Removing Covering from Wood-Constructed Models


Written by Greg Gimlick
How to Do It
How-to
As seen in the Fall 2015 issue of
Park Pilot.


It doesn’t matter how good of a pilot you are, sooner or later, something bad is going to happen and you’ll be faced with a repair. Usually that repair will involve stripping off some covering to fix the damage and then preparing the model for recovering. If you’ve tried it and had trouble removing the little pieces of covering that seem to stick with a vengeance, don’t lose heart—just read on.




The tools required to remove covering are few.


The tools are simple: gather your heat gun, knife, gloves, isopropyl alcohol or acetone, clear packing tape, and sandpaper. The first step to removing the damaged covering is to give it a little heat. Don’t heat it to the point that you shrink the covering—simply enough to soften the adhesive.




Heat the covering and carefully begin to peel it back.


If you’re only stripping it back to a particular spot, you might want to score that stopping point with a knife or razor blade. Be careful not to cut into the wood. Score it only enough to cut the covering.

After you’ve softened it with a little heat, you can begin to peel back the covering. Work slowly and reapply a little heat if necessary.

The Lazy Bee in the photos has been waiting for repair for approximately 18 years and it was covered more than 20 years ago. That covering is stuck on well and has become a little brittle with age, so it’s stubborn! Working slowly got most of the covering off, but as you can see, some pieces refused to come off.




Little bits of covering will likely remain. They can be heated, covered with clear tape, and peeled again.


When you’re down to the little pieces that refuse to come off, grab your heat gun and clear packing tape. Heat the spot slightly more, and while it’s still warm, stick a piece of clear tape on it. Press it down completely and then give it a little more heat. Slowly begin to peel the tape off and watch as the stubborn remains come with it.

The process won’t always get it all, so just reapply the tape and work it some more. This is not a speed contest. Work slowly and repeat the process as necessary.

When you’ve removed as much as possible, you might see some discoloration on the wood. This is usually glue and paint residue, and not the actual covering. This can be removed using a rag and either alcohol or acetone. Remember to wear a mask and gloves while using acetone and use it sparingly. Stay away from any ignition source (water heater, furnace, etc). I try isopropyl alcohol first because it’s less toxic and less volatile.




After a wipe with isopropyl alcohol to clean up the paint residue, sand the surface clean.


If you’ve had to use solvent to finish the job, let it dry completely before moving to the next step. The final step is to sand before re-covering.

Sometimes, no matter how hard you’ve worked, you’ll still see a little color in the wood, although it’s smooth as a baby’s skin. This won’t be a problem if you’re recovering it with the same color because the main goal is a very smooth surface.

If you’re going to apply a different color, you may want to work a little more with the acetone and sandpaper until the discoloration is completely gone. If the new covering is a darker color, it should cover the remaining color residue.




This same process can be used for framed structures.


The key to removing covering is to go slowly and methodically. Don’t try to simply pull it off cold and fast. Always use a little heat to soften the glue and covering. It’s not a pleasant job, but doing it properly results in a repair job that doesn’t look like a repair job.

Whether you’re stripping sheet wood or a framed structure, the process is the same. Go slowly, be precise, and get your favorite airplane back in the air.

-Greg Gimlick
maelectrics@gimlick.com






Article: 

9 comments

Be sure the Acetone has evaporated before reapplying the heat gun! Fire would ruin your recovery process. Acetone is very volatile- be sure you are working in a well ventilated space as well (basement is not good idea unless you have good air exchange!)

The method described in the article works fine with Monokote or similar. I have several old models covered with silk and dope. Sometimes old silk tears up as you are removing it, but if you carefully work using dope thinner or maybe laquer thinner it can be removed successfully. A little heat can be used on silk as well. Color sometimes remains as you describe, but careful sanding usually works. If you are going to recover with one of the plastics they tend to cover up the remaining color.

I don't fly too may balsa planes. But,now I may. Since I have a working knowledge of repairs.

Thanks

No mater how long you are in this sport there is always something new to learn. I liked the clear tape idea. I always would use a hobby knife