Boat repair

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NickParker
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Re: Boat repair

Post by NickParker » Mon Jul 09, 2018 3:38 pm

This is a friend's Ocoee I'm refurbishing with all new wood and some hull repairs. In the "before" photo you can see that the hull is in decent but worn condition. There are three significant soft spots underneath the front edge of the saddle. The vinyl layer was worn thin at the stems and throughout the entire center area of the boat, including the chines. I started by thoroughly washing the hull, then cleaning the work areas with acetone.
IMG_20180629_152626_790.jpg
I used a heated metal rod to punch holes into the soft spots so epoxy could be injected. After the epoxy cured I used a sharp chisel to cut away the excess epoxy and the ABS that bubbled up around the holes.
IMG_20180702_173658_285.jpg
I used ABS slurry to build up a new wear layer where needed. This took several coats. I mixed the slurry about the consistency of wood glue for the first couple of layers. I used a sharp low angle block plane and a random orbit sander to level the new ABS between coats. The surface was cleaned with compressed air and wiped down with acetone between coats.

Before I laid down the last two coats I taped off boundaries so I could get a nice looking edge. I mixed the slurry quite thin for the top layers, so it would lay down flat. The final coat was not sanded.
IMG_20180709_093439_182.jpg
The red colored ABS came from MakerGeeks.com. You can find cheaper ABS filament, but beware that some of them have non-ABS filler material. The stuff from MakerGeeks is pure ABS, and available in many colors.

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yarnellboat
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Re: Boat repair

Post by yarnellboat » Tue Jul 10, 2018 12:36 am

I've used ABS slurry as well with success, just to try it, but now I think I'd stick to G-Flex.

For similar wear through the vinyl layer and delamination, I've cut away all the vinyl and rotten layers - don't be shy, get rid of all the soft areas. Then I just filled with layers of G-Flex and glass. At the time I'm sure I had theories on whether larger or smaller patches went down as the first layers, and how the fibers were oriented, etc., but whatever. Do you one area at a time so that you you can angle the repair for the G-Flex to self-level.

I've also been happy with Aquaseal as a filler/glue for internal little cracks, but it might get expensive for larger areas, and I'd probably want to finish with glass and I'm not sure how that would work.

Cut, fill, sand, re-paint.

There's probably a load more detail (and conflicting opinion) if you search this forum for "royalex repair", "delamination", "G-Flex", "ABS slurry", "PC epoxy", "JB Weld", "s-glass", etc.

Good luck, Pat.

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yarnellboat
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Re: Boat repair

Post by yarnellboat » Tue Jul 10, 2018 12:38 am

p.s. I like how you say the hull is in decent condition! You'll be just fine as a ww canoeist!

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oc1kev
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Re: Boat repair

Post by oc1kev » Mon Aug 13, 2018 2:07 am

I've done a number of hull repairs like the crack above. I've done the repair a couple of different ways over the years. I used to just cut back the outer skin layer until there was absolutely no more separation between the foam inside and the outer hard layer, and then cover it all with a glass kevlar combo... but within the last 10 years, I've added in the step of rebuilding the foam layer using Gorilla Glue.

Since Gorilla Glue reacts with water by expanding into a foamy substance, what I would do is drop in the Gorilla Glue, add some water using a paint brush, and wait for it to expand. Then, after 10 min or so, I would start working it in with a putty knife, compressing it over and over.

Then let it sit a little while, and AGAIN compress it with the putty knife. This process takes a good bit, but what you end up with is a 'filler' that very closely matches the original royalex foam core material.

Once it fully dries, I would take my trusty rotary sander and grind the dried foamy Gorila Glue until it is flush with the hull. This rebuilds the under-structure of the boat.

Then the hull is ready for the glass/kevlar layers.


When I did this repair in 2015, I documented it with my iphone with some stills to show a buddy of mine.

I'll dig through my phone and see if I can string them all together into a single video and load it up to YouTube or somethin and post it here in a couple days.

[update]

I originally had video's and stills from the full procedure of prep work, cutting the hull away, adding the Gorilla Glue, then grinding it down and finally the glass/kevlar layup... I definitely have the video's from the glass work... still tracking down the videos of the Gorilla Glue foam-restore.
-You look cool, for a naked chick in a booth...

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yarnellboat
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Re: Gorilla Glue injection?

Post by yarnellboat » Mon Aug 27, 2018 3:46 pm

The chines on my Ocoee are getting pretty spongey. But they are relatively large areas, and I don't know if want to take the time to try and cut it all away, as I've done with smaller spots.

