What material to use to make cores?

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What material to use to make cores?

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atlantis	atlantis posted 4 Years Ago HOT Topic Details
Group: Forum Members Posts: 16, Visits: 114	I want to make parts for which I need a mould that has inside narrow areas where it will be hardly possible to get a bag inside properly, let alone get the mesh and peelply out afterwards. In such cases it seems to be a possibility to make a core first that will stay in the finished part and that is a little smaller than the mould to allow for the carbon material around it. Of course a second mould is needed to make the core. However I wonder what material the core should be made of. It should be pretty light, it must be possible to kind of cast it and it shouldn't be overly expensive. The first idea of mine was to use ordinary pu installation foam but probably there's other or better possibilities. Of course it would be super cool if the core would expand a little under vacuum to press the material against the mould but I don't know if this is feasible at all.
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beliblisk	b beliblisk posted 4 Years Ago HOT Post Details
b Group: Forum Members Posts: 53, Visits: 2.8K	+x atlantis - 11/24/2020 1:46:39 PM I want to make parts for which I need a mould that has inside narrow areas where it will be hardly possible to get a bag inside properly, let alone get the mesh and peelply out afterwards. In such cases it seems to be a possibility to make a core first that will stay in the finished part and that is a little smaller than the mould to allow for the carbon material around it. Of course a second mould is needed to make the core. However I wonder what material the core should be made of. It should be pretty light, it must be possible to kind of cast it and it shouldn't be overly expensive. The first idea of mine was to use ordinary pu installation foam but probably there's other or better possibilities. Of course it would be super cool if the core would expand a little under vacuum to press the material against the mould but I don't know if this is feasible at all. Perhaps part isnt doable by infusion process? A picture or two would help
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oekmont	oekmont posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 550, Visits: 27K	Almost anything is possible with infusion or light rtm. The typical material for such applications is cast polyurethane foam. Depending on where you are from this might be difficult to get. If the area is small, an intensifier cast out of silicone will work too. This can be removed during demoulding. If the area is a bit larger, you could add little grooves along the planned resin flow direction into your casting mould (the grooves should be in the pattern you take your mould from). Depending on the size the flow media should be cut away over the intensifier.
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atlantis	atlantis posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 16, Visits: 114	Sorry, there's nothing to take pictures from yet ;-) Cast polyurethane foam is probably what I'm looking for, I remember that I've heard about a product called Foam-It some time ago but didn't make the link straight away now. It isn't easy to get in Switzerland however as you say, these foams seem to be rather a North America boat building thing. I could get it from Germany though I think. But this stuff is pricey too, if somebody knows a competitive product available in Europe please let me know.
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Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	+x atlantis - 11/25/2020 8:05:06 AM Sorry, there's nothing to take pictures from yet ;-) Cast polyurethane foam is probably what I'm looking for, I remember that I've heard about a product called Foam-It some time ago but didn't make the link straight away now. It isn't easy to get in Switzerland however as you say, these foams seem to be rather a North America boat building thing. I could get it from Germany though I think. But this stuff is pricey too, if somebody knows a competitive product available in Europe please let me know. Foam-It is a Smooth-On product, which is an American company. You will probably find Smooth-On distributors in Europe but you'd have to look. You can also look for 'GP330' or 'GP6'. These are pretty common names that different brands share for the same product. It should be extremely cheap, its about AU$35 for a 2kg kit here, which makes about 70 litres of expanded foam.
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Lester Populaire	L Lester Populaire posted 4 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	+x atlantis - 11/25/2020 8:05:06 AM Sorry, there's nothing to take pictures from yet ;-) Cast polyurethane foam is probably what I'm looking for, I remember that I've heard about a product called Foam-It some time ago but didn't make the link straight away now. It isn't easy to get in Switzerland however as you say, these foams seem to be rather a North America boat building thing. I could get it from Germany though I think. But this stuff is pricey too, if somebody knows a competitive product available in Europe please let me know. https://shop.swiss-composite.ch/pi/Harze/Polyurethan/Schaeume/PU-Standard-Schaum-Arbeitspack.html swiss composites does have some PU foam. It is rather light and might form large-ish pores. I would call them and ask if they would recommend this product for your application. they are always super helpful. Ciao!
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