Infusion Plan

Discussion in 'Fiberglass and Composite Boat Building' started by jorgepease, Jun 4, 2012.

  1. jorgepease
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    jorgepease Senior Member

    I said from the start this project was a learning experience. Here is how I know I could have done it, had I known what I know now. It's half way between using a jig and a mold.

    You get many of the benefits of using a mold without the cost or having to store molds and the tool is flexible, adjust it to build all your boats. The cnc cut acrylic panels are reusable. If I wanted to build say 4 different boats one at a time, I would only need this one adjustable jig and 4 sets of acrylic panels. Of course it's not going to work on all hulls but you can add as many adjustable support brackets as you need and from virtually any angle.

    Adjusting the entire extruded aluminum jig could be done in virtually one day, including battens! Laying the cnc cut panels on top of the battens wouldn't take much longer! The aluminum extrusions with all the accessories exist already, a couple of custom brackets would be needed, that is it.

    I would screw right through the bag with tacky tape on either side. Who cares if you have a pin hole leak, the bag is accessible all the way around, top and bottom.

    If I decide to retire, I would love to build custom boats using this system. Just like 10 per year, no stress, have my dog hanging out with me, LOL.

    [​IMG]
     
  2. groper
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    groper Senior Member

    The problem with using a bag on both sides of the layup, means you still have to fair the surface as all the glass overlaps still produce a thickness variation in these areas. If you infuse onto a solid mold or table surface, you dont get this. The surface comes out dead flat even in the overlapping glass areas.

    The core you are looking for is called infusion grid cut and perforated. Yes, you dont need infusion media or perf film anymore - im on the same page as you on this, next boat will use this instead of the scrimp method. Diab are now making a new "infusion lite" grid pattern with each groove now only half the volume of the normal version. This has almost halved the weight of waste resin that stays in the foam when the panel is finished. However, they have told me you can only use it for laminates upto 1200gsm, heavier laminates and they still recommend the normal profile. With this lite infusion grid, the panel weight is less than 5% difference to a flow media infused panel in most instances of panels typical of what we are doing.
     
  3. jorgepease
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    jorgepease Senior Member

    There is an acrylic sheet attached to the battens but inside the bag so you have that hard layer like you are doing now. The glass would go directly against that. Did you see that or am I missing something.

    Here is part of the console wrapped on one side. I didn't do the other side because would have been a major pain. So yeah, infusing as panels on a table is def the way to go.

    [​IMG]

    In fact I am going to do all the rest that way, I don't need the nice surface for the deck but it's just way faster. I guess I have to do my own perfing!!

    3 hours to to do this little thing, I think I may try hand layup for the inside of the console lol!!!

    The only good thing is I have three parts which I can shoot sequentially same day to save on resin. I am using the progressive method and going to mix small batches.
     
  4. groper
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    groper Senior Member

    Ah yes i missed that... seems very risky, those battens touching the bag could put a hole in the bag, and everything would be tricky to setup with everything floating like that... all seems a bit adhoc...

    Using your current hull for example, i would have infused the bottom and sides as 3 seperate peices, done in 1 shot on the table both sides. The transom could have been attached to the hull bottom panel during the infusion also. Then tape the inside and outside along their joining edges by hand laminating and your hull is done in about 3days allowing time for epoxy to cure and flipping it over to do the other side. Pull the panels into shape with straps or other means, then fillet and tape to lock in place. The stringers in the flat part of the hull could also have been done in this infusion, as they would have been on the bag side and just pleated over. The curved bow section would have needed the forward part of the stringers to be added later as a small add on job afterward, the panel itself could have been bent upwards. After all this, theres no fairing either, just paint it if you leave rabets along the panel edges where the exterior tape joins are. I use strips of polyethlene sheet on the table to make these rabets, rout the depth into the core edges and lay it face down, proceed as per normal.

    If you did all this using infusion grid core, it would all seem a bit too easy doesnt it :)
     
  5. jorgepease
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    jorgepease Senior Member

    I wish there was a way to infuse only one - Good - side then the foam would still easily bend into shape and then shoot the whole inside including transom, tunnel and stringers etc. I know it would still take longer, I just don't like the idea of kerfing those beautiful sandwich panels :)

    I still like the idea of the support structure because you shoot the whole boat like it was a mold. You would just need many more of those adjustable supports than I drew. To set it up would be simple, just clamp 1/4 inch hardboard station patterns to the adjustable jig and then align the supports to the pattern.

