Fabric-Resin % Data Test

General Composites Discussions Composites Talk
#1

Hey all, I just finished a little experiment / sample / data / test. lol I’ve been infusing now for a while but never really tested to see what the final ratios and thicknesses are at the end of the infusion. So with that said I made up some data samples as follows. I just used relatively small sample squares about 4"x4" with the exception of the staged thickness samples that were about 10"x2.5"

Infused with Derakane VER catalized at 1.5%.
Vacuum Held at 26.5HG (Modified Fridge pump that does pull a full 29")
Full infusion took only 4mins

[ul]
6oz Fiberglass 5 Layers staged thicknesses
63.42% Fiber
36.58% Resin
Before- 7.8g
After- 12.3g
Diff- 4.5
[/ul]
[ul]
5.7oz 2x2 Twill CF 4 layers staged thicknesses
61.27% Fiber
38.73% Resin
Before- 5.3g
After- 8.65g
Diff- 3.35g
[/ul]
[ul]
5.7oz 2x2 Twill CF 6 Layers
62% Fiber
38% Resin
Before- 6.82g
After- 11g
Diff- 4.18g
[/ul]
[ul]
Kevlar Hybrid 2x2 twill 3layers
53% Fiber
47% Resin
Before- 4.35g
After- 8.09g
Diff- 3.74g
[/ul]
[ul]
Texalium 3 layers
68% Fiber
32% Resin
Before- 4.12g
After- 6.0g
Diff- 1.88g
[/ul]
[ul]
Plain Weave CF
58% Fiber
42% Resin
Before- 3.08g
After- 5.27g
Diff- 2.19g
[/ul]

#2

Thank you for these facts! I take it you did a burn off test to get these figures?

It appears that with VIP you end up with less that the ideal 50% to 50% ratios but I’d like to see an impact and destruction test between those and a 50% to 50% resin to reinforcements comparence test.

Thanks again!:cool:

#3

The ideal ratio is definitely not 50/50. That would be a tremendous weight penalty when building something like a yacht or plane.
The accepted optimum ratio is generally 30-40% resin.

Thanks for taking the time to post these test reults. There can never be enough info like this.

#4

I should add that we often achieve 32-35% resin ratios when infusing large parts using multiaxial fabrics.
The lack of crimps reduces resin consumption, and produces stiffer structures.

#5

Burn off test?? Don’t think so, weighed before and after on a digital scale.
optimum fiber content is considered to be 60%-70%, which is what most pre-preg manufactures strive for.
The texalium result might be off due to the binder used to hold the weave together. During infusion that binder probably gets “washed” away.
Wish I had a sample of 100% Kevlar instead of just the hybrid fabric.

TET, I’m going to try the test again when I get some woven and other fabrics in stock

#6

Well, maybe I’ve been into this too long as 50/50 was always the target…I guess and old dog can learn too just as I tell my students!

Burn off test is where you weigh the reinforcement, lay it up with the resin binder, weigh it and burn it off in an oven and weigh the left over which is the reinforcement. Standard of the industry.

PM me your mailing address and I’ll send you some 100% Kevlar samples.

#7

ahh cool, so it only burns the resin. makes sense, i guess that removes other variables that can be in the initial weight?
I think for wet lay-ups a 50/50 is ideal, and from what I’ve read actually pretty hard to accomplish

PM sent, thanks for the offer :slight_smile:

I’m wondering what things could change to get the ratio closer to that 70/30 with full even distribution. Adding a layer of “multiaxial” like TET suggested, or changes in flow media, peel ply etc.
That would be cool if I could come up with a system that is on par or rivals pre-preg :eek:
Any thoughts??