Is some 1708 harder to wet out than others?

Hi all... I did a good bit of googling last night but could not find any info on this question so here goes!

I have been laying up some small skiffs out of a mold. After the skin out, the main laminate is 1708. Many many rolls of 1708 had all wet out the same, which I would say was easy. Basically a really heavy soaking with a 3/8ths nap roller would totally saturate the cloth in a few passes. Even most air bubbles would be eliminated with the nap roller. Occasionally I would need to fin roll some smaller bubbles.

Fast forward to last night when I opened up a new roll of 1708 (from the same supplier, North American Composites). The weave seemed really tight and the cloth seemed stiff. Compared to the previous 8 rolls, it was a nightmare to wet out. It certainly doubled the time if not more than the previous stuff.

I googled my fingers off last night about this... what gives? Thanks in advance!

 

Have you checked the weight? It might be heavier just labeled wrong..

 

I will give that a look later today when I get to the shop. I do remember reading "biaxial cloth" on the box as I ripped it opened. I don't recall ever seeing 1708 specifically... however 1708 is what I ordered and read on the invoice.

In the large sections I cut out for layup it did not feel heavier. I did closely examine it. Same strand size, patters, stitch, mat on one side... everything. It's just much tighter and stiffer.

 

Have you spoken with the manufacturer and or supplier?

 

The differences between manufacturers, and the difference in products within a manufacturers lineup can be significant.

Glass can also be affected by temperature, humidity, age, etc.

So yes, there can be huge differences in how it may work for your type of application.

 

The winding machine that makes the rolls is the most likely culprit. Somebody set the drag too tight.

Maybe unroll it and roll it back up on an old cardboard tube. Don't know if that will help, but it's worth a try.

 

Had a chat with the supplier today and thats the conclusion we came to. I will be switching brands on the next roll!

 

Who knows! I will see if that helps at all. Fortunately it was only a 120lb roll so eating the loss is not so bad as a 220lb roll... My supplier the taking a look into the different brands/ manufacturers to ensure future rolls are consistent.

 

Weight is the same... cut some test samples of the same size and they were identical.

 

It sounds like you got the wrong cloth, and the wrong finish. The tight weave is suspicious. If it doesn't look like the weave you have been getting, it probably isn't. The appearance should not change from lot to lot or manufacturer to manufacturer.
It should look like this:


The wetting problem is likely to be the finish, but tight weaves are also harder to work with. There are a lot of silanes and other finishes that are normally applied to the cloth to enhance wetting and bonding. The two links below provide a decent explanation of finishes and a long list of finishes. Not all finishes are compatible with all resins. In a nutshell, the finish molecules have two different ends, one bonds well to the glass and the other wets and bonds well to the resin.

Good general finish primer:
How Fiberglass is Finished and types of Finishes https://thayercraft.com/how-and-why.html
Laundry list of finishes and typical uses:
List of Finishes https://thayercraft.com/list-of-finishes.html

 

Had the opposite with a local supplier, picked up some 2415 after running low in my stash. Visibly looked like a different product, figure qc and required lot to lot variation must be different to other companies.

 

Ok so here is the difference between the two... they are both 1708. The sample on the right is what I am used to working with that wets out like a dream... the sample on the left takes more than double the time. I had a decent chat with my sales rep/ supplier. We eventually figured out what I was used to working with was from a different brand. Usually the sales reps do not care which brand of 1708 I get sent. However in this instance we will ensure the brand I order is consistent. I have a new roll coming this week so hopefully it all gets sorted out!

 

Did you notice any difference on resin amount you used on those two? Looking those samples makes me think the one on the left you get better resin/fiber ratio, ie stronger laminate. And it also looks more like the biaxial I'm accustemed to.

 

The sample on the right is much poorer quality construction. Weave is very inconsistent. May not comply with ISO.

 

The right side sample might be from the end of the roll so not a good sample..