Which is stronger?

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Which is stronger?

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Junior	Junior posted 7 Years Ago HOT Topic Details
Group: Forum Members Posts: 73, Visits: 473	Just a quick question, is there any difference in strength between 1 layer of 500g fabric compared to two layers of 250g fabric?
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Steve Broad	Steve Broad posted 7 Years Ago HOT Post Details
Group: Forum Members Posts: 408, Visits: 4.1K	Assuming we are talking about a 2x2 twill or similar, not really. The main advantage of using two layers is the option of rotating the layers relative to each other in order to adjust the bending resistance characteristics. The main advantage of using 500gm fabric is that it will cost only a little more than one layer of 250gm, so the cost of 500gm of material is almost halved. You may find that when using one layer only that there will be pin holes that extend through the material, ie it will look like a star map when held up to the light :-) Two layers will greatly reduce this possibility, but not necessarily remove them all.
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Junior	Junior posted 7 Years Ago HOT Post Details
Group: Forum Members Posts: 73, Visits: 473	+x Steve Broad - 8/31/2018 8:26:22 PM Assuming we are talking about a 2x2 twill or similar, not really. The main advantage of using two layers is the option of rotating the layers relative to each other in order to adjust the bending resistance characteristics. The main advantage of using 500gm fabric is that it will cost only a little more than one layer of 250gm, so the cost of 500gm of material is almost halved. You may find that when using one layer only that there will be pin holes that extend through the material, ie it will look like a star map when held up to the light :-) Two layers will greatly reduce this possibility, but not necessarily remove them all. Ok, so as an example.. 1 layer of 1200g biaxial fibreglass, or 2 layers of 600g biaxial fibreglass. 1 layer works out cheaper, but will it be as strong?
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Steve Broad	Steve Broad posted 7 Years Ago HOT Post Details
Group: Forum Members Posts: 408, Visits: 4.1K	+x Junior - 8/31/2018 8:31:36 PM +x Steve Broad - 8/31/2018 8:26:22 PM Assuming we are talking about a 2x2 twill or similar, not really. The main advantage of using two layers is the option of rotating the layers relative to each other in order to adjust the bending resistance characteristics. The main advantage of using 500gm fabric is that it will cost only a little more than one layer of 250gm, so the cost of 500gm of material is almost halved. You may find that when using one layer only that there will be pin holes that extend through the material, ie it will look like a star map when held up to the light :-) Two layers will greatly reduce this possibility, but not necessarily remove them all. Ok, so as an example.. 1 layer of 1200g biaxial fibreglass, or 2 layers of 600g biaxial fibreglass. 1 layer works out cheaper, but will it be as strong? Good question. Again, I don't think that there would be much, if any, difference. However, you have have difficulty in thoroughly wetting the 1200gm FG which would result in a weaker composite. Personally, I would go with 2 x 600gm if using cloth this heavy.. What I forgot to mention is that an advantage of using lighter cloth is that it is easier to drape and conform to a mould's shape.
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