plastic ratio and wait times, etc), was unnerving to me when I considered trying it.

More unnerving was the thought of spreading acetone slurry on an already damaged RX hull and possibly getting it into the foam core. With the extensive damage and outer skin cracks on the bottom of the OP’s Raven I’d keep any aggressive solvent as far from the hull as possible. A barely damp and quickly flashed-off swipe at most, or maybe just wash, dry and alcohol wipe the hull and keep the acetone in the next room.

The tales I’ve heard from owner’s admitting their boo-boos and from manufacturer’s telling stories of customers getting acetone into the foam core sound harrowing, like a creeping leprosy unstoppably eating into the foam core.

Speaking of manufacturer’s Royalex tales, with RX gone the way of the Dodo perhaps some “Now it can be told” RX stories are waiting in the wings; foam cores that didn’t expand properly, ovens that malfunctioned (or were re-assembled incorrectly after a factory move), bad Royalex sheets received from SparTech or PolyOne (with some manufacturers purportedly accepting RX sheets that others rejected), and the difference between pre and post 1991 Royalex when the sheet manufacturing process was changed.

I gotta wonder if any manufacturer rejected their last precious RX sheets they were able to order from PolyOne in its dying days. There could be another slug of queer RX hulls in the pipeline, similar to the oddities from 91/92.

(The best of those oddities may have been a friend’s OT Pack – that “Pack” must have weighed 50 lbs. The paddlers is a big guy and he removed the thwart, so the only cross-support in the canoe was the dowel hung seat. He still has the Pack and still paddles it thwart-less; it may truly be the world’s “best” OT Pack, at least until you pick it up).

In those “Tales that can now be told” department I still wonder why some (few) wood gunwaled RX hulls cold cracked and many others didn’t. I believe it was due most likely due to some combination of manufacturing miscues above, and not some peculiar freeze/thaw/expansion that could occur even in more temperate Maryland or Virginia and not crack every wood/RX hull in the northcountry.

It’s a mystery, and if RX sheet or factory mistakes are the reason I can see why the manufacturers were happy to have cold cracks remained unresolved and ill-explained.


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PostPosted: September 10th, 2014, 1:57 pm 
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I've heard of people using spray-on coatings that are designed to protect truck beds or undercoating or other "rock guard" parts of cars.

What about paint-on epoxies like those advertised for garage floors and driveway repairs - everytime I pick a Canadian Tire flier I look at those paint-on epoxies and wonder how'd they be for repairing delaminated Royalex.

This thread got me thinking, because I've got some repairs in my future.

Given how much I like how Aquaseal has done as a filler for inside cracks, maybe I'll just try some of that in some outside cracks/voids too??

Thanks for any thoughts on those ideas.

Pat.

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PostPosted: September 11th, 2014, 9:24 am 
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yarnellboat wrote:
Given how much I like how Aquaseal has done as a filler for inside cracks, maybe I'll just try some of that in some outside cracks/voids too??

Thanks for any thoughts on those ideas.


Pat, Aquaseal runs about $11 for ¾ oz (12g). G/flex runs about $20 for two 118ml tubes of parts A & B (236ml total, about 8oz).

Without any consideration for G/flex being tougher and bonding better the quantity cost alone would make me prefer G/flex.


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PostPosted: September 11th, 2014, 3:10 pm 
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Good point for big repairs. Aquaseal here is $7 for the 3/4oz tube (21g), which seems to have just gone up in price - I thought it was something $4.50. And I though G-flex was expensive.

I guess the big difference for me is that I readily know where to pick up Aquaseal, but when G-flex became all the rage, I'm not sure was available in Canada? Maybe that's changed?

What about those cans of epoxy paints (as far as whether they'd be an effective material, not price)? Anyone ever tried them? Or considered them and had a reason for steering clear?

http://www.canadiantire.ca/en/tools-har ... ay;site=ct

I'm going to ask on c-boats.net too.

P.

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PostPosted: September 11th, 2014, 4:56 pm 
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Yes, $7 for a small tube of Aquaseal is the going price here in the US. Aquaseal is great stuff but it is simply a sealant. It is not, in any way, going to affect a structural repair.

Personally, for any exterior hull cracks, especially if the interior is affected in any way, I am not only going to bond the crack but also apply an exterior patch of some type of cloth, probably S fiberglass. That might in some instances be overkill, but I would rather do it once and do it right.

I have not used epoxy paints.


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PostPosted: September 11th, 2014, 5:17 pm 
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yarnellboat wrote:
Good point for big repairs. Aquaseal here is $7 for the 3/4oz tube (21g), which seems to have just gone up in price


pblanc wrote:
Yes, $7 for a small tube of Aquaseal is the going price here in the US.


My bad. I buy the Aquaseal packs that come with a bottle of Cotol and mix it at recommended 3/1 ratio.

http://www.rei.com/item/694051/mcnett-a ... 40-sealant

It is much easier to apply that mix with a tiny paintbrush (not the one in the package) on the edges of patches or seams and it cures faster.


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