Many hackers learned some new skills in seminars during their high school days. Whether it is carpentry, welding, or patient and delicate technical drawing skills, they have been the backbone of secondary education for decades. However, composite materials are new enough that they are not the main feature of the course. For those who wish to fill some gaps, [Easy Composites] has some great videos on carbon fiber technology.

This video involves the manufacture of pipes with complex cross-sections, but these techniques are also applicable to more complex hollow sections, such as bicycle frames. Starting from the mold, the first step is to cut a rough template. Then it is used to lay the first layer of pre-impregnated carbon fiber material and make more accurate templates. The remaining steps include making safe lap joints between subsequent layers and how to properly use vacuum bag technology on hollow parts.

It is a useful primer on the basics of using prepreg to produce hollow carbon fiber parts. We have introduced composite materials before, and this bulletproof armor is a particularly good example. Video after the break.

I have watched a few of their videos in the past. As far as I know, their videos are very instructive and very accurate (or rather state-of-the-art). (My scientific background: I am a master student in materials science, and I have had some compound lectures in the past 3 years). You will immediately realize that those videos are not the idea of ​​the public relations staff, but the idea of ​​the engineer. I believe this is the best advertisement you can do. I just ordered epoxy resin a few days ago to start my own project (unfortunately, due to high import taxes and shipping costs to my home, I cannot support them).

This is another interesting technique for complex shapes, which uses a sacrificial plug printed with PLA. This technique takes advantage of the fact that PLA becomes soft and pliable at a temperature below the glass transition temperature of epoxy resin, causing the plug to collapse and pull out of the finished carbon fiber part.

Or use ABS and "dissolve" (soften) it with acetone...

For hobbyists who only make a few parts, cloth and epoxy may be a better choice than prepreg. Messy and real, but with a longer shelf life.

Assuming high-performance materials, the shelf life of two different types of materials for the two processes is usually very close. In each case, your epoxy resin will be limited, although over time, the fabric may exhibit fiber sizing problems. Depending on the brand, strength requirements and required rheology, if stored properly, the initial shelf life is usually 6-18 months. Some materials can extend the shelf life while still maintaining good structural capabilities, but usually the other processability of the material will change.

If you want to manufacture parts that do not require high structural requirements, then yes, the storage time of wet laminated materials will be longer, but in wet areas, the water absorption of resin components may be a problem.

Wow! Too bad, when I made bicycles about 15 years ago, this series had not yet appeared. My bike doesn’t look pretty, but I’m still riding it. I applied a wet compress on the foam armature and packed it in a vacuum bag. I will never forget the panic when I overestimated the setting time in the 90-degree garage and had to try to remove the peeling layer and blankets soaked with epoxy after the epoxy had cured.

Is it me or is this completely the wrong way? First of all, there must be 3d software that can print out the correct template, not this manual method. But most importantly, why try to lay fiberboard in the mold? Are you sure you will 3D print a soluble stent tube, can you wrap it up?

You can get more precise, better and simpler details on the surface facing the mold. I guess you save a lot of work on the finishing of that surface, especially when it must be perfect.

This guy did say that for simple straight pipes, it is easier to wrap the sheet on the mold. This technique is suitable for more complex shapes.

There are some tools that cost a lot of money to create the laminate shape, but for this application, this is a perfectly reasonable approach. I also use Excel to create layer shapes. This is just an example of using the right tools to get the job done. This method also allows ordinary builders to access these methods.

For the soluble mandrel, the challenge is to find a material that can handle 250°F at the lowest curing temperature while still remaining soluble and not swelling so much that all the resin is squeezed out of the composite. Silicone rubber can also be used as a mandrel, although it also has a very large coefficient of thermal expansion, so unless it is designed properly, it also faces the challenge of extruding all the resin. Thin-walled silicone bags are sometimes used in this application.

The next consideration is which side you need to smooth. If it is internal flow, then the external hard mold will almost always cause the internal flow surface roughness. Therefore, you need to have hard tools on the inside, while the outside is rough.

The technology you use to make a part sometimes depends on how the part is used. If you put it in the mold, as you did in this video, you will prioritize the external shape, size, and surface finish. As suggested, this part can also be made by placing the fiber on top of the soluble armature, which will prioritize the internal shape, size and surface finish. Another consideration is how many parts are needed. The mold can be reused, but the soluble armature is disposable, and each part must be made a new one.

[Stuff Made Here] Brother’s note, didn’t you say you want to make a violin? Okay, make a carbon fiber violin. (C:

I believe that some instrument manufacturers use this process to make carbon fiber violins. If you are looking for Lindsay Stirling on YT, you can see that one is playing here. They have a beautiful shiny surface finish, and the sound is as good as a traditional wooden body with pickups. I am very interested in the comments here because they are more rigid and you can amplify them louder!

Any ideas on using carbon fiber without a vacuum bag? I know if there are bubbles or air gaps, it will not be so strong, but I don't know how important it is. WJP004 on YouTube treats the carbon like fiberglass, brushes it with epoxy and lets it air dry.

IMO bagging is more about weight...though it also helps to reduce voids.

Voids and porosity can cause fatigue problems and lower overall mechanical properties, depending on their size and location. For parts that require complex and need to be inspected by non-destructive testing, it can mask the area of ​​interest.

In the past ten years in composite repair work, vacuum has always been the first choice, but if you are just starting out, you can make the mold shown in the video and use a wet lamination of carbon and epoxy instead of using Prepreg, but it's more like a mess. However, if you use the mold as above, you may put the bicycle inner tube into the mold and explode it to get enough internal pressure. Many homemade windmill blades and bicycle parts are made in this way.

This guy is using some old Volvo carbon fiber to make all the detachable body parts. https://www.youtube.com/channel/UCsx-HTIYPn3CiBQFd4rMyXw 68 videos so far.

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