I agree with you, hindsight is a wonderful thing. I think the reason I decided to do it how I did it was that you could stagger the layers of carbon on either side so it would be less likely to delaminate or similar
Wondering, why didn't you print the inner side of the mould instead of printing the outer side, if you did, you could have wrapped the carbon fibre laminate around the mould instead of inside the mould ? think like a mandrel, also, I think your part will be more durable if you made it like that (you don't have fibre discontinuity at the edges), and its much easier to fabricated as you only have 1 long sheet of fibre to be wrapped around the mould... what do you think? Also, I read somewhere That PTEG doesn't stick to thermosets (like the epoxy), so it may allow you to skip the release agent step, not sure of this, you might want to investigate more.
As we needed the outside surface to be as smooth as possible, it made more sense to have the outside of the part be the part touching the mould, rather than the inside of the part touching the mould. Remember, the surface finish on the mould surface will be almost identical to the final part on that side. Hence, a female mould was more applicable in this circumstance. Also, it's generally better practice to make parts from a female mould as it's more often than not more dimensionally accurate. Normally you would make the male plug, then make the female mould from the plug, and then make the final part from the female plug, but you are right in thinking you can make a final part from a male plug. On the point of using one long piece of carbon fibre, realistically there isn't much gain in strength when overlapping different layers compared to using one long piece. When vacuum bagging, everything is consolidated and the epoxy is pressed into the carbon layers, so at the end of the day whether you use one continuous piece or overlap multiple pieces, your final part is only going to be as strong as the epoxy holding the layers together. In addition to this, for this application, as there is little to no force going through these parts we didn't need to add many carbon layers. We went way too overkill adding 3 layers on either side, could've done with 1 layer on some places with 2 layers in places that needed more reinforcement (such as where it is mounted) Lastly, I have never really experimented with using PETG. I too have read that PETG doesn't need a release agent, however, I believe this is typically with smooth sheet materials compared to printed parts. Even then, I would always use a release agent as it will make your life 10 times easier. In addition to this, if you don't use a thick release agent such as PVA release, the final part will be mechanically locked into the 3D printed mould, meaning it won't release. Even if you could get past the mechanical locking with a 3D printed mould, there is no reason to not use a release agent when working with composites. I only used PLA as it is what I had readily available. Hope I've answered your questions
@@CoalescenceGP Oh, I didn't think of the surface finish, the side facing the peel ply will barely be covered by epoxy, so, you can't polish it, the side facing the mould is very soft, even if you get some air bubbles you can polish it to smoothen it. If you made it the way I described it (from male mould), then, the surface finish for the outer side will be mate and rough (basically fibre finish), I am wondering, if you apply a layer of epoxy after the part has dried out, will it bond to the part? if yes, then you can apply 1 or more layers, then polish it to be perfectly smooth, will that work? "your final part is only going to be as strong as the epoxy holding the layers together." I disagree very much, if this was true, then why do we need the fibre laminates? It would be much easier to just have the part made of epoxy. I think the epoxy only provides structure and distributes the load to the fibres, the load is carried by the fibre. I agree durability isn't a factor, and I also am not sure if having discontinuities in the fibres really degrades the performance or not, so discard my comment. Same goes regarding the PTEG, PVA is cheap and easy to apply, no reason to skip it. Regarding the mechanical locking, if fresh epoxy bonds to cured epoxy, then, my suggestion in the first part of this comment is possible (adding layers and polishing for smooth finish), if the fresh epoxy does NOT bond to cured epoxy, then, you can apply a layer of epoxy to the mould, wait for it to cure, polish it, and now you got rid of all the print lines that cause the mechanical locking. In the world of figurines, they use epoxy or CA glue to get rid of print lines and to obtain a smooth glossy finish, in your case, if it will bond with the fresh epoxy, it will be a disaster to remove the part after curing.
