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Micro-leaks and weeping


Islandpiper

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I am using the old standard 8 oz ( now apparently shown to be 6 oz.)   Happy with the fabric,  as it was easy to use, etc.   

 

I am using the Marine line of Rust O Leum oil based enamel.  I thinned the first coat and rolled it on.  Rolled on the second coat right from the can.  The next day it was obvious that there were a million micro-pinholes through the fabric/paint combination.   So, i manually brushed on the third coat.  That took care of most of the micro-sparkle spots.  Just tonight, i set the boat upside down on saw horses and put a desk lamp inside, then went around with a cotton swab and put a dot of enamel on each remaining sparkle that I could find and massaged it in.   

 

I sure do hope that does it.  I really don't want to put another 3-4 pounds of enamel on the boat.   

 

Am I alone in this part of the adventure or are these little micro-weepers common?  Any standard cure?   Thanks, Piper

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I know exactly what you mean. My "cure", right, wrong, to otherwise was one of two things. One dab your offending pinholes and wait about an hour or so, and smear some paint into the hole with it half cured so it won't just flow right back out and recoat. Or two, some Rustoleum universal bonding primer, spray on, give it about a minute to thicken up and brush it into the pinholes while it doesn't want to flow and recoat. It was a PITA for me, but my boat finally stays completely dry on the inside.

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I have only completed one boat(a freebee 14).  I used the older fuzzy cloth and rustoleum (although not the marine line).  I thinned the first coat and then added 2 more coats straight from the can.  The fuzzy cloth soaked up paint like a sponge.  I had the same issue of leaky pinholes and used the same method of putting a light inside the boat to see them. I didn't worry about the deck and focused on the bottom and sides with the boat turned over on sawhorses.  I simply brushed or rollered over the hole. I can see some of the spots I went over but I figured it was the bottom of the boat and didn't really care about the appearance.  I did it at night with the garage lights off so the pinholes would really stand out. I was able to see when it filled in.  It took 2-3 sessions with a trip to the lake in between each to get them all but perseverance paid off.

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A lot depends on how you apply the paint. Had a student that put on thin coats in a class and I didn't notice what he was doing. His boat leaked like a seive so I watch them much closer now and make sure they apply the paint thick enough.  For me, 3 coats takes care of it. 

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Thanks to all.   I ran right out of the first quart of paint and will be off to Lowes for a second quart today.  So far, i have less than $20 invested in all the wood for my boat, and the doggone paint costs about $16/quart.  I'm a thrifty ( cheap ) guy, and that's killin' me.  

 

I have just the thinned coat and on full coat on deck, so i needed more anyway.  

 

Jeff, do you mean three full coats or a thinned coat and two full coats?  

 

Oh……the wood.  I bought a 14-foot 2 x 4 ( $5.38 ) and ripped all the stringers and gunwales out of it.  I had another leftover 2 x 4 laying here.  I used 1/4 sheet of plywood for the sawn frames.  I ripped up an unused longbow blank for the bent frames ( not a Kudzu design, sorry) and then bought a pricey 1 x 4 ( $.8.00 ) for the rub rails and outside keel.  Plus, bits of scrap mahogany which was taking up space in my shop.  I'll post pics if i am allowed to show an "outside" design.    Thanks, Piper

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I know I'm new to this but I have painted lots and have worked with fiberglass a fair amount but, I've also had a lot of trouble with pin holes.  It seems that if I put on the paint thin there are lots of them and if I put it on thick it runs...so far I haven't found the Goldilocks consistency...I wonder has anyone here tried adding Colloidal Silica to the paint to thicken it up? I've used it as an additive to fiberglass resins while working on fiberglass airplane floats, it's light and doesn't affect the strength or curing time of the resin much....just wondering...still have two more boats to skin before my work season starts up.

 

So far I've got three full coats and one more partial coat in the trouble areas and still have some pin holes left

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Using Rustoleum I thin the first coat so it soaks in evenly and leaves a nice finished color on the inside.  The next two coats I thin but not much. Some colors are pretty thick so I add just a little thinner to make it go on easier and evenly.  But not nearly as much as the first coats.  I will use most if not all of a quart just on the hull. Different paints will go on differently so keep that in mind.

