Cloth application Sequence

Fiberglassing over plywood and one-off fiberglass methods. See: "Boatbuilding Methods", in the left-hand column of the Home page.

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whj
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Cloth application Sequence

Post by whj »

I have a question about the best sequece for putting the cloth on the hull.

From what I have read, it seems that the suggested method is to put on an individual piece of cloth at a time. For example 1/2 of the bottom

1. Apply 1st piece of cloth
2. Apply wet out coat
3. Apply 2nd coat.
4. Apply finish coat(s)
5. feather edges
6. Apply second piece of cloth, overlapping first
7. repeat 2-5 until done.

Is this the appropriate sequence? I would have guessed that it would easier to apply the finish coats to the entire boat at the same time. A sequence more like the following:

1. Apply 1st piece of cloth
2. Apply wet out coat
3. feather edges
4. Apply second piece of cloth, overlapping first
5. repeat 2-5 until all cloth is applied.
6. Apply 2nd coat to entire boat
4. Apply finish coat(s) to entire boat.

Any suggestions from those of you who have been through this process?

Thanks,
-Bill

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Graham Knight
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Post by Graham Knight »

Your second sequence is correct.
Graham in Shepperton, England

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Dave Grason
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Post by Dave Grason »

Some time back, I bought Glen-L's video: "How to Fiberglass a Boat." It was worth every penny and after seeing it the first time, I was chomping at the bit to go at it. They say a picture is worth a thousand words so this video is worth at least a cool million words.
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

whj
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Post by whj »

Thanks for the info.

I think I will get the video. I have the book, but it wouldn't hurt to actually see the process.

-Bill

Robert A
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Post by Robert A »

On several small boats I have approached the fiberglassing in two difference sequences. First as described above. The other I sealed the bottom and sides of the small boat with epoxy - - sanded - - and then applied the cloth and wetted it out. The advantage was that I didn't have to use as much epoxy wetting out the cloth and the cloth was much easier to adjust, stretch and shape without snagging on the plywood surface.

I assume it is best to overlap along the keep and stem.

Appreciate any comments as I will be into a much larger project (Thunderbolt) in a couple of weeks.

Robert A.

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leakcheck
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Post by leakcheck »

The one thing I will do when i perform my next fiberglas operation is: apply all epoxy as soon as possible within the limits of the epoxy, before it takes a hard set or starts to blush. The reason I would prefer this method is I believe (I have no proof just seems logical) that a chemical bond is stronger than a physical bond. (I learned that from my wife)

In the past I have epoxied, let cure, wash surface, sand and reapply more epoxy. If you have the time to epoxy and then before its final set reapply more epoxy it would seem to me to be "sronger". It may also be thicker and make take more epoxy but there is a give and take with everything I guess.

Steve

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Dave Grason
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Post by Dave Grason »

leakcheck wrote: If you have the time to epoxy and then before its final set reapply more epoxy it would seem to me to be "sronger".
I agree and I use a cotton ball to tell myself when to reapply. If the first coat of epoxy just tugs on the cotton ball enough to pull a few strands without making a mess or getting slurpy with the entire ball, it's time to go with the next application.
Isn't it amazing!! The person that never has the fortitude to pursue his own dreams, will be the first to try and discourage you from pursuing yours.

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go
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Post by go »

Fiberglassed my Zip hull this weekend. I used 50" wide 6 oz cloth that fit perfectly from the keel centerline and down to the sheer. I have decided to not use any overlaps on the cloth,
I really see no reason doing it...
Some pictures on my website: www.bhs.is/zzzip

Ingólfur
Iceland

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Bill Edmundson
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Fiberglass

Post by Bill Edmundson »

Great job! Go. I really like that plan holder behind you in the picture.

Also, West System epoxy says that you can get chemical bond as long as the first/previous coat is in its inital cure (will dent with finger nail). West also says you can apply over the amine brush during this time. The Canoe Craft book says about 2 hours (This should be about the same as Daves method.).

I plan to "prime" the wood then apply glass while the resin is still active.
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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go
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Post by go »

Thank you Bill,
I´m slow... I was thinking what does he mean by "plan holder!" Ok, I´ve figured it out....!

Ingólfur

basilkies
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Post by basilkies »

I'd go with the second set of steps, but put a coat of epoxy on the boat before you start with number one. This will keep the wood from soaking up your wetting the cloth proceedure and make it go easier.

Also, get your boat to temperature before you apply resin and absolutely don't let the boat or room get warmer while the epoxy is drying. A warming temperature will creat bubbles in your job.

jake1.11
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Post by jake1.11 »

Ingolfur,

I am truly inspired as I eagerly await your updated posts of your Zip build. The detailed photos have been very helpful, I check them as I go to make sure that I am on the right track. One question, you state that you didnt overlap any of the fiberglass joints. Considering all the fiberglass joints also fall over plywood joints does this provide enough structural strength? Also, with the flexing of the boat is there potential for a joint to open up and allow water through?

Just curious

Jake

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go
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Post by go »

We know that this boat was designed long before fiberglass and resin so you do not need
fiberglass for structural strength. The fiberglass and resin are applied for watertightness
and abrasion resistance but I hold the extremist view that the main reason for applying
fiberglass cloth is to being able to quickly build up a required /adequate thickness of epoxy.
If you overlap the cloth for example from bottom aft down to the transom you have to blend
in the seam and on such flat surface there is a tendency to sand too much into the overlap or just
sand it all away. On the other hand I´m going to put fiberglass tape on the stem, in that area
it is easier to blend in the seam.

Ing.
My ship came in but I was at the airport

Ingólfur Hreiðarsson
www.bhs.is/zzzip

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Graham Knight
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Post by Graham Knight »

I take your point about strength, but personally I'd want either a continuous piece of cloth, or an overlap, or tape on all the corners, especially the sharp ones as they are rather vulnerable.
Graham in Shepperton, England

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go
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Post by go »

In my opinion the abrasion resistance of a single layer of 6 oz cloth may be overephasized (spelling?).
I have constructed two stripbuild kayaks and using single layer of 6 oz cloth inside and out is called "light layup" These boats are 16 kilos and I am not the heaviest paddler, still when beaching these boats they can suffer severe scratches to the bottom.
My ship came in but I was at the airport

Ingólfur Hreiðarsson
www.bhs.is/zzzip

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