I just bought a used UL Wenonah Boundary Waters. Overall it's in really great shape--no tears/holes, loose rivets/etc. The only thing I need to work on is in a few areas of the hull the epoxy (or vinylester resin--I'm not sure which one Wenonah uses) is worn through and you can feel the fibers beneath. Most of these areas are deep scratches/gouges, but there are two areas closer to 20-30 square inches of wear.

I'd like to touch up these areas, and I'm curious to know the best way how. I tried doing a search, and so far the best post I found hows how one guy redid the entire hull: Great post

I'd prefer not to redo the entire hull. My goal is:
1) Protect the canoe (we mostly do lazy-ish rivers, flatwater, BWCA), so no whitewater (the BW isn't really the canoe for that anyway...). But going over the occasional rock isn't out of the question. And certainly on landings.
2) Keep the canoe as light as possible
3) Keep it looking faily decent if possible

My first question is if it matters what epoxy I use? Can I use Bondo for just a partial patch Bondo ? Or will that only work if I sand down the whole thing? I don't see much value in sanding down the entire hull except for cosmetic purposes--the white marks don't bother me. Can I just sand down part of the current resin around the exposed fibers and then apply the Bondo over that whole area?

My second question is--does it matter if I use Bondo vs West Epoxy? I saw Red Rock's posting suggesting West Epoxy's system, but honestly the posts on that site rubs me the wrong way--it seems like he knows what he's doing but he seemed extremely biased towards SR and very much against Wenonah (I understand people have preferences--we love our boats-- but people have been loving both brands for years. I figure any boat from SR/Wenonah/Bell is a great boat--and any boat that gets you in the water is a good one). A number of posts there just seem condescending and I have a hard time taking advice from someone like that unless I know them or someone I trust can vouch for them. Otherwise I was ready to buy some West Epoxy from Jamestown Distributers.

So I'm hoping to get others opinions here--the West system is pretty expensive. Bondo is pretty affordable. I don't know if there are other, better, alternatives. I'd like the canoe to last me a good amount of time. However, I will get a nice salary raise in 3 years (I'm a medical resident right now) and could, if I wanted, buy a new kevlar UL at that time, so it's not necessary that this be my final end-all boat. (Someday I'd like one of the kevlar Bells :) But I do like holding on to things since I get attached, so I'd like the job to be done right.

Anyone go through this same procedure and have recommendations?

You don't have to use epoxy. Even if you do, you don't have to use west systems. I used Aeromarine epoxy which is cheaper and it has held up very well.

You don't really gain much benefit using the epoxy on a Wenonah since they're not done with epoxy to begin with and you'll have to deal with the UV exposure if you go to epoxy.

Not sure about bondo- never tried it. Maybe someone else can chime in.

I believe that Wenonah uses vinylester resins but it does not matter. I have used epoxy for various repairs on quite a few boats from different makers that were built with vinylester resins and it has worked fine. You can use vinylester resin for repairs if you choose, but you will likely have to buy more than you need, it has a limited shelf life so any you don't use will probably go to waste, and the methylethylketone peroxidase catalyst can make you blind if you get it in your eyes. In other words, use epoxy.

You have a skin-coated boat. These are constructed without any polyester gel coat. A thin layer of resin goes in the mold before the outer layer of fabric. Without gel coat, there is no real protection against abrasion and it is common for the thin outer layer of resin to be worn away. After that the fabric becomes subject to abrasive wear.

Bondo is basically a filler putty. I have heard tell Cliff Jacobson has used it to fill in scratches and dings and then painted over it. I haven't used it, so I won't comment but I would certainly use epoxy rather than Bondo.

You do not need to redo the entire hull but you might find it worthwhile to consider doing the entire bottom up to a 3 or 4 inch waterline since it will provide some additional future protection and will significantly improve the appearance of your hull.

UV degradation is really not much of an issue. It takes around 6 months of continuous UV exposure before epoxy begins to seriously degrade. If you boat spends a lot of time upside down outside being car topped or stored you can just put a coat or two of marine epoxy or Helmsman Spar urethane over your epoxy and it will be protected. I know folks who have applied epoxy to their skin coated boats and skipped this step and have had no issues.

West System epoxy is certainly not the only good epoxy. Many of us use it because it cures so reliably and West has excellent support services. It is more expensive than some brands and a quart with the appropriate volume of hardener will set you back more than $50. But if you choose to just do a relatively small area, you can get a repair kit with a small amount of resin and hardener in packets in the appropriate mixing ratio:

http://www.jamestowndistributors.com/userportal/show_product.do?pid=759&familyName=WEST+System+101+Repair+Kits

The small kit may be sufficient to cover just the worn areas. I would think the larger one certainly would be.

