Hull layup schedule??

sparky774 · Aug 6, 2012

Im wondering what kind of schedule should i use for laying up repairs in two areas that i ground out heavily, they were cracks approx. 1 foot long which had an area approx 6 inches of delamination around them. I have completely ground out all delamination and i was going to use 17 oz biaxial cloth with no mat and just build up like that sort of a terrain map style build up then i was going to glass over everything with 24 oz roving.

Im pretty much a noob to layup schedules but i do fiberglass repairs at work all the time so i do have some experience, just not in heavy structural areas like a hull.

Im thinking 17 oz biaxial is maybe to heavy for building up in this area? I would like to match the number of layers i ground out. i ground out maybe 6 layers of cloth/matt before hitting solid glass. Im trying to figure out what weight glass the factory would have used in this area. Also is 18 oz a better idea for glassing over everything or should i go all out and use 24 oz?

The boat is a 24 foot excalibur cigarette style boat.

Woodonglass · Aug 6, 2012

Re: Hull layup schedule??

Do you have access to the inside of the hull? Are you using Poly resin? VinylEster, Epoxy? You did not mention CSM. If using Poly or VE you must use CSM between each layer of Cloth for proper adhesion. Approx. how thick is the hull? Got any pics?

sparky774 · Aug 6, 2012

Re: Hull layup schedule??

Yeah i can get some pics tomorrow. The cracks are on the inside of the hull ONLY.

They are symmetrical cracks (or they were they are completely ground out now.) in the engine bay about a foot and a half up from the bottom of the VEE on both sides.

Im using epoxy.

Hull is about 3/4 of an inch thick ground down honestly about 1/4'' or more maybe closer to 1/2'' down in the deepest spots.

I tried to level out the area a bit and contour/smooth it to make layup a simple oval shape. The hull was layed up with polyester (pink) with numerous layers of cloth and matt (is this 1708 biaxial??)

sparky774 · Aug 8, 2012

Re: Hull layup schedule??

anyone else have any advice... trying to get the pics up right now

Trooper82 · Aug 8, 2012

Re: Hull layup schedule??

WoG will steer you in the right direction...he just needs all the info first...

Woodonglass · Aug 8, 2012

Re: Hull layup schedule??

best way to post your pics is to open a free photobucket account and load your pics to it. Then copy and paste the IMG code to iBoats. It's almost impossible to help you without pics. If you are using epoxy you do not use 1708 or CSM you only need to use fiberglass cloth. You could use 3-4 layers of 8 oz cloth or 2 layers of 1700 biax. Epoxy is very strong and with the biax you would have an extremely strong patch. A 3/4" thick hull would be very rare. Post the pics so we can see what you're dealing with.

sparky774 · Aug 8, 2012

Re: Hull layup schedule??

Woodonglass · Aug 8, 2012

Re: Hull layup schedule??

Where is this area?

sparky774 · Aug 8, 2012

Re: Hull layup schedule??

This is directly below the engine on the sides of the vee above the pad, replacing my motor and i opened this can of worms, better to be safe then sorry though with a nice big hole in my hull and my new engine sitting at the bottom with the rest of my boat hah. Here is a picture of the boat just to see what were talking about

So how bad is it lol....

Oh, btw you are right the hull is by my estimates approx. 3/8 inches thick or a little bit more.

Woodonglass · Aug 8, 2012

Re: Hull layup schedule??

Ok, your boat is made from Polyester resin. You do not need to use epoxy. Not saying you can't, just saying you don't have to. Most people here on the forum don't. The normal layup for this type of repair would be to wash the area down well with acetone and then apply a layer of 1.5 oz CSM followed by a layer of 1708 biaxial cloth and then continue alternating this until you reach the desired height. I'd say you would need not more than 2 layers of each. You mix the resin with MEKP @ 1.5% ratio. Pretty basic and similar to what your used to. First patch about 1 1/2" larger than the cracked area and the the final 1 1/2" larger than the 1st patch. If you use Epoxy, it's all the same except you just use cloth, NO CSM just use Biaxial cloth. You can use woven roving but the biax is much easier and lots stronger.

sparky774 · Aug 8, 2012

Re: Hull layup schedule??

Ok great but i already have all the epoxy so unless there is something better about polyester i would prefer to use it. If i do use epoxy what kind of cloth weights and layup should i use? So i should not try to match the contour of the area ground out? i was thinking like match the glass weight starting with a small cloth like 8x4 inches then make each layer bigger and bigger until the area is level. Is that a bad idea.. maybe not very strong?

Woodonglass · Aug 8, 2012

Re: Hull layup schedule??

Ok, How "Thin" is the hull now in the area that you have ground down? I assume it's feathered toward the center somewhat? So.. the first piece of cloth will be the smallest and then each successive piece will be larger. You need to determine how many layers will be needed to bring the hull back to its original thickness. Using epoxy I'd say you could use 2 to 3 layers or 17 oz biax or 3 - 5 layers of 8 oz. I would make them what ever size needed to equally fill the area. Kinda like a Target if that makes sense.

sparky774 · Aug 8, 2012

Re: Hull layup schedule??

Yep i know exactly what your saying, i picture a topographical map with the radiating circles outward. It is pretty thin in that area i beleive i tried to capture it with the ruler like a straight edge over the area.. i think the white you see through it is gel coat, so i think im pretty close to the outside in some spots. I would say i am 3/4 of the way down through from the original hull thickness in the worst spots.

Im hitting the sack i will catch up on this tomorrow.

Thank you for the help, much appreciated

Woodonglass · Aug 8, 2012

Re: Hull layup schedule??

I think I'd use 3-4 layers of 8 oz. IMHO it would be much stronger. Just as long as it's close to the original thickness it should be good to go.

ondarvr · Aug 8, 2012

Re: Hull layup schedule??

Using epoxy on this repair you can just build the surface back up the same level as it was before and it will be much stronger than before the damage was done. Don't stress over the exact number of layers or covering it with roving, it will be more than strong enough.

sparky774 · Aug 9, 2012

Re: Hull layup schedule??

I have another question, when i am trying to tab onto existing roving (24 oz) do i need to grind the roving down so that all the paint stuck in the mesh of the weave is gone???? it seems like if i grind it down this much there is nothing left of the roving that was there and i am basically replacing it.

Woodonglass · Aug 9, 2012

Re: Hull layup schedule??

If you're just talking about specks and flakes then, I'd wash and scrub it really well with a wire brush and acetone. It'll stick. If it's coated then keep grindin.

Yacht Dr. · Aug 10, 2012

Re: Hull layup schedule??

sparky774 said:
I have another question, when i am trying to tab onto existing roving (24 oz) do i need to grind the roving down so that all the paint stuck in the mesh of the weave is gone???? it seems like if i grind it down this much there is nothing left of the roving that was there and i am basically replacing it.

Yup .. you have to prep it all the way down .. Properly speaking ..

YD.

Yacht Dr. · Aug 10, 2012

Re: Hull layup schedule??

Grinding sucks dont it

.. thats glass for ya

..

YD.

Decker83 · Aug 10, 2012

Re: Hull layup schedule??

Nice looking boat you have.
You or getting some of the best advice from some of the best gentlemen on i-boats. Follow what they are telling you and you will not go wrong.

Hull layup schedule??

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