A wild mixture of tutorials on composites is presented. Though related to airplanes, the focus is composites and, thus, relevant to other fields. We present several tutorials showing how to produce high quality composites, such as Nomex® and AIREX® sandwiches, and various modern production methods, including vacuum resin infusion. We kindly answer questions and share our experience. Most videos were shot while building our own microlight Nurflügel airplane. This channel is a must for those who are into this kind of airplanes.
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Excellent video
Exactly what I was looking for, thanks!
still need an electrolyte for corrosion to happen.
yes, which is almost always available due to condensation. Big sailplane producers made the mistake to underestimate this and had really bad issues with galvanic corrosion.
Nice demonstration! How do you like the LG 735 resin for regular layups/ vacuum bagging? I'm not sure if you are using L285 in the video,but in general, is there a better resin than L285/287 available,even though it might not be certified yet? I'm asking because small 1 gallon (4KG) containers of L285 cost over 300USD in the US,and H287 sells for over 100USD per kg,plus there are additional substantial hazardous freight charges for the H287.
We used L160 + LH260S in the video. L285 and 385 might work as well, but L160 has lower viscosity and allows making larger parts with thicker layups. LG735 from GRM is very nice, it suits vacuum infusion very well, and we've produced a couple of non-ciritcal parts with it. LG735 is pretty much the same as Hexion's RIMR 935. There are certainly other industrial resins around, that are very good and maybe better than certified ones. So why does it sometimes makes sense to use a certified resin at all? Well, for several reasons: - requirement: you might not be allolwed to use uncertified material. At least in Germany it's the case for usual non-ultralight airplanes. - availability: chances are very high that you'll get a certified resin, such as L285, in the future. That's unsure for other resins, such as LG735 - in particular true when there is only one distributor. - quality: certification means that the resin is constantly controlled and its properties are bery well documented. Parts produced with certified resins are known to keep their strength even after decades of use. So for critical parts, which failure would be catastrophic, for example, a spar, taking the risk of using an uncertified resin might be intolerable. Based on this, we decide which resin to use. For critical parts, we prefer to use certified resins, while other industrial grade resins suit very well for the other parts.
Hi Andres. Thank you for you video. Very good testing and explanation. I'm seeking your advice whether is it possible to bond metal steel with carbon?
Thank you for the English subtitles.
Good job on infusing that thick laminate😊. I have some problem with pinhole on my infusion method. I using low viscosity resin so it can penetrate well, no bubble, and Its leak free but it was still in there (pinholes). You mention in the video that slow infusion prevent dry spot ,but in my case because the resin is so runny the vacuum sucked it fast. Is this the problem that i had?
Thanks! Pinholes can occur due to several reasons: resin not sufficiently degased, too dry laminate, wrong or not suffiently ventilated release agent, ... It's always better to infuse slowly, in particular when the laminate is thick, as it takes time to wetten all the layers. Use a clamp to control flow speed and use good flow media, so that the infusion front is even ideally a line. It's important not to close the resin inlet right after the infusion front reached the end - unless you really know how much resin is needed. Else you might end up having a too dry laminate with pinholes. Let it flow somewhat longer. With a MTI hose you can wait until almost no resin is sucked up anymore. With a resin trap, wait until a good portion of resin is trapped. You can check of your product is properly wetted by checking the fiber volume fraction: A properly wetted laminate should have about 50%. For nice looking surfaces its better to wetten it slightly more, say to 40-45%. I hope that helps!
@@andreschavarria1450 Thanks for your advice that was great. I saw many youtube chanels like EC, RWC and many more did it in very good result but when i tried myself its just about those pin holes lol. Let me do some more practice.
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You failed to mention that galvanic corrosion will only occur is the parts are touching (or are connected via conductor) !AND! ARE SUBMERGED IN ELECTROLYTE! If the different metals are touching but not submerged in electrolyte, galvanic corrosion won’t occur!
