Resin Infusion - light weight

Discussion in 'Fiberglass and Composite Boat Building' started by method_nzd, May 14, 2011.

  1. method_nzd
    Joined: May 2011
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    method_nzd Junior Member

    hey all new here, need help...
    currently building out rigger canoes OC1.. 1 person 21'6 long uses alloy akiu, and a 6'3 ama... they are built in hawai using epoxy vac baged with 3 9 oz (0-90)carbon 3mm h80 foam and S2 glass( not 100% on weight).. they get hull down to under 10kgs... and the ama down under 2kgs...
    i have been resin infusion from when i started boat building in new zealand.. many perfect jobs under belt....

    problem the carbon has a really open weave so holds alot of resin once infused = weight... tryed using soric (MASSIVE fail... holds over 10X its dry weight in resin)... tryed using 2mm cork core,higher dry weight,..but holds less resin.. only problem is need to use tac spray glue to hold into shape of mould...another fail.. tac spray glue and cork = delamination... have gone to using a very light weight 105 grms DB carbon.. 3mm h80 foam (heat formed into shape) and 105 grm carbon... the foam has 1mm holes drilled ever 20mm and only needs 300 grms per sq meter to wet out under vaccume perssure = light weight,....use a thin film gel coat ( wicked stuff cut out over 1/2 weight of normal gel coat )..

    the carbon has to be so fine to be light and not print, with the vac pressure its locking off and leaven dry spots,.. over here in aust not many people are brave enough to try infusion.. so reps over here know nothing of any use to help me out...

    im thinking,..... i need something like soric that lets resin feed in the center on the carbon to wet out both layers... instead of feeding through the holes of the foam and wetting out outter layer slower and locking off....but it needs to be light weight or hold very little resin once infused but still be strong... i know its a ask but there has to be someone out there doing light weight infusion and has some ideads....
     
  2. Herman
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    Herman Senior Member

    Read technical data before you spend time and money. Soric holds approx 500-600 grams of resin per m2 per mm thickness.
    That is not my experience. I suspect you overuse on spray glue. Use as little as possible.
    Is this gelcoat sprayed on? Or brushed? The orange peel of sprayed gelcoat helps infusion on the mould side.
    What I read of it is that your infusion is not balanced. Your speed above the foam is too high in relation to the speed below the foam. Do you use any infusion media, and which one? What is your infusion time, do you use a runner system, and how is it located. Any picture perhaps?
    Carbon (especially 100 gr/m2 biax) is a pig to infuse well. (low) speed is critical here. Infusion is not a race. If it is a race, your resin is too fast.

    What you can do for now is make an imprint of chicken wire in the backside of your foam. This can be done relatively easy. This helps flow in the toolside of your laminate.
    For other recommendations I would need more info.
     
  3. method_nzd
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    method_nzd Junior Member

    the soric i have access to the bit i cut out weight 138 grms and weight 1230 grms once infused i think its the shape of the of the soric that makes it hold more resin and it is 2mm.. when i ordered it the soric i had hope to get was hex shape but what i got doesnt looking anything like it...looks like shaved shagg pile carpet..sort little fingers is best was to describe it.....

    because of the shape of the mould ( 4 bits bolt together)it has a reverse and a little spray doesnt work,.. even tryed the vinylester friendly tape.. i bag in tube... place entire mould under vac pressure...

    gel coat is sprayed on with paint spray gun,.... works well and bonds great to vinyl.. i dont use spray on the gel coat... let it go off for a good amount of time and wipe when a rag and little aceatone.. sticks first lay down great......

    have a center feed 12mm sprial wrap and and vac down each side 12mm wraped in 450 csm.. use flow med looks like shade cloth to me,.... cut flow med so its 70mm short of where the csm vac line starts....i make sure the csm is touching both layers of carbon and the top of the foam/core.....i have even tryed cutting layers longer and inserting the csm vac line in between them....
     
  4. Herman
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    Herman Senior Member

    The "Soric" you had was very probably just regular Coremat. As in: you have been fooled.

    All Soric has hexagonal islands, except for the TF version. Pictures are on the www.lantor.nl website.

    As for your core: you could try Airex R63.80, which is more flexible than cross linked PVC. Or use Core-Cell C-Mat (if they still have it) which is a micro-scrimmed thin core.

    But I would try the chicken-wire solution first, to have the laminate infuse from the bottom upwards.
     
