FibreGlass help

Discussion in 'Boat Tips' started by RT1, Mar 2, 2006.

  1. RT1

    RT1 New Member

    Messages:
    28
    State:
    kansas
    Hi guys,
    need some tips/help on fibreglass molds,i have a mold that i want to lay fibreglass over,what do i need to put on the mold to let it release itself,i was guessing i might be able to apply vasaline but not sure if that will work or not ,and how long do i need to wait to keep adding FG as i want to build this up pretty fast,and should i let the first coat completely dry and slip it from the mold then continue to add the reat of my layers.
     
  2. davesoutfishing

    davesoutfishing New Member

    Messages:
    479
    State:
    Menominee Michigan
    PROPER MOLD CARE

    To extend the life of your molds here are a few tips on how to care for them. All molds must be kept clean and free of debris. The pouring surfaces must be protected from scratches or gouges which will appear as defects in the concrete product. Molds, of any material, should not be dropped, thrown, hammered, or bounced. If demolding becomes difficult it is usually not the mold at fault. If the mold is clean and free of residue demolding should remain constant and relatively easy. To clean your molds a solution of warm soapy water and a soft brush is very effective. On fiberglass molds muratic acid may be used. Also on fiberglass and steel molds that become stubborn a proven method to aid in release is wax. After the mold has been thoroughly cleaned apply two coats of a quality car wax. According to label instructions. The mold will still require the normal use of a release agent after waxing. The wax will fill and smooth microscopic imperfections in the mold which concrete tends to grip. The wax application should be done every six to eight weeks or as needed depending on frequency of pouring a certain mold. Latex rubber molds have their own unique characteristics. Latex molds will at times absorb moisture from concrete. This causes the latex to swell and become too large for the fiberglass backing. The cure is simple. For two days out of seven, across the weekend usually, leave your rubber mold open out of its backing. Place in a ventilated area and allow it to dry out before reassembly. This is generally only necessary on molds which you pour every day during the week. A word of caution. Do not store, pour, or ventilate latex molds near or on fiberglass, steel, or ABS plastic molds. The reason for this is that contact between the latex and any petroleum product, such as release agent, will cause a rapid deterioration of the latex. It will soon become totally unusable and will have to be replaced.

    MOLD RELEASE

    To allow a finished concrete piece to be more easily demolded a release agent is applied to the mold prior to pouring. There are many different types and brands to choose from. There are two important factors to remember when choosing a release agent.

    1) There are different types of molds. This is in reference to the material from which the mold is constructed IE steel, fiberglass, ABS plastic, latex rubber.
    2) Some mold materials need to be seasoned before use and all require an occasional thorough cleaning.

    For molds made of latex rubber, from Nunnikhoven Group these come with a fiberglass backing or outer shell, a non-petroleum base product is needed. We recommend a mixture of 1 part caster oil to 8 parts methanol alcohol. This is a long proven reliable release agent for latex molds. You may also choose one of a variety of commercial products on the market. Be sure they are specifically for latex rubber molds poured with concrete.

    Steel, fiberglass, and ABS plastic molds require a petroleum based release for best results. Fiberglass molds must be seasoned prior to pouring. To season these molds release agent should be applied and allowed to dry three to four times over the course of two to four days. The mold should then be wiped clean of any excess residue and have release agent applied just prior to pouring each time in the future. We recommend Cast-O-Magic from Rostine Manufacturing as a release agent for these three types of molds. The choice is yours however to use whatever works best for you. The home-made formula for release agent, for these molds is 50% motor oil and 50% diesel fuel. Caution here because it may cause staining of finished concrete if improperly used or if inferior products are used to make this release.

    Please also note that in many instances the first one or two pours of a new mold, of material, may not yield a good piece. Give it a chance and by the third pour you should have want.

    Alcohol based release agents should never be used on plastic or fiberglass molds deteriorate them.

    Hope this helps
     

  3. RT1

    RT1 New Member

    Messages:
    28
    State:
    kansas
    Wow Thanks Dave,
    after reading my post i guess i should of put some more info in there,the mold is made of wood and has paint on it with some clear coat,i dont care if the mold doesnt make it out in one piece as this is a homemade mold ,its a baitboat i made out of wood.
     
  4. Snobal

    Snobal New Member

    Messages:
    40
    State:
    Canton, OH
    My dad made a fiberglass replica of a 56 T-Bird hood scoop. He used an actual hood that had been cut up before he bought it. If I remember correctly, he put a layer of wheel bearing grease in it as a release agent. May have to do some sanding to smooth the surface after removing the mold but should work just fine for you.
     
  5. metalman

    metalman Well-Known Member

    Messages:
    3,447
    State:
    IN
    Name:
    Winston
    RT I think you want to lay up on the outside of the "mold" you want to use. Is that correct?
    If so, that will make the outside of the part the rough or non-mold side which will result in a lot of finish work to get it nice.
    A better way might be to make a F/G mold from your part and then lay up the piece you want inside that.
    That will put the smooth mold side on the outside of the part you end up with.
    Car wax is an excellent releaser for simple F/G lay ups.
    We do this a lot in my shop, ask if you need more help /info...W
     
  6. RT1

    RT1 New Member

    Messages:
    28
    State:
    kansas
    i made a bait boat out of wood and now re-doing it in f/g ......I actually i did it today at work,and yea laid right up the out side (inside had alot of obstructions to deal with :rolleyes: ),used a product we have at work called invisalube ,sprays like wd-40 sets up like grease,(put about 5 coats of it on) it worked had a few spots that stuck were the paint was gone,but a little push and pull here it finally gave it to me :) ..and yea i can see the ruff side going to probly need some work.. so all ask this im going to put/have 4 layers of fibreglass on it,do i need to go ahead and get a semi good finish now before i add the other 3 layers or will the other layers bring it out ok,cause it really dont have to bad a first layer,got a few spots the dremel down.and my first 2 layers are regular f/g and the last 2 will be f/g mesh(didnt no there were different types :rolleyes: lol) hehe i think thats all the questions for now.. and thanks " Snobal ,davesoutfishing ,and metalman for all the help and info ..
     
  7. metalman

    metalman Well-Known Member

    Messages:
    3,447
    State:
    IN
    Name:
    Winston
    If you are going to add layers you need to sand the surface really well to get a good bond for the new layers. It doesn't have to be "smooth" but but you do have to sand the whole area where you are applying new layers. To avoid having to do that again, put all your new layers on one after the other while the resin is still tacky on the last layer you laid down. Once the last layer is on you can "paint" a few layers of resin over it, applying each before the previous layer has fully cured. That will make it the same as one really thick layer as they will all chemically bond to each other during the cure. When it has all cured you can then sand it to get a nice smooth finish. When you are happy with the smoothness "paint' on a couple more coats of resin same as before and that will give you a nice finish, kinda like varnishing it...W
     
  8. zappaf19

    zappaf19 New Member

    Messages:
    1,574
    State:
    Monticello,IN
    A friend use to own a boat factory and to release the hulls and decks. Mold release wax. You would still have to use the spatchala (sp) tools to pry with. But once the get loose they just POP out.
    Bill :)