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Build with Magnets

Written by Webmaster

Building a plane from scratch might not be considered a dead art, but it is dying. With the proliferation of inexpensive ARF's, not many people seem to want to build anymore. When I got into this hobby I was immediately drawn to building a plane for myself. My main motivation was to have a plane that was "one of a kind" and I would know that everything was done correctly.

When I wanted to build my first plane, I needed many things to get started. The thing I needed first was a table to build on. I had the idea to get a large metal desk from a used office supply store which turned out to work great. However, I didn't want to build directly on top of this desk since the top wouldn't last long. I visited many websites dedicated to building from scratch and took notes on how they assemble their planes. Just about every website suggested using some sort of material that you can stick push pins into, such as acoustic ceiling tiles. Some use glass tops to build to and just tack glue their parts directly to the glass or use lead weights to hold parts in place. Just before I decided to mimic their building practices, I came across a website that made a strong argument for building planes using magnets. After visiting the website http://airfieldmodels.com, I decided to make my own magnetic building board. I highly suggest that if you are interested in the art of building from scratch that you check out that website. The author of the website is extremely talented and does some beautiful planes that are one of a kind.

buildingboard1Above is the outer wing tip of the Top Flite Corsair 60 kit I’ve been working on. I use the magnets to hold the ribs and spars in place. I use the round magnets with a bolt through it. I then drilled a hole in a strip of 1/2” maple and used a wing nut to make a downward vertical pressIn the past, I came across the "Magnetic Building Board" from Great Planes that sold for about $130.00. It seemed like a great idea since you use magnets to assemble and jig up your build. However, it seemed kind of expensive, the building board seemed small to me, and you didn't get many magnetic fixtures. So I never gave this a second thought. But airfieldmodels.com showed for just a little more money than the Great Planes kit, you could have a truly impressive building board system. A recent check into the status of the Great Planes Magnetic Building Board has shown that Great Planes discontinued this product. So if you want this system of building, you'll have to make it yourself!

The first thing I had to order was 150 magnets from www.magnetsource.com. The part number is "CA41LWH" and if you order more than 100 magnets, their price was only $0.55 per unit. These look to be identical to the ones being sold in the Great Planes kit at a fraction of the price. They have a zinc coated plate on each side of the ceramic magnet to increase its strength when stood on edge. They have a rating of 12 lbs of holding strength. I also ordered about 10 of their round base magnets (part RB45 and RB50). So for a little over $110.00 (this included shipping and handling) I had all the magnets I needed to get started.

Next, I needed some sheet metal. I had to give special thought to the size and type of steel I could use. I didn't want to paint the metal to prevent corrosion because I knew it would get scratched and the metal would rust. So I took a couple of magnets to KH Metals and Supply in Riverside to see what they had in stock. I learned that stainless steel isn't magnetic so that wasn't going to work. They did have a type of stainless steel that my magnets would stick to. The magnets weren't as strong as they would have been if they were sticking to true steel, but at least the surface wouldn't rust and I wouldn't have to worry about scratches. I spent about 40 bucks for a 4'x4' piece of metal (16 gauge) that they cut into three different parts for me. If I ever decide to remake my building board, I will get better steel so the magnets hold stronger.

buildingboard2These horizontal fixtures hold everything 90 degrees to the building board. This was helpful when dealing with the gull shaped root section of the CorsairThe final step was to cut the fixtures. I was able to make 24 fixtures from one 12"x24" 1/4" sheet of aircraft plywood. These fixtures range in height from 1-1/2" tall to 9-1/2" tall. If you decide to build one of these fixtures, make sure you find the flattest sheet of plywood you can find. I had to go to two stores just to find a flat sheet. I opted not to make my fixtures with the vertical presses. I have come across a couple of situations where I wish I did. I'll make more fixtures if it starts becoming a regular occurrence where I need a large vertical press. If you would like my cut list template that I used to maximize the number of fixtures I could get from one sheet of plywood, please feel free to email me  and I'll be happy to send you a copy. Once I cut all my fixtures I coated them with two heavy coats of polyurethane to protect the fixtures. Each fixture used four of the square ceramic magnets so I burned through 96 of the magnets which didn't leave me as many as I had hoped for as extra. Assuming you use two of the magnets per rib for instance, you can burn through a lot of magnets very quickly. In hindsight, I should have ordered 200 magnets. I have been able to make due with what I have, but from time to time, I have to be careful not to run out of magnets for whatever I might be building at the time.

Having built a couple of planes now, I couldn't imagine building using pins. I can cut and jig up parts without worrying about a pin falling out or shifting. I also have the added benefit of never causing damage to the wood by splitting it with a pin. This whole system speeds up my assembly time and ensures all my joints are tight and exactly where I want them to be. So dust off a small corner of your workshop and build a magnetic building table for yourself. I promise you'll get so much more satisfaction out of building a plane yourself!