  5. method_nzd
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    method_nzd Junior Member

    im 10,000% sure its not core matt...
    after looking at web site its the tf verson.. lots of little finger like things.. holds alot of resin that stuff... the hex shape stuff is what i wanted when i placed my order, but because im using light weight lam's guess they sent the tf as it says its less print....
    printing isnt really a problem as they have come to accept it on canoes....
    that LRC soric is what i was after...
    it has to be a solid core... some cheap china canoes are using h60 as its lighter but when u pick them up to place on car roof.. people are leaven dents from their thumbs...
    we run over the 3mm h80 with heat gun its forms into the shape and once cooled stays close enough to the hull shape to not hold up 2nd layer or carbon and cause bridging..
    infuse from lower point in center of mould and stuck up to top of hull from center feed to vac line is at the max 400mm ...mix small amounts of resin at a time and have a tap on resin feed to stop/slow feed down as needed or if resin is low.. also lets us put newer fresh resin into feed... have a shipping container set up with air con everything is keeped at 23c 24/7....

    i could try the chicken wire idea but i dont see how doing that will help the laminate between the foam and the gel coat where the dry spots are...and if i did it on outside of foam hate to think of the print from it
    i really just thinks its cause of how fine the carbon is cause of its weight its compressing to much.....
    can be easyly fixed by going back to epoxy and vac bagging.. but i just dont want to give up on infusion these canoes just yet... i know it works great on hulls with heavier lam's...
     
  6. Herman
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    Herman Senior Member

    Try one on the outside "chicken-wired" You do not need a deep impression, just very light. This helps tremendously.

    I guess even Soric LRC will be too high in weight for your purpose, but you could try it.
     
  7. method_nzd
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    method_nzd Junior Member

    foam we use has a resin uptake of about 300gm2 + weight of foam.. if lrc sorci is of same weight as tf soric i think it will work out about the same maybe a lil more.. i use tf soric on another ama i do but is alot bigger and it works well use a 167grm kevlar 2mm tf and a 450 db... only put peel ply under resin feed and a little where vac lines touch.. no flow med and the soric is enough to wet out both lam's fine..never had a dry spot or a lock off ..
    will the LRC soric work alwell as tf as a flow med core??
     
  8. Herman
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    Herman Senior Member

    Speed of LRC is less than TF, but it could work in your application. It does take 350 gr/m2/mm of resin though.
     
  9. latman
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    latman Junior Member

    LRC does print fairly bad though method_nzd ,Those Hurricanes and Kaiwaa boats are 2 layers of 100g Uni prepreg each side (o and 90 degrees)and vacuum bagged/cooked with a heat resistant PVC foam core , then 2 pack primered,sanded and painted which will still be lighter than your gelcoat i ithink .Are you using epoxy, Poly or VE resin ? Maybe you can get some cans of Infuzene imported (http://www.infuzene.com/ ) which are styrene based and will not interfere with interlaminar bonding if using Poly or VE . I personally think Infusion will not get you the light weight you want , cheers Lats
     
  10. method_nzd
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    method_nzd Junior Member

    wait for lrc.....hey i passed some foam between a old wet out machine and inprinted the flow medium onto the outter side of it,.... when i get some time i will try it...pulled another one today only one dry spot, only place i didnt redrill the foam after sanding the edge bevel.. teach me for trying to cut corners

    latman use ve resin, keep everything at 25c 24/7 and keep everything under vaccume for overnight helps with print i find,....gel coat for a 21'6 hull is a little over 1kg, which is about -60% on normal gel coat weight...got a hull and deck fitted out with rudder/tubes/,peddels and akiu mounts, and comp bouy came out at 11kgs which im happy with as the canoe feels stronger then the epoxy core matt ones, using the 3mm foam
     
  11. latman
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    latman Junior Member

    we have just put small nails through a piece of (1/2 A4 size ) MDF with a handle on the back and punch all the holes in one go , they are smaller and therefore weigh less when filled with resin but what happens is they make little "pillars" which are very visible if the foam ever shrinks , also foam dents easy as only the outside skin resists point pressure.
     
  12. method_nzd
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    method_nzd Junior Member

    latman the foam i use is h80 3mm doesnt not crush on thumb pressure points.. with only 101 XCDB skin... plus the h60 even tho its lighter foam has a high resin uptake.. so was better for us to use heavey h80 foam
     
  13. latman
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    latman Junior Member

    yes i'm sure it would be , i even found 110kg foam made lighter laminates than 80kg due to resin filling the opened cells, DIAB can /will also sand it to 2mm if asked.
     
  14. method_nzd
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    method_nzd Junior Member

    herman i have had a roller made much like a check roller but with less ribs and not a thread pattern.. lets me put graves in foam at 5mm with only being .4mm deep.. waiting for new fresh resin as latest batch was over 6month old and was thick as
     

  15. Herman
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    Herman Senior Member

    Was it polyester?
     
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