Fiberglass question

[Marcel1952]

Again a newbie question, but now about material.

I read alot of post and watched a lot of videos about transom, stringers and deck repair.
Great information and good to see that I'm not alone.
In the posts and videos they talk about 1708 biaxial polyester mat.
I know this means 17 oz for square yard with 8 oz per square foot csm.
However I live in Sweden so need to convert this to the metric dimensions, so it would be then 450gr/m2 biaxial and approx. 280 gr/m2.

Now the problem, I can only find here localy biax 450gr/m2 without CSM.
Would this okay to use this on my stringers and transom, without the CSM and lay a layer of 300gr/m2 of CSM between the biax layers?
Also I found biax 600gr/m2, is that beter to use?

Need some advice.

 

[DeepBlue2010]

Your calculations is a little off. 1708 doesn't have 8oz/sf CSM. Rather it has 3/4oz per square foot of CSM

0.75oz /SF = 228.8 g/m2

and 8oz/sf = 2441.2 g/m2 not 280 as you calculated


17oz/Squre yard = 576.4 g/m2 Not 450 as you calculated

 

[Woodonglass]

600gr/m2 with a Layer of 450gr/m2 CSM
This link has some good info..Fabricating Decks, Stringers, and Transoms

 

[DeepBlue2010]

Based on the calculations above, and if you want to stay closer to the 1708 fabric, you need to use the 600g/m2 bi-axial and the closest to 228g/m2 CSM you can find

 

[Marcel1952]

Foot, yard, oz, inch, I mix up everything but thanks Deep, glad you corrected this.
Also that link is great info and I think I now have a plan and start getting the materials in.
A lot of 600gr/m2 and 450gr/m2 CSM. :joyous:

Instead of 1 layer of 1708 I use 1 layer of 450 gr CSM and a layer of 600 gr biax to get the same result is that correct?

 

[DeepBlue2010]

450g/m2 csm is equivalent 1.5oz csm which is twice as heavy as the layer included in 1708 fabric. You can use it if you want, it is not wrong or anything. However, if you want to recreate the 1708 out of whatever available in your country, you need to use lighter csm

For stringers and transom, you need at least two layer of bi-axial and 2 layers of csm. The laminate schedule would be

CSM
Bi-Axial
CSM
Bi-Axial\

 

[gm280]

I would suggest that you could order it from USA and have it shipped. But that stuff is very heavy and the shipping cost would be huge... So most anything you can get close to the material suggested will work. Trying to find exact material weights is not necessary, but something close is all it will take. And if that means you have to use separate layers, then have at it. JMHO!

 

[Marcel1952]

Thanks all for the replys.
I will see if can be as close as possible to the 1708.
If it's close, it's definatly 200% better than off factory because at the inside of the stringers at the back there was only 1 layer glass that was thinner than a newspaper sheet.:facepalm:

 

[Woodonglass]

Another note make sure to saturate the wood with resin first making sure to soak the edges and then when it tacks lay down another coat of resin and then lay down the CSM on top of the WET Resin. Dab don't brush the CSM into the resin forcing it up thru the strands from the bottom and then add more resin where needed to make it go clear. Start in the middle and work towards the edges. Or use a 4" nylon roller and pour some resin on top first and roll it out to the edges. Don't over roll it and Don't use to much resin. When it goes clear you're done!!! With fiberglass less resin is best. Lay the fabric down just as soon as you get done putting down the CSM. No need to wait for it to cure and it's actually better if you don't. You'll get a much stronger bond.