Infusion Plan

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

  1. groper
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    groper Senior Member

    indeed, the distances peter has quoted are about what id consider typical safe distances for the laminates i do using a 200cps viscosity resin @ -101kpa and 30% shade cloth as flow media. A different epoxy ive also used @ 350cps, i had to bring the distance back to around 600mm absolute maximum, 500mm is what i design for as getting to 600mm is a real stretch with this resin, but it does have a longer gel time so it can just get there after about an hour elapsed time.

    Jorge, next boat i build, i think i will use infusion grid scored / perforated foam... The sandwich composite end up a bit heavier as the resin stays in the grooves on the foam, but not having to deal with flow media and perforated film will make the setup even less painful... a good infusion epoxy can be pulled upto 2000mm through the infusion grid so setting up the resin feeds is simpler also.

    When you envelope bag small parts, you dont get the benefit of a dead flat mold side... the bag will show the glass overlaps, print, core uneveness, and other imperfections on both sides of the part, not to mention the parts can be warped as the bag pulls tight theres nothing to keep things "in plane". So if the parts are just flat panels, its better to infuse with a top film bag on a glossy flat table so you can get 1 good side which is very flat and fair, and the whole part will be "in plane" or without warpage (provided your table isnt warped that is)

    A single sheet of melamine covered MDF board are great for this, and theyre very cheap from the hardware stores or kitchen cabinet suppliers. Word of caution is to look after the melamine surface, any deep scratches and it will vacuum leak through it...
     
  2. groper
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    groper Senior Member

    Oh and jorge,

    just another thing - going off your previous photos, i would have clamped off the resin lines (assuming you didnt have that dry patch you were trying to fill) when the resin front was located where it is in the "9mins" photo (assuming the dry spot wasnt there)

    The excess resin in the laminate closest the resin lines, will continue to even out and fill the parts that havnt infused yet giving the best possible fibre volume fraction... when you can judge when to clamp, so the part still fully infuses, but the resin stops moving beyond the area your trying to infuse (such as around the flange etc) then youve nailed it just right... YES, theres very anxious moments whilst your waiting to see if it fills knowing youve clamped off the resin :p

    However, when infusing a 2 sided laminate, remember to account for the flow lag on the side you cant see, as it can be somewhat behind if theres a big difference in permeability (such as no flow media) .... again it just takes experience and practice...
     
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  3. jorgepease
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    jorgepease Senior Member

    Yes my gauge was at the pump. You could grab a pleat and maybe lift it 1/8 of an inch where you grabbed it. It did require considerable force but before resin you wouldnt have been able to do that.

    I really would like to get away from spiral wrap resin line, I have read about enka channel but do not fully understand that. The idea of using strips of mesh is appealing except that mesh is a pain to get flat and stay that way :)

    But that gives me an idea ... I wonder how it would work with a bundle of heavy test monofilament line ... Like 200-500 pound test. I guess you could use monofilament to bind the bundle or even zip ties??

    Maybe I will do a small test with it
     
  4. jorgepease
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    jorgepease Senior Member

    I like the idea of a long flow but I also like seeing that resin get pulled fast out of the bucket :) ... although I have to say, it didn't kick off as quick as I expected it might, it behaved really well.

    I like the idea of the scored core, wish I had gone that route, not only does it save labor, I like anything to minimize the use of plastic. Tempted to score the remaining panels but I think a saw kerf might be too thick?? Maybe a thin kerf blade ... how deep would you score it.

    Are you infusing both sides when you infuse on the flat glossy surface then? I guess that would be the way to go if your panel is not needing to bend.

    I like the idea of using a scored core infusing the side which lays on the glossy surface so you get a nice exterior but just doing one side so the panel is still flexible enough to bend into place ... for one off boats like this. That would have been a great way to do this if that works.


    On clamping off the lines, the MTI people say you just let it flow and no more resin will flow when the bag is filled because no resin can exit the bag ... and no resin did exit the bag but I still had that excess so I agree, the lines should still be clamped off but in truth it was not much excess, switching the feed to a vacuum would have done away with that.

    I was planning on infusing the transom on both sides. I was thinking to stand it up so I can see both sides and run the resin line along bottom and vac line along top. I will post a pic later. The transom is 2 layers of 3/4 coosa laminated so I don't think it will warp that easy but I will leave extra bag just in case.
     
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  5. groper
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    groper Senior Member

    yes, you can infuse both sides at once on the flat table, and is my preferred method because you get both laminates done in 1 shot, saving time and money. Tthe foam core needs to be perforated to allow the resin to flow from the top side resin lines and flow media, down through to the bottom side. The bottom flow front lags behind the top flow front in this fashion.

    The completed panels are demolded, then can be handled in a similar fashion to plywood sheets... they will take a bend without kerfing, how much depends on the laminate weight, fibre orientation and core thickness... same as plywood really... tight radii bends need to be kerf cut on 1 side, clamped in place, then reglassed on the same side to restore the laminate. If you know the radii will be there, i just leave the laminate off 1 side when i infuse the panel... kerfing and cutting the panels to shape is easy with a TCT blade in a circular saw... again, just like cutting up and working with plywood...

