Mold stuck in Plug! Help!

Discussion in 'Fiberglass and Composite Boat Building' started by coolgps, Jun 25, 2013.

  1. coolgps
    Joined: Jun 2012
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    coolgps Junior Member

    Somehow, workers mixed duratec EZ sanding and high gloss coating together on plug to save one time spraying. Then we end up with a stuck mold. The other plugs we sprayed seperately, they were fine.
    Then we filped the plug mold over, drilled holes to blow in compressed air and pump in water try to float the plug, none of these can help.
    Now we are breaking the plug, which will give me a terrible mold..

    Anyone has an idea about this??
  2. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    That's pretty bad luck, was the same wax etc used? Some times Duratech sticks up apparently, in the literature they reference sanding & letting the surface "breath" off the thinners & a wait before building the mold as some "surface energy" might lead to stick up.
    Looks like there may be some patient worrk in store in De-constructing the plug carefully.
    All the best with it from Jeff.
  3. coolgps
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    coolgps Junior Member

    Yes, wax applying is the same, the only variation is mixed spraying.
    Thank you Jeff.
  4. Wynand N
    Joined: Oct 2004
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    Wynand N Retired Steelboatbuilder

    You did not by any chance used something with silicon? This will guarantee stuck molds.
    BTW, it always pays to apply a thin layer of pva mold release to plug, no matter how well polished it is and you will always have a mold that release from the plug this way.
    To get the mold surface back to flawless if the pva left some light marks is easy and small price to pay for guaranteed release. :cool:

    FWIW, I always did my final (mirror) surface finishing on the mold itself and not the plug, hence I always used PVA release agent on my prepared plugs.
  5. coolgps
    Joined: Jun 2012
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    coolgps Junior Member

    We just used paste wax,meguair, 9 times waxing.
    It is the mixing spray killed me. The porosity of EZ sanding stucked the mold. When we pull off the plug, EZ sanding is still glued on the mold. We have to chip it off and give me a horrible surface to deal with..
  6. waikikin
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    waikikin Senior Member

    Here's Hawkeye's take

    Hawkeye Industries Inc.
    P O Box 415 Bloomington, CA 92316
    Tel 909-546-1160; Toll Free 800-977-0060; Fax: 909-546-1161
    Email Web www.
    Hawkeye Industries Inc.
    Duratec® Polyester EZ Sanding Primer
    Duratec Polyester EZ Sanding Primer (702-
    060 Black, 707-060
    Gray, 714-060 White)

    Pattern surface sticks to mold
    upon release
    Improper release preparation.
    Follow manufacturer’s instruc-
    tions when applying release ma-
    Primer not fully cured before
    compounding and polishing.
    Follow instructions in the appli-
    cation guide for pattern surfac-
    Excessive gel time for tooling
    gel coat.
    Follow manufacturer’s recom-
    mendations for gel time.
    Improper release materials.
    Use only sealer-glaze and wax
    release materials.
  7. tunnels

    tunnels Previous Member

    How big is the mould and what is it !! what's the plug made from ??
    Simple !!get the guys responsible and its there job to get the bits off and repair the mould till its totally finished !! :eek:.
    Basic rule one is never mix products !! never ever at any time !! :mad:
    if its possible dismantle and take the plug out in bits as cleanly as is possible . If it rips the gel coat off the new mould just do it any way then grind the edges and fill immediately with the same gel coat as the mould is made from !!
    It has to come off and there arnt any simple methods sorry !! :(

    I always take pictures of anything like this and print off big pictures and put them up on the wall for everyone to see but at the same time its a good learning tool as well ,specially good clear close ups to see what the damage really looks like !! :)
  8. tunnels

    tunnels Previous Member

    anyfeed back ??