 

Also, I roll my paint on or spray it on.  If you're brushing it is harder to get it applied evenly and you will have thin and thick spots.  Another plus is the rollers are faster.

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I agree about rollers and sprayers being easier to apply an even coat. Most people have no idea how to use a brush. I was taught to paint before the spray rig became popular, and still paint with only brushes. Yes, Virginia, I'll paint a whole room with just brushes. No tape, no tarp. Although, I can't cut with my left hand anymore because it's getting a little wiggly...

But... A roller requires very little skill to apply heavy-ish, even coats of paint. Think of laying down a nice film, a nice even layer. It is hard to do on fabric, hard to get even coats of uniform thickness, with a brush. Easier with a roller or sprayer.

I had no trouble coating the recycled poly with three coats of latex porch and floor. It has been exposed for most of its almost two year life, and still keeps out water. I used a 3" brush. :)

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I put another coat on deck for a total of one thinned, two regular, and 99% of all the pin holes are gone.  Good enough for a deck.  It now appears that the spot-massage job on the hull went well.  I'll know more when I can launch it.  I have now purchases two quart cans of Rustoleum Marine enamel, both Sand Beige, from the same Lowes, about a week apart, and the paint seems different…seemed thicker in the first can, thinner in the second.   Hmmm

 

But, all's well that ends well.  

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  • 4 weeks later...

I'm not trying to derail this thread but am a little concerned after reading this thread. I'm doing research for my first skin boat build by reading this forum. Do these boats really rely on a few coats of paint to make them waterproof? I just started kayaking with a clc 17 and have already lost some paint entering and exiting my boat in Sandy beach areas. If I do that with these boats am I going to constantly be fighting a wet possibly unsafe cockpit? Sorry if the is a total newbie question and Im not trying to be negative toward the design. I just want to .learn

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I have paddled nothing but skin boats for many years but since I sell them I hope others will chime in to share their experiences.

 

Yes, paint or varnish  is your waterproofing. The fabrics uses are uncoated and as porous as a sieve when put on the boat. You have to apply something to water proof it and most people use paint. Properly applied it is surprisingly durable.

 

Unlike your plywood boat, paint doesn't just sit on the surface, the first coat soaks into the fabric. Additional coats bond to the first coat and I have never seen paint chip off.  I do not baby my boats, I paddled them across muddy flats scraping bottom. I slide across rocks, downed tree's, etc.

 

At the same time I do not abuse my boats. I don't go out looking for things to drag it across. I  try to go around obstacles if I can but I don't worry if I can't. I DO NOT take my boats down moving shallow water, they are Sea Kayaks, not white water boats and the constant banging and abrasion in the same spots over and over will ruin the skin. I don't beach my boats unless they have rub strips. Just like white water, rubbing the same spots over and over will eventually rub a hole in the skin. With the brass strips I beach it and never give it a second thought.  Because they are so lightweight, I pick it up and carry it rather than drag it across the ground (most times).

 

With that said, I have had one boat that was several years old and heavily used that started to leak a little. It could have been a small hole or just wear on the paint allowing water to seep in. The way I used and beat that boat I wasn't surprised. The cure would have been another coat of paint on the bottom. It is the only one I have ever had to leak like that.

 

With that said, I hope other will chime in and share their experiences.

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In more than a dozen dozen boats I've built and owned over the years, and the several I didn't keep, I've never had one leak from paint problems. I've poked a hole once, ripped one a little once, but those boats were both cotton canvas and varnish.

My freeb is about 2 years old and has lived outside the entire time, including a stint stashed in the wild under some foliage. She didn't leak the other Sunday when I took her out, although you can see a few spots that might could use some touch up.

