Written by Jerry Smith
Tips for covering with film
Product Review
As seen in the March 2019 issue of Model Aviation.
Throughout many years of model building, I have covered aircraft with all kinds of material. I have used nearly every kind of film covering from the very lightweight types to heavier MonoKote and UltraCote.
For larger, heavier models, I prefer MonoKote. It was the first on the scene back in the mid-1960s. I can remember going to the Toledo Show and watching Sid Axlerod of Top Flite demonstrate his newfound wonder with a crowd of modelers looking on in amazement. MonoKote and other films have changed the way we cover our models throughout the years.
It was not initially accepted by those who used silk and dope and painted their models. To them, it cheapened the model and they looked down on it, but Sid kept selling it, and in time it became a desirable covering medium.
Covering Steps
- Sand the airframe to perfection.
- Clean the workbench and airplane parts with a vacuum.
- Seal the covering all the way around after trimming with the iron set at 225°.
- Use a heat gun to shrink the covering.
- Iron the covering to the wood with the iron set at 350° using an iron sock.
- Apply any graphics.
Some people have become experts at covering with it. Their airplanes have no wrinkles and look as though they were painted. They achieve this with patience, learning how to use the film and how it reacts to different temperatures and, above all, sticking with it. Of course, we don’t cover models every day and it might be a long time before we do it again. For that reason, it is a good idea to keep notes to remind yourself of how you did it.
Everyone has a different approach to covering. Whatever works best for you, keep on doing it. Here is the way that I cover to get smooth, wrinkle-free surfaces. I hope you will get some tips that will help you with your covering.
Sanding the Airframe
This is where you lay the foundation for a good covering job. Joints, dings, and dents are often not filled and sanded to a level condition, creating an uneven surface. This will show through the covering. Pay close attention and make sure to do this.
I use Hobbico HobbyLite balsa-colored filler to fill dents and uneven surfaces. White won’t look as good beneath transparent covering. Sometimes during the building process, I see a need for filler and apply some to save time later while it cures. When encountering a particularly rough surface, I use a Great Planes Easy Touch sanding bar with 80-grit sandpaper.
I then go over it with 220-grit sandpaper and finish with 400-grit sandpaper. I can’t stress the sanding part enough. I typically spend more time sanding than covering. Sand, sand, and sand some more.
After the parts have been sanded, get out the vacuum and clean. Clean up the workbench and the surrounding area. Now run the vacuum over the aircraft parts and keep it handy for in-between parts covering. Removing the backing creates static electricity, attracting dirt and dust. Good housekeeping is the rule.
Plan for Covering Usage
Lay out the MonoKote roll with the back side up. Now lay your parts down and trace around them with a Magic Marker. Plan for the best usage as you go along. Trim around the outline leaving a 1-inch margin. When laying out two pieces that include the other side, flip the parts so that the glue side of the covering is against the wood. Don’t get caught with two pieces that look alike. You need opposites.
Seal the Edges
Set your iron temperature at 225°. Center the piece on the part and tack the covering at one end. Now go to the other end, pull gently, and tack it. Go to the middle and tack both sides, gently pulling the covering. After you have it arranged, seal it all the way around. Roll the iron outward away from the part as you do this.
Trimming the edges can be done with scissors or a sharp blade. I use both, as well as a Harry Higley Eversharp Trimmer for perfect overlaps and seams. The trimmer uses inexpensive razor blades. Machined from solid bar stock, the film travels in one of eight slots, which provides eight cutting edges!
Get Out the Heat Gun
After covering both sides, lay the part down on a flat surface and apply heat to the covering. Let the hot air blow over the surface, not down on it. You can control the heat by holding the gun level with the surface then tipping it upward to get more heat.
It is important to keep the heat gun moving. Spending too much time in one spot or letting it touch the covering can cause an unwanted hole to appear. At this point you should have a mirror finish on the covering and be tempted to leave it, but not yet!
Turn Up the Heat
I generally use two irons: one for sealing and one for ironing down, which is the final step in my covering process. For this purpose, I set the iron temperature at 350° with an iron sock installed.
Lay the part on a flat surface. If it is a large part such as a wing, weigh it down before ironing the covering to prevent warping. On the sheeted surfaces, lay the iron down and move it in a circular motion, ironing the covering to the wood. Do this at every place the covering meets the wood. This will keep the wrinkles out and give you a nice, tight covering job.
MonoKote Over MonoKote
Sometimes we trim our airplanes to make them look better and stand out. After the aircraft is covered with MonoKote, why not use the same material for trim? A good example is putting a stripe down the side of the fuselage. This is not a problem. Here is how I apply mine.
First, clean the application area with alcohol, making sure it is dust free. Next, spray on a little blue Windex and push around the area with your finger. Lay the stripe in place, pushing it around to make sure it is straight.
Using a credit card as a squeegee, start from the center and move out, wiping away excess Windex with a paper towel. Keep squeegeeing until all of the moisture is gone. Heat your iron to 200°. Using an iron sock, iron it down in a circular motion and this will be a perfect job every time.
This method can be used to apply any MonoKote over MonoKote. I have not tried other types of covering with this method; however, it is likely to work as well.
There you have it. This is my way of covering using MonoKote. I have had good success with this method. I hope it gives you some ideas and will help you with your next covering job. Good luck!
SOURCES:
MonoKote
(800) 338-4639
Harry Higley and Sons, Inc.
(410) 732-3500
Hobbico HobbyLite Filler
(800) 637-6050