    Well what is the state of play ??
    Did you manage to save the mould that's the main thing ??
    Would be really interested to see some picture s !! its not to boast about but to show others here what can happen if you don't do what you should and the consequents of trying to be smart or not thinking !! :D:p
  9. coolgps
    Joined: Jun 2012
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    coolgps Junior Member

    We have ripped off the plug with mold gel coat. The surface is terrible.
    You can give your email address, and i will send you some pics of it.
  10. tunnels

    tunnels Previous Member

    A great big THANK YOU !!

    just click on "TUNNELS" second one down the drop down list has a place to go and send private message off boat design messages
    So you are in China as well ??

    I have a huge library of mishaps and pictures of gel coat problems and bad glassing things usually associated with bad workmanship . In a really big workshop I carry a small pocket camera all the time at work and have been able to pinpoint lots of problems by zooming in on the pictures and seeing close up what and how things destroy during a stick up.
    There's a lot to be said for using Vinylester resin as well ,its stronger for the first couple of layers of glass and you get less fibre print through and plugs tear before moulds most of the time !! but does reduce damage significantly enough to warrant the extra cost !!
    Just found that from taking good close ups pictures and zooming in on my laptop !! cant see some things with the naked eye !!:D
  11. coolgps
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    coolgps Junior Member

    OK, after i upload some pics on flickr. I will send you the pics links.
    I am a camera fan too. Nowadays, we can use cellphone camera to record everything. Pics are the proof of what was happenning and what you were doing.
  12. tunnels

    tunnels Previous Member

    I have been caught in the situation of being lied to by different people so that's one of the reasons for the camera also its had a marked affect on quality on most every job as no one wants to be caught making a shoddy job any more .
    Here I china when I pointed the finger at he person or persons responsible I got sick of being told " no it wasn't me " so I take photos and then they couldn't try to back peddle with a red face , has pictures have time and date and the person involved !! so get out of that one !!

    I started all this long time ago when I did wooden flooring . When I went to give a price for a job I took my measuring tape and my video camera and spoke into the camera all and everything including measurements . so had a recording of everything like wet carpets doors with leaks ,ranch sliders that didn't close properly ,rotten floor boards and the reasons why !! etc etc . Used to store on rewriteable dvds and keep for a year or so could wipe clean and reuse the discs over again . :D

    First time I ever saw this being done was 1993 in Japan when I lived there ,the guys digging in the streets where theres cables and pipes by the hundred going in all directions they always had one guy there with a camera watching and recording just about every shovel load of dirt that came out of a hole all the time they were working , so everyone was covered and no questions had to be asked !!.
  13. Herman
    Joined: Oct 2004
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    Herman Senior Member

    On plugs: Always have them breathe / cure for a while, then apply a sealer, then a release (the release can be a simple paste wax, like Meguiar M87.

    There is also a Rexco document, which recommends PVA for the mould, and the first 2 products from the mould, to reduce surface activity.
  14. tunnels

    tunnels Previous Member

    who really know all the anwers ??

    Yip I read that a while back after some one else posted it . Am inclined to agree with some of what they say but there's other things that should be added as well . not all products in every country are the same as whats used across the borders and over seas . similar yes but not the same . There are a great long list a variables and a short list of things that do work, will work and have worked for long time !!. its when people step over and try to use products that are not on the short list of mix things that's really should never be mixed . its one hell of a guessing game to look at a stuck mould / plug if you don't have all the truthful facts . our Scotsman friend was headed down this path and really didn't like hearing the truth of the possibilities of a potential disaster in the making and doing things that were a no no and charging off after he was asked a heap of questions !!
    So there's a million reasons why moulds stick to plugs and the margin for error is quite small as to why they don't stick if !! and in my experience once you have a system that works every time don't change it for any reason . waxes and how to apply is a questionable and there's never two people will totally agree !!. As is the use of and application of PVA release . I have a method I have posted and others have don't it and complimented on its ease of use and how easy the products released but in reading instructions it is the worst thing you can possibly do . so who do you believe !! Its all just good luck and keep your fingers crossed and pray a lot !!:eek:

  15. waikikin
    Joined: Jan 2006
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    Location: Australia

    waikikin Senior Member

    Great link Herman, glad I've been doing it the same "dumb old way" I was shown 30+ years ago.