If you read the comments below, you'll see that we mention that an electrolyte is needed. Nevertheless, you're wrong when you think that it has to be submerged in it. It is sufficient when condensed water and some salts are available. That's the reason why some sailplane producers had problems with galvanic corrosion, though the airplanes are seldom submerged in electrolyte.
Thanks for your efforts!
Great to see you again Andrés!
So great to see a new video from you. Merry Christmas :)
Question for the experienced composite wizards out there - Are you able to achieve a vacuum seal that allows you to seal and remove the vacuum pump, or is continuous vacuum pump operation required while the resin cures? If continuous pump operation is needed, would you find an automated pressure switch helpful in allowing the pump rest periodically?
Most of the times we could turn the pump off. For example, our vacuum is perfetcly solid when we make vacuum resin infusions. Sometimes we turn off the pump, but sometimes there is way to much material/effort behind the piece, so we do not want to take chances. We designed and built a simple pressure regulator for vacuum bagging. So in case the bag is slightly leaky, the pump goes on and off as needed.
How may i prevent ic corrosion on my carbon fiber infusion im doing on my ek chassis interior????
very helpful thanks
Did you use anything to attach the bearings, or are they just press fitted?
Am so glad KZread finally put one of your videos in my feed. This project is fascinating, your knowledge is admirable and you two are an impressive team 😎🎩♠️💙
I assume this is gel-coat (or an epoxy equivalent)- that it’s being applied to the plug, in process of building a mold for the final part. Also assume the plug was waxed and/of PVA release coated. Is the white powder that you sprinkled on top, a media for ensuring key between the gel-coat and the next component in the mold? Maybe it’s Flox (flocked cotton) or chopped fiberglass.?. I certainly understand if you don’t have time to answer 😎🎩♠️💙
This project is very Very interesting and your skills are enviable. I understand that filming, editing and producing these videos is difficult and requires time that could be used for other tasks. But please forgive my being selfish. I really hope you resume creating and sharing them. I’m now following you on Facebook but these videos are just the best 😎🎩♠️💙
You Sir, are an artisan ♠️♠️♠️
that what i call of high quality. impressive dude! congrats
What adhesive did you use afterwards? And if you remember what was your spindle speed?
sehr schon!!
Very interesting, thanks! Does kevlar fibres conduct or is the same than fiberglass? Now that I'm aware I thought of using that because of its superior resistance to abrasion, i suppose better than fiberglass too.
would it be a good idea to layer the inside of a carbon fiber fuel tank with fine fiber glass to prevent explosion?
I need similar part for my Harley Davidson XR 1200x gera lever, you can do in Carbon?
Wie cool!
Hi! Can I ask how long does it take a part to make? Im working on the same field, but with other cnc cutters and our product is similar.
Crazy Job i Love it, i m a Warships Modeler and i want a build a mold of model ships like this, Thank you very much to show us your experience and Ideas we learn from you.All the best and Good Luck. Sofiane
You do beautiful work as a team. Congratulations on the finished product. I have a similar size one-time compound fairing (and mirror) to make. I chose to 3D-mill the foam from a CAD model, hard coat with epoxy, and fill and smooth. At that point I was going to use 50 microM thick polypropylene bagging sheet to isolate the wet carbon layup from the foam but I do not like the wrinkles left in the bagging material. I think I will use painters tape and release agent or lots of car wax. I will verify this part with a little experiment first. Then it is just a bunch of epoxy, peel-ply, carbon fiber cloth and some sanding and polishing. The final shell is a bit heavier than bagging and proper molds, but a very fast and simple process.
Thinner fiberglass tends to drape better, though this is *very* interesting.
Yeah, I think both have good and down sides. Thin glas fiber is great until you sand through ;-) When the core is not resistant to putty, things get really complicated ...
Hi! Is this mold suited for prepreg?