    With coosa board, you should be ok on the warpage... its a stiff board... youll still have to fair both sides tho.... make sure you put plenty of glass on that transom! :D
     
  6. jorgepease
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    jorgepease Senior Member

    What is a TCT Blade?

    I am thinking to double the laminate schedule on the transom to about 100 oz each side. It's going to be supported full height both forwards and backwards. Forwards to the stringers and tunnel and then backwards to the sponsons like most of the TX Scooter boats do.

    Was just looking at it and I think I am going to infuse the transom, outer side of tunnel and sponsons in place in one shot.

    The stringers I will try infusing infusing both sides like you mention above.
     
  7. groper
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    groper Senior Member

    TCT blade = tungsten carbide tipped blade. The blade i use is this one;

    [​IMG]

    You will have an equivalent in the USA, theyre typically called a "metal cold cutting wheel"... They are used to cut thick steel sections or plate, rather than an abrasive type cut off wheel. They are very expensive blades, but they work great on glass... for other cutting i use a jigsaw with metal cutting teeth, and a grinder with the thin metal abrasive cutoff wheels... you can use diamond blades but theyre expensive and i find the thin abrasive wheels work better because theyre so thin and removing less material theyre faster to cut on a grinder. Replacing them is cheap...

    A transom laminate of 100oz per side would be an absolute minimum, ... id suggest going upto 130oz to make more certain - the added weight and cost is minimal...
     
  8. jorgepease
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    jorgepease Senior Member

    Interesting blade, we have the carbide tipped and we can cut through nails but never thought of them as being able to cut metal plate. It's probably a heavier duty blade than the one I am comparing it to.

    Well I am going to have a chance to test it on glass today, have to cut the tunnel opening.

    Thanks for the tip on the laminate for the transom. Seems like this transom will be super strong. I am also going to put a large steel plate on the inside, bolt the jack plate to that.
     
  9. groper
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    groper Senior Member

    timber cutting blades are carbide tipped also, but the blade spacing is typically much greater and the tips much smaller... if you try to use a timber blade, it will leave a messy edge as it tears up the laminate... if its a metal cutting type for cutting steel, your good to go and its leaves a nice clean edge... another bonus is it generates a course dust or chipping that doesnt really get airborne rather than a fine airborne dust that abrasive wheels generate...
     
  10. jorgepease
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    jorgepease Senior Member

    I tried my carbide tipped blade today and it cut a nice line. The dust was pretty coarse but still a little bothersome, I think the peel ply helped keep the edge nice, no ragged edges. The blade was a regular crosscut carbide tipped carpentry blade.

    Dropped the tunnel into place for a fit test, have to finish smoothing out the joints but looks good.
     
  11. jorgepease
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    jorgepease Senior Member

    I have got the transom and transom supports tacked in place. I still have to sand tunnel down before I attach that, it's just sitting there to make sure everything else fits.

    I guess I will also infuse the transom supports and tunnel with 120 oz of glass. I am going to graduate the layers of cloth about 3' past tunnel, that ought to give me a nice strong connection and that will also cover the area that had the leak just for the heck of it

    ... Im definitely using MTI hose on this one LOL!!

    Tested the stiffness of a panel I cut out of boat, dang, I am super impressed! I am thinking 2 thick stringers will be plenty of support for deck and hull.

    Unloaded
    [​IMG]
    Loaded - 180 lbs
    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  12. jorgepease
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    jorgepease Senior Member

    Im getting ready to start laying laminate ... any advice on this infusion. I was hoping to do the inside of the boat tunnel and transom and inside of sponsons and transom supports.

    Then I was going to continue the stringers and deck and then flip the boat one last time to infuse the bottom of the tunnel and outside of transom and sponsons.

    Does that seem like the best way to go? Thanks

    [​IMG]

    [​IMG]

    [​IMG]
     
  13. petereng
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    petereng Senior Member

    Hi Jorge, If you are confident the best plan is to do as much as possible in the bag you have proposed. So outline the most stuff you can do in the bag, then figure out the risky bits and not do them. You could even do both sides at once if your up for it. Regards Merry Christmas and a Safe 2013 Peter S
     
  14. jorgepease
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    jorgepease Senior Member

    Hi Peter, Thanks, Merry Xmas and Happy New Year to you as well!!
     

  15. jorgepease
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    jorgepease Senior Member

    Hi, its about that time again. I still have a couple more layers of glass (10 total layers at transom tapering to 1 layer 8 feet forward of transom. The stringers on each side will rise up all the way to top of high part of transom, this is going to be a very strong transom :)

    This is the infusion plan. I am wondering if I need to run some fishbones up on that 24" dimension?

    [​IMG]

    - Is there anything I am not taking into account that you can see?
    - I will be using the MTI hose, still have some left over.
    -Last, where would you put the inlets? I am guessing CENTER FRONT and BACK of Tunnel.

    Thanks, Happy Holidays ... I'l be fishing starting the 25th to the 1st :) If I am lucky the infusion will go down the 24th
     
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