Laminate Sample #15: Vacuum Bagged "Wet-Preg" Carbon / Epoxy with Foam Core
2024 ж. 12 Мам.
87 354 Рет қаралды
This laminate sample demonstrates how to get nice light high-performance cored composite panels with a careful bagged wet-layup process. Using sheet plastic and scrap vacuum bag to sandwich the "wet-preg" carbon allows for a very controllable resin content and easy handling.
It may be overkill for a flat panel - but this process really makes complicated secondary bonding and wet-layup projects easier and neater. Resin content here is comparable to a carefully infused panel but there is probably 10% more resin that a similar pre-preg panel would deliver.
This Proset 135 resin works best with a post-cure and for structural applications that would be a good idea.
For more information:
explorecomposites.com/materia...
This was EXACTLY the technique I needed for an upcoming project that I really want to come out right. Your overdubbed narration method is perfect. We don’t have to listen through background noise or poorly controlled recording levels. AND you provided so many tips along the way. I learned more from this one tutorial that from the 50 I’ve seen on other channels. Subbed for sure.
Awesome demonstration!
Awesome video
This video has earned my like and subscribed
thanks for sharing these videos and tips, it's quite helpful for a composite newbie like myself.
I'm glad its useful!
Great video, thanks for sharing.
Glad it was useful. The wet-out on plastic thing is something you kind of have to see and then it makes sense!
Great video; thank you!
Thanks for a great video explanation, I'm planning on making a laptop computer stand from carbon laminate sandwiched foam and this has shown me how to easily make the main panel.
I'm glad it is useful - for a flat panel, you could probably get away with layup in place like in Laminate Samples #18 and 24 - just make sure the core is perforated!
Great Vid! Why did the vac bag (or did the vac bag) not crush or soften the outer edges? Could you use this method over common pourable foam perhaps? I'm thinking of 3d printing a shell mound for foam,filling and then vaccing down against the foam which can either stay or be removed or hollowed out later? I have seen a lot of machined or sheet foam vac bag composites but never over a poured pu foam. (or even from spray cans)
It shouldn't round over the edges at room temperature with this foam - but its relatively dense stuff. Spray or pour foam is usually light density and it might crush especially on sharp corners. Lighter foam would be more prone to denting or delamination - so would need more fiber over it to be similarly tough. It's worth a try but I'd look at it more as an experiment than a for-sure kind of thing. Lots of variables!
Awesome video - Thank you! Is it also possible to run with peel ply on both sides of the material so that two adhesive surfaces are made instead of having one smooth surface and one peel-ply surface? Does that change the process at all in terms of vac process or anything like that? Currently rebuilding a high performance boat and looking at making a whole sheet of this for reinforcements on the inside to distribute loads. Thanks in advance!
You can, but you'll have to wet out the peel ply as if it were a very thin piece of reinforcement - and it is possible to trap air and make it much messier. If you are secondary bonding it then this isn't a huge deal. For a flat panel it might be easiest to lay out the peel ply on the mold (table) surface and pull it flat and smooth with some masking tape holding it in place and then wet through with resin and a squeegee. You can do the same for the carbon too - and it will be quicker and easier than wetting out on plastic. The plastic method is great for complicated laminating jobs because it is easy to do a very neat job and use patterns... for sheets of material you may as well just wet it out in place.
Check out sample #5 and #18 and #24 for more details on this.
@@ExploreComposites Thanks so much for your reply! I'll be sure to check the other samples!
Around 3:40 you mention that the wet-preg has longer handling time than the epoxy in the pot, why is that? Due to the self-heating in the pot, or is something else in play? Awesome set of videos and this wet-preg looks like a really nice trick, I wish I had known about it for my last project where I had to make cut-outs and spent quite some time swearing!
Yes this is all about not having a big pot full of resin self-heating to destruction. Once its in the thin sections it will be more about the gel time than the pot life. This just lets you front load the wet-out instead of doing it in steps. It does really help with fussy jobs, especially with patterns or tapes.
Great video. How would you go about making a CF panel with a core to add rigidity, but where you will see the exposed edges?
Lots of ways - some harder than others! Its still a mess but this article has pictures of edge details: explorecomposites.com/articles/design-for-composites/composites-details-edges-holes-and-joints/
Thank for this great video. I want to make Caravan with this composite.. Do you recommend it? or What do you recommend for making for exterior of a caravan. Thanks
I am not at all familiar with this application - never built a caravan so don't know how they are typically engineered. I'd guess that fiberglass would be plenty good instead of carbon but the general layup method sounds fine. You may be able to do a open molded layup and save the trouble of bagging the skins. Bagging core is always nice on curved surfaces. Is weight a huge issue?
