Cedar Strip Canoe Build # 26 Bubble Patching

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Blog entry by farmerdude posted 01-22-2016 11:24 PM 1933 reads 1 time favorited 10 comments Add to Favorites Watch

Today is the day to fix those pesky bubbles. I tossed some wood into the stove and waited for some temperature. I tackled the stove side first (closer to the heat, I may be foolish but I’m no fool). Here is the bubble.

I use the edge of the sander to keep it to a small area at first. Sand until the piece of cloth falls off. It will fall off because there is no epoxy holding it on.

Once it falls you can see how big the hole will be. Now you have an idea how far to feather the edges back. Just feather enough to keep the hole from having sharp edges.

It’s not a great pic but you should be able to see that I sanded through two layers of cloth. This means you will have to patch in two layers of cloth to keep things even and flat. If you’ve been following this blog you know that there are three layers on the ends so I was in no danger of sanding down into the wood.
Now to sand the other side. It hardly seems worth it but i can’t stand to leave it.

I got lucky, the two spots are directly across from each other.

I was helping my father do a project and he dashed home to get something, so I cut the cloth and started putting it on while he was gone. In the rush, I forgot to take a picture of the cloth. It was two pieces about 3”x 5”. The fact that they are across from one another means I can fold the cloth right over the end and get both holes with the same piece of cloth. I mixed a small batch of epoxy. One squirt resin, half squirt hardener. I used a chip brush to carry some epoxy to the cloth. I held the patch over the hole and dabbed the epoxy on to hold it there. Then fold it over and stick it to that side. I didn’t wet out the whole piece, it’s bigger than I need.

Once both sides are wet out, stick on the other piece, and wet that out. No need to wait for the first one to cure.

When that is done, use a squeegee to take off the extra epoxy. Be careful here not to pull the cloth out of place.

Here are both sides done.

I went back to my fathers project. About half an hour later we finished, and when he left I went in and grabbed a quick lunch, and went out and checked the patch. As I expected, there was a bubble on one side.

By now the epoxy is getting thicker, so I fixed the bubble with my favorite bubble fixing tool. My big, fat, thumb. One squish and it was gone.

So this is both sides done for the day.

After this cures I will sand off the dry cloth. I will also sand off a large part of the wet out cloth. You can’t leave too much or this double thickness will leave a bump even after you feather the edges. You will want to take almost to the edges of the holes. It’s hard to see that because it’s clear. I will judge most of it by feel, and using a flashlight. When it’s done it will be smooth without bumps.
The next job for today is to sand the whole hull with 80 grit to rough it up for the last filler coat of epoxy. That’s when my luck ran out.

This is the end farthest from the wood stove. It cooled to 40 in the shop overnight so it was too cold for the epoxy to cure enough to sand. When sanded it will ball up under the paper and then stuck everywhere.

So that ends the canoe work for today.
Next time I get into the shop I should be able to sand the hull and fill the patches. The only thing to do with the patches is to sand them and fill them with the same amount of mix as the rest of the hull. You should not be able to see the patches when they are done.
I’ll get back out there first chance I get, and give you an update. See you then.

-- Jeff in central Me.

10 comments so far

View English's profile


682 posts in 2085 days

#1 posted 01-23-2016 01:05 AM

Great work!! I don’t know how you get the Epoxy to cure with the low temps. The Epoxy I used would freeze at a little below 50 degrees. The resin would get milky. It would then have to be heated up to un freeze it, get the milky out of it, before I could use it. So I kept the temp in my shop at 75 for weeks while laminating fiberglass. I live a good bit South of you so heat pumps work well.

I noticed you were using a mid range resin, do you have much trouble with runs on the vertical sides?

You are doing a great job documenting your build, keep up the good work. And thanks for sharing!!

-- John, Suffolk Virgina

View farmerdude's profile


670 posts in 2647 days

#2 posted 01-23-2016 01:39 AM

English, I used that resin on the advice of the man that owns Raka. It’s the only one I’ve tried. Yes, it does run,you need to keep it checked closely. I’ve never had it freeze or get milky, thankfully. I just need to let it sit longer when it’s this cold. Thanks.

-- Jeff in central Me.

View shipwright's profile


8453 posts in 3406 days

#3 posted 01-23-2016 03:06 AM

Looks like you have it all under control, good work.

Have you ever used sheet plastic to cover these kind of patches? It allows you to work the bubbles out with a squeegee or your fingers right off the bat and prevents the bubbles from reforming by surface tension and sealing off access for air to get in. When cured it can be popped off and the surface will be smooth, even and need little filling of cloth pattern.
You certainly know what you are doing.Tthis is just a little trick that I have used for years that I thought might help you. There is a better description of the process here.

-- Paul M ..............the early bird may get the worm but it’s the second mouse that gets the cheese!

View bearkatwood's profile


1809 posts in 1619 days

#4 posted 01-23-2016 03:24 AM

Very nice. Thanks for showing that. That is some finicky stuff you are working at. When I touch epoxy it explodes all over the place. Keep up the great work.

-- Brian Noel

View JoeinGa's profile


7741 posts in 2615 days

#5 posted 01-23-2016 12:54 PM

You’re attention to detail is excellent ! The final outcome will certainly be a better finished piece for it!

I try to be that attuned to what I’m doing but my (lack of) patience sometimes gets the better of me. My wife just tells people that I’m “anal” about things I’m working on. :-)

-- Perform A Random Act Of Kindness Today ... Pay It Forward

View farmerdude's profile


670 posts in 2647 days

#6 posted 01-23-2016 08:28 PM

shipwright, that is a great idea. I never would have thought of it. I will be sure to try it next chance I get, anything to make things easier. You are wrong about one thing, I don’t really know what I’m doing. This is my third canoe, I’ve never done fiberglassing before this. I’m learning, but have a lot more to learn. Do not be afraid to jump in with advice, I need all the help I can get. I’m a fair woodworker but this epoxy thing is something else. Thank you for the input.

-- Jeff in central Me.

View farmerdude's profile


670 posts in 2647 days

#7 posted 01-23-2016 08:30 PM

bearkat, it is different, that’s for sure. Thanks.

-- Jeff in central Me.

View farmerdude's profile


670 posts in 2647 days

#8 posted 01-23-2016 08:33 PM

Joe, thanks buddy. Nothing wrong with being a little anal, and you’re not the only one with patience problems. Sometimes I have that problem too.

-- Jeff in central Me.

View hoss12992's profile


4166 posts in 2501 days

#9 posted 01-23-2016 09:27 PM

Absolutely love your attention to detial in the blog. I had a ton of questions when you started it and each blog answers more and more questions. Looking great. Thanks buddy

-- The Old Rednek Workshop

View farmerdude's profile


670 posts in 2647 days

#10 posted 01-23-2016 09:49 PM

hoss, if you have any questions don’t be afraid to ask. Thanks for following buddy.

-- Jeff in central Me.

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