Viny Ester

Discussion in 'Materials' started by Fred707, Mar 12, 2013.

  1. Fred707
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    Fred707 Junior Member

    When working with vinyl ester (no surfacing agent) how long do I have in between layers. What I'm working with is a mold for the Divinycell deck of my boat. The way I have it planned is to layup one side one evening (face down in a mold) & lay up the other side in the morning - face up side. Its my understanding that the portion exposed to the air will remain tacky for a subsequent layer?........for how long. I m planning on spraying on a PVA coating to finish the cure.
    Thanks
     
  2. gonzo
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    gonzo Senior Member

    Air inhibited resin will stay tacky forever. It is also somewhat soluble on acetone, which is one way of removing the sticky outer layer. The better way is to either use PVA, mix wax in the resin or use a film. The resin that is against the mold will not be tacky since there is no air to inhibit the cure.
     
  3. Fred707
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    Fred707 Junior Member

    Thanks Gonzo - good info
    It will be a lot of work but Ill do both sides of the deck, at the same time, & hit it with PVA - totally sealing it against the air.
     
  4. ondarvr
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    ondarvr Senior Member

    The length of time between laminates can vary depending shop conditions, ambient temperature and humidity. In a cool somewhat humid environment the surface will be more inhibited than in a warm dry climate, so the time line may be extended a bit.

    Sometimes the bigger issue is contamination of the surface, dust, dirt, other things being sprayed in the shop, pollution, rain, etc, can create problems even if the time between layups is short.
    The exact resin will be a big part of determining a safe amount of time too, some surface cure to a much greater degree than others rather quickly. If you are only waiting overnight, or until sometime the next day, you shouldn’t have any problems.
     
  5. tunnels

    tunnels Previous Member

    How soon between layers !!! all depends how much glass you laying each time, 1 layer, 2 layers, or 3 layers, and the weight of the glass ,and size of the area ,and how much resin you using each time, and whats the catalyst ratio you using ,and what is the gel time ?,and is it getting warm ?,and if so for how long does it stay warm for ??
    Once the resin has completely cooled out than just carry on with the next lot and do the same each time . :eek:

    So you woried about the stick thing !!, just put some wax in the last lot of resin ! simple easy all done !!!
     
  6. ondarvr
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    ondarvr Senior Member

    Not what he asked.
     
  7. tunnels

    tunnels Previous Member

    oooh sorry for breathing !!:confused:
     
  8. ondarvr
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    ondarvr Senior Member

    The time frame for applying PVA is rather short, it should be done before any cross linking has begun, this will yield the best results. Waiting until the next day will greatly reduce its effectiveness, and may do almost nothing to reduce the tackiness of the surface.
     
  9. Fred707
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    Fred707 Junior Member

    I should of posted a few pictures to clarify my question. The idea is to use a melamine mold for the deck which has to be made in sections to fit in the boat. I'm planning to lay the glass - 1 layer of 3/4oz csm + 2 layers of 1808 + resin into the mold (the top of the deck is face down at this point) then butter up the Corecell with a thickened vinyl ester then set the Corecell into the mold/glass. The glass will then be brought up & over the rounded edges where it will cover about 3" of the top at the edges. Since vac bagging equipment seems to cost $500+ I'm trying to avoid it just for four of these sections. I will then weight the top of the Corecell until the resin sets possibly overnight. I will then lay two layers of 1808 to the edges hit it with resin & hit it with a good layer of PVA........Sound feasible as far as the exposed resin/glass being able to wait until the next morning for the final layer of glass?
     

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  10. tunnels

    tunnels Previous Member

    2 x 1808 !!! does it have a 3/4 0z csm one side ?? you need csm between the cloth layers and on top for the core to adhere to it better !! using weights to press the core down is always an absolute no no and you will get voids nothing surer!!
    Have seen weights used so many times and always there voids some where and not just one or two but quite a few !
    what is the thickness of the core you using ??
    high density core ??
    When you say butter the core with a mix of vinylester , what will you mix with your resin and how will you apply ???
    Resin + carbosil and what else ???
    i hope you not intending to use Q cells in you mix any where are you ?? :confused:
     