@@Alhussainba With this "your final part is only going to be as strong as the epoxy holding the layers together." I more meant that the laminations will only be as strong as the epoxy. Of course we need fibres for it to be strong but in terms of the different laminates, the only thing holding the two layers of carbon cloth together if you stacked them on top of each other is the epoxy. I should have clarified. With the actual carbon fibre weave, irregularities in the weave don't really make a difference to the strength of the part either. Easy composites "black stuff" carbon fibre is their cheap carbon fibre - its made of the same stuff as high grade carbon fibre cloth but the weave has imperfections, however this has a negligible difference on the strength of the final part. You are correct in saying you can coat the rough side of the part with epoxy - one of the uses of peel ply is to provide a rough surface so that it is easy to bond other things to the surface of it. You would be more than capable of applying a layer of epoxy over the top of carbon fibre and then sanding / polishing to make it perfectly smooth. Easy composites XCR coating resin is specifically designed for this, but I would imagine regular laminating epoxy would do the job just fine - it just might not look as good compared to using proper coating epoxy. However, the downside of this is that it makes the overall part heavier, as you are adding roughly 200 - 400 grams of epoxy per square metre so its about weighing up the pros and cons. Using epoxy as the top of a mould also works - there are no issues with the mould and part bonding together. As long as the surface of the mould is smooth, cured and you apply a proper mould release, then the part will release just fine, even if you use epoxy for the final part. In this video I spray painted the 3D prints with spray paint, lightly sanded it and then put vinyl over the top, as this acts as a barrier which prevents mechanical locking. It was also a really quick way to go from 3D print to mould without a huge amount of preparation. For reference, when I did the second mould it took me about 2 hours to go from 3D printed parts, to a mould that I was laying carbon fibre into. When finishing a mould with a layer of epoxy you add a massive amount of time in curing , and then sanding/polishing so I found my process was way easier.
there are better wrap options available than vinyl, try some polyurethane seethrough car wrap, I guess its going to release better and last longer without tearing
As these were only one-time moulds I didn't see a reason to find a more solid surface finish, and the yellow vinyl was what I had laying around so it was cheaper too.
Reading the comments I understand why you did a female mould with vinyl. For a better user experience when laying up the carbon you could print a 2 part male mould, lay up onto that, then transfer into the female and remove. Or you could try the compression technique that easy composites uses for forged carbon Fibre.
I mean, yes you could theoretically do this but there would be no benefit to doing it this. It would double the amount of 3D filament you would need, which adds unnecessary cost to a project that was meant to be done on the cheap, and I'd rather have to spend an extra 20 minutes laying up carbon onto a difficult to reach surface than doubling the cost of 3D filament.
This would be possible, however, we wanted a good surface finish, which when making a part from a male mould, you can never achieve to a high standard.
Great video! Wrapping the 3D print with vinyl film was ingenious! Great technique if you want to stay away from spraying a high build surface primer and sealing. I noticed you used a shop vac and vacuum bag. What bagging system was that? Thanks
Thanks! I'm not sure when I got the idea but it was like "hang on, I could just be wrapping these things with vinyl to save me preparing the surface". Definitely one of my finer ideas. The vacuum bag was just a clothes storage vacuum bag - you can pick them up on amazon though I would definitely get a branded one like spacesaver linked in the description as they have thicker plastic and are less likely to have a puncture/leak than a cheap one. Not meant for composites but still very much useable! We have also cut the one-way valve off of these vacuum bags and used it with a traditional vacuum bag made with plastic sheets and gumtape to great effect. We did that with the top shell of our car Hades, and we made a video on it.
Quite a lot of the reinforcement materials that Easycomposites sell are 1 metre wide rolls at any length you need - The carbon we used here was their 10-metre roll of their own brand carbon fibre.
Hi, thanks for the question! If you look at 3d prints through a microscope you'll see they have many little ridges, especially in these prints as I printed at 0.4mm layer height. I tried to reduce them before applying the vinyl with the spray paint - that makes the surface a little smoother but you still have these microscopic ridges, so if you tried to make the part directly from that, it will become incredibly difficult to release as there will most likely be a mechanical lock. You could theoretically get around that mechanical lock by printing with a 0.1mm layer height with spray paint and plenty of PVA mould release however the surface finish won't be very good, and it wouldn't be very easy to release. The purpose of the vinyl, therefore, was to create a smooth surface without the microscopic ridges, meaning it will be harder to cause a mechanical lock. In effect the vinyl acts as a gelcoat would do in an ordinary mould, but only takes 10 or so minutes to apply compared to 24 hours with a gelcoat and it makes a good enough surface finish for the mould. If you were to make a mould properly, I would definitely spend the time making it perfectly smooth and I would use a gelcoat, but for a quick prototype, the vinyl works fine. I hope this answered your question!
