Fiberglassing the hull in a carport

[DayTripper]

For folks who fiberglass the outside of hulls in an uncontrolled environment like in a carport or outdoors under a canopy, do you epoxy the cloth after sunset to have falling temperatures to prevent outgassing from rising temperatures causing air pockets under the cloth? What's your procedure?

[Todd Bradshaw]

I've always done my glassing in a garage with the door open, starting in the morning and have never had serious outgassing problems. Air pockets under the cloth are much more likely being caused by tension, and the usual cure if you see one starting is to roll or squeegee toward the pocket, moving more cloth in that direction to ease the tension. If you are really worried about outgassing you can always roll a coat of resin on the hull before starting with the cloth layers. The drawback to this is that it will often raise the grain a bit, which makes sliding and spreading the cloth around prior to saturation on all those little stickers somewhat more difficult.

See any bubbles from outgassing? Me neither.

D3a.jpg

[Tomcat]

Thanks for the roll to tip, Todd, I have been doing this with good results for 40 years, but I try to pull the bubble flat, usually from the long side. There is always something new.

I live on a shore of the Great Lakes, or a great lake near the Atlantic. I basically ignore this stuff. When I roll late out of bed and get organized, have lunch, and get on it, I do it. From reading the Gougeons book way back I used to worry about what the wood would do. But over the years I have just not had much trouble.

Early on, I used to use the slowest epoxy I could get. These days I tend to use fast. The fast that System 3 classic makes is too fast for me, but Gougeon, MAS, Raka, I don't have much trouble with. Or I will mix hardeners. Even when it tends towards 80 degrees, I can use fast. Keeping the project rolling takes some experience, but if it cooks real fast, it won't have 6 hours for bad things to happen. While I do the odd stripper, I mostly make boats that will be painted. There might be some mixing bubbles in a workboat finished boat, under the paint. But no way would I tolerate outgassing or suckage. I do some glassing in the garage or I will do it in the open. I won't sand in the garage shop, so that forces me outside a fair bit.

[DayTripper]

I've always done my glassing in a garage with the door open, starting in the morning and have never had serious outgassing problems.

Really good to know!

Air pockets under the cloth are much more likely being caused by tension, and the usual cure if you see one starting is to roll or squeegee toward the pocket, moving more cloth in that direction to ease the tension.

That is a valuable tip. As a novice, I would have done just the opposite and pressed down on the center of the pocket and then rolled or squeegeed from the center of the pocket outward.

If you are really worried about outgassing you can always roll a coat of resin on the hull before starting with the cloth layers. The drawback to this is that it will often raise the grain a bit, which makes sliding and spreading the cloth around prior to saturation on all those little stickers somewhat more difficult.

Nope, don't want to roll a coat of resin first because that would make smoothing the dry cloth difficult.

See any bubbles from outgassing? Me neither.

D3a.jpg

Precisely my goal 👍.

[DayTripper]

Thanks for the roll to tip, Todd, I have been doing this with good results for 40 years, but I try to pull the bubble flat, usually from the long side. There is always something new.

I live on a shore of the Great Lakes, or a great lake near the Atlantic. I basically ignore this stuff. When I roll late out of bed and get organized, have lunch, and get on it, I do it. From reading the Gougeons book way back I used to worry about what the wood would do. But over the years I have just not had much trouble.

Another, just do it during the day experience. Thanks!

Early on, I used to use the slowest epoxy I could get. These days I tend to use fast. The fast that System 3 classic makes is too fast for me, but Gougeon, MAS, Raka, I don't have much trouble with. Or I will mix hardeners. Even when it tends towards 80 degrees, I can use fast. Keeping the project rolling takes some experience, but if it cooks real fast, it won't have 6 hours for bad things to happen. While I do the odd stripper, I mostly make boats that will be painted. There might be some mixing bubbles in a workboat finished boat, under the paint. But no way would I tolerate outgassing or suckage. I do some glassing in the garage or I will do it in the open. I won't sand in the garage shop, so that forces me outside a fair bit.

Fast does make sense to cut down the curing hours for bad things to happen. I already bought the West Systems 206 slow hardener so I'll go with that. Probably better as a first timer using epoxy to glass, to reduce stress 😉.

