Airfield Models - How To

Make a Magnetic Building Board System to Build Model Aircraft

October 30, 2014



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Airfield Models (http://www.airfieldmodels.com/)Magnetic Model Aircraft Building Systems

I have been building on a magnetic building board for years and do not see myself ever going back to pinning things to a board.

Building with magnets is the best system ever conceived.  My thanks to Eldon J. Lind for introducing me to this idea.

Throughout this site you can see how I use this building system.  There are so many advantages to working with magnets that I can't document them all here.  Study various photos in the gallery to see how I use this system.

This series of articles presents a detailed look at magnetic building systems.  Also available are free drawings you can download to make magnetic fixtures.  I sell fixtures and accessories if you do not want to make your own.

Why I use magnets instead of another building system

All systems have advantages and disadvantages.  If the disadvantage makes it less likely what I'm building is going to be accurate then it's a lesser system.  Magnets significantly increase my odds of building accurately.

  • Fixtures and magnets quickly fine tune assemblies into precise alignment.

  • Magnets and fixtures are rigid.  They firmly secure and hold assemblies where I want them.

  • Magnets apply varying degrees of clamping force.  I can join magnets using their own power for concentrated force or spread them for uniform pressure over a wide area.

  • Magnets allow me to create accurate, stable and repeatable jigs on-the-fly and that's what I love most about them.

My magnetic building system is simple, fast and very user-friendly.  It does what I want it to instead of fighting me each step of the way.

 
 

The Minimum necessary for an effective magnetic building system

Knight Stik

Knight Stik is one of many models I've scratch-built using a magnetic building system.  It was designed on the board which meant a lot trial-fitting and adjustments.

The only way I know that parts fit is to fit them.  Magnetic jigging can be assembled, tested and disassembled in only minutes.  I know my jigs will work well in advance of using them.

See the gallery for photos of magnets in use.

Dry-fit using only magnets.

The fuselage dry-assembled using magnets and fixtures.

Structures can be removed from the board to do work outside the jig and then placed back in the jig exactly as they were.

I disassembled this structure several times when fabricating the kit.  All I had to do was move fixtures slightly away from one fuselage side while leaving the opposing fixtures in place.  Everything goes back into place exactly as it was.

A scratch-built "kit".

I can't imagine pinning all this together and then taking it apart to make adjustments just to pin it all back together again.  Model-building isn't about battling with pins.

I really don't like using pins to laminate edges.

Perfect conformity, nothing cracked and a strong joint.

 
 

Magnets

A small steel board hung on the wall is an excellent way to store magnets and magnetic fixtures.Ceramic magnets are the magnets to use.  They are large enough to be easy to handle and in the correct strength are unlikely to damage anything.  Ceramic magnets are available in a large variety of sizes and strengths.

Good ceramic magnets are not weak particularly latch-type magnets with steel plates attached.  The plates are poles that greatly increase the power of the magnet.

If the plates are removable then the magnet is dual-power.

The two drawbacks of ceramic magnets:

  • They can be broken if you're not careful with them.  Dropping or carelessly tossing them around the board is a good way to crack magnets.  Don't over-tighten hardware used to attach magnets.

  • If magnets and loose bits of metal (hardware, drill bits, pins, razors, etc.) are not kept away from each other you'll find all those bits every time you pick up a magnet.  This problem doesn't go away with other types of magnets.  An organized, uncluttered shop is a good thing no matter what building system is used.

Rare-earth magnets are much too powerful for model-building tasks.  At the correct strength they are very small and difficult to manipulate or remove.  They concentrate too much force in a small area.  Think about trying to separate small, powerfully-attracted disks and squares that are crushing your balsa.

Rubber magnets (craft and refrigerator) are very weak but may have their uses small stick models maybe.  I have some round craft magnets but haven't found a use for them.  The problem with them isn't their strength but that they are cheaply made.  The disks are obviously punched from sheet and have a tapered edge so they can't be counted on to hold anything square.

Electromagnets - All the magnets must be in place exactly where you want them when you turn on the juice.  All the magnets let go at the same time.  This system won't work well for us.

The magnet that I have found most useful is a latch magnet.  These can usually be found anywhere cabinetry supplies are sold, but will be expensive if you buy them that way.

I purchase part number CA41LWH from The Magnet Source.  Each of these magnets is advertised to have 12 lbs of holding power with the metal plates attached.  I didn't measure the actual pull, but they stay in place - even when bending 3/8" square spruce.

The magnets are much less powerful without the plates, but are very useful in lighter duty applications.

Forty magnets will not get you very far when you get deeper into using the system.

If you're serious about building then I suggest you start with 100 magnets.  If you make your own fixtures you'll need 200 magnets.  A set of 20 fixtures uses 80 magnets.

When you start building a wing using 4 or more magnets to properly align each rib plus magnets to hold the spars, leading and trailing edges you'll understand why you need a lot of magnets.

A storage board (right) is a very good idea.  It stores your magnetic tools where they stay together and are not attracting loose metal items in your shop.  Mine is mounted on a wall where it's accessible but out of the way.

 
 

Magnets vs. the most used System - Pinning into Soft Boards

Like many people I was told pins were the way to build model airplanes.  They are a way to build but not the way to build.

Pins are fiddly, easily dropped and a danger to your body and to your animals who might think they are something to play with.

I used pins for years but there were too many things I didn't like about them and I wanted something better.

  • Pins do nothing for vertical alignment.  They hold parts to a board and to each other but do not apply clamping pressure more than a fraction from their location.  Pins are rigid for about 1/8" inch and from there they can't be trusted.

  • If wood is strongly resisting bending to shape, the first pins placed won't hold it and may split the wood.  That usually means weighting or clamping until pins are inserted.  Often the clamps are in the way of the pins being inserted.

  • Inserting a lot of metal-head pins heads through balsa wood and into boards using my thumb loses it's appeal pretty quickly.  Plastic pin heads have broken during insertion which sent the newly exposed bare metal end of the pin deep into my thumb or finger.

  • Magnets can suspend and clamp leading and trailing edges.  The pin way is to cross-pin through the leading and trailing edges at every single rib.  It's one magnet per rib instead of two or more pins.  It takes one minute instead of however long it takes to put all those pins in place.

  • Pins punch holes through the wood.  I don't find that objectionable until I accidentally bend a pin and it rips a big hole in the wood that can't be repaired without leaving an ugly scar which as far as I know could bring the end of the world.

  • A pin hole is only tight once or twice.  If I have to pin a part in place to dry fit it and make multiple adjustments then the pin won't hold securely when the part is glued in place because the hole has loosened too much.  That means I have to pin it differently than I did when I dry fit.

  • After a pin is in place it is difficult to fine-adjust the assembly without completely removing the pin and reinserting it in a different place.

  • I haven't found a surface into which pins are easily inserted yet hold with security.  I always feel I have to tip-toe around the model because bumping it might mean a bunch of pins coming loose.

  • My shirt sleeves snag on pin-heads protruding from the structure and usually pull the pin.

  • Boards that accept pins (ceiling-tile, drywall, etc.) are generally warped or curled and must be held to a workbench using weight, clamps, adhesive or hardware.  They also tend to decompose around the edges unless taped or sealed in some way that thickens the board around the perimeter.

  • Replacing pins in a cushion is tedious and time consuming.  Storing pins in a container meant having pins stuck in my fingers when retrieving one.

 
 

In this series

Making the System

Steel Building Surfaces

Download Drawings

Also see

 
 

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How to paint a scale pilot bust
How to make a wing cradle

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