Laminate Sample #38: Prepreg Carbon with Reinforcing Structure

This one's kind of cheating! Laminate Sample #38 is the first to have a panel-and-structure kind of approach to the 300mm square. The base panel has two flanges - each reinforced with unidirectional material. Spanning the flanges, tow omega-channel type stringers support the panel. The are bonded to the panel with toughened epoxy.
This sample includes machining a separate mold for the stringers on my little Tormach - and some upstands placed on the panel tool to form the flanges. We have debulking and cooking and applying process materials. Bonding and masking and quick and dirty adhesive application. Lots of details - and lots of corners cut!
Material is Gurit HEC300 and RC200 with SE84LV pre-preg. Adhesive is Proset.
Have a look at this article at Explore Composites! on Laminating with Pre-pregs:
explorecomposites.com/article...

[@JunoW712]

This channel is basically free gold!

[@foesfly3047]

This is the most useful project lesson I’ve seen yet. Several individual lessons learned within the project. I’ll be applying them to molded wet layups and vacuum bagged processes with West System Epoxy.

[@fredygump5578]

Thanks. I learned several tricks that you probably didn't realize would be helpful. Like that router bit setup to trim the flange to a constant width. And the double stick tape w/ tongue depressors to hold the channels in place. Or just leaving the peel ply one as masking during the secondary bonding.

[@ExploreComposites]

Those diamond wheels are awesome! I never know what to focus on with these so I just pick a few things and hope its helpful.

[@tvepaddler]

I totally concur: the "random" ramblings about various aspects of the process are really helpful!

[@foesfly3047]

Ditto!!

[@MacGyverKilla]

Thx for your great and informative videos!

[@GrantOakes]

Great video as usual.

[@ExploreComposites]

Thanks! This was a fun one - prepregs are the best!

[@saugod]

hey awesome video mate, i was wondering how would i go about doing rib and skin construction with carbon composites, like an FSAE chassis.

[@ExploreComposites]

Not sure - curvy surfaces are harder! Look at how it works with large airplane construction - not that that would be efficient for a one-off. Core is often the best way though!

[@saugod]

@@ExploreComposites Yeah I think you're right. Most of the designs I've seen so far from my research its either space frame or core composites.I made a few models in fusion of an all carbon chassis with carbon ribs, the weight was significantly lower. Did some 3d printing on a cheap fdm, but manufacturing out of composites is a whole different issue, now that i've stumbled upon it. Most forums and people i've asked said that i should started the design with composite manufacturing in mind. Well foolish me, back to square one now.

[@ExploreComposites]

Well they’re right to think about manufacturing from the start... but without testing it’s hard to know what real weights look like. You can add stringers by using beveled strips of core that conform easily and laminating over - in one shot possibly. Many cores can be thermoformed easily.

[@KDD8]

4:52 Can you tell me what those fittings are that you put the hose onto for vacuum bagging and where to find it?

[@ExploreComposites]

Many composites “stuff” sellers have these - they are a base plate and a gasketed locking ring with a fitting threaded in. Look at torr technologies in USA or as an example of the variety available.

[@KDD8]

@@ExploreComposites thank you!

[@sayithigher]

Hello, where did you get that cutter for your router?

[@ExploreComposites]

I think that one came from Bodi - (bodico.com) but they are called diamond grit mounted cutoff wheels - or something like that. You can also get arbors and the diamond cutting wheels separately.

[@sayithigher]

@@ExploreComposites Thanks very much.

[@andrewsawyer3222]

What are you using as heat source to cure

[@ExploreComposites]

The aluminum plate is 1/2" MIC6 with a silicone 3D primer bed heater stuck to the bottom. Plate is supported up off the work-table 1" or so with little feet so there's an air gap. The heater is 110v and run with a PID controller and solid state relay. Works really well!

[@TWX1138]

It may simply be too expensive to build molds to test it, but it would be interesting to see how making the underside structure in either a series of box-shapes or triangular shapes would work, versus just the two. Unfortunately it would undoubtedly either require machining a massive piece of aluminum, or would require machining a bunch of smaller pieces then welding them together to form a lattice.

[@ExploreComposites]

Do you mean like a bunch of rectangular tubes side by side with face laminates over? There are tons of fun options and so little time! Hoping to do more with nonuniform structure soon.

[@TWX1138]

@@ExploreComposites I guess the best reference I have for it would be when Destin from the KZbin channel "Smarter Every Day" visited a rocket factory. kzbin.info/www/bejne/pWHJeJKio7ubftk At around 8:20 they start looking at machined aluminum that is used for the fuselage of the rocket. It's shaped to be as light as possible while transferring forces in a particular fashion and simultaneously resisting internal pressure as the rocket body also acts as the fuel tank walls. I wonder if making a piece of carbon fiber on top of this shape (while it's still laying flat before being rolled to a round rocket body), then bonding the resultant corrugated panel to flat carbon fiber on one or both sides, would result in an incredibly strong board. Something with a thickness not entirely unlike a thick plywood, but weighing almost nothing and capable of supporting a larger amount of weight if it's not too concentrated on a single point. Such a shape would not only be strong, but the channels could be used to chase cables.

[@ExploreComposites]

Yes! I know what you mean - an isogrid type of structure. Plans for something like this coming up. Actually have the chunk of aluminum for the tooling.

[@dhavalshihdod9953]

Im interest the Solar calls make

[@imusuallycorrect]

Ohhhhh... no keying up the surface. Do you not think it's beneficial? Thanks for another great video.

[@ExploreComposites]

Like so much of this it’s not clear what the best way is. Pulling an uncoated peel ply leaves a great low energy bonding surface but sanding is often better - depends on what paper you read and what materials. Same for solvent vs. dry wipe. I just did it here to show that its an option.

[@dhavalshihdod9953]

Hii