Thank you for all the detail explanation. I’m very new to resin lamination, but I have a big dream project to make a foldable bike camper out of fibre laminated polystyrene… I’m still on the research part, but I still haven’t seen someone use polystyrene with resin and fibreglass, do you know why? I need that thing to be rigid and light cause we are gonna pull it with a Surrey Bike… I would appreciate any insight on the matter
instaBlaster...
some resins will melt polystyrene foams
You don't know until you test it... and probably best to stick to epoxy. I've heard of people doing it though but never seen the results. It would be kind of like a box built like a surfboard - low impact strength. Not sure how light it would be compared to a thin sheet on frame construction. Thin plywood on stringers is pretty light!
@@ExploreComposites really ?!😃 you think that the end result may be as heavy as plywood? Cause plywood is way easier for me as a material.
its interesting how this came out alot lighter than other corecel techniqes in terms of resin to fiber. I'm working on a h-45 divinycell surfboard and i'm trying to make a plan for preventing resin absorbtion in the open surface cell structure. Looking at this technique it looks like you fully wet out the surface then used the vacuum to pull some of that resin through. Do you think the same surface adhesion could be achieved by rolling on a surface layer of resin instead of full wet out? My alternative technique would be q-cell fairing prior to lamination, probably apply the fairing and let it gel then laminate. Also, do the closed cell PVC foams have a miximum vaccum pressure? I mostly do EPS which i have to be careful not to pull to much vacuum on. Thanks for these videos! these are great!
First off I think my 50% resin by weight estimate is way wrong - maybe 40% is more like it. The squeegeeing between plastic is quite effective at getting even and minimal good resin ratio. The M100 core is denser than double density so it has smaller cells and absorbs less resin. In a larger part it would be good to skim/roll the core with a thickened mix (cabosil/q-cell mix or similar) which would further reduce weight. Surface adhesion with epoxy should always be stronger than this low density foam if well compacted and not too well filled - 100% q-cell on 8lb foam would be a weak link. For your H45 a tight screed of filled resin either peel plied and cured or just laminated over should work well. Even just straight unfilled epoxy won’t be too much heavier. You can bleed off easily with slightly higher vacuum. 15inHg is tops you’d want - less is fine. You shouldn’t crush 3lb foam unless you have a very pointy corner - sure the compression strength is well above even 14.9 psi! EPS is just so much weaker and sort of randomly strong so it compresses in uneven ways - at least in my experience...
@@ExploreComposites Thanks for the reply and the awesome vids! I'm going to do some test panels this week and see what they feel like. This h-45 has a suprisingly tight cell structure (i had previously used the green foam PVC products which were terrible) so i have a feeling straight epoxy might work out
@@ExploreComposites What is EPS?
Could you add a peelply and breather under the piece as well as the top to avoid needing to drill holes in the core and give you a textured finish both sides for bonding? I'm constructing a thick foam core panel that needs to be bonded both sides and I don't want to drill holes through it, I'm just concerned the breather might not compress evenly so distort the part?
You could but it might not be very neat. The breather is not a great help as it would get choked off with resin very quickly. Maybe if you used a perforated release film between the breather and the peel ply - same top and bottom - it would work ok? I've never done it and it might not work! Short of laminating one side and then the other in two separate operations I don't have a fool-proof way to glue skins to core without some perforations. I tried that in sample #24 and things don't go well!
great video explanation. Im planning to make a prototype vehicle with monocoque chassis, what a core material appropriate to hold a 60 kg driver with budget friendly . thank you
There are lots of variables and I am not the one to weigh in on monocoque engineering! A structural foam core like the one used here could be a budget-friendly alternative to a honeycomb core but realistically, when you take tooling into account, the core is a pretty small fraction of overall cost. A simplified chassis assembly made from flat cored panels taped together might be more cost effective for prototyping because of the flexibility to make changes and much-reduced tooling costs.
Nice video. Why not gluing ready to use carbon fiber sheets together with foam with added pressure?
You could, and for flat things this would be great. I have a sample video of this process with G10 sheets onto honeycomb core.
pak apa nama plasik bening tipis yang anda gunakan pertama kali saat memberi resin pada serat karbon
how would you add a non compressible mounting point somewhere on the panel? is a hole drilled in the foam core and filled with graphite powder mixed with resin or some sort of metal insert better? do i need a specific kind of graphite powder? i'm building a front splitter for a car that needs to withstand substantial downforce
Drilling and backfilling with filled resin works. It needs to be a sizable fill completely touching each skin. Core can be dug back with an L-shaped tool in a drill. You can also mold it in with G10 of carbon plate if location is predictable. G10 tubes work well for through fasteners as compression bushings too - sized right they can be tapped too. Assuming carbon because you say graphite filler (silica filler is good too) but aluminum inserts or tapping plates are common with glass laminates but no good long term with carbon.
