Making a dissolvable foam plug?

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Making a dissolvable foam plug?

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Andrew R	Andrew R posted 5 Years Ago HOT Topic Details
Group: Forum Members Posts: 9, Visits: 94	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
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Andrew R	Andrew R posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 9, Visits: 94	+x Warren (Staff) - 1/20/2021 9:50:20 AM 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. Thanks that's what I ended up doing, putting the seam more on the underside. Frankly it looked better BEFORE I wet it and bagged it - maybe it wasn't even necessary to vacuum bag it ? FWIW the smaller end of the pipe is millimeters away from a turbo charger, which will get very hot so I do have some heat to consider. Tacked down, perfectly smooth: After bagging, with some mild veins/wrinkles. How can I improve? Not enough resin? Poor vacuum?
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raygun	r raygun posted 4 Years Ago HOT Post Details
r Group: Forum Members Posts: 22, Visits: 126	+x Andrew R - 1/21/2021 1:15:44 AM +x Warren (Staff) - 1/20/2021 9:50:20 AM 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. Thanks that's what I ended up doing, putting the seam more on the underside. Frankly it looked better BEFORE I wet it and bagged it - maybe it wasn't even necessary to vacuum bag it ? FWIW the smaller end of the pipe is millimeters away from a turbo charger, which will get very hot so I do have some heat to consider. Tacked down, perfectly smooth: After bagging, with some mild veins/wrinkles. How can I improve? Not enough resin? Poor vacuum? Side note: the cold side (compressor housing) of a turbo really doesn't get that hot. I'd be really, really surprised if it got anywhere near 80C (176ºF). The incoming air as well as the cooling system block between the turbine and compressor keep that side relatively cool. Now, the hot side (turbine) is another matter entirely. That thing will literally glow under the right circumstances.
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Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	+x raygun - 1/31/2021 4:27:03 PM +x Andrew R - 1/21/2021 1:15:44 AM +x Warren (Staff) - 1/20/2021 9:50:20 AM 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. Thanks that's what I ended up doing, putting the seam more on the underside. Frankly it looked better BEFORE I wet it and bagged it - maybe it wasn't even necessary to vacuum bag it ? FWIW the smaller end of the pipe is millimeters away from a turbo charger, which will get very hot so I do have some heat to consider. Tacked down, perfectly smooth: After bagging, with some mild veins/wrinkles. How can I improve? Not enough resin? Poor vacuum? Side note: the cold side (compressor housing) of a turbo really doesn't get that hot. I'd be really, really surprised if it got anywhere near 80C (176ºF). The incoming air as well as the cooling system block between the turbine and compressor keep that side relatively cool. Now, the hot side (turbine) is another matter entirely. That thing will literally glow under the right circumstances. Mmm no, it most certainly can get very hot. Ive got logs from my race car showing the intake charge out of the turbo gets as high as 170° C, this is why we have intercoolers. Just because the turbine side can get up over 700° C doesn't mean the compressor side isn't also very hot. The intake pipe going into the turbo doesn't get quite so hot, but it will still see up over 100° right at the inlet. Ive got a carbon pipe on mine that I made with pre-preg cured at 100°, and it has done fine but is severely yellowed on the last 50mm next to the turbo, and you can see the pressure from the hose clamp on the silicone joiner distorted it a bit. So definitely still gets hot.
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Andrew R	Andrew R posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 9, Visits: 94	+x Hanaldo - 2/1/2021 2:05:16 AM +x raygun - 1/31/2021 4:27:03 PM +x Andrew R - 1/21/2021 1:15:44 AM +x Warren (Staff) - 1/20/2021 9:50:20 AM 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. Thanks that's what I ended up doing, putting the seam more on the underside. Frankly it looked better BEFORE I wet it and bagged it - maybe it wasn't even necessary to vacuum bag it ? FWIW the smaller end of the pipe is millimeters away from a turbo charger, which will get very hot so I do have some heat to consider. Tacked down, perfectly smooth: After bagging, with some mild veins/wrinkles. How can I improve? Not enough resin? Poor vacuum? Side note: the cold side (compressor housing) of a turbo really doesn't get that hot. I'd be really, really surprised if it got anywhere near 80C (176ºF). The incoming air as well as the cooling system block between the turbine and compressor keep that side relatively cool. Now, the hot side (turbine) is another matter entirely. That thing will literally glow under the right circumstances. Mmm no, it most certainly can get very hot. Ive got logs from my race car showing the intake charge out of the turbo gets as high as 170° C, this is why we have intercoolers. Just because the turbine side can get up over 700° C doesn't mean the compressor side isn't also very hot. The intake pipe going into the turbo doesn't get quite so hot, but it will still see up over 100° right at the inlet. Ive got a carbon pipe on mine that I made with pre-preg cured at 100°, and it has done fine but is severely yellowed on the last 50mm next to the turbo, and you can see the pressure from the hose clamp on the silicone joiner distorted it a bit. So definitely still gets hot. Agreed. After a 30m highway drive in 75F weather a week ago, I'm seeing temps right at the inlet of around 120F. I would expect slightly hotter temps during city driving where there is less of a cooling effect from the incoming air. Sounds like I've recreated a very similar piece in your engine bay, Hanaldo...... anything you'd recommend I do differently on the next one? And if I were to make a small 'batch' of these.......I wonder if a split-mould makes more sense, though I'm hung up on where it would be split and how to incorporate the bungs. And also not sure what additional investment that requires - does split moulding equate to using pre-preg? I've already started making another plug and it's going much faster than the first time - so it's not that intensive. Just not too confident in creating a mould. Thanks
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