: Since you only got 35:65 (epoxy:glass) with biaxial using a vacuum, I think
: these figures are in error.

: 35:65 is usually regarded as good bagged work with biaxials.

: 40:60 is good bagged work with satin weaves.

: 50:50 is good bagging work with plain weaves.

George,

At least try to be coherent when you attempt to argue against a result you don’t like. If “35:65 is usually regarded as good bagged work with biaxials”, then my result was consistent with good bagged work. So why would the other values be incorrect, except for the fact that they refute what you wrote in a previous post? I followed the same standard to measure the fiber content for all of the samples. I conditioned all of the samples for the same period of time in the lab. I used the same analytical balance to measure the initial and final masses. I used the same pyrolysis conditions for initial burn-off, and I used the same furnace for final pyrolysis of all carbonaceous material (actually, I did several samples in the same day).

If the hand lay-up fiber content that I attained was better than values that are “usually regarded as good bagged work” then the rational conclusion is that bagging single layers of light woven material will not offer an advantage. Yes, I found that out through experience. Furthermore, the values you mentioned are good target ratios when bagging. One could easily obtain such a high fiber content that the lay-up would be weakened, hence the problem of resin starved regions.

Perhaps you don’t have much personal experience with biaxials. What I have found is that they tend to have more resin rich voids between fiber bundles than plain weave. Although the fibers aren’t crimped around the crossing bundles, they tend to clump together leaving significant space between bundles –even with vacuum bagging. This leads to a bit less efficient use of resin than any books or product literature will let on to. Therefore, you can obtain as good or marginally better resin to glass ratios with single layers of light woven goods, than with heavier biaxials. Even so, the straighter fibers in a bagged biaxial will result in better mechanical properties, even on a weight-normalized basis.

The samples were good, the data was good, and the results were correct. Even if you don’t like it.

Sam