Floating fabric on the wetout coat

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mvettori
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Floating fabric on the wetout coat

Post by mvettori »

I glassed the inside of my boat over the weekend. It went much better than the outside. On the outside, I experienced many air bubbles, blisters, and the finished product had a waviness to it. I corrected some problems with the process and the inside job didn't produce any bubbles or blisters like I had on the ouside. :applause

However, I still have a somewhat wavy texture to the fiberglass on the inside...is this normal? The "waves" (ranging from a 1/4" to 1/2" wide) aren't air, but resin floating the cloth. I was very diligent in the squeege'ing process to remove as much of the excess as possible without starving the cloth. I went back and did this several times and the cloth was flatwith not that much resin left behind, but the waves appeared to develop over time. What doesn't make sense is that the waves are vertical, from the sheer down to the centerline. If i had excess resin flowing down from the sheer, I would expect the waves to be horizontal.

Its not that big of a problem. The waves will go away with a couple of sanding/fillcoat iterations just as they did on the outside, its just annoying that I'm not getting it right the first time and its not clear to me why.

Is there something I'm doing wrong or is this one of those things you'll learn after several tries? :confused

Mike in Collegeville
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davidb54321
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Post by davidb54321 »

Mike,

I experienced the same thing with my canoe. It did "flatten out" somewhat with additional coats of epoxy. This is one of those areas of the building process which will improve with subsequent boats.
David Bartlett

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mvettori
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Post by mvettori »

Crap...I was hoping for a different answer! :laughing
canoeblderinmt
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Post by canoeblderinmt »

Mike,
I'm not sure if I am understanding your waviness issue, but I never really noticed it as the subsequent layers of epoxy, as you noted, will make them pretty much invisibible. If you are squeeging, you are bound to be pushing the glass around as yo do so and "waves" will appear, but I don' think this is very much to worry about. As for excess epoxy floating the cloth, next time try wadded up paper towels to soak up the resin in the bilge turns and near the stems where it starts to pool. This excess epoxy isn't really a problem; it just adds weight without any attendant strength gain.

Keep us posted,

Greg
" Choose to chance the rapids, Dare to dance the tide..."
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ealger
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Floating fabric

Post by ealger »

Mike, this is why we have to build 4 canoes: The first 2 you donate to the Boy Scouts as they only want them to float! The 3rd one you keep for yourself and the 4th you give to your son!
:smile
Ed..
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Patricks Dad
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Post by Patricks Dad »

As the scoutmaster of a local troop, I'll be happy to accept your donations of your 1st and 2nd canoes on behalf of our scouts!
Randy Pfeifer
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Jeff in Farmington, MI
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Post by Jeff in Farmington, MI »

Mike,
I experienced the same issue as well when glassing the inner surface of the hull. There were ripples in the glass covering the bilge, especially where the hull narrows toward the bow and stern. No matter how many times I worked the area with the squeegee, the ripples would return. Eventually, of course, the epoxy sets up and can be worked no more.

Although the cloth was spread out smooth when it was dry, for some reason the cloth would gather in ripples after it was wet out. I ended up sanding the ripples smooth, which meant that that I also sanded through the 6 oz glass in these local areas. To ensure that the hull was structurally sound, I then added an additional layer of 4 oz glass. The 4 oz glass followed the hull contours much better.

Someday, I intend to build another canoe, and I would like to improve my technique in this area. Do the more experienced boat builders have any thoughts on this?

Jeff
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mvettori
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Post by mvettori »

Thanks Jeff. The ripples occurred when I glassed the outside too. The way i got rid of them (and what I'm currently doing on the inside) is continue with the fill coats. This pretty much fills in the area between the ripples and adds enough epoxy on the tops that I can sand them smooth with the confidence that i won't sand into the cloth.

This worked great on the outside and so far so good on the inside. The only downside is that when i take it outside in the sunlight, I can still see the ripple areas in the light's reflection. You can barely see them, but they are there nonetheless.

Mike
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Glen Smith
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Post by Glen Smith »

I find that precoating reduces the risk of rippled cloth since you can concentrate on wetting the cloth and not worry about starvation since the wood isn't absorbing any epoxy. Being extra careful during epoxy application and squeegeeing reduces problems also. One other thing is if your cloth is wider than the hull you can place the cloth at an angle to the keel line on a bit of a bias. The cloth will conform to curved surfaces more easily.
AlanWS
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Post by AlanWS »

I think Glen Smith just hit the secret of life: it's not 42, it's that you want your glass on at least a slight diagonal, and that you get rid of ripples by smoothing it at a slight diagonal to the weave.
Alan
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mvettori
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Post by mvettori »

The oddity in all of this is that as I squeegie'd the excess, the fabric was laying nice and flat...I thought I had the problem licked! I did this two or three times and the wrinkles developed afterward. I don't think the fabric was moving becuase it looked fine after I was done working with it...the wrinkles developed over time, assumingly (is that a word?) from still having too much resin on/under the cloth. I can't think of any other reason.

Mike
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Post by Dan. »

Is sanding necessary after a precoat?

Sanding the inside of the hull has been by FAR my least favorite job so far.
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Glen Smith
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Post by Glen Smith »

Depending on the brand of epoxy you used, if you wait too long , yes you will have to sand. However, this would be hand-sanding with 120 grit paper or even an abrasive pad.

Also, if the precoating raised a lot of grain, it might catch on and damage the cloth when you lay it on the hull. In this case, sanding would be good.
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Jim Dodd
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Post by Jim Dodd »

Mike
How did you apply the resin?
Did you use a brush, squeege, or a roller?
Excess resin on the inside will flow towards the bottom before it sets, thus floating the cloth, as you described.
Notice that this doesn't happen on the outside, you work the excess resin towards the shear.
On the inside, excess resin flows towards the bottom and collects, sometimes at a wrinkle, and floats the cloth.
Often times we apply the inside wet out coat, it looks good , so we walk away. Come back later and find these raised spots. Stay with the resin until it sets.
Jim
Keep your paddle wet and your seat dry!
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Jim Dodd
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Post by Jim Dodd »

Try a foam roller the next time.
Keep your paddle wet and your seat dry!
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