confused over coring for deck - plywood, honeycomb/nida, coosa, foam?

Discussion in 'Boat Design' started by leaky, Apr 21, 2016.

  1. Steve W
    Joined: Jul 2004
    Posts: 1,825
    Likes: 63, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    To be clear, VE and PE have exactly the same smell, they both use MEKP catalyst, they wet out heavy glass the same, (easier than any GP epoxy due to lower viscosity) For all intents and purposes you would not notice any difference in use, it just that the properties are better for VE. When you buy in drum quantities the cost difference is not that much and much less than epoxy, even the less expensive brands.
    Keep in mind what I said about the coosa, i have seen residual mold release make the resin bead so be sure to talk with the manufacturer about this and do your own testing. I don't know how they make it but I suspect it is foamed between metal sheets with some kind of mold release, it may not be an issue and I have not have had the time to conduct my own testing so would not do anything large with it until I do.
  2. leaky
    Joined: Sep 2008
    Posts: 207
    Likes: 13, Points: 18, Legacy Rep: 14
    Location: nh

    leaky Senior Member

    Hmmm, thanks Fred - for some reason that's the first recommendation I've heard on foam in the deck. This boat actually does have the airex foam core in some areas, namely where I'm not mounting anything of substance but when you want some structure (like the deck up on the bow). Other areas the builder recommends substituting airex for high density coosa, which is the case in the gunnels where I will mount a bunch of things, because of the compressive problems with foam (ie you can't crank a bolt down on it). We are going to 3/4 inch 26 lb coosa along the entire cockpit washboard running up to the windshield. I thought for the compressive differences foam was not well suited, as a heavy force applied to one small spot will more easily crush the core?

    Thanks Steve - it is just what I was told, that the VE has a worst smell. The builders definitely hate using it for some reason though. I'll price it out right when I'm buying it anyway, initially I came up w/ (for barrels) $1000 for polyester and $1400 for VE, but I suspect since the guy paying $1400 is building a 48 foot even if I used his account my price will be somewhat more on a single barrel. Shelf life does kinda matter though because I'll likely be building over the course of 18 months. Within 6 months I'll do the bulk of the glasswork but there will be some items left for 18 months later. Basically important things get done, boat goes in the water after a year, then at the end of the season I haul out early and finish the creature comforts.

    Is the problem w/ storing VE related to solvents escaping? I could re-container a portion of the barrel such that it fits tight in smaller containers for storage if so. It'd be nice to buy 1 barrel and use it for everything.

    As far as the bonding goes, thanks and I'll definitely check into that too - maybe needs a light sand or solvent wash. Plenty of people using it so there might be some unwritten tricks.

  3. ondarvr
    Joined: Dec 2005
    Posts: 2,779
    Likes: 466, Points: 83, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Coosa sheets are pre sanded and residual mold release is not an issue, bonding to the sheets is no problem.

    PE and VE do have a slightly different odor, but styrene is the dominant one, and there can be different levels of styrene that can affect how intense it is. If you use a PE resin (straight ISO or ORTHO) or a straight VE, the styrene content will probably be in the 45% range. If you use a production resin that meets the emission standards in the marine industry it will be at 35% or less styrene. This is done by blending any of these resins with a DCPD resin that needs less styrene to lower the viscosity and get it into a usable range.

    VE's tend to be slightly harder to work with, they feel stickier and may wet out a little slower, but his varies with the exact VE resin used.
  4. ondarvr
    Joined: Dec 2005
    Posts: 2,779
    Likes: 466, Points: 83, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    Promoted VE resin isn't quite as stabil as PE, so long term storage can have more of an affect.

    Most VE's are sold unpromoted because after a short time the gel time can begin to drift out, by adding the promotors shortly before use you get a more consistant and reliable gel time, you can also vary the gel time significantly for different parts of the project if needed.

    Promotors are typically cobalt and DMA, sometimes an inhibitor will be used to lengthen the gel time even further.

    That pricing on PE might be a little high, the VE price would be close.
    Joined: Oct 2002
    Posts: 4,519
    Likes: 110, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "because of the compressive problems with foam (ie you can't crank a bolt down on it). "

    Our thru deck mounting for heavy loads is,

    Spot the item to be mounted on deck and drill an 1/8 inch hole thru the center of each mount hole..

    Depending on the bolt spacing a 3/4 or larger hole saw is used thru the top of the deck and down thru the core to but NOT THRU the inner laminate.

    Pry the cut piece out , put masking tape inside over the drilled hole.

    Fill with dense epoxy to the level of the deck top surface.

    Glass over the deck as many layers will be required to support , spread the high load.

    When done go inside and drill up again with a 1/8 drill to locate the center of the reinforcement .

    Glass over the inside to the thickness that will be required to mount a substantial.backing plate.

    Drill again from the top to locate the bolt holes on the backing plate .

    Use a drill press to create the proper sized bolt holes in the plate.

    Finally drill the bolt hole thru the entire reinforced area from the top , with the item again as your guide.

    Once you get into the swing of it it does not require that much effort, although there is extra time while the epoxy hardens , and extra effort to laminate the added deck and under deck thicknesses..

    Sadly when building our cruiser I did not know this technique and made the transom a single thickness to handle rudder loads.

    With a Great Cabin Aft the hassle is when temps get to about Zero F , and the solid laminate radiates cold!!!!
  6. Steve W
    Joined: Jul 2004
    Posts: 1,825
    Likes: 63, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    While I have not had any bonding issues with coosa i have only used it in areas where I know something is going to be through bolted, some of it in infused items where I would not see any sign of resin beading but when I have seen it beading in hand layups it makes me uncomfortable, there is definately some sort of wax on there that causes the resin to bead, so for me i will not risk it for anything that is not backed up by the fastenings of a piece of hardware until i talk to the mfg and do some testing of my own.
    Of course there are slight differences in smell from one formulation to another with VE and PE, but it is very minor. Epoxies also smell different to one another, west smells different to systems three to epiglass etc. All resins are formulated for different purposes and have different handling characteristics, I just did a layup yesterday with VE, love the stuff.
    The way FF describes dealing with the holes when using foam core is of course necessary when using balsa, not for compressive strength of course, end grain balsa has plenty of that, but to protect it from water intrusion.
    I have not had a recent price on PE but on VE it was about $1300 for infusion VE.
    I would defer to Ondarvr on the shelf life issues with VE
  7. ondarvr
    Joined: Dec 2005
    Posts: 2,779
    Likes: 466, Points: 83, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    I sell Coosa to several customers, plus I just traveled with the Coosa rep a couple of weeks ago and the subject of surface prep came up. The surfaces would not be contaminated with a release agent during production with the methods they use, plus they are sanded smooth in the manufacturing process.

    The pre lamination prep they recommend was blowing off any dust or loose particles that may have collected on the surface during shipping and handling. The sheets are stacked on each other during shipping, so the vibration between the sheets can create a little dust on the surface.

    Being a foam, and having been sanded, the surface would be porous and resin may tend to not fill the tiny pits and leave small fisheye looking craters if it's not worked into the surface.

  8. brian eiland
    Joined: Jun 2002
    Posts: 4,964
    Likes: 188, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Polyurea Coatings

    Let me thru out a different idea if you are looking for a deck that will stand up to really tough treatments.....
    How about incorporating some of this Polyurea material.

    Google this product,...might turn up some interesting things.
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.