[Todd Bradshaw]

In many cases, the light is much better during daylight hours as well, and you do want to be watching carefully up until the point where the resin really gets stiff enough that nothing can move. I always glass in one marathon session. Typically, it starts with the main fiberglass layers. Once they have hardened enough that I won't disturb them, any other pieces (like stem reinforcements for example) go on. Once those are reasonably stiff, I'll start with the rolled-on filler coats. I keep them fairly thin to avoid drips as much as possible and often end up with a total of five or six of them, done rapid-fire as soon as the previous coat has stiffened enough. Rule of thumb: roll coats on until the weave texture is gone, then add one more as a sanding cushion. This will also bury transitions pretty well, where you may have reinforcement patches over the main glass layers. Filler coat applications are really quick, followed by a long wait while it hardens, but it may be worth working round the clock as needed. If you have to stop - like overnight - wash for blush the next day (plain water and a scotchbrite pad) before resuming filling. No sanding gets done for at least a week to ten days to give the resin time for full cure and to become less toxic. You do not want to risk getting sensitized to epoxy.

[DayTripper]

In many cases, the light is much better during daylight hours as well, and you do want to be watching carefully up until the point where the resin really gets stiff enough that nothing can move. I always glass in one marathon session. Typically, it starts with the main fiberglass layers. Once they have hardened enough that I won't disturb them, any other pieces (like stem reinforcements for example) go on. Once those are reasonably stiff, I'll start with the rolled-on filler coats. I keep them fairly thin to avoid drips as much as possible and often end up with a total of five or six of them, done rapid-fire as soon as the previous coat has stiffened enough. Rule of thumb: roll coats on until the weave texture is gone, then add one more as a sanding cushion. This will also bury transitions pretty well, where you may have reinforcement patches over the main glass layers. Filler coat applications are really quick, followed by a long wait while it hardens, but it may be worth working round the clock as needed. If you have to stop - like overnight - wash for blush the next day (plain water and a scotchbrite pad) before resuming filling. No sanding gets done for at least a week to ten days to give the resin time for full cure and to become less toxic. You do not want to risk getting sensitized to epoxy.

Thanks for the additional info. For my first glassing job using epoxy, one marathon session will be too much for me to handle. Since I'll be using PeelPly, I'm thinking of glassing my boat in sections on consecutive days. Then I'll be able to overlap the cloth without having to wait a week to sand the overlap area as prep for the next session. Hope that's a workable plan.

[DayTripper]

For folks who fiberglass the outside of hulls in an uncontrolled environment like in a carport or outdoors under a canopy, do you epoxy the cloth after sunset to have falling temperatures to prevent outgassing from rising temperatures causing air pockets under the cloth? What's your procedure?

I've been thinking, can outgassing even happen when fiberglassing marine plywood? With no voids in the plywood and glue between the layers, there's only a thin layer of wood for the outside layer that will be glassed. Doesn't seem that there's air that can expand in that one thin outside layer of wood.

Anyone ever experience air pockets under the cloth caused by outgassing when fiberglassing "marine" plywood?

[Todd Bradshaw]

You are way too worried about outgassing. Glass the hull and while that first layer is hardening, don't go anywhere. Stay and keep an eye on it, making sure it is free of defects of any sort while you still have the ability to fix them. With the amount of money, materials and labor involved in building a boat these days, other than maybe the house catching fire or other major occurrences happening, you have nowhere more important to be. Personally, I'm not a big fan of peelply on initial glassing layers because it hides defects and by the time you finally get to see them, fixing them is a whole different story. I'd much rather be able to see that the fiberglass is all properly saturated, down tight on the wood, bubble and flood-free with a very even cloth texture squeegeed or rolled on the surface everywhere.

[DayTripper]

You are way too worried about outgassing. Glass the hull and while that first layer is hardening, don't go anywhere. Stay and keep an eye on it, making sure it is free of defects of any sort while you still have the ability to fix them. With the amount of money, materials and labor involved in building a boat these days, other than maybe the house catching fire or other major occurrences happening, you have nowhere more important to be. Personally, I'm not a big fan of peelply on initial glassing layers because it hides defects and by the time you finally get to see them, fixing them is a whole different story. I'd much rather be able to see that the fiberglass is all properly saturated, down tight on the wood, bubble and flood-free with a very even cloth texture squeegeed or rolled on the surface everywhere.