  11. Fred707
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    Fred707 Junior Member

    Tunnels
    Thanks for taking the time to help. It is my understanding that the 1808 has a layer of 3/4 oz csm on one side so I will need the additional layer of 3/4 oz csm I'm planning on to start with. The additional layers of the 1808 will of course have the csm on the side I need it on.
    The core thickness is 3/4" A500 Corecell which is doubled up at the hatches. By the time the glass is added the deck thickness will be 1" in the field & 2" at the hatch/s. The bracing under the deck is close together so I'm sure the deck is going to be very solid. I did a test section & it appeared very solid.
    I was considering resin + milled fibers + cabosil applied with a notched trowel to butter up the corecell unless there is something better. As far as using Q-Cell I was not considering it at all.
    As far as using the weights the only reason I considered it was the fact that the corecell sheet measures (not a full sheet) 7' x 40 " & the fact that it lays perfectly down in the mold. The idea was then to lay the divinycell down into the resin rich glass (of course back yard method) & weight it down with bricks....sounds crude but looks good in person on a trial basis.....ideas?
    Thanks again for taking the time to help
     
  12. tunnels

    tunnels Previous Member

    To the recipy of the butter id also use Talc !!
    So resin ,talc , milled fibre , carbosill The talc helps make it more solid !!
    the consistancy is the key in all of this and a notched trowl your better to use a vee trowel so the foam is 99% covered with butter mix , notchs leave those clear areas between the rows of butter where as vee dosent . Is best to pre resin the foam with a resin mix ,needs to be gelled hard before you apply the butter so the core to butter bond will be much better , weights such as sand bags are better than just blocks of something hard and heavy as the bags cover a much bigger foot print !!. but voids are almost a certionty !
    How many panels you making ??:?:
     
  13. Fred707
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    Fred707 Junior Member

    Tunnels
    To get an idea of the consistency of the butter is it + - like thick/heavy cake icing or?
    You have me thinking about voids something I don't want for sure. I just might bite the bullet & go the vacuum bagging route. I might be able to do it for less money that I original thought. Just to confirm after applying straight vinyl ester to the foam - "pre resin" it should be set firm as in let it set/cure for a few hours.
    I will be making four deck panels & two + - 3' x 3' side panels for the helm so there is actually a little work to do on it.
    Thanks
     
  14. tunnels

    tunnels Previous Member

    Have you done baggng before ??

    ok if you vac bag then you dont need to butter the foam but juts suck it into the wet glass . just add another layer of you csm and really wet and hard roll then wet the core core and lay down onto the wet glass flip up the edges and peel ply completely over the top of everything then a scrim layer to bleed the air out then a then a pipe wrapped with scrim and over the end to stop the bag from getting sucked into the pipe and bursting then the bag all pretaped so its just peel and stick with pleats put the 4 corners down first then the pipe and totally seal then work away from the pipe to each corner !!.Bags are always 250mm larger all round all 4 sides so they are loose !!
    Have you done baggng before ??

    So you save on one thing and spend a little on something else The secret is pre resin the core and lay wet core onto wet glass make sure the foam is perfirated with a million small holes to let the air out and the resin suck through from below sealling the bag and doing everything you will be like a one armed paper hanger !! but keep your catalyst to it minimum for vinylester you using and learn what your gel time will be and that how long you have to get it all together . being totally organised and everything right at you fingertips and a ticking clock so you know how long you have !! .
     

  15. tunnels

    tunnels Previous Member

    The secret to doing any job with multipal steps is to per cut and fit everything dri right to the point of having the bag over the top of the whole kits and kaboodle just ready to switch on and suck !! Then very carefully take what you have apart and lay out in the exact order it comes off same way round same order , so what went on first is the last thing left !! Last on first off !! . For a pipe inside the bag i like to use conduit abott 18mm dia abd drill small holes 3 or 4 mm dia about 300 apart all way along then tape and wind a couple of layers of scim or shade cloth and wrap over one end and tape so wont come undone The other end you can push the suction hose inside and tape 1. The pipe needs to be long enough to go almost the complete length of the bag so you will be able to tape around the hose not the pipe !!

    DEPENDING on what sort of a pump you end up with you will need to bleed air into the line to regulate the amount of suction !!. how much is enough ?? when all the holes in the foam have resin come through to the top and wet the peel ly and the resin has come out from under all round and everything look 100% ok then that all the suck thats required !!!. its only resin so could only need 25% or a little more of what the pump is capable of sucking!!

    after the risin has gelled and is hard enough that you cant dig your thumbnail into it then switch off and debag and get all the stuff off the top and leave the panel on the mould for at least 4 to 6 hours . then could be gently relased off the mould and after inspection placed face down on the floor and on with the next one !! To save bag material make you first bag quite a bit larger and each time cut the seal taped edge off and add new seal tape !!. The part round the hose can stay as it is just with new seal tape added !!. so could get all 4 panels made using just one bag for them all !! peel ply and scrim or shade cloth ar history but need to be got off the foam befor they get to hard !! ita can be a reall tug of war to get it off other wise !!
     
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