Is it possible to use this method to make very large panels such as 8' 6" X 20' with a 4" thick closed-cell foam core? I am in the planning stage of building a 6x6 overlander and the composite panels would be the walls, floor, and ceiling of the living habitat on the back of the truck frame. The foam core needs to do double duty as part of the structural sandwich panel and as high R-value thermal insulation for the most extreme climates.
I get a little worried about very thick low density core without fairly skins on it - denting, delaminating and buckling are just really concerns. Lots of people seem interested in the structure+insulation combo and I don't have much experience with it - but SIP panels work for houses. For the sizes you mention, I would suggest starting with pre-cured sheets of fiberglass and gluing them to the foam panels. It is really hard (and heavy) to bleed off air through 4" of foam when the foam has to provide compression to the bottom skin. One interesting thing I have wondered about is if it might be better to build a skin on stringer construction like an airplane and then spray or apply a totally non-structural foam to the inside. Overall weight might be less and would be more damage tolerant. Sticking stuff to the inside of the foam might be an issue and there would be probably lower thermal performance and more thermal bridging, but could be worth a look...
@@ExploreComposites Thank you for your reply. I guess I left out one key piece of information the main structure of the habitat will be welded 90 degree 3/8"x4"x4" stainless steel along every edge and vertically in the corners, it will be build like a Conex oceangoing shipping container. The composite panel would be epoxied and riveted to the inside of those steel members just to make an air tight enclosed box to live in. Any significant weight inside the habitat like the battery bank, water tank, etc will have adequate fiberglass reinforcement in the floor to disperse the load to a larger surface area. I have seen SIP panels and these would be similar. EPS foam used for insulation come in 15 and 25 psi compressive strength. Anything of any weight(kitchen cabinet panels, interior wall panel) would be secured primarily to the floor and using secondary securement to the walls as needed. The stainless exoskeleton along with the subframe under the floor will bear the brunt of any major loads.
Can I guy large volume of Carbon fiber from china..and use it to build a catamaran to make it super light? Seems like the costs in china are very low, when buying in bulk.
I have brought carbon from China, Japan and the USA before for my high school/university RC boat project. The main difference that I found was the shine and aesthetics of the finished product, Japanese carbon was the shinest with a very even and smooth pattern, while the other two lacked in the shine and evenness of the carbon pattern. however, from my testing, there was no structural difference between the three.
Do you ever conduct mechanical testing of the samples you make?
Not really, but I'd like to. The problem is that doing mechanical testing right takes a lot of work and some equipment I don't have. I do a little core shearing in a newer sample - #43b - but it's nothing special!
Why don't you use roler for apply resin on carbon fiber ? Roler is very simple for applying
The squeegee forces resin deep into the fibers rather than coating just the top layer of the cloth
Rollers are good too. For larger parts, a paint roller to apply resin, squeegee to spread it and laminating roller to remove air from between plies are all very useful.
4:15 "and...... the main downside is that it is a waste of plastic" I missed the part where that's my problem
Strength test?
Sorry, I’m not set up to do testing that would give you anything useful - hopefully in the future!
No strength test?
Not yet - working on it! What kind of "strength" data would be most helpful for a sample like this? I'd be inclined to test the skins in tension and compression separately and then some kind of longer beam test with the full cored sample to get a core shear and failure mode understanding. I have a small "Instron style" tester but still have lots to learn before I feel comfortable releasing actual numbers on the internet!
Why is FRP appied on the outside over CF ?
I'm not sure I understand. There isn't anything over the carbon except the peel ply and vacuum bagging stuff. This all gets removed after curing.
@@ExploreComposites my bad ... I was watching another build ... and I saw him using FRP Woven Roving Cloth being laid as the first layer ... I asked there ...but there was no answer ... so like i asked here. Sorry for not being clear.
Dude epoxy=use of raspirator. Even if the smell is mild the fumes are there and they are very toxic
You are totally right!
You may wish to make a note in every video that these processes are not the best for aircraft parts. Most of the methods you show will result in parts that are too heavy for aircraft.
With the right choice of core and skin reinforcement the method shown here would be adequate for aircraft parts - small or one-off especially. Aircraft parts are made with nearly every possible composites manufacturing method and success (including weight targets) depends on engineering and process control.
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