"Was" way too worried about outgassing but now I don't think it will happen when glassing marine plywood. Adding that Tomcat and you said that you don't have problems with outgassing when fiberglassing in the mornings or even mid-day, I don't think it will happen. I already bought the PeelPly so I'm going to try it and learn from what ever happens. Will keep your methods in mind while I'm glassing. Thanks!

[rgthom]

I have glassed 1 marine ply hull. At the time, several builders of similar boats were complaining of outgassing bubbles due to using heaters under the hull in cold weather. To be safe I did mine in summer, starting near the hottest time mid-afternoon. No bubbles, but probably not necessary.

[DayTripper]

I have glassed 1 marine ply hull. At the time, several builders of similar boats were complaining of outgassing bubbles due to using heaters under the hull in cold weather. To be safe I did mine in summer, starting near the hottest time mid-afternoon. No bubbles, but probably not necessary.

Thanks for contributing. All info helps.

[John Meachen]

Its interesting seeing what different concerns people have.I have done some glassing in a carport and outgassing wasn't on my mind,rain coming in was more of a cause for anxiety.

[adamarthurryan]

I like to glass in the morning, before it gets too hot. Usually I'm still going in the full sun though. The epoxy goes on fast, each batch is only in the pot for a few minutes before it gets spread out on the cloth.

I don't like glassing in the evening because it gets really damp here. Seems to sometimes make the epoxy go a bit cloudy and weird. A funny thing happened on my last job, a teardrop trailer... not exactly sure what the problem was but it had something to do with how the wood changed temperature (and maybe humidity) in the evening. The parts of the trailer that were backed by insulation got kind of cloudy, but the patch where the insulation was removed for repairs didn't.

[Todd Bradshaw]

A couple of other things which may or may not be needed in this case, but are worth being aware of:

When glassing over complex shapes the cloth will often drape and conform better if you go in before you begin saturating it and trim off the woven selvedge edges. It tends to free up the weave a bit, allowing the yarns to move on themselves, parallelograming slightly where needed, reducing tension and helping the cloth stay flat and tight to the surface.

Glasscloth doesn't do very well when being wrapped around tight edges, like stems and transom corners, sometimes resulting in bubbles where it pulled away. However, if you cut strips of cloth on a bias (diagonal to the weave) you can get the strips to wrap cleanly around just about anything, like the tip of this kayak paddle or a sharp stem.

prijon-tip.jpg

[ShorelineJohn]

I have had very bad results doing that. Mater of fact I think its one of those mistakes you only make once. In my shop I can get away with the last thing I do is epoxying but outdoors, covered in Seattle in the summer the dew will get it. It could be soft and milky white in the morning, just not worth the chance.

[DayTripper]

Its interesting seeing what different concerns people have.I have done some glassing in a carport and outgassing wasn't on my mind,rain coming in was more of a cause for anxiety.

Yes, rain blowing in would be a disaster. Another consideration to be aware of in a carport. Thanks.

[DayTripper]

I like to glass in the morning, before it gets too hot. Usually I'm still going in the full sun though. The epoxy goes on fast, each batch is only in the pot for a few minutes before it gets spread out on the cloth.

I will start glassing at or just before sunrise. Thanks.

[DayTripper]

A couple of other things which may or may not be needed in this case, but are worth being aware of:

When glassing over complex shapes the cloth will often drape and conform better if you go in before you begin saturating it and trim off the woven selvedge edges. It tends to free up the weave a bit, allowing the yarns to move on themselves, parallelograming slightly where needed, reducing tension and helping the cloth stay flat and tight to the surface.

Will be sure to trim off any woven edges when dry fitting the cloth.

Glasscloth doesn't do very well when being wrapped around tight edges, like stems and transom corners, sometimes resulting in bubbles where it pulled away. However, if you cut strips of cloth on a bias (diagonal to the weave) you can get the strips to wrap cleanly around just about anything, like the tip of this kayak paddle or a sharp stem.

prijon-tip.jpg

Probably a worthwhile exercise to practice making the cuts at the transom corners using some scrap fabric first.

Thanks.