My plywood sailing canoe? Scratched all the paint off a few spots on the bottom first day out... :)

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Experimenting a little on my latest project, I decided to try the skim coat of Loctite PL Premium construction adhesive prior to paint.  If you are careful and thorough, it totally fills in the weave of the loose fabric quite nicely.  As best as I can tell, from the get go, with two coats of Rustoleum applied afterward, only (2) individual pinholes were found.  Compared to the 100-ish pinholes I was fighting on FreeB, after 3-5 coats of paint, this is a massive win for the economy fabric.  It's not the prettiest underlayment to paint over as you can see a bunch of the bondo spreader lines from smearing the adhesive in, but no more unsightly than the pile of extra brush marks from trying to fill in the spot areas where the paint didn't fill in with just paint.

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I will throw in another opinion.

Latex paint interacts differently with the cloth than oil based paint, by simple virtue of the binder. I think the latex paint literally forms a skin of rubber on the boat, like on anything else, but the weave of the cloth, and the way the paint soaks in a bit, allows the sheet of rubber to resist peeling away.

As an example, put a thin film of latex paint in a plastic bowl. Let it dry, then apply about 3 more coats. When dry, you can pop it out and have a blue latex bowl. I think this same effect happens to the boat, but the weave of the cloth allows more tooth for the binder to key into than smooth plastic, so it won't peel off. Ever seen latex painted over old oil based paint without proper prep? Those big sheets that peel off the door...

On my long suffering firefly, I had some problems with the econo cloth pulling badly at the stem, so I painted the cloth with one coat of latex paint to keep it from unraveling or holing more while I sewed. When I went back later to sew on patches, I could hardly piece the painted fabric because it had a film clogging all the little pores.

I'll get to painting her one of these days, with porch and floor paint, which is my go to boat paint, unless I want some two pack gloss...

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I think the key to the durability is using soft paints.  This is why old fashion alkyd oil works so well.  I have been hearing stories in this forum about how hard this may be to find.  Try visiting http://www.kirbypaint.com/. It is a seriously old formula used by many traditional plank on frame boat owners and professionals.  They make it themselves, they take phone orders and ship.  They also do custom colors.

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Dave, I have a few old family recipes for paints. I still use the milk and egg tempera paints all the time. One is an oil-based paint called barn paint. Guess where the red color comes from. :)

I don't even mess with trying to make the complicated paints, by the way, as the knowledge chain was broken, and I was only left holding the notes long afterward.

Those guys at Kirby are treasures, or wizards. That stuff is liquid Maserati.

I can't even guess the number of gallons of latex or acrylic paint I have slung in the last 25 years. I'm used to it, know how it works. Brush marks, for example, mean too much brushing, or not a nice enough brush. Get a nice synthetic brush, a soft one you can't stop petting, because it's so soft, then keep it clean. Keep paint on the tip, away from the ferrule, and clean it immediately after use.

I have a 1" sash brush I bought in 1988 that I still use regularly. Primers and first coats you can be a little rowdy with, but don't over brush. Flow it on, smooth it out, and go!

If I had my druthers, by the by, I would only paint with alkyd porch and floor, warmed up a bit by setting the sealed can in the sun, with maybe a TOUCH of penetrol, if it's hot... Oh, talk about flow and coverage and brush feel. Of course, for oil paints you use a hair brush, right? Hair, not synthetic...

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Something just occurred to me. The new Economy Fabric I sell is a very loose weave fabric and it is hard to seal. Some of the comments you are seeing are probably related to that fabric..  With the original 8 oz. three coats of paint (assuming you don't skimp on the coats) is what it takes to seal it. 

 

Sealing the Economy fabric is a whole 'nother story.  Not real found of it for this reason but the price is great and people like cheap. But the original 8 oz is much easier to work with and well worth the extra dollars.

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Wow thanks for the information. I think my worries have been put to rest. It's hard not to want to build one of these kayaks when there is such a great support community. Not to mention that I have one thread and one post in someone else's thread both of which have been addressed by the actual designer of the boat. If that doesn't give confidence to a new builder I don't know what will. Looking forward to joining all of you.

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