Single 4oz vs 2 layers of 2oz?

Forgive me for having to ask, I tried searching but found nothing. 

I am interested what the community thinks about using more layers of lighter cloth VS fewer layers of heavier cloth?

I can only assume more layers would be stronger and heavier, but I wonder if its really that simple?  Am I overlooking anything that those with experience can elaborate on?

I am thinking of using 2 layers of 2oz (total) on my deck as opposed to a single 4oz (for a performance/short life shortboard).

 

 

Give me a sensible reason WHY two layers of 2 oz. are better than one layer of four??

I dont know either. I have to assume multiple layers are better in some way as the ENTIRE industry seems to use at least 2 layers of something on the deck.  Hence my question.  I also am assuming that  there would be more surface area of the glass and thus more chemical bonding to the resin at the atomic scale, more cross hatching of threads for more strength, three ‘‘layers’’ of resin, less chance of pinholes when using a single resin coat. etc.

I liken it to using more rebar (thin gauge) in concrete as opposed to less rebar of a thicker gauge.

I am thinking of replacing a 4oz cloth with 2 layers of 2oz.

Do it.        It  IS stronger.   

Puncture resistance of double vs single layers has been tested in a quantified manner and improved puncture resistance in the double layers has proven to be the case.  

The problem you will likely encounter is the weave of 2oz cloth and it’s ability to conform to tight curves when doing overlaps. Unless you resort to multiple relief cuts, the stuff is likely to bunch up as you progress around the nose and tail areas.

As to why two layers are better than one… I think it has something to do with the way individual strands of cloth in one layer back up the other layer so as to provide better coverage between the weave.  A single layer of heavier cloth will end up with more gaps between the warp and fill fiber directions.

 

No as simple, depend weaving type, kind of stress, resin tuning. But because surfboards skins experiment flexural and compression stress 2 layers can be better.

Also, I believe there are more, smaller glass fibers per square yard in 2 oz than 4 oz.  If so, this should create more surface area of fibers bonding to the foam and each other between layers.

EDIT:  Assuming the fibers are circular, a smaller diameter fiber will have a greater surface area to volume ratio than a larger diameter fiber.

A normal deck consist of one layer of four ounce and one layer of six.  Performance shortboards  are sometimes done with two layers of four on the deck.  So if you are speaking of the deck;  What would be the point of two layers of two ounce substituted for the four combined with the six or another   layer of four.  Your deck will be multilayered anyway.  So the strength is already there.

Also if you did away with the four all together and did straight 2 oz. with no six you would need four layers of 2 oz. to equal a double four.  But don’t mind me.  Do a 10 oz. deck(single 4 & single six) with straight 2 oz.  let me know how it goes trying to lay up five layers of 2 oz.

It definitely has merit.  All one has to do is spend 2 minutes perusing the Thayercraft website to get all kinds of ideas.  When Ben Thompson was doing his experiments, I remember him swearing he was going to switch to triple-3 oz on the deck, laid with offset fiber orientations.

As has been pointed out, the trickiest part may be figuring out exactly which weave and finish you want.

If you want a strong deck use a layer of “S”.  Six ounce E-- four ounce S.  problem solved.  Quite a few industry types are specking a layer of S these days.

Becuase I am making a lightweight shortboard and considering a total of 4oz deck.  I am thinking of using 2oz Innegra, and 2oz E (or S) cloth.  This is the reccomended schedule per Innegra.

Having had similar ideas in the past, in my garage I have two large rolls of 2 oz glass, neither of which I am using any more.   Maybe for special applications, but in general, plain weave 3.7 oz glass (commonly called 4 oz) with the right thread count is just more efficient.

S glass is great stuff, I just wish I could find it cheaply again.  Prices on it are too high for me.

 

Hopefully this link will work for you.  Benjamin Thompson and George Gall did some great work on this. I am unable to open the chart on this but seem to remember a major improvement using 2 layers with alternating weave directions…

http://www.swaylocks.com/forums/tests-results-13-unique-constructions

I’ve done multiple players of lighter cloth and opposing off-axis orientation, and I believe it works.  That includes the use of S-glass.   I’ve done innegra and it works, too.  But innegra is not light  - even under vacuum  - so you can put that one out of your mind.     

I think your choice of core and resin is more significant to the result than your choice of glassing cloths.   I think that more core + less cloth is better than less core + more cloth.  

But your mileage may vary.  

Perfect, thank you so much.  Pretty much confirms it for me, more layers of lighter cloth, preferably at angles to each other is superior to fewer, heavier cloths. 

Where’s the water?  My horse needs a drink.  Or is that koolaid??

Plenty of water and plenty of Koolaid to be had.  

Depends on where you stable your horse.

…surfboards fiberglass only come in 4oz and 6oz. All other fiberglass is not for surfboard application. Of course all use 7.5 in wide classic heavy longboards, fins, 2oz, etc, but the quality is not the same.

Hey mate,

Whats your thoughts on inegra for surfboards? (sorry to hijacking) 2oz plane weave

Ta