View Full Version : Fiberglass print showing threw paint finish?
While getting my boat ready, cleaning and maintance, I noticed seeing the fiberglass fabric showing threw the painted hull. You have to look hard but it's showing. Just curious if this is the epoxy shrinking, or do I have a different problem? Boat is two years old.
03-08-2004, 07:33 AM
Manufacturor tossed you a real problem, heh? But seriously, if all that's showing through is a bit of dappeling it's likely been there since jump. A little too much vacuum in the bag or whatever. If you're really seeing a lot of the warp and woof the the glass either someone in the past sanded a bit deep or it's poor construction.
If you've exposed fibres, you'll want to sand out the hull and put a coat of epoxy down, assuming that the original resin is compatable with epoxy.
03-08-2004, 08:16 AM
Normal depending on if this hull is plywood, or wood and glass, for several reasons depending on the fairing compounds as being one of the biggest culprits. Even on straight fiberglass hulls, it will do this, which is even polyester resin. Need more information to answer this one, at least I don't see enough.
The show through that you state, is it just a pattern of glass, or fibers showing through?
[ 03-08-2004, 08:18 AM: Message edited by: Oyster ]
Thanks for the response, No fibers just a little print. You have to look hard to see it, I just never seen it before. I applied four coats of epoxy over the glass, just wasn't sure it was enough. Hull is made of Okume. If I have a problem, figured nows the time repair.
03-08-2004, 08:58 AM
This is normal sometimes. Upon applying the resin coats, you get a telegraphing affect if you don't really sand it down smoothly, or upon some shrinking in the resin combined with drying of the topcoats, usually in two part paints also. Darker colors will almost always do this with the temperature changes of the hull. As long as you don't have any voids or release of the fabric from the plywood, you should be okay. Sometimes a repaint of the hull will take care of this, but not necessary. Give it the six foot test and if you can't see it, then forget, IMHOO.
03-08-2004, 10:07 AM
Problem is cosmetic, not structural. Search for Conrad S. comments and he describes a heat curing/finishing procedure to minimise the chance that this will happen if you decide to repaint know, but IMHO, let it ride until you need to repaint and by that tin=me the epoxy will be fully cured with now more "room" to shrink and with new primer and paint it won't come back on a plywood hull. Cold molded or strip planked is a different story. Those seams reappear as the moisture content cycles.
03-08-2004, 05:26 PM
If you find a reasonable solution to the print thru problem, you can be elected our finish guru. It happens. There have been several opinions on the cause but I think it is most likely due to shrinking of the coatings over the glass weave which allows it to show through. Darker colors that get more temperature cycling seems to be worse than light colors and of course, it's worse down south. Even an initially perfect finish will eventually show the problem if the conditions encourage it.
Just subscribe to the 10' finish and forget it.
03-08-2004, 05:46 PM
Print through is common in the fiberglass industry. It has to do with the different frequency's of light rays. It is not a stuctural problem and your hand cannot feel the surface differences.
Thanks for all your help,
When the weather permits I will repaint. I have been using System 3 LPU. I find it to be very durable, just wish I could learn how to spray it.
Drys so fast. Foam brushes for now.
You'll probably need an impractical amount of paint buildup to hide the cloth weave, probably just have to live with it. That lpu paint really eats up the foam brushes, doesn't it? smile.gif Great paint, though.
03-09-2004, 07:03 AM
Originally posted by JimD:
You'll probably need an impractical amount of paint buildup to hide the cloth weave, probably just have to live with it. That lpu paint really eats up the foam brushes, doesn't it? smile.gif Great paint, though.Jim, when you sand down the existing surface, you remove some of the telegraphing of the print, or in another way of putting it, you are removing the "highs" when you go back and repaint these types of situtations. But as its stated, very seldom any strutual problems are in this typical scenario of one to two year old new work.
03-09-2004, 02:54 PM
Is your hull a dark color?
This causes it to absorb more UV, so it's more common on darker colored hulls.
In order to avoid cutting the fibers, I'd fill in the lows, rather than sand off the highs.
03-09-2004, 04:46 PM
Harrumph! Let me tell you a thing or two about print through. I was crawling around under Prairie Islander this morning as she sits on her trailer to see what I could see. She is covered with two plies of 6oz cloth below the water line. I can see, when the angle of the light is right, the grain of the wood and the line between the Western redcedar planks. I do not see the weave of the cloth, however. But, you know what? It does not bother me in the least. Can't see it from a few feet away and unless there is delamination what's to fret?
The Hull's painted Sea Green LPU from System 3, not really that dark. There is really no problem other than looking hard and seeing the weave. Like I said, I never noticed before so I figured this would be the only great place to find out. I have built ten boats over the years. I'am not a good poster, just a reader.
I have learned alot here.
[ 03-10-2004, 06:27 AM: Message edited by: Topo ]
03-11-2004, 11:45 PM
Topo, if you live near a store that sells water skis, find time to see how the ski manufacturers make the weave work for them under the paint. A lot of manufacturers will fill the indentations with a different colour to the base colour. You could have a dark blue hull for example, with a uniform pale blue dot. The indentations are filled using a squeegee, then cut back very gently to gain uniformity, then a few coats of clear are applied. This look is as cool as.
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