HELP DIRECTORY - 9-M
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 NOTE : THE HELP TOPICS
The help topics consist of links and Help Topics accumulated over the years.
Many of them were from RCM Model magazine that is now out of business. 
Please review these help topics.
If we have a topic or LINK listed and you are the author and do not want this published in this E-book,
Just notify us and it will be promptly removed.
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  • TOPIC LISTINGS :
    Metal Shaping and Topics
    Metalshapers Association : This site is about learning how to shape metal. There is an album section for models: Hand Fabricated Metal Miniatures
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    Micro Aircraft
    DERA micro air vehicle - microjet
    Matt's Micro R/C Planes      Good site devoted to this increasingly popular branch of the hobby.
    Micro Flight USA     Online retailer of Electric Micro Helicopters.
    Shamim Mohamed     Soaring FAQ, Plotfoil software, plus other interests.
    Stefan Marti's Free Flying Micro Platform     autonomously hovering microhelicopters in different stages, from dumb to ultra-intelligent.

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    Model Linkages  Ailerons, Rudder, Elevator
     Pull-Pull Controls - Giant scale - R.Forgues
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      Model Tracking 
    Cheap and simple tracking for downed models

    MOLDING TIPS
    ONE PIECE FLAT BACK BLOCK MOULD
    A Flat Back Block Mould is defined simply as a block mould with an open back.

    A straightforward process of placing your Master/ Model into a mould box (containment field) and pouring liquid rubber over the Master.
    Once cured, the rubber is removed, resulting in a one piece mould in the shape of a block. This is the one of the easiest types of mould to
     produce and a wonderful introduction to the mould making process    .

    The Master/Model. You need to consider what your Master / Model (original piece) is made from. Some materials can cause curing
     inhibitions with certain silicones. If unsure, check with your supplier. Masters made from porous material (ie plaster, wet clay, cement etc.)
     will need to be sealed.

    Your Master / Model for this type of mould will need to have a wide, open, flat back. This open back will be where you will be pouring your
    casting compound. Consider if your Master / Model has any deep undercuts. Turn it upside down, imagine you are trying to remove it from
    your mould. Are there any areas where it will not come out of the mould easily. These are call undercuts. And if your Master / Model has
    deep undercuts, you may need to think about using a two part mould

    The Mould Box. The Mould Box or containment field will hold the liquid silicone while it cures. It will need to be approximately
    12mm – 20mm larger than your Master, on all dimensions and "leak" proof. So make sure there are no openings (except the top) or splits.
    You can use just about anything non porous for your mould box; a plastic cup, leggo blocks, take away container etc
     

    Seal your Master / Model if required. Glue or embed in clay to the base of your mould box (containment field). Ensure that it is secure and
    that all edges are sealed. You don’t want the rubber seeping under the base of your Master.

    Assemble your mould box around the Master, allowing approximately 12mm – 20mm around all edges and above the highest point of your Master. This will be the thickness of your mould walls. Your mould walls will need to be this thickness to support the casting compound while it cures. Place on a flat, level surface. If you are using a mould box sitting on a tile or similar, use some non - porous clay (Klean Klay)
     and seal the bottom edges of the mould box. This will help prevent leakage.

    Measure your rubber Part A & Part B into separate cups/containers, according to manufacturer’s instructions (Ultrasil is a 100:10 mix).
    For example 250gms of Part A = 25gm Part B. If your silicone is measured by weight, the use of digital scales is recommended.
    Use a flat-sided stirring instrument, such as a spatula, paddle pop stick or knife. Stir slowly and deliberately ensuring that you scrape the
    bottom and sides of your mixing container. Use a scooping motion rather than a whipping stir. This will assist in keeping air bubbles
     to a minimum. Allow to sit for several minutes. You will see the air bubbles rising to the surface. Most moulding rubbers allow approx
    20 minutes to mix and pour, so no need to rush the process

    Pour the silicone rubber into the corner of your mould box, from a height of around 150mm, in a slow, thin, constant stream.
    Allow the rubber to rise up and over your Master. Pouring the mould rubber in this manner helps in the dispersion and minimizing of air
    and air bubbles. Air bubbles will continue to rise to the surface as the rubber cures.

    If your master has very fine detail, you can use a disposable brush to brush a first layer of silicone, using the brush ensure silicone gets
    into all areas. Then continue to pour the silicone as above.

    Leave the mould to cure. Curing will take between 1 and 24 hours, depending on the moulding material used.

    Use the old "cake test" method to check your rubber has cured. Push gently with your finger, if the rubber bounces back and the
    correct curing time has elapsed (or close to it) it is ready for demoulding.

    A spatula or flat sided tool comes in handy here. Gently push the spatula between the rubber and your mould box to "break the vacuum",
    between the rubber and mould box edges. Then break apart your mould box. Slowly lift the rubber away from the base of your mould box.
    You may find that the Master will let go of the base and remain in the mould. Don’t panic. Gently remove your Master from the mould.
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