cloth or mat fiberglass for repair?

[ksubigbuck]

As you probably assumed, this is my first FG repair. There was some chipped gelcoat on the bottom of my boat's hull, and I sanded it down to reveal some delaminated glass. I ground outward until I saw no more delaminated glass, and I am now ready to build it back up. My question is, should I use mat or cloth for the repair, and why? I have both. The repair is on a step in the hull, and has to make a 90* upward turn, then 1" later it has a 90* outward turn, if that makes any difference. I'll probably finish it with Marine Tex.

Thanks,
Hunter

 

[ondarvr]

Re: cloth or mat fiberglass for repair?

With polyester resin use mat as the first layer and then the cloth, with epoxy only the cloth is needed.

Getting it to lay down around the corners may be a little tricky, but make sure you sand a nice round radius for it to follow.

Read the sticky at the top of this forum for more details.

 

[ksubigbuck]

Re: cloth or mat fiberglass for repair?

Good info, thank you! I will be using polyester resin, so I'll do 1 layer of mat first, then a couple of cloth. Then, I'll top it off with some marine tex.

Thanks again,
Hunter

 

[Bondo]

Re: cloth or mat fiberglass for repair?

so I'll do 1 layer of mat first, then a couple of cloth. Then, I'll top it off with some marine tex.

Ayuh,...

The Mat goes Between the layers of Cloth, when using Polyester resin...

What's the Marine-tex for,..?? It's Epoxy based,+ can cause some issues....

What's the final coating you're going to use,..??

 

[ksubigbuck]

Re: cloth or mat fiberglass for repair?

I'm using the marine tex because the repair is on a compound corner (a small step in the hull) and it was impossible for me to get the glass to take that shape. I used one layer of mat followed by two layers of glass to get the basic shape. I'm now going to get the rest of the shape by building up with the marine tex and sanding back to the hull's original shape. Does all of this sound right?

Thanks,
Hunter

 

[erikgreen]

Re: cloth or mat fiberglass for repair?

You need mat in between each and every layer of glass fabric to promote a good bond... it keeps a resin-rich layer from forming at the boundaries of the cloth.

Not sure how to proceed if you've already glassed on two layers of fabric next to each other... I'm sure the poly resin guys will say something.

Erik

 

[ksubigbuck]

Re: cloth or mat fiberglass for repair?

You need mat in between each and every layer of glass fabric to promote a good bond... it keeps a resin-rich layer from forming at the boundaries of the cloth.

Crap. I guess I could grind it all off and start over...but I really don't want to.

On another note, I really hate the mat. It is messy and sticks to my gloves and tries to pull away from the repair when I try to pull my hands away. Aweful stuff.

 

[Bondo]

Re: cloth or mat fiberglass for repair?

Ayuh,...

What are your plans for the Topcoat...??

If you're thinking Gelcoat,...
It won't stick too well to Marine-tex.... It's epoxy based...

If you're going with Paint,..... Nevermind...

 

[ksubigbuck]

Re: cloth or mat fiberglass for repair?

Yep, topcoat will be paint.

 

[leisjohn]

Re: cloth or mat fiberglass for repair?

Using the mat & cloth is a bit messy. I like using 1708 Bi axle it already has the mat attached. It's a bit more money but twice a strong as regular cloth.

 

[ksubigbuck]

Re: cloth or mat fiberglass for repair?

If I ever have to do this again, and I'm sure I will, I'll be sure to check out the biaxial cloth.

Thanks,
Hunter

 

[ondarvr]

Re: cloth or mat fiberglass for repair?

Biax is a very good product, but in most situations isn't needed and can be more difficult to work with when it comes to conforming to odd shapes or a tight radius.

 

[MrPhotographer06]

Re: cloth or mat fiberglass for repair?

i just put two layers of mat on top of each other because i ran out of cloth..

but i think it'll be fine. Its getting a short strand bondo on top...

 

[ondarvr]

Re: cloth or mat fiberglass for repair?

If its just the auotmotive bondo it won't hold up, you need something a little better, designed for marine type use.

 

[MrPhotographer06]

Re: cloth or mat fiberglass for repair?

Its short strand fiberglass bondo..

 

[badbowtie]

Re: cloth or mat fiberglass for repair?

So if using the biaxial cloth with poly resin you just use that every time or still need to use on then the other and what is the best to use for the top layer. And post a pict and lets see how it turns out.