Greetings. I am experiencing problems with the laminate produced by LG-700 resin. Externally, I get a beautiful result, as in your video, but after the sample breaks, fluffed brushes of dry fibers are visible on the edge. I can't figure out how to fix this flaw
It's probably too dry, either because you are not infusing enough resin or the infusion speed is too high. Check your fiber volume ratio. Full laminates should not have higher ratios than ~50%.
@@andreschavarria1450 My LG-700 fills the mold quite slowly, a 30 cm part is filled within 30 minutes with heating with a hair dryer. I don't use filling foam, just perforated XPS. Both layers of the sandwich and all the voids are filled perfectly, but the fiber bundles inside remain dry. The resin weight in the laminate layer is, of course, less than 50%
Why use such complex technologies and expensive materials for the matrix? After all, the required rigidity can be gained due to the usual thick glass mat and simple resin.
There are a couple of reasons, including low weight and high stiffness. Large molds with full glass laminates are very heavy and deform under their own weight. The ideal mold is light but stiff. If you mean polyester resin by "simple resin", then you should consider that it has a much higher shrinkage than epoxy and is, thus, not that well suited to make molds of high precision.
It is not entirely clear from the video - the composition of the sandwich is as follows: carbon-flax-foam layer - flax - carbon? Only 5 layers?
Two quasi-isotropic face sheets, a layer of flax on top as preotection and a PVC core. The exact composition isn't that relevant, as it depends on the needs of application. No high count of layers are needed, as using thickness at low total weight is the basic idea of sandwiches.
Are all CNCs capable of cutting carbon fiber? What are the special CNCs?
In principle you do not need any special CNC-machine to route carbon fiber. The machine should have sufficient stiffness, though. Regarding the milling tools, you should use solid carbide tools, preferably with diamond coating. Carbon is very abrasive and blunts usual tools very fast.
Very nice.
Thank you for the video! Do you have an example on any parts with galvanic corrosion? I'm looking for some photos or video as some evidence that corrosion is an issue in discussion I had.
You find many examples by searching the web. For example: www.compositesworld.com/articles/-optimizing-fasteners-for-cfrp-automotive-parts I know that galvanic corrosion was a big issue in german sailplanes after carbon composites were introduced.
I realize it's been a while since this was posted but your wife has been an awesome help in your videos! Did she get the first flight?
We're still working on the wings. So no maiden flight till now ;-) You find more on the current status on our Intagram account (instagram.com/hortenmicrolight) or on our blog (hortenmicrolight.wordpress.com/)
Just coming across your page. I'm curious if this is still an active project?
Yes, it's still active. We've been reporting somewhat less in here, but the project is still moving on forward. We post updates more regularly on Facebook and Instagram: instagram.com/hortenmicrolight facebook.com/hortenmicrolight
请问为什么要放上下两层隔离膜呢？有什么特殊的好处吗？
Ok, so the main point is electric isolation between those two components... Good explanation. Thanks.
How do you get conduction through the epoxy resin which is impregnated throughout the fibres?
You do not have to do anything to get conduction. The carbon fibers touch each other, so that the piece is conductive in total.
Hi, thanks for sharing!!! Is the laminate in fact a sandwich? Did not know that it's possible to use infusion with a sandwich laminate.
Here, it's a full laminate. Pure carbon fibers and no sandwich. There are some sandwich cores that can be infused, such as Soric and some perforated foams.
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Nice! Can you show how to isolate with glass fiber? Thx!
why are you using PVA instead of a chemical release agent ? I think the surface would be better with a chemical release agent, or am I wrong ? Nice Work, I hope you continue to upload videos :)
What machine is this being milled with?
Splendid, but could it be possibly worth the work ?!
Great video.Those are the, not so well known characteristics of mixing construction materials.Add H2O/moisture from the road/air to the mix and you have an actual battery. H2O acts as a catalyst accelerating the corrosion, deterioration and eventual material separation.A reality in other fields as well such as, auto racing and high end bicycle manufacturing.