Laminate Sample

[@TheGreatOldOak]

Thanks for making more videos! I remember binge watching them out of fascination/procrastination.

[@foesfly3047]

For someone who ‘doesn’t know what he’s doing’, you have an admirable, experience-earned, knowledge base. Thank you for posting 😎🎩♠️

[@russellmiller2564]

“Take it for what it’s worth, I don’t trust the equipment calibration and I don’t know what I’m doing!” Just that classic New England sarcastic humor we all love you for

[@foesfly3047]

Russell Miller, I thought exactly the same thing 😎🎩♠️💙

[@johnlithgow5792]

As a newbie, these videos are incredibly interesting and helpful. These last two were particularly useful to see the comparison between two similar layups. I'd be really interested in similar comparisons. For example, how much impact do different weaves vs stitched biaxials of similar weights have on panel strength.

[@ExploreComposites]

This is interesting to me too as a way to build better intuition about material properties. I am going to try to do more comparisons in the future. So many variables!

[@russellmiller2564]

On a more serious note, did you post cure these samples at all? The machining of the coupons seemed like the answer is likely no… I’ve really found with pro-set it needs a legitimate postcure for decent secondary processing, otherwise it just goes gummy And finally, were the cure conditions consistent between the two samples? Something else a post-cure would help remove variables with

[@ExploreComposites]

Great point! These were treated similarly but didn't receive a post-cure above 35C - they're also different resins. The gummy machining is as much the core as the resin - it's very rubbery - and I was using a little burr cutter which made it worse. I will make sure to address cure in future videos about testing because it is an important detail. I just figured that at this density and skin weight, the core shear would be the critical failure and was really looking for any impact of full cells. I have seen reference to 5-10% increase in shear properties from resin in core kerfs/slices and wanted to see if it would show up here. A significant number of samples and failure to remove other variables calls into question even the slight appearance of a pattern though!

[@russellmiller2564]

@@ExploreComposites certainly makes intuitive sense to have improved core shear properties.... lots of little squares held only on the faces by the laminate vs lots of little squares held on the faces by the laminate and fully encased in the matrix..... the last one please for me! That is until you realize how heavy infused cored structures are....

[@imusuallycorrect]

I am using PET core for a job I'm doing right now. It's horrible! I have to shape it and bevel it. The way the sheets are made and then sliced means there are parts harder than others. So when it is sanded the soft parts sand easy and the hard remain. This is leaving a wobbly line! In the video you mentioned the infusion mesh took about 90 grams per square ft. If one sq ft = 0.0929 sq meters then that is about 968g a sq meter. That seems very high - is my maths correct?!