Thread: 2 layers of Fibreglass ???

Originally Posted by Mickj

Hi Guys,

My Navigator build is coming along nicely. Have a look...
http://picasaweb.google.com.au/Micks...sfordNavigator

I'm at the stage where I'm thinking about sheathing part of the hull in fiberglass. There are some sections where I would like to put 2 layers of fiberglass on(mainly the bow section). I have only just discovered that my boat doesn't have a brake, so I figure I'll be bumping into things(a lot!!), hence the need for 2 layers of fiberglass.

Do I put both layers on at the same time, or do I apply 1 layer at a time, filling the 1st layer before putting on the seconf layer?

I'm open to all suggestions, so please feel free to tell me where to go.

Cheers


Mickj

What a beautiful boat Mick! I glassed the hull of the boat that I built, so I'll report my experience here. I also glassed the foredeck because I knew that it would be subject to wear and tear from such objects as anchors. There are various cloths, of course. I used West Systems epoxy, which is just fantastic. You can choose the rate of the hardeners and keep mixing it as you need it. Brushes on or rolls on over the glass like a dream.

You might want to consider the weight it will add, but for a sailing craft, I imagine that that would only be a plus. You can add layers easily, and here's the deal: If you roll the epoxy on the hull, apply the cloth, and then roll more epoxy on the cloth so that its wet, you won't have too many places to worry about at all.

Keep in mind that epoxy has different stages in its curing. As long as you apply a second layer while the epoxy is still in its "green" state (not tacky, and you can make an impression with your fingernail) then you are free to apply another coat (with or without glass).

I don't know what you mean by "filling" it. If the hull is perfect and flat and the stuff is put on well, you won't be repairing anything. At the end, once everything is cured, you will be lightly sanding the surface back before you put your finishing coats on top. I used a 2-pack Hempel's polyurethane on mine and believe me....it's tops. I pulled my boat up on many a sandy, pebbly and sometimes a bit reefy shore, but never once had to do anything to the hull. If you are using anti-fouling, do contact the manufacturer regarding how to apply over glass. Good luck and hope that helps!

Michael

PS- Just saw that you're here in W.A.. Send me a pm if you want to talk on the phone. I can give you information about where to buy the West Systems and glassing supplies at the best prices around, as well as applicators, rollers and such.

Howdy,

For what it is worth, it is very rare to damage the bow of a boat much. Usually it is so well oriented toward any loads that the thing you hit will be worse off.

I doubt one extra layer of glass will make much difference.

If you are commited I would generally do the second layer in the same process. It is best to wait for the epoxy to gel a little bit so the previous coat is held down a little bit and is not very mobile.

The last thing you want is TWO layers sliding around!!!

Good places for glass are where there is going to be serious long term abrasion. For example along the keel. The Navigator is a bit heavy to lift so it will be dragged up on the shore ... so an extra tape along the length of the keel or even the front half of the keel would be a more worthwhile strategy.

Best wishes
Michael

Hi Mick & Michael,

Thanks for your comments, much appreciated.

I'll probably do as Mick suggested and only place a 2nd layer of fiberglass on some strategic spots. I don't mind the extra work, but if the effort provides no extra benefit, then I'm happy to focus on something more worth while.

So Michael, you wet the surface before, you lay the cloth down ?
I assume this helps keeps the cloth flat on the surface.
Do you use any fasteners to hold the cloth while you're rolling the epoxy into the cloth?

When I mentioned "Filling", I was referring to the weave.
How many applications does it normally take you to completely fill the weave.
ie the surface is completely flat.

I'm using Bote Cote, and am finding that it is starting to behave differently
as the warm weather approaches ie Its hardening much faster now.
So I'm a bit weary about trying to do too much in one application.

I'm about 2-3 weeks away from having to apply the cloth, so I'll do as much preparation as I possibly can. No doubt I'll ask more questions as the day approaches.

Working with epoxy is very new to me, so I'm a bit cautious, especially with the changing weather. This will probably be the biggest 'single' epoxy job that I will be doing on the boat


Thanks for your help

Originally Posted by Mickj

Hi Mick & Michael,

Thanks for your comments, much appreciated.

I'll probably do as Mick suggested and only place a 2nd layer of fiberglass on some strategic spots. I don't mind the extra work, but if the effort provides no extra benefit, then I'm happy to focus on something more worth while.

So Michael, you wet the surface before, you lay the cloth down ?
I assume this helps keeps the cloth flat on the surface.

No... With normal woven cloth the glass will go through from the top OK. If you wet the surface it can be very hard to get everthing flat to start with. With heavier stitched cloths (biaxial triaxial, even heavy unidirectional) it can be hard to get the resin through so prewetting is needed in those cases.

So do it dry.

Oh ... The Navigator is a faux lapstrake boat. So you will need to do each plank separately. Actually I would consider doing the two bottom panels on each side and not worry about the rest. Just 3 coats of epoxy on the unglassed sections. But if you want to do the whole thing ... run fillets on the undersided of the laps on the outside of the boat. When you glass do the flat of the plank and go up onto teh fillet and trim off roughly.

Do you use any fasteners to hold the cloth while you're rolling the epoxy into the cloth?

Just bits of masking tape in strategic places. And be aware of the selvage edge in the manufactured edge of the cloth.. Just before starting to wet out look very closely and you will see three or four threads that are thinner than the others. They will not go clear and will leave a mark on the surface if they are not removed. You can simply pull them out of the edge of the cloth starting from one end.

When I mentioned "Filling", I was referring to the weave.
How many applications does it normally take you to completely fill the weave.
ie the surface is completely flat.

You only need the weave mostly filled ... I generally describe it as 95% ... most areas will not show much weave or just perceptible but a few areas you might see a little bit of weave. Generally it is filled a tiny bit better than you think it is.

I'm using Bote Cote, and am finding that it is starting to behave differently
as the warm weather approaches ie Its hardening much faster now.
So I'm a bit weary about trying to do too much in one application.

It is all in the handling... if it is sitting in the tray or tin or bag you won't get much working time. YOu need to get it out on the surface fast. Big flat areas you can generally do a quick spread with a squeegee (sand the corners to a small radius) and then finish with the foam roller. Another way is to do smaller amount and start from one end of the boat ... then when you run out of resin or it starts to go sticky, ditch it and make up another batch. As you get used to the process you will make up bigger and bigger batches.

I'm about 2-3 weeks away from having to apply the cloth, so I'll do as much preparation as I possibly can. No doubt I'll ask more questions as the day approaches.

Working with epoxy is very new to me, so I'm a bit cautious, especially with the changing weather. This will probably be the biggest 'single' epoxy job that I will be doing on the boat


Thanks for your help

A pleasure!

Best wishes
Michael

You might find some of this interesting/useful .. most of the relevant stuff goes with my plan sets.
http://www.storerboatplans.com/Faq/faqindex.html

Thanks for the advice Michael.
I think you saved me quite a bit of work.

BTW, I knew I was going to have some spare material left over, so I ordered a set of PDR plans.
Very Nice Work!!!. A lot of detail, and very well laid out. You must of put a lot of thought into the build process.

Anyway, thanks again for your help.

Cheers

Mickj

Cheers to you too!

Best wishes
Michael