    But I would sand the battens and round the edges for sure. Maybe you would even use rounded rectangular aluminum extrusions as battens with threaded inserts (ikea). You would still have to fair the line where the acrylic panels meet, I have to think about it more, I think a rubber female to female grommet so the panels align might work nicely :)

    First things first, get this boat done hahaha!!!
     
  6. groper
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    groper Senior Member

    You can...

    Simply infuse the panels face down on the table and omit the bag side laminate...

    However, the panels will bend quite alot with both sides intact... for instance, your hull sides would take that bend without kerfing...
     
  7. jorgepease
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    jorgepease Senior Member

    How would you distribute the resin if it normally comes from the bag side?
     
  8. groper
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    groper Senior Member

    You still have flow media on the top, or use the grid core we spoke of earlier to distribute the resin... it flows across the topside and down through the perforations in the core same as if there was a top laminate... when its done, demold the good side and peel off the infusion media from the other side and you have 1 perfect glossy side with nothing on the other - except the foam will have its surface porosity already filled on both sides - which is about 300grams of resin per square meter per side. I would have a peel ply against the foam so you can peel it off, then commence your inside layup without having to sand the whole thing.

    Heres a pic showing the bend in my sheer panel, it could have been bent quite alot more than this if i needed to. Its just sitting in place for rough fit, still need to trim up the edges before glassing it to the deck. The shiney side is facing outward on the sheer panel, whereas the deck has the good side facing down - as the ceiling of the cabin underneath - i didnt want to fair the ceiling overhead inside the boat, plus the deck is covered in non-skid anyway...

    [​IMG]
     
  9. jorgepease
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    jorgepease Senior Member

    Got you! I like that idea!! Your boat is much larger, I think it's easier to bend those long panels. I know I had to use clamps on just the foam core up by the bow.

    I just had another idea, if you were to prop up one end of the tool and let it sag in the middle to approximate the curve, the panel would be much easier to bend.
     
  10. groper
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    groper Senior Member

    Bending radius all depends on the panel foam core thickness, and laminate schedule... the thickness is obvious, but if you need to bend across the fibres its also a problem and if there is a heavy schedule the radius is also much more limited. With the fibres aligned at 45degrees to the bend, it will take a tighter radius compared to fibres at 0degrees etc.

    You can use all sorts of apparatus to help pull a bend into a panel, ratchet straps i use alot... if you need tight radii, then you have no choice but to either kerfcut 1 skin of the panel or bring both skins of the panel into a single skin laminate. I did the latter in the following photo - it was still all infused in 1 shot. The bending area has a solid laminate of 4 layers 750gsm triax, quite a heavy shedule - so none of the fibres are at right angles to the bend but i did need the sun to heat and soften the resin and 5 ratchet straps to pull it around for about a 3 inch radius. When you do this, you need to chamfer off the edge of the foam core, preferably at 30degrees but i used 45deg router cutter - the lower the laminate transition angle the better... The single skin laminate did not need stiffening i discovered, due to the tight bend, it was very stiff from the egg shell effect.
    [​IMG]
     
  11. jorgepease
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    jorgepease Senior Member

    That is amazing! :)
     
  12. groper
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    groper Senior Member

    i found the pic of this panel being infused... [​IMG]


    You can use a combination of techniques to get your desired result... At the end of the day, the only thing you cant do with infused flat panels, is compound curvature... thats when you need to go back to doing things like you did originally and infuse 1 side at a time unless you can be bothered building a mold.

    This panel was infused like i described earlier, leaving off the inside laminate entirely and just doing the shiney side face down so i could bend it. After i had it bent where i needed it, i hand laminated the inside skin to lock in the bend. This way i still had a nice exterior face off the table... this is exactly the way i envisioned doing your hull bottom with the turn up at the bow...
    [​IMG]
     
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  13. jorgepease
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    jorgepease Senior Member

    I see what your saying. That worked out perfect.

    In the first picture, you have breaks in your infusion medial between the feeds, is that so you can even the front from feed to feed.

    on the panel I have wrapped already I didn't do that and I was wondering about it because I know at the inlet point it's going to infuse the fastest. I was even thinking of staggering the inlet points, damn I hate to break open the bag, do you think I should redo it with breaks between feeds?
     
  14. groper
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    groper Senior Member

    No... i made the breaks in the flow media because of the transition from sandwich panel to single skin laminate. To get rid of the top/bottom flow front lag before the transition comes together, otherwise you risk a dry laminate on the bottom side from the top resin front locking off the vacuum to the bottom due to the convergence in front of the lag... You dont have to worry about this in your setup... just wait until the front has passed all of the next feed line before you open the next line...
     

  15. jorgepease
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    jorgepease Senior Member

    okay, thanks.
     
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