    Some interesting points (to me) highlighted... from Herman's link to Rexco "Is There a Foolproof Way?

    Yes, there is a method to avoid the chance of sticking on mold initialization. In a word…PVA. Polyvinyl alcohol (PVA) is a parting film which forms a physical barrier between the mold and the part. PVA has been around since the beginning of the fiberglass industry and certainly is not considered new technology. PVA functions not just as a mold release but more importantly as a surface reactant which accelerates creation of an inert molding surface.

    Creating an Inert Mold Surface

    What has developed from … research is a mold initialization procedure that is as foolproof as we have at this time. The procedure is as follows:

    Prep the mold with a PVA compatible mold release agent.
    Apply PVA.
    Apply production gel coat (and optional laminate).
    Fully cure gel coat.
    Pull gel coat and clean mold.
    Repeat steps 1 through 5.
    Once 2 pulls with PVA are completed, prep the mold with the production release agent and run first production part without PVA.

    This procedure applies to cosmetic gel coated parts and avoids having to sand and polish the initial pieces. If parts do not require a high gloss finish, simply run the first 2 parts with PVA and eliminate the PVA for the 3rd pull. The reported sticking rate following this procedure is less than .1%, assuming proper PVA application. After 2 applications of PVA it appears that tooling surfaces become sufficiently inert.

    PVA – The Good, the Bad and the Ugly

    We’ve seen that with the proper application of PVA the mold break-in period can be accelerated and sticking frequency greatly reduced. However, PVA in itself can cause problems. The two most common problems are the PVA etching into the mold surface and polystyrene hazing on the surface. Both problems are a result of thin PVA. Remember, it is better not to PVA than to spray thin PVA.
    The problem with thin PVA is that the polystyrene from the production gel coat penetrates the film and becomes trapped between the film and the mold surface. The etching occurs when the tooling surface actually softens and deforms. Hazing of a mold surface is in reality microscopic sticking, which will tend to be chronic in that area of the mold.
    It is imperative to spray PVA in a film thick enough to be peeled off the mold in sample areas. When holding the film up to the light, no pinholes or porosity should be present. Proper PVA application involves using a siphon cup gun and gradually building up a number of thin passes to form a continuous thick film.

    The Logical Conclusion

    Here is a summary of the information:

    Polyester molds stick because of the surface reactivity of the tooling gel coat.
    Properly cured tooling gel coat is essential to reducing surface reactivity.
    A mold that has been initialized (broken in) has an inert surface.
    If mold release without PVA is used for the initialization, between 13-15% of molds will stick.
    The type of mold release has very little bearing on sticking of new molds.
    Assuming adequate coverage, the number of coats of release agent has little bearing on mold sticking.
    PVA accelerates the reduction of surface reactivity, creating an inert state relatively quick.
    The outline PVA initialization procedure has a significant effect on successful commissioning of a new mold.
    PVA must be applied in a continuous film. Remember, no PVA is better than thin PVA.

    The information contained herein is intended by REXCO to provide a more clear, non-technical explanation of why polyvinyl alcohol (PVA) coatings can be beneficial when working with a new or reconditioned mold. All information and recommendations contained herein are, to the best of our knowledge, accurate and reliable. Individuals should make their own tests, however, to determine the suitability of PVA for their own particular purposes and uses."

    The above really reinforces what I was taught as an apprentice. One job I had a stick up on was molding some 1/4 internal corner molding taken from the outside of some large PVC storm/sewer pipe.... apparently a very reactive surface, I'd molded off similar with epoxy just using wax very successfully, on my first gelcoated/polyester ones a very well bonded part resulted, lucky the tooling was "cheap". The only way I could pull the moldings was to shoot a multi pass, very thick layer of PVA. With care & low dust conditions the PVA had good gloss &I've seen some $hitty molds look better after a PVA spray.
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