Hi folks-

New to composites/CF, pardon in advance if I don't have the terminology proper.....but several questions arise as I research and plan this part

The project is an inlet/intake tube - from an airbox or filter to the turbo inlet.  Picture attached of the approximate shape, note that there are two 'bungs' or ports or however you like to call them - that connect to the PCV system. They're aluminum the example below but don't necessarily need to be.  They're plastic on the OEM inlet. 




My thought is to create (carving, sanding by hand) a foam plug, slide a single carbon sleeve over it, wet layup and vacuum bag it.   Approximate dimensions are 3" diameter at the smaller end gradually widening up to 5" at the larger end.  It's about 15" long in total.  

Several questions arise as I try to think through the multiple steps....

-Will the acetone harm the cured epoxy/CF?  I've found using a small test piece that the foam melts away quickly with acetone. 
-Do I need to wrap or coat the foam with anything before the wet layup?  
-What I'm really hung up on is how to add these ports for the accessory hose connections?  I've thought of cutting off or removing the ports from the OEM (plastic) pipe and somehow integrating them into the layup?  Or, integrating a large nut into the layup, allowing me to use a corresponding male threaded barb as seen below?


The part in the above picture was from someone's DIY write-up for a similarly functioning piece, and thus the inspiration for my project.  Thanks very much in advance for any thoughts or pointing out any mistakes in my thinking.  

Andrew

Polystyrene will work well for a project like this.  It dissolves with acetone.  Acetone is fine on a fully cured part.  

I have seen dissolvable foams and some 3D printed dissolvable cores for similar applications but not seen them readily available on the market.

The Hose tail barb could be bonded in from the inside if it has a suitable flange or use a threaded barb and a locking nut.  Use some resin and maybe a little carbon tape to ensure a leak tight seal.  You can get these self sealing take offs for silicone hose which could be modified and bonded in from the inside. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

I would recommend to "seal" the plug with a layer of release tape or packing tape and to use some mould release on top of that. The PS foam with acetone makes quite the mess and this way you will get a much nicer surface and a lighter part.

Oh yes I neglected to mention - I found extruded polystyrene sheets at my local Home Depot and have glued them together to form a block.  It melts away so quickly with a few drops of acetone.  Lester - PET tape would be a good choice here yes?

Were I in the UK, I would certainly send my business to you folks.  But being in the states, I've found a couple of epoxy options - anyone have any thoughts if any of these are more appropriate than another? Also, does one typically use the same epoxy for the layup as the additional (finishing?) layers?   Thank you again.t

System Three Kit

635 Thin System

820 kit OR the West System 105/207

Thank you for the replies - very helpful!

Figure I'd post an update, for anyone looking in the future. Ended up doing a layer of 3k 2x2 fabric first, then a 5" sleeve on top - in one layup, vacuum bagged (though using a pseudo-bagging technique....the large ziploc bag and shop vac method). It still has some flex to it, so I think I think I'm going to add one more layer of fabric on top, as I'm not thrilled with how the outer sleeve layer ended up looking (had to cut/piece together at the narrow end of the pipe).  

Any recs for a final coat urethane(?) with some heat resistance.....in a can? And sold in the US? :-)
Thanks

For the final layer, use a 2x2 twill fabric with the overlap/seam on the underside out of sight.  Most decent epoxies will go to around 80C with a post cure which should be fine for a cold air pipe like that in an engine bay.  That way you can use a good quality coating resin on the surface to give a smooth finish.  The resin can be sanded then polished or lacquered much like you would with skinning. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Just the way vacuum bagging works really, you've got an excess of material because you made it to fit around the pipe unconsolidated and then when you bag it you squeeze it together really tightly and all of a sudden there is too much carbon, so it gets pinched. The vacuum bag and peel ply all do the same thing and you end up with wrinkles everywhere.

For this sort of process you are better off without vacuum, you don't need it. You are essentially skinning the pipe, so follow that process and it will work well.

All finished, appreciate the tips everyone!