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Advice, Suggestions and General Help New Topic Printer Friendly Version

  Refinishing kevlar...varnish or epoxy?
  Posted by: mcimes on May-05-14 5:38 PM (EST)
   Category: Canoes 

-- Last Updated: May-06-14 10:53 AM EST --

****Pics posted below***

I took my solo out for a paddle yesterday and when I got home, I noticed it was weeping a little water out of some cuts in the hull.

Its a 1988 Crozier J200 solo race boat. Its a Kevlar ultralight layup very similar looking to Wenonah's UL layup. It has the diamond core and ribs. Well, obviously water getting in the core is really bad. I got a quote to repair and refinish the hull and they wanted $250 to apply 3 coats of varnish and another $200 and possibly more to repair the 3 cuts weeping water. (No water gets to the inside of the boat).

Im no glass expert, but I also dont have $450+ to spend on a professional refinishing job. As much as it scares me, I think Im going to attempt to repair and refinish my baby.

There are 3 cuts weeping water. two of them are about 12" long, one is around 30" long. It appears the last owner ran over some very sharp rocks on a river in WI. The fibers are severed parallel to the boat, but there is very little actual damage. They're within 2' of the seat on either side, where you would expect to bottom out most severely. The cuts were so clean, I didnt even notice the 2 smaller ones until I saw them weeping water. The bigger one I noticed when I bought the boat last year, but never saw it weeping until yesterday.

The cuts dont require a cloth repair in terms of filling a divot or gap or anything, but I figure I'll probably need to put some cloth or cloth tape on it to repair the structural integrity. I mean, without a cloth repair, whats going to prevent the crack opening up again as soon as I run over a dead head or something? They really look like you just took a knife and cut the outer layer of kevlar. they're that clean.

I have several questions:
1. What are the advantages/disadvantages of using varnish vs something like West Systems 105 epoxy? After reading about MAS slow, it looks like a good choice.

2. Is there anything better than WS105? Im a glassing newbie, so ease of use and 'flow out' is valued more than low odor or anything else

3. What/How should I repair the cuts. I was thinking of glassing in 2" kevlar tape? is that enough overlap? would fiberglass be better?

4. Do I need to back fill the core underneath the cuts with something? the biggest cut is *slightly* soft, but not what I would call rotten.

4.1 If I should back fill the cure under the cut, how do I get goo/epoxy in there? There is no gap to fill, I would have to make a gap (ie: cut a V into the core, which I dont really want to do)

5. I searched on here and google, but didnt find a great tutorial for how to reglass a boat. If someone knows of a great tutorial, can you link it?

6. What is your favorite release film? I've never used it before, but I figure ill have to use some to get the cloth patches flush to the hull.

7. How worried should I be about core rot? **See below** The core is still stiff everywhere, but the repair guy I talked to said that old boats could have used Balsa wood or something else that is rot prone. I dont think mine is wood, but could it really be a treater/coated cardboard?


** Core Rot: I removed the seat column to lower it and I noticed that the 'core' of the kevlar seat mount was not foam, it looked like honeycomb cardboard almost. I couldnt tell if it was cardboard or not. If it was, it looked like it was coated with a resin or varnish of some type.




Sorry, that was long, but $450+ to fix it floored me. Considering I paid $800 for the boat, Im willing to gamble with my own attempt. Any help is greatly appreciated.

Also, if someone in the Minneapolis area wants to do this for me, Ill offer $200 + supplies, plus Ill deliver/pick up the boat within 3 hours of the metro area.


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Messages in this Topic

 

  ??
  Posted by: CEWilson on May-05-14 6:15 PM (EST)
You've a cardboard honeycomb core. You'll need to get all the water out, ir bake it, then fill the opened honeycombs with epoxy using an irrigation needle and syringe through the cuts. Then cover the slits with glass strips because it can be sanded smooth.

After that, I'd mask off a 5' waterline patch and apply varnish because it will form a smooth surface where rolled on epoxy may require hours of sanding.

I kinda doubt anyone who knows how to do these things will be interested in $200 for their time.
 
 
  ya...
  Posted by: mcimes on May-05-14 6:22 PM (EST)
I know the offer was a looooooooonnnnng shot. But you never receive if you never ask...

Im not sure if its cardboard. I dont *think* it is...but I havent been able to get a hold of Crozier to ask what he used back in the day. Ill keep trying.

Does epoxy not flow out smooth even of you use slow hardener? I've only done a couple projects with G flex and it flowed out smooth, but this isnt quite the same I realize.

 
 
  Do it your self and it will cost about
  Posted by: JackL on May-05-14 6:40 PM (EST)
a hundred dollars for materials.
I was given a J-200 several years ago that was ready for the scrap heap. It was in very bad shape and had holes here there and every where.
In the past I had made many repairs to several of our ultralight Wenonah racing boats and our Jensen 17, so I knew there would be no problem repairing it.

First use the West systems epoxy.
Get the pumps which will meter you the proper mixtures
Get a quart of 105-A resin and a pint of 207-SA hardener. This gives you a good long working time
Repair the cuts first. I use fiberglass because I can cut it easier then Kevlar, but either will work. it sounds like fiberglass tape is the way to go.
Sand around the whole area first, and then clean it with Acetone or equal. Wet out the fiberglass and smooth it over the cut. While it is wet, take a piece of overhead clear plastic film or equal and press it down over the patch and tape it down as tight as you can get it.
Allow a day or so, and then peel the tape and film off.
If you did a good job it should come out glass like smooth.
If it is rough or if any of the fiberglass strands are showing, sand it lightly and repeat the process except don't put another layer of fiberglass.

When your are satisfied that the repair work is good, then lightly sand the whole hull, clean it with acetone, and using a mini roller or squeegee coat the whole hull with a light coat of the above. The above is slow drying, and you can even roll it again several hours after coating it if you notice it running or if it needs more.
One of my boats required two coats while another one only needed one.

With all of this said, e-mail or call West systems, and they will walk you through the entire process.

good luck!

Jack L


 
 
  use both epoxy and varnish
  Posted by: pblanc on May-05-14 7:35 PM (EST)
-- Last Updated: May-06-14 9:40 AM EST --

I would try to let the core dry as much as possible and then try to inject some epoxy into the areas that feel soft as Charlie suggests. This can hopefully be done by only enlarging the fabric cuts at a few places by drilling some holes big enough to accept the tip of a dental syringe or a syringe with a blunt irrigating "needle". You will need to drill multiple holes to vent air.

After that I would cover the areas of external fabric damage with fiberglass cloth rather than aramid. S fiberglass is best but E fiberglass will work. I would probably go with 6 oz/sq. yd. cloth but if you want to minimize weight you might be able to get by with 4 oz./sq. yd. cloth. I would not use aramid (Kevlar) on the exterior hull bottom that will be subject to abrasion. Furthermore, fiberglass when fully wet out will be nearly clear, unlike aramid.

I would also not use fiberglass tape. The selvage edge on fiberglass tape resists fraying but presents a thick edge that is much more difficult to feather out. I would cut pieces of fiberglass cloth big enough to overlap any visible fiber damage by 1 1/2 to 2 inches in all directions. Use of a mold release fabric ("peel ply") can reduce the time needed to feather patch edges, but is not essential.

I like using mold release fabric better than plastic wrap or waxed paper because it is easy to get pleats with the latter (at least in my hands).

In order to fully fill in the weave of the cloth you will have to use at least two and possibly three applications of epoxy. I usually feather the patches after the second application, then apply a final thin epoxy coat.

G Flex epoxy is quite viscous compared to conventional West 105 resin and hardener and does not level that well. I have not used the West 105/207 combination but I have used System Three Clear Coat which is an extremely low viscosity epoxy which levels well and wets out fiberglass cloth well:

http://www.jamestowndistributors.com/userportal/show_product.do?pid=754

The Clear Coat epoxy can be applied with a disposable foam brush or foam roller. It behaves much like a varnish and is subject to runs and sags if you try to apply too thick a coat at once.

If you have a skin-coated, aramid boat you may find that the external resin is starting to wear off and the aramid is beginning to take on a bit of water. If so, after completing the patches I would consider applying a coat or two of low viscosity epoxy to the entire hull, or the entire hull bottom. I would then wet sand any areas you have epoxied down to 400-600 grit or so, and cover the epoxied areas with three coats of a good quality marine varnish.

If you want a mirror finish, wet sand with fine paper between varnish coats, and do a final wet sanding down to 1500-2000 grit. The varnish will protect the epoxy from UV deterioration.

 
 
  My experience with 105 and West
  Posted by: ezwater on May-05-14 11:38 PM (EST)
hardeners (205 and 206) is similar. Rolling on several coats, one after the other in close succession so rise of amine would not affect adhesion, I ended up with a somewhat orange peel surface. But after cleaning the surface, a random orbit sander leveled it out nicely.

Given that some unevenness is likely with epoxy, it's important to put on enough thickness that sanding won't cut through what one has added.

West epoxy has leveled better with single applications painted on prepared wood, but there was still some unevenness that required sanding. Then, varnish.
 
 
  Pictures
  Posted by: mcimes on May-06-14 10:32 AM (EST)
Here are the pics. It was hard to get anything to show up. It just looks like a small streak.

http://i258.photobucket.com/albums/hh254/mcimes/Crozier/BottomCut1_zps5a60cf1b.jpg

http://i258.photobucket.com/albums/hh254/mcimes/Crozier/BottomCut2_zps9439a7c9.jpg

Now you guys have me all worried about getting a smooth finish. Are there any tricks or tips to avoid orange peel or other defects?

Are factory boats so smooth because they have been vacuum bagged into a mold?
 
 
  It isn't that hard
  Posted by: pblanc on May-07-14 7:49 AM (EST)
Looking at your pictures I would probably only try to inject epoxy into the core if areas of the hull bottom adjacent to the cuts felt spongy, and then only in those areas.

To me, the aramid of the hull looks as if it is taking on moisture as suggested by the precipitation rings. I would probably cover the whole hull with epoxy, or at least the bottom, after patching.

Sometimes epoxy or varnish will orange peel or blister for reasons that are unclear but most of the time it really isn't that hard to get a decent cosmetic result. Avoid working in direct sunlight. As you apply your epoxy, maintain a "wet edge" as you would with varnish. It is usually easier to do this if you run a piece of masking tape down the center of the hull along the keel line and only apply epoxy or varnish to one half at a time.

Keep the coats even and thin. You will get better results applying three thin coats than trying to apply one thick coat. If areas of epoxy don't appear to be leveling well, sometimes wafting a hair dryer or heat gun over the surface will help, but don't overheat. If you get sags or runs or blisters, let the epoxy cure enough to sand and get rid of them before applying more epoxy. Sags and runs only get bigger if you don't do this. If in so doing, you sand off some of the epoxy on the adjacent hull completely, no big deal. Just apply some more.

Here is a West System article on the use of 105 resin with 207 hardener followed by varnish. It focuses on treating wood trim but the same results can be achieved with a canoe hull:

http://www.westsystem.com/ss/varnish-over-epoxy/

The same technique applies to the System Three Clear Coat I mentioned earlier.
 
 
  Thanks
  Posted by: mcimes on May-07-14 10:11 AM (EST)
Thanks, thats good to know. I was wondering what the rings/spots were from. Those are caused by moisture intrusion? They were on the boat when I bought it, so I didnt think much of it.

Like you're saying, Ill probably glass over the cuts then coat the entire hull with one or two coats.

When you say its helpful to tape off half the hull, when do you finish the 2nd half? I mean, do you wait for side 1 to cure then do side 2 with a day in between , or do you pull the tape right after you're done with side 1 and do side 2 immediately?
 
 
  Do the other side immediately
  Posted by: pblanc on May-07-14 11:01 AM (EST)
It is just hard to maintain a wet edge when applying epoxy or varnish if one is trying to go back and forth working both sides of the hull at once.

You also like to keep the batches of epoxy relatively small. Unless you are spreading a batch of mixed epoxy out in a thin layer (like a paint tray if you are applying it with a foam roller) mixing up larger batches tends to make it "kick" too quickly due to the exothermic reaction.
 
 
  Thanks for posting the pictures.
  Posted by: ezwater on May-07-14 11:15 AM (EST)
I always learn from such, even if I don't know what to do about the pictured issues.

You shouldn't have problems with your planned use, but if I were attaching a seat frame to a hull that might get serious thumping, I would try to oval the attachment zones to reduce the tendency of imposed stress working hard along a straight line.
 

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