r/Composites

I've been working with fiberglass and epoxy resins for my personal RC plane projects, but since I'm doing a lot of testing and prototype designs that get discarded during the design process, I feel increasingly guilty about all the waste and microplastics that come along with it. Unfortunately for the shapes that I want to make going with pure wood is just not an option.

I've been researching eco-friendly alternatives for making composite layup projects, and there are some for fibers (flax, hemp, etc.), which unfortunately have much reduced mechanical properties when compared to fiberglass, but still suitable for my use case.

However, I can't seem to find any decent alternative to epoxy resin that would make the final composite material naturally biodegradable, so using either of these fibers becomes a moot point. Closest thing I found was ecopoxy, which unfortunately is very expensive and almost impossible in retail quantities to get where I live (EU).

Can anyone suggest any decent alternatives that are fully biodegradable, affordable and have at least somewhat comparable mechanical properties to fiberglass+epoxy for wet layups? Anything better than paper+PVA glue is worth considering to me. I've found this paper that suggest jute fiber and shellac, which boasts quite impressive mechanical properties for such crude materials, but they used mechanical pressure and heat treatment to achieve that, which is not practical in home conditions, and I'm unsure of how much mechanical strength would be lost without it.

I have a gunite swimming pool that has a fiberglass coating over the gunite. There is a crack in the fiberglass coating on one of the walls, near the waterline.

I asked the fiberglass repair person what materials he plans to use, and he said:
Polyester-based resin matting
Polyester-based gelcoat

The repair person’s main business is fixing fiberglass boats with occasional swimming pool fixes. He mentioned he has fixed fiberglass pools before and had no complaints.

The water will be lowered for the repair and the material will be allowed to cure before the pool is refilled.

My main concern is health/safety after the repair is fully cured. Since this area will normally be submerged in chlorinated pool water that people swim in, are fully cured polyester resin and polyester gelcoat considered appropriate/safe for this application?

Are there particular chemicals or ingredients I should be concerned about, or certifications/specifications I should look for?

I don’t have the exact product names yet, but I plan to photograph the containers/labels when the contractor comes to do the work.

First timer here, i want to build a foam plug, finish it properly, build a female mold from it, and then build a few identical parts from that mold. sold of a small scale manufacturing project to build myself and. a few friends some parts.

I think I understand the how-to well enough, but am overwhelmed by the material/resin options. is there a concise source that can help me make heads or tales of this? i’d like to understand enough about differences that i can shop around and find the right products

I was making a part via VRTM, and I passed the leak test PERFECTLY, the gauge didn't move a single centimeter for 30 min wile I went off to do other shit. I then infused resin into my part, sat with it for 10 min to monitor, still had absolutely 0 leaks, then left for abt 20 min to continue my other project. When I came back my bag was completely depressurized and there was a thin cut about an inch long going down my vacuum line a few inches down from where my clamp was placed. My part was fucking ruined ofc, and not even my instructors with 10+ years of experience could tell me what the fuck happened. I'm like 80% a certain male student whom was lurking around my part the entire setup (and who's ego was def hurt that all of my parts always came out perfect when his didn't) was responsible for this. He was also suspiciously interested in staring over the instructors shoulder when he was pointing out everything wrong with my part AND he was quick to come up to me when I was upset and gave me an overdone condolences that my project turned out like shit and his didn't. There has always been a one sided competition between us and I think he was sick of "losing". Am I just paranoid? And if so pleeeeease give an explanation for wtf happened because I am hard stuck on finding an answer.

Shows modelling plies (applied to whole tank) the satck up is defined as [+-30,90]2s

I am trying to run a analysi with pressure as BC in this CFRP based SRM Casing project. but i am not getting the fibre direction correct, the dome area looks reallt wrong and how am i suposed to correct it,The rosste is correct - the x axis is along the comspite SRM casing x axis and Y axis is along the radius.
i got to knwo about CADWIND/CADFILL softwares - These are not avaliable - so how can i properly manage the analysis ?