[DayTripper]

I have had very bad results doing that. Mater of fact I think its one of those mistakes you only make once. In my shop I can get away with the last thing I do is epoxying but outdoors, covered in Seattle in the summer the dew will get it. It could be soft and milky white in the morning, just not worth the chance.

I'm going to start glassing in the morning so the next morning's dew will not be a problem. Thanks.

[adamarthurryan]

I will start glassing at or just before sunrise. Thanks.

Good on you! I can never seem to get going much before 10:30 am.

[DayTripper]

DayTripper said:
I will start glassing at or just before sunrise.

Good on you! I can never seem to get going much before 10:30 am.

You must be retired. I am and starting work at 10 am is my usual routine.
"The best thing about being retired is getting up when you're done sleeping" ... 😎😉

[Rigadog]

For curves and abrasion resistance I like Xynole or dynel

[pez_leon]

As a fellow fiberglass novice I will make a recommendation against using peel ply here, particularly if it’s your first time trying this stuff. I just used it for a few small joints and struggled to accurately meter epoxy. I resented cleaning up the few small areas that I overfilled. Wouldn’t want to learn this the hard way on a complete hull! I am going back to successive thin coats, as described by Todd above.

Have you read Epoxy Basics by Russell Brown? Best five dollars I’ve spent in a long time.

- James

[DayTripper]

As a fellow fiberglass novice I will make a recommendation against using peel ply here, particularly if it’s your first time trying this stuff. I just used it for a few small joints and struggled to accurately meter epoxy. I resented cleaning up the few small areas that I overfilled. Wouldn’t want to learn this the hard way on a complete hull! I am going back to successive thin coats, as described by Todd above.

Have you read Epoxy Basics by Russell Brown? Best five dollars I’ve spent in a long time.

- James

I've watched Russell Brown's youtube video on fiberglassing hulls. He is a master of fiberglassing using epoxy.
One thing that he did in that video was quite different. He wrapped the bottom cloth only about an inch on the transom. Logic was to sand that overlap off and do the same thing when glassing the transom. The meeting point of the bottom cloth and the transom cloth is only at the corner joint of the transom/bottom which eliminates having to fair the overlapping cloth. In other words, no strengthening of the bottom to transom joint using overlapping cloth.

Regarding using PeelPly, I already bought it so will have a learning experience. Will post what happens.

Thanks.

[Todd Bradshaw]

The peelply is clearly the thing most likely to screw up your first glassing job, and it's cost is nothing compared to the cost and effort that would be required to fix a bad fiberglassing job. Honestly, you aren't experienced enough with fiberglass to expect to be able to do it blind, where you can't clearly see what is happening under that stuff.

[DayTripper]

The peelply is clearly the thing most likely to screw up your first glassing job, and it's cost is nothing compared to the cost and effort that would be required to fix a bad fiberglassing job. Honestly, you aren't experienced enough with fiberglass to expect to be able to do it blind, where you can't clearly see what is happening under that stuff.

My plan is to epoxy the cloth like how Russel Brown does in his youtube video. Then apply the PeelPly over it. Will strive to have the cloth correctly saturated before the PeelPly is applied. I'll glass just the bow plate first to see what the result is. If OK, then the transom. If both OK, then the rest of the boat.

[adamarthurryan]

You must be retired. I am and starting work at 10 am is my usual routine.
"The best thing about being retired is getting up when you're done sleeping" ... 

Ha, sort of. I set my own schedule, which means I start my work day about when the sun goes down and there aren't so many interesting things to distract me. Works pretty well in the winter, but it's hard to get everything done this time of year.

[DayTripper]

Have you read Epoxy Basics by Russell Brown? Best five dollars I’ve spent in a long time.

Where did you buy Epoxy Basics for five dollars from?

[pez_leon]

My mistake! It is $6.00 if you can accept the digital format. Even as someone who loves printed books, I think this one is short enough that you can get by with the digital copy.

http://ptwatercraft.com/ptwatercraft/EPOXY_BASICS.html

[DayTripper]

My mistake! It is $6.00 if you can accept the digital format. Even as someone who loves printed books, I think this one is short enough that you can get by with the digital copy.

http://ptwatercraft.com/ptwatercraft/EPOXY_BASICS.html

Thanks. I just bought and downloaded a copy.