Dry spots? in 12oz tape

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rezab
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Dry spots? in 12oz tape

Post by rezab »

Hi all,

Started laying down tape on the inside of the hull. I first filleted the keel/bow and had hoped to lay the tape down wet on wet, but that didn't quite end up happening, and I ended up laying up the glass when it was tacky still. In the process, I noticed that there were a few spots that just didn't seem to wet out, and now a day after it still looks like there might be some dry spots.
IMG_0736.JPG
IMG_0734.JPG
Do these need to be sanded out? or is it passable?

Dan_Smullen
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Re: Dry spots? in 12oz tape

Post by Dan_Smullen »

I'm no expert, but they look passable. I believe areas that deserve attention are those that can be pierced with a screw driver.

Rather than grinding, drilling a small hole and filling with a syringe is the way to go for these rather than grinding them out.

fallguy1000
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Re: Dry spots? in 12oz tape

Post by fallguy1000 »

So, your post is a bit confusing. I'd like to better understand when things got tacky.

From your pictures, yes you have some air pockets and micro voids. But on the inside of the hull; they are sort of okay. You just don't want water to get into those holes and rot the wood.

You should use a 1 centimeter rule on the inside. Anything equal to or bigger than a centimeter, consider a flaw, grind it out and repair it with thickened epoxy or inject.

The business of tacky sounds a little like it was kicking when you wet it out. Avoid wetting out tapes with hot resin; it'll usually end up much worse.

Also, consider using a bubble buster consolidation roller. What roller are you using? They look a bit hand applied and that is not quite enough pressure to force out entrained air. I have a few years experience now.
My boat build is here -------->

viewtopic.php?f=12&t=62495

rezab
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Re: Dry spots? in 12oz tape

Post by rezab »

fallguy1000 wrote: Mon Nov 15, 2021 11:08 pm So, your post is a bit confusing. I'd like to better understand when things got tacky.
The underlying thickened epoxy fillets were tacky.

fallguy1000 wrote: Mon Nov 15, 2021 11:08 pm From your pictures, yes you have some air pockets and micro voids. But on the inside of the hull; they are sort of okay. You just don't want water to get into those holes and rot the wood.

You should use a 1 centimeter rule on the inside. Anything equal to or bigger than a centimeter, consider a flaw, grind it out and repair it with thickened epoxy or inject.
Ok great, that is good to know. Since the quality of work is generally so high on this forum, I have a hard time telling where the line between acceptable and unacceptable flaws are.

fallguy1000 wrote: Mon Nov 15, 2021 11:08 pm
Also, consider using a bubble buster consolidation roller. What roller are you using? They look a bit hand applied and that is not quite enough pressure to force out entrained air. I have a few years experience now.
I have mostly been using a brush, and squeegee. I find it hard to effectively use the bubble buster roller around the the chines and keel, but perhaps I just need more practice.

OneWayTraffic
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Re: Dry spots? in 12oz tape

Post by OneWayTraffic »

Having experienced some of that myself I would reject that job and peel it off with a heatgun. Done in 5mins. Alternative is grind out the holes, putty and glass over. My own work is far from perfect, but that would bother me knowing it was in there. I do not think that it will break the boat though, depending on what the boat is.

Edit: Yours is a C17 same as mine. Probably not a structural issue to grind and fill as long as the bond to the wood under is good, but I would still remove it, and try again. It's like 0.1% of the build cost for some peace of mind.

rezab
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Re: Dry spots? in 12oz tape

Post by rezab »

OneWayTraffic wrote: Tue Nov 16, 2021 4:46 am Having experienced some of that myself I would reject that job and peel it off with a heatgun. Done in 5mins. Alternative is grind out the holes, putty and glass over. My own work is far from perfect, but that would bother me knowing it was in there. I do not think that it will break the boat though, depending on what the boat is.

Edit: Yours is a C17 same as mine. Probably not a structural issue to grind and fill as long as the bond to the wood under is good, but I would still remove it, and try again. It's like 0.1% of the build cost for some peace of mind.
I think it will bother me too. I'm going to give it a shot with the heatgun

OneWayTraffic
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Re: Dry spots? in 12oz tape

Post by OneWayTraffic »

I stripped 5m of glass off mine in two days with a heatgun after mucking around for two weeks with grinder and power planer. At the time it was definitely the low point of the build for me. After getting through that and other initial issues I feel like I can handle anything short of a sinking. Little part of me still wonders if it will all come apart at the seams on launch, which might explain the urge many of us have to overbuild.

Anyway, use the heat gun to heat and lift a corner. You can make it easier by scoring slits with a multitool diamond blade or similar. Then get the pliers under the softened epoxy and peel with steady pressure. Keep it going with a hot edge and it should just lift up taking little or no plywood with it. Fill any damaged areas of plywood with putty when you reglass. Since it's on the inside a mix of microballoons and cotton fibres or wood flour should approximate the strength of the plywood core. Small areas glass over wet, larger ones it's easier to cure and sand to a smooth surface imo.

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