Title
Creating Your Own Air Duct

Author
McKay

Published
Saturday, July 14, 2007

I came across this problem while building my Porsche 959. I needed air duct tubing to finish the connection to the Turbo units. The only after market product I could find was from Renaissance, France. Their product looks very nice. It is available in two colors, three sizes and very expensive. I wanted something that I could make, in any size and color. So on another forum I posted the question for help. I received the idea of using wire and Plumbers Tape from a guest user. Plumbers Tape is a very thin white Teflon material. It is used to seal pipe threads. You can purchase this product just about anywhere plumbing supplies are sold. I made this idea even better by discovering that adding Polymer Artist Medium to your acrylic paint will make painting the duct tubing easy, with a flexible and chip resistant finish.



Begin by selecting brass wire of any gage size from 20 to 30, depending on the scale and application you are working with. Any other type of solid metal wire with casing removed can be used. Just make sure that it is easy to work with. Wind your selection of wire around a tube the diameter that you need. In the photo above the brass tubing is 1/16" diameter and the wire is 30 gage. If you have ever made your own springs on previous builds you will be at home for the next two steps.



Wind the wire nice and tight and bunched together to start. Trim excess wire.



Roll the tube on a flat surface with the wire still on it and this will help tighten it up.



Next, spread the spirals out in a uniform manner until you get the length you need. From the length of the wire you see in this picture you can make two smaller segments of duct tubing like the finished units shown above.



Next you apply the Plumbers Tape. This can be tricky. It is very thin and flimsy. Did I mention that Plumbers Tape is made of Teflon? Nothing sticks to Teflon right? Well this tape does stick together. Don't start in the middle as is in the photo. Start from the left and work to the right. Apply the tape well before the first spiral and wind overlapping the previous round until you end well past the last spiral. While you overlap as you wind around the wire be careful not to double up too much. Work at this step until you get it right. Practice makes for a perfect job.



Roll the wire and tape combo between your fingers while it is still on the tube. This will help the tape to stick together. Do not press too hard because the wire will cut through the tape. Trim any excess tape from the ends.



In the above photo I have cut the wire in half to give me the two pieces of duct tubing I need. On the CD paint palate I have some gray Tamiya paint and a small drop of the Polymer Artist Medium. Polymer Artist Medium is an acrylic liquid used to make paint more flexible, with elastic properties. Just mix a little with your brand of choice acrylic paint.



You may not cover the duct tubes on the first coat of paint. Nothing sticks to Teflon. Right! Well paint will stick and when it dries you will be amazed at how flexible the finished product is, so be prepared to apply a second coat. If you are making several duct tubing pieces then I recommend you mix up a batch of paint and polymer in a container that can be closed air tight.

Here are two photos of the final product mounted on the model.





You can really have a lot of fun with this. There is lots of flexibility such as tube diameter, length, and color etc. As you continue on with other model projects you will no doubt find many uses for this technique.