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?

Thanks for all the help... I just ordered my 17 oz biax and I will be using epoxy probably 2-3 layers and then some spiderWeb ribs in the bottom of the bilge.

I am also needing a lay up schedule for a boat bottom. What did you learn.

thanks

Depends what resin you are using, if polyester you to alternate cloth with mat from what i understand. Using epoxy it doesnt matter but mat is weak so it makes no sense to use it. I was told that i could either do around 4-6 layers of 8 oz cloth or 2-4 layers of 17 oz biaxial. This is what i am doing for a deep area of delamination. I tend to go overboard so i will probably be doing an additional layer of 17 oz biax over everything and then putting some spiderweb ribs in the bottom of the pan under the engine.

One thing i did notice when i was doing all this is that the tabbing that is on the stringers (24 oz roving) really made the area of the hull around the stringers way way stronger than the rest of the hull which was made out of numerous layers of cloth and matt, thats why i decided to lay biax over everything to strengthen it up.

Now im just waiting for my glass ordered it last night so wont be laying glass till next weekend

I will try to add to this thread when i get back by my computer. Been away and only have my droid phone. Did you order a matless 17 oz biax?

Yep matless biax 17 oz. Any help appreciated!

Also i have been wondering, what application is 24 oz or 18 oz roving more desirable than 17 oz biax? is the 17 oz biax considered stronger than 18 or 24 oz roving??

The 17 oz biax is really the only fabric you need. Roving is an outdated fabric that isn't really used much anymore. Epoxy likes a linear non woven fabric, the crimping in a woven fabric takes away some strength.

Thanks for the reply.

Any tricks for prepping existing 24 oz roving for additional glass without grinding it down too much, its hard to get the paint out of the divits and get it prepped

Sandblast it clean