You could also use System Three Clear Coat epoxy:

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

This is a very low viscosity epoxy that applies much like varnish. I have used this on two hulls to fill in scratches and spider cracks by applying multiple coats with wet sanding in between and it has worked very well. It mixes in a 2:1 resin to hardener ratio and can be applied with a disposable foam brush (as can West System epoxy. The pint and a half would be several times more than you would need to do the entire hull, but I don't think you can buy it in smaller volumes.

I would not concern yourself too much with adding weight. I applied 2-3 coats of System Three epoxy to an entire Bell Wildfire hull topped with two coats of marine varnish and it only added about a pound.

I have redone so many Kevlar canoe bottoms that I have lost count. I use West System epoxy and like it, but that's what I started with and it is pretty forgiving if you mess up the mix ratio. Here are some ideas, I have done a number of false water line bottoms and have colored the epoxy to match or accent the rest of the canoe a few times. I simply tape off a waterline around the canoe and then only epoxy the bottom using a small foam roller to roll on the epoxy. The epoxy will take color by using acrylic paint that you buy at a craft store. West suggests maybe a 10% mix of color to epoxy. Too much and the epoxy becomes very thick like a paste,

Should I be adding color to the epoxy? I thought that what the Wenonah comes with is already colorless (other than the slight amber tint of the epoxy)?

A UL kevlar skin boat requires no color.

quote CharlieLoon: "Should I be adding color to the epoxy? I thought that what the Wenonah comes with is already colorless (other than the slight amber tint of the epoxy)?"

I was only making a suggestion that if you wanted for what ever reason that you could color the epoxy. I had a cream colored Mad River Malecite and I came pretty close to matching the color when I rolled on a new bottom

I e-mailed Wenonah for input, and they told me to make sure to use a polyester resin, which is what they use in their canoes. But when I e-mailed System Three, they said it'd absolutely work--just rough up the prior resin with 150 grit sandpaper.

Are there any cons to using epoxy instead of a polyester resin? My understanding is the polyester resins last longer (as in degrade slower) and have UV protection, but the epoxies are more durable.

If I want this to look decent, is my best option to re-epoxy the entire hull, or should I really only epoxy up to the waterline?

I just want to make sure I do this right. Thanks for all your input.

Well, we seem to have conflicting information. My understanding was that Wenonah, like most composite manufacturers, has long used a vinylester resin.

That is supported by Charlie Wilson who states in this thread that Wenonah uses "Co-Rez Vinyl Ester":

http://www.adkforum.com/showthread.php?t=11975

and also by this article which actually comes from the Co-Rezyn manufacturer that states that is the product used by Wenonah in their composite boats:

http://www.interplastic.com/UserFiles/File/C_Wenonah.pdf

Either way, epoxy can be used over either vinylester or polyester resin. Many have used epoxies for repairs of Wenonah boats. Here is a thread discussing this issue:

http://www.paddling.net/message/showThread.html?fid=advice&tid=1399747

Are there cons to using epoxy? Well epoxy is more expensive. Most epoxy resins have higher viscosity than polyester so polyester can be a bit easier to apply. If you ever wanted to apply polyester gel coat to the boat you would not want to use epoxy as polyesters and vinyl esters may not cure over epoxy. I don't know about polyester being more UV resistant than epoxy. In fact, Gil Gilpatrick in his book "Building a Strip Canoe" says of polyester resin that:

"The finished product is even more susceptible to the sun's rays than is epoxy, and the result is that it becomes even more brittle."

Perhaps UV resistance varies with the type of polyester resin. As I said before, the UV degradation issue is not a concern if you plan to cover the epoxy with a couple of coats of marine varnish or of a linear polyurethane with UV protectants, and I know of some people who have omitted that step.

The disadvantages of polyester is that it gives off rather foul, obnoxious fumes and is much more brittle, and therefore less durable than epoxy.

As for how much of your boat to recoat, you could mark off a 3 to 4 inch waterline and do that much and then decide whether or not to do the rest. The only downsides to doing the whole boat is that it takes more time and more epoxy, and adds a little more weight.

If you choose to do the whole boat, or a large part of it, it would be nice to have a helper. Epoxy has a limited pot life and working life. These will vary with the brand of epoxy used, the hardener used, and above all, the ambient temperature. I would advise mixing up only small batches of epoxy as you start out so that you don't run the risk of the mixed epoxy "kicking" before you can get it applied. Also, epoxies produce an exothermic reaction when mixed. The larger the batch you mix the more heat it will produce, and the warmer the epoxy becomes, the shorter the pot and working life.

To apply epoxy over a large area, a 3" long foam roller will probably work best. Applying epoxy is rather like applying varnish in that you want to maintain a "wet edge" to avoid lap marks. It can be difficult to achieve this when doing both sides of a large canoe so it is sometimes best to run a strip of masking tape right down the center line of the hull bottom, apply epoxy to only one side, then immediately pull the tape and do the other side. If there is a faint lap mark running down the center it won't look bad.

