DIY Prepreg?

Discussion in 'Composites' started by RSD, Oct 2, 2019.

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  1. Oct 2, 2019 #1

    RSD

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    Has anyone here made their own prepreg carbon fiber? Either for immediate use or store and use later? Asking because when incorporating honeycombs into a layup it seems like using prepreg is the most time efficient way to do a layup.

    There are some snippets of information on the www about making your own prepreg but certainly there isn't a ton of information. Unfortunately when you google DIY Prepreg you get lots of results about DIY projects using prepreg.
     
  2. Oct 2, 2019 #2

    Geraldc

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    Not intentionally.A job went bad so I rolled the wetted cloth in plastic and put it the freezer.It was OK to use later and cured as normal.
     
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  3. Oct 2, 2019 #3

    BJC

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    Not really pre-preg, but still an interesting and related technique here

    Chris has designed and built airplanes, and was a member here for a short time. He left because of incessant criticism.


    BJC
     
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  4. Oct 2, 2019 #4

    Mcmark

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    I have carbon sheet 3 layer that i got from a friend, done as a wet layup on a waxed formica table. Might not be "the perfect ratio" but have used it for all sorts of little projects. Originally was going to use it for fuse skins on the race airplane.
    Having work with John and his mentor Peter Van Dine (RIP) they keep the resin to a minimum. Wet it out and squeegee out what you don't want or need. IMG_3457.JPG IMG_3458.JPG
     
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  5. Oct 16, 2019 #5

    RSD

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    I read an interesting post in a forum (and I can't find it now) about how someone was using two metal rollers with fabric and resin to essentially make a "use now" prepreg - they did some experiments to work out the correct distance between the rollers to get the right cloth to resin ratio and were setting the roller distance with feeler gauges. This seemed like an interesting technique to produce consistent results - but how on earth do you get the resin off the rollers afterwards? Is there a magic "Resin Off" or "Resin Begone" product?
     
  6. Oct 16, 2019 #6

    BoKu

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    I seem to recall that David Algie was doing that or something like that with the LP-1.

    --Bob K.
     
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  7. Oct 16, 2019 #7

    FritzW

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    Is the idea to get as much resin out as possible (within reason)?
     
  8. Oct 16, 2019 #8

    RSD

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    I think it is to get excess resin out and leave the correct amount in there.
     
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  9. Oct 16, 2019 #9

    Voidhawk9

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    I sometimes use a roller to squeeze out extra resin for a 'use now pre-preg'. I place a thin film of plastic over it first, so the roller remains clean and dry.
     
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  10. Oct 16, 2019 #10

    RSD

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    That might work... put a sheet of plastic down, lay the cloth down, wet it out with epoxy then put another sheet of plastic over the top and then feed the whole thing through the rollers...
     
  11. Oct 16, 2019 #11

    RSD

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    Do you have any links to that Bob?
     
  12. Oct 16, 2019 #12

    BoKu

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    Not any more. Google would be your best bet.
     
  13. Oct 16, 2019 #13

    wsimpso1

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    A common practice for making parts with cloth or for making tapes for assembly is to do as described, with the cloth in one or more layers wet out and squeegeed between two sheets of PE film, cut out and applied. I have built a number of parts in molds this way and all of my tapes for assembly. Works nicely.

    The term pre-preg means it was impregnated ahead of time, so it is a pre-preg if you store it then use it, not a pre-preg if you use it immediately.

    Orion had reported that he built using purchased pre-pregs that he ordered with higher resin contents than the standard products. This was done because he was vacuum bagging in ambient air and needed more resin for good parts than the pre-preys used for autoclave cure. I believe he also used a different resin designed to cure in his processes. I suspect that you can search up this topic internal to HBA.

    Billski
     
  14. Oct 16, 2019 #14

    RSD

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    Cheers Billski once again. I've got a shipment of cloth on the way and I'm currently looking for a rolling machine - like a dough roller or similar to experiment with trying that method setting the distance with feeler gauges to try to get the optimum resin to fabric ratio.
     
  15. Oct 26, 2019 #15

    RSD

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    I've been able to locate several suitable rolling machines for rolling cloth up to 1.2 metres / 4 feet wide - will probably be up and running ready to experiment with this in about a month - currently building a new work room to do carbon fibre work in - will have good insulation, ventilation and lighting.
     
  16. Oct 26, 2019 #16

    Lendo

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    RSD,
    My mate who is building a Carbon Cub (that's fully Carbon) has a Carbon Infusion Company in Nambour - if that of any interest to you.
    George
     
  17. Oct 27, 2019 #17

    Rocket29

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    The French epoxy manufacturer Sicoin have a 'home made' prepreg system call SiPreg. After wetting out the fabric it takes about 24 hours to b-stage and then you have DIY prepreg with a decent outlife. The system does require heat cure.
    Andrew
     
  18. Oct 27, 2019 #18

    litespeed

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    What do you mean by full carbon?
     
  19. Oct 27, 2019 #19

    User27

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    RSD, I don't agree with your original assertion. Store bought pre-preg is expensive and a pain to keep (large freezer). Its also not that easy to use away from an industrial setting as most need heat and pressure (or vacuum) when curing. Are there many benefits from rolling your own? Is film adhesive readily available (never tried to buy it)?

    Wet lay-ups with a long pot life resin (285/287 or longer) will provide most of the benefits with fewer problems. It might take some planning, and you may need help to get large components laid up - plastic sheet technique can help as mentioned above - but overall much cheaper?
     
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  20. Nov 2, 2019 #20

    RSD

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    Probably best to ignore the term pre-preg and think more about what I am trying to achieve here which is cloth that is passed through a machine that has two rollers that are adjusted a precise distance apart so that when the cloth passes between the rollers the excess resin is removed leaving cloth that has the correct fabric/resin ratio ready to be applied to a mold or foam etc.
     

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