Vacuum Infusion.. ideas for improvement

Discussion in 'Boatbuilding' started by ryanonthebeach, Jun 4, 2016.

  1. ryanonthebeach
    Joined: Mar 2007
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    Location: CA

    ryanonthebeach Junior Member

    Hey Guys

    Looking for some advice on better ways to do infusion for one-off boat parts / panels.
    I've tried a few things with relative success (and a few mess ups). Wanted to improve on vacuum bagging. Some questions:

    1. For the thru bag infusion fittings... is there something reusable or economical that folks use? Sealing the pipe directly through the bag into breather material is difficult and thru bag fittings can get pricey.
    2. Resin flow rate is a pain in the a$$, what resins work well for you? I've tried a few but am trying vinyl ester next apparently has better viscosity. My thinking is better flow rate means less infusion thru bag fittings means less chance of leaks and less set up time.
    3. What hose do you find the best for infusion? neoprene? Polyethylene ?
    4. I've tried the (Membrane Tube Infusion) at ACP. Seemed to work.. although my flow rate on the experiment messed it up, anyone using this membrane successfully?
    5. Making flat panels.. I've bought some Mylar sheet to make it smooth. thinking of clamping the panel in the bag between two boards and Mylar. Any thoughts?

  2. Jim Caldwell
    Joined: Aug 2013
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    Location: Cleveland, Ohio

    Jim Caldwell Senior Member

    1. you need to use Infusion Resin only with a 250 CPS flow rate with 45 min. to 1 hour and a half pot life depend on your environmental's.
    2. you probably need to Slow down your infusion rate to about 1" a minute, your resin line should be about 1/2 the size of the vacuum line or use a clamp on the resin line to adjust the flow.!/
  3. ryanonthebeach
    Joined: Mar 2007
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    Location: CA

    ryanonthebeach Junior Member

    Thanks Jim, that's helpful.
    Will find a way to adjust the flow.

    I bought some vinyl ester resin which seems to have a better viscosity for the job.
  4. Tungsten
    Joined: Nov 2011
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    Location: Canada

    Tungsten Senior Member

    Panels can be stacked and separated with peelply/realese film so multiples can be shot at once.
    i go through the tape/seal with just hose and T fittings,i drill out the T 's after each use and reuse.
    Any flat leak free mould/table will give a nice flat shinny surface on one side.

    You mentioned breather material?? Or do you mean peelply?
  5. antonkov
    Joined: Mar 2010
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    Location: Vancouver,BC

    antonkov Junior Member

    The most common option for the bagging table top is MDX melamine board. I tried it, but found it to be a bit fragile for a long term. Instead, I started to use a tempered glass sheet(s), like a store display window. Got them for $5-10/sheet (8x4ft) from a home supplies recycle shop (like second hand home depot). Now I can see whether the bottom skin is fully saturated and, if needed, can quickly heat up the glass from the underneath and help the flow in the down skin.

    Tungsten, how do you take apart several panels that were shot at once? Also, does the normal perforation allow for an adequate flow 2 cores and 3 skins deep?
    1 person likes this.
  6. Tungsten
    Joined: Nov 2011
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    Tungsten Senior Member

    Hi,the perforated film lets the panels come apart for same size shots,smaller ontop of bigger im not sure ,ill bet you'll get cured bridging around the smaller panel so peelply/perf film needs to ext over to get them apart.

    i perimeter feed so the bridging you get from stacks acts kinda like feed lines.Reg perf core seams to work fine, scored on the mould side eliminates flow media.

    After cure on same size panels you'll need to cut the goo edge off, i used a skill saw, so you can see and get a knife into perf film between the peelply and separate.

    I like the glass idea,no fears of it leaking.

  7. SamSam
    Joined: Feb 2005
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    Location: Coastal Georgia

    SamSam Senior Member

    The glass is a very good idea, it's one of the flattest surfaces around and comes in very large pieces.

    I got a large piece of plate glass one time from an old store, it was free but I had to move it myself. It was heavy and I feared it would break from it's own weight as I lowered it down from vertical to horizontal, but it didn't. It was put in a house that got a lot of wind, large wind gusts. It would bow in and out almost 1/2" sometimes, like it was breathing and I would keep everybody away from it until the storms passed, but it never did break.

    If I was to do it again, I think I would make the table for it first, secure it to the standing sheet of glass and then lower it down to horizontal. Maybe a lattice work type thing,


    of 1x4s or 2x4s on edge spaced every foot or so and supported to be perfectly flat.

    There was a company here that made the sides for semi trailers and other things and we could buy seconds for dirt cheap. I always wondered how they got such a flat table to make them on, I think the glass idea would work fine.

    The pieces were random sizes, some were like 10' square, I got 2 pieces 8' x 24' and used them for a roof, some folks built additions, porches etc.

    They were 1/2" marine ply, sometimes 3/8". Maybe it wasn't even marine ply, but there were almost no voids. Joints in the ply were just butted, with no scarfs or such, and there was a layer of light mat and woven roving and gelcoat on each side, both sides smooth and shiny. The joints weren't weak, in that if you bent them over a butted joint, the bends were fair. We used polyester resin on them and had no adhesion problem, so I assume they were made with the same.

    I can imagine building them on a glass table...gelcoat/resin, fiberglass, plywood, gelcoat/resin then top it off with another piece of glass (or polyethylene plastic sheeting) and then vacuum bagged, unless you can get infusion to travel that far.
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