Critique My Plan

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#21

I don’t even know how to do wet layup. The steps for making a hood through infusion look incredibly simple, so I can’t imagine things getting easier than that.

[ame=“http://www.youtube.com/watch?v=UgKvDw1E60E”]How to Make a Carbon Fiber Car Bonnet/Hood - Part 1/3 - YouTube[/ame]

[ame=“http://www.youtube.com/watch?v=YWbGx_BJVvM”]How to Make a Carbon Fiber Car Bonnet/Hood - Part 2/3 - YouTube[/ame]

[ame=“http://www.youtube.com/watch?v=P8ucNBRaBYs”]How to Make a Carbon Fiber Car Bonnet/Hood - Part 3/3 - YouTube[/ame]

And the guy that motivated me to start working with carbon fiber started with a hood as well. He was successful first try, and has been driving around with that hood on for several years now.

#22

Yeah I know those videos well, very good info there.

I’m not trying to turn you off infusion, I just think it’s much better to have a full knowledge. For instance you may go straight into the hood project and infuse your first part perfectly. But then you might have problems on the 2nd part. And you may not necessarily know what went wrong on the 2nd one… and may not know what went right on the 1st one…

By all means go ahead and get all your supplies and equipment ready, I just mention this “bottom up” approach to try and save you some potential frustrations down the line.

One thing is for sure though, if you jump in the deep end you will learn to swim fast! All the best with it!

#23

Thanks. Do you know of a good tutorial for wet layup? I’m sure there are tons online, but I might not know a good one from a bad one without experience.

#24

I don’t actually know of any wet layup tutorials online… I mean there are tutorials that show the use of wet layup, but none that are wet layup specific (that I’ve seen). When people say “fibreglassing” the default is wet layup, so just lookup fibreglassing vids and I’m sure you’ll find plenty.

This guy has some interesting videos on his channel: https://www.youtube.com/watch?v=GXzR17LktSg

I’ve never seen him do anything other than wet layup, so you could check those out. Note that some of his techniques would be considered “dodgy” by some… but it shows you what is possible, and he gets the job done!

I started off by reading Competition Car Composites. I found it good because it explained everything well, from the ground up, so you don’t get to the end of the book and suddenly find yourself saying “wait, how did he do that…?” From what I remember it focussed mainly on wet layup.

#25

Thanks so much! I’ve still got several months worth of deployment to go, so I’ll go ahead and start looking into this too.

I wanted to save money in the long run by buying in bulk, but now I’m starting to think of maybe buying just enough to infuse a hood, just to see how it goes. I’ll have lots of free time when I get home, so I could probably start the hood process and during the times I have to let it cure, I can try some smaller household-type projects just to get my experience up.

Other than screwing up the ratios when mixing chemicals, I’m quite confident I can knock out a successful hood in one try thanks to those videos. If I do mess up, it shouldn’t bother me too much. I’m already expecting lots of mistakes and “learning experiences”. Obviously if composites were cheap and easy, no one would be buying any finished products.

Also, I’ve been thinking about what herman said in posts #16 and 18. I really need to work with it at least once to have any sort of understanding about how many layers and what weight material to use for future projects.

#26

Haha, yep if it was easy, everyone would do it!

And yes, definitely try out some experimental/test layups for yourself. If you’re wondering what thickness a part needs to be, just do a small test piece - you’ll learn a lot from that. And it doesn’t need to be anything fancy, wet layup is probably fine for that in most instances.

Just don’t rush into making something until you have a firm understanding of each part of the process. And if you are using some new materials, do a small test part before applying them to a large job. Always test, test, test any new process or materials that you haven’t used before (or maybe haven’t used together on the one part before).

You should be fine as long as you don’t rush, and make sure you understand each step.

#27

http://www.compositescentral.com/showthread.php?p=55764#post55764

#28

Not to be a dick, but you’re starting to get border line spammer… I think we’ve seen your other ‘advertisements’ in threads. You should contact the guy direct rather than just trying to bump the thread with a one line “i can sell you some stuff”

#29

Anthony this is an ambitious project but a few words of caution is necessary. Start with the smallest, simplest pieces first (perhaps even a few test samples first to learn the characteristics of the resins,flow media, etc. You would probably need one layer of 200g 3k 2/2 twill as an outer cosmetic layer which will give you a thickness of 0.22mm and two layers of 400g 2/2 twill. This will give you a part thickness of approx. 1.1mm. Twill fabric is going to allow you the best drape ability around compound curves. You will probably mess up a few parts but you will learn from every failure (and success). Just be careful of the Easy Composites videos as while they are undoubtedly the best and most informative on the net, they use dissolves to shorten the time frame which could over simplify the process. Try to research the physical process of resin infusion and visualize how the resin would flow through the laminate, of which important physical considerations such as resin viscosity, fabric architecture (orientation of the fabric), vacuum levels, ambient, mold and resin temperatures are the most important. I personally am also new at the procedure. I have also not done any wet layup yet. Between the various techniques available you will realize that infusion has it’s application for larger pieces such as a car bonnet (hood) as it is cheaper than prepreg. Prepreg however is more suited to to small to medium sizes pieces but will require you to have a oven for out of oven post curing. Although prepreg is the way to higher quality parts, it is not without it’s drawbacks. Consolidation and debulking of the prepreg laminate layer could entrap air and cause voids. Benefits of prepreg would allow you to add extra layers of fabric and vary the orientation of the weave, which would strengthen parts where needed (which is not so easy with infusion).
Consideration need to be given to your molds as if they are made with polyester resin, your parts might not fit due to shrinkage. So you have the added cost of epoxy molds. My advice is don’t try to get a perfect gelcoat finnish directly out of the mold but rather apply your gel-coat in the form of a uv resistant 2k layer afterwards. I don’t think Lamborghini, Koenigsegg of Ferrari put any gelcoat into their molds (clarity welcome).
The main defects you are likely to encounter are voids, weave distortion and bridging.To prevent these defects spray a very light mist of spray ahhesive onto the fabric to hold the weave while you very gently press the fabric into the mold. If you spray any adhesive directly into the mold, let it be a very small amount and as you apply the fabric into the ( usually female) mold be careful that the fabric does not adhere to top edge (the highest part of the mold) as you press it in. Ensure this top layer is well pressed in so as not to have any bridging, which is your next defect and will cause resin to race through the part possibly causing resin rich areas (very thick resin only areas with no reinforcement in it), also you could possibly get areas to be isolated ( dry areas) by the resin racing ahead of the main resin front. Vitally important is viscosity and ambient temperature as this can cause voids. See all the white papers written by our scientists about this problem. Voids weaken your parts substantially. In the aero-space industry where lives depend on part integrity you will find that voids are a major concern.
The part I chose to make first is a petrol (gas) flap on my Toyota Corolla. It took me four attempts to get it right but I learnt from all the failures by scrutinizing and analyzing the parts very carefully as they told me what I was doing wrong. I looked at the defects I had and sourced the answers from the internet. Lastly the most important ingredient is determination as even the best plastics technicians had to also learn and I’m sure they also made mistakes.

#30

Some good advice there Beryl but not sure the OP is about any more. His last post was Oct last year.

#31

Yes, thank you, Beryl. I’m still here, just didn’t log in for a long time. I still have yet to begin my journey into composites, but I think I may be starting soon.