Around with glass

[Sergi]

Hi there!

Do you think that this biax has enough thickness?

The supplier whom I bought from, said it is a 600g/m2 so it's in the invoice. But I find it a bit flimsy.

I have two suppliers nearby. The one where I bought this biax it's supposed to be experienced on boat application and technical resins, but the recent days they do more eolic stations than boats. In fact they tried to sell me whatever foam they pour inside the blades for my transom or stringers and advised against honeycomb on the deck. That seemed to me strange. Boat builders around don't buy from them. Not a cheap place. :cold:

They buy from my other nearby supplier, but it happens to be a paint store.
There they have CSM in three weights (300/400/500 gr/m2) some 90deg roving that they tell it's 800g/m2 (it's like the one that I took out from the boat) and they have combination.

The combination they have also seems to me light. but they tell... "uhmm label is missing, and it's on the wrong place, but I'm almost sure that is 600biax+300csm" Perhaps biax and combi seem always lighter than CSM and woven?
What is worrying me is that the biax it's 90deg plain square one and strands are clearly smaller that on the roving they also have, but I also find it lighter to be 600gr/m2.

It's the combination normally made with square biax or should I better stay with the biax on the image above+300g CSM?

I also have the handicap of dealing with imperial-international system units. And there are plenty of calculators online that throw wrong results.
As per my calculations a 1708 should be around 400gr/m2 + 200gr/m2. It's that correct?

Best.

 

[Bondo]

Re: Around with glass

I also have the handicap of dealing with imperial-international system units. And there are plenty of calculators online that throw wrong results.

Ayuh,.... Welcome Aboard Sergi,.... You've sure got Me confused....

Donno's I can Help,....
But if ya think the stuff you can get is too light, lay down More layers of it, to build the strength yer lookin' for....

 

[a1964rn]

Re: Around with glass

What type of resin are you using? Polyester oe epoxy? According to my calculations, what you have is lighter than 1708. 600 gm/m2 = 21.164 oz. per sq. meter. A sq. meter is 0.914 Sq. yd. 1708 is 25 oz. per sq. yard (17oz. of Biax + 8 oz. of mat). What you have is Biax without the mat, correct?
What are you going to use the foam for? Transom and stringers? Not sure I follow you on that.

 

[Georgesalmon]

Re: Around with glass

I'm a bit confused to cause I'm not used to metric. However to answer one of your questions; to me anyway Biax feels "lighter" because its a stiched fabric and the warp and weft lays flat unlike WR which goes up and down so to speak. Do what Bondo said, if you think you need more stiffness than add more layers. WR of the same weight/yd is stiffer (not stronger) when wet out than Biax beacause it is thicker.

 

[Sergi]

Re: Around with glass

Excuse me boys for not to be clear enough. And thanks for your responses.

@Bondo: I live in Europe, and there no-one has the fiberglass labeled in oz per sq yrd. Here It's all labeled as grams per square meters and vendors don't know what they're selling so they're not any help.
SI Units I was referring to the system you must use when you do physic calculations, that is metric. (err... well, I'm physic)

@a1...: I'm using Polyester. Even the structural glue I bouth is poly based.
Yes, by now I've biax without the mat at 600gr/m2, that as you write is 19oz and I also have 300gr/m2 MAT that would be half of it, 9,5oz.
Those I was laminating together, so 1909? But I feel that I'm wasting some resin in between layers.
(Btw If you put "600 grams square meter to oz square yard" in google it says 25oz)

I'm using the foam for both transom and stringers. I already opened a build thread, ff you want to take a look.

@George: I understand, so it's normal to biax to seem lighter by it's "ordered" disposition as opposite of csm. It's my first boat. So I don't really know how much is stiff enough nor when to stop. In fact, while repairing a hole I was thinking that the "patch" was thin. Only when it finally cured I saw that it already had 1cm of thickness.


This midday I went to the first shop and they told me they have combination at 800/300 gr/m2 or 500/450 gr/m2.
Both of them having the cloth layer not in +-45.
The other shop didn't have the roll labeled and was guesstimated at 500-600/300 gr/m2. And that shop is waaay cheaper.

What one's do you find more adecuate or common?

Today I'm laminating the transom and I want to know what is better.
Instead of gutting a full width layer of foam, I'm putting two layers with a layer or two of biax in between to give it a little bit of stiffness at the middle section where the hole is located. I will also make PB "inserts" for the outdrive bolt holes and some trough holes with a crossing glass layer every sq feet or so to avoid delamination.
After that glued in the aft mirror I'll put 2-3 layers of combination covering. Well that's what I guess I must do.

 

[Woodonglass]

Re: Around with glass

When using polyester resin it is required that you use Chopped Stand Mat between the layers of the Biaxial Cloth. If I was doing it I'd use 1.5 oz CSM and then a layer of the heavier cloth. Another layer of CSM and a final layer of the Heavy Biax. But, that's just me, others may have different opinions.