Print this articlePrint this article


Written by Don Slusarczyk
Free Flight Indoor
Column
As seen in the April 2016 issue of
Model Aviation.


For many years, as I razor-planed down my glider wings, I wondered if those shavings of wood could ever be reused, especially when they were from a nice piece of 1/4-inch, 4- to 5-pound C-grain balsa. Most of that great wood ended up as scrap in the garbage can. The curls of balsa were very tight and the wood was cracked, so it was not usable. This was something one simply accepted when making a glider.

Throughout the years, I saw that some people were actually successful using razor-planed wood for EZB propellers. It was not until I saw sheets cut by Jeff Hood during a local contest, and how well the sheets came out, that I decided to look into this method.

Jeff published an article about razor-planing wood in the 2009 National Free Flight Society (NFFS) Symposium. His article was well written and allowed me to successfully cut my own sheets using this method. I know some have never read this article, so I will provide a quick guide on how to use this technique.

The first item—and the most critical—is the razor plane. I use a David Combi Plane. It is difficult to find in the US, but can be purchased from sources in the United Kingdom for approximately $12, plus postage. I suggest buying two, as well as a spare pack of blades. A quick Internet search shows the plane and spare blades can be bought from HobbyStores. The company ships to the US.

The reason for this specific razor plane is because the wood is cut at a shallow angle and does not crack as it curls.

When you have the razor plane, you need to wet-sand the bottom of the razor plane to make it smooth and flat. The David Combi Plane is made from cast aluminum and the bottom is milled, which is okay for general planing, but if you want to cut sheets down to .005- or .006-inch thick, you will need to polish the bottom of the device.




The razor plane on the left needs a little more work to remove the machining marks. The one on the right is ready to use.


To smooth and polish the bottom, get some wet sandpaper in grits ranging from 400 to 1,500. I buy single sheets from my local Ace Hardware.

This next step will take some time, but it is worth the effort. I used a small piece of glass as my sanding base, but anything will do as long as it is smooth and flat. The sandpaper is placed on the flat surface, then some water is added to the paper.

Lay the razor plane on top of the wet sandpaper and start sanding by moving the razor plane in a circular motion while pushing it down slightly. After a few minutes of sanding, lift the razor plane up and rinse the sandpaper with some clean water. A small container of fresh water nearby makes it easy to clean the sandpaper.

Go back to sanding. I watched a TV show while doing this to help pass the time. You will eventually see all of the machining marks disappear from the bottom of the plane. When this happens, go to the finer grit to polish and make the bottom very smooth.

Now you are ready to start making some cuts. Install the blade and set it to make a cut approximately .010-inch deep to get a feel for using the razor plane. You will want to use a balsa sheet roughly 1-inch wide or less to be able to cut a full-width sheet across the plane’s blade. For practice, I used 5- to 6-pound wood approximately 1/8-inch thick.




The razor plane needs to be skewed approximately 45° to achieve the best cuts.


To make your cut, skew the razor plane roughly 45° to the sheet. Go at a slow, but steady, pace. After you make your first cut, you will need to measure the thickness to see how deep you are cutting and whether the sheet is the same thickness across the width. Make adjustments to the blade to get an even-depth cut across the width of the sheet at the thickness you want.

The reason I suggested getting two razor planes is that you can set them up for two different thicknesses. I have one set to make cuts approximately .006-inch thick, and one set for cuts roughly .010-inch thick. This way I do not have to readjust the blades each time because it can be time consuming. After you have it dialed in, you can start planing the good, lightweight wood.




Only a few minutes of work will yield a huge supply of propeller wood.


As you start planing, you will be able to achieve one long rolled-up curl from full-length, full-width sheets. When you have cut approximately 10 of these curls, you can start to flatten them. Fill a sink with hot water then drop the curls into the water. They will begin to uncurl and soak up the water.

After a few minutes in the warm water, carefully take out the uncurled sheets and lay them on a sheet of glass. I run my finger along the sheets to press them to the glass, squeeze out excess water, and let them air dry overnight.




Flatten the wet sheets on a glass surface to dry overnight.


When removed from the glass, the sheets will be fairly flat and perfectly usable for making EZB or F1L propellers. The sheets can be sandwiched between larger blocks of balsa for storage, which will also help keep them flat.

Until next time, keep the weights down and the times up!

Don Slusarczyk
don@donsrc.com


Sources:

HobbyStores
www.hobbystores.co.uk

NFFS
www.freeflight.org






3 comments

Great article!! Would love to see more like this!

Great article, I heard this from a fellow
Indoor modeler and I thought he was putting
Me on! It just goes to show, modelers
are eternally creative. Thanks for the
article.
Sincerely
Jon B Shereshaw
NJ, USA
AMA 23895

Great, Will try it soon.
Thank You

Add new comment