I like the sounds of the Gorilla Glue that expands a bit. Sounds like it has some working time too. Do you think the Gorilla Glue would work as an injection (as pictured with epoxy at the top of this thread)? Exposing it evenly to water would be a problem if that's a key to the expansion.

Thanks for any thoughts on cutting away vs. drilling holes, and Gorilla Glue vs. Gflex.

My concern with the injection method (with either epoxy or Gorilla Glue) is being sure that it's filled all the delaminated areas. I'm imaging working over the area with a rolling pin? But I guess if you find soft spots later, you could deal with the same way, either by cutting or drilling. Nick, do feel the epoxy injections spread to fill all the voids?

On the brightside, I've got nothing to loose, because Plan A is just to let the boat continue to delam until it's too soft to use. So, if have an unsuccessful repair, well, it was headed to its end anyway. Just a question of whether I can make the time to do the repair.

Pat.

p.s. I think there are a lot of "Gorilla Glue" products - is it the original you used, because I think there are also variations of super glues and gels, and I assume they do not all expand. Does the product you use say anything about expanding with water? Thanks Kev.

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Re: Gorilla Glue injection?

Post by NickParker » Mon Aug 27, 2018 4:40 pm

One of the criticisms of epoxy is that it is too rigid for this application. I did some test pieces with West System 105 resin & 207 hardener. Some were just epoxy alone, of various thicknesses. Some had a layer or two of S glass. They were all quite flexible. I was convinced that 105/207 alone would be plenty flexible and strong enough for an injected filler, so that's what I went with.

I used a heated piece of metal rod to punch holes through the outer layers, making several holes in each soft spot. I put some holes near the edges. By poking around after the epoxy cured I feel confident I fully filled the voids. I think the only thing I'd change is to make only one central hole large enough for the syringe injector, and make the rest smaller just for air to vent out.

I recommend that you fill it and leave it alone, if you try to clamp something over it or otherwise apply pressure, you're just going to squeeze out resin. The point is to keep it in there to completely fill the void.

Gorilla Glue -- I know it has it's fans, but I'm not one of them. Gorilla Tape is some great stuff, but not so much with their glue. Regarding filling voids in Royalex, when I mix epoxy in a cup I know I'm getting a good mix that I can inject into a void. Trying to evenly coat the inside of a void with water is a losing proposition. Regarding woodworking, when Gorilla Glue first came out I bought some and made some sample joints in hardwood. I reached the conclusion that it was less strong and more of a pain in the butt to work with than PVA (yellow wood glue). I threw the Gorilla Glue away and have never used it again. Fine Woodworking magazine subsequently published an article that confirmed what I had found, Gorilla Glue is weaker than PVA wood glue. They have great marketing for a very mediocre product.

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yarnellboat
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Re: Boat repair

Post by yarnellboat » Mon Aug 27, 2018 5:31 pm

Thanks for that. I do like that Gorilla Glue expands and approximates the consistency/flexibility of the of the foam layer, but I'll save that experiment for a repair where I cut away the entire outside of the delam.

For injection/epoxy, what's the dif between West System 105 & 207 vs. GFlex? I've used the GFlex 655 thickened epoxy adhesive. Is GFlex not a newer West System product that was designed to provide more flex?

I quick look on the web about glueing plastics is an overwhelming volume of plastic names (polythis and polysomethingsimilar) and adhesive products (Loctite, LePage, Gorilla Glue, JBWeld, and many, many more).

I'm just going to trust that the popularity of GFlex and other West System epoxies on canoe forums mean they are the best epoxies for Royalex canoes, but what's the difference between them?

Yes, tough call to just inject and trust it or to try and squish it around so it gets everywhere (but at risk of pushing it all back out). I don't think I could resist the temptation to work it around a bit though!

Maybe I'll do a comparison - one chine cut away & use Gorilla Glue, and the other side injection and use GFlex. But I'm leaning to injection because it's less work than cutting away.

Thanks, Pat.

NickParker
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Re: Boat repair

Post by NickParker » Mon Aug 27, 2018 5:49 pm

I had 105/207 on hand, but was concerned it wouldn't be flexible enough, and that I would need to order some GFlex. That's why I made some test pieces. My concerns were without basis, the 105/207 was plenty flexible. I'm sure GFlex is more flexible, it is certainly more expensive. But I didn't need any additional flexibility over what the 105/207 offers.

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