A second person can mix up additional small batches of epoxy as you go so that you can keep rolling. It might also be necessary for someone to follow along behind you and "tip out" the rolled epoxy with a disposable foam brush to level it.

quote pblanc:

Are there cons to using epoxy? Well epoxy is more expensive. Most epoxy resins have higher viscosity than polyester so polyester can be a bit easier to apply. If you ever wanted to apply polyester gel coat to the boat you would not want to use epoxy as polyesters and vinyl esters may not cure over epoxy.

"

I have also heard that generally when you layer different types of resin over each other there's always some potential for delamination since the two materials have different mechanical properties and they degrade, flex, expand, and contract differently under certain conditions. I haven't seen it happen firsthand, but it's something to consider that may come into play over the long term. I'm still watching for it on the first canoe I refinished and it's been about 5 years now.

There are a few older & a few newer threads on this topic & I have been reading along & working up my courage to do a few repairs to my Mad River Explorer Kevlar canoe. The last time I used marine epoxy was to bond new things together like rod holders & cup holders & maybe a spot patch. The last time I did a bondo job was on my 1973 Dodge Coronet when it failed inspection for body rot. So I've been putting it off afraid I was going to screw it all up...now I realize how ridiculous that was...just go for it...and listen to the good people here for tips. I do know how to ice a cake...I know I don't want my canoe to look like an iced cake...how bad could it be?

Had a good thumb sized gouge where the fibers were hanging out after failing to navigate a rock. Under the waterline, mid canoe, on the side. Later in its life, the whole canoe went flying when someone carrying it tripped & it landed stern first on a rock, cracking the finish in a jagged, angry looking line. Few beaver dams later...couple scrape ups. Wow, my beautiful canoe...it's looking...not good..not to mention I could further damage it by leaving the Kevlar exposed.

So I am planning a trip & have to get these things fixed. I took lots of the advice here. Got my West Systems epoxy with the pumps & a roller. Fine grit foam sanding block, plastic disposable containers for mixing epoxy, box of popcicle craft sticks & a roll of Saran Wrap.

I decided to just repair the damaged spots & use the roller to seal the keel. I wanted to forgo the spar varnish because the whole thing is in pretty good shape & I can always do it down the line if I feel it needs it.

Sanded the spots to scratch it up, careful with the fibers. Mixed epoxy, 3 pumps of each, made a good amount to work with. Mixed a minute plus, carefully painted each spot with the popcicle stick to tamp down the fibers & scrape any drips up. Got a thin first coat on, then I used the Saran Wrap to smooth the areas out...and then I took it back off, I did not leave the Saran Wrap on. The plastic wrap took a bit of epoxy with it, but left it smooth with no drips. Um...happy with that part..wow.

A day later I was back at it, it looked nice & sealed up. I coated the spots again, Saran Wrap on & off again. Then I used a West systems roller cut in half to cover the keel in epoxy. I did the same with the Saran Wrap along the keel. Nice & smooth. At this point my resin was starting to harden, so I went back over the 2 worst spots & really filled them in working the epoxy into the crack in the stern & smoothing that thumb gouge. Watched for drips, Saran Wrap again to smooth & off again. Huh...nice & sturdy & it looks great compared to what I started with.

So today it's 94' hot as hades...Later I'm headed down to do a bit of sanding on the 2 spots & put a thin coat on to hopefully finish it up. It may need 1 more touch up after that. So far, I'm super happy with what I have accomplished & will post a few pics. What made it easy is the premeasured pumps & the Saran Wrap. I can add another layer easily, I don't think I've spent an hr working on it in total.

Thanks to all that have posted recently & in the past...you all have given me the courage to put epoxy to canoe & that has made all the difference.

Before sanding, second coat of epoxy.

Hello CharlieLoon. You posted my refinish link. Thanks! I did all of that work a little over 8-years ago now. Just these past few weeks I did it all again. And I learned a bunch of new things.

Both times I have refinished I emailed Wenonah directly to ask them about the resin to use. Both times they told me to buy Unsaturated Polyester Fiberglass Resin and a Methyl Ethyl Keytone Peroxide (MEKP) hardener.

I bought Bondo brand from Home Depot but I don’t think brand matters as long it is of the chemical type I listed above.

You don’t have to do the entire boat like I did. I picked up a used outfitter canoe and it really needed it. This most recent time (a few weeks ago) I just sanded and re-fiberglassed from just above the waterline down. I did take the boat down close to the fibers. And this time I did 3-coats of resin; sanding between each coat.

If you have any questions just shoot me a message here.

My favorite boat builder said this to me one day and it became an absolute for me: How long do you want you boat to last? 30 years? Or 100 years?

That’s the difference between poly and epoxy.

For surface coating I’m sure poly will make a great skim coat and last at least a year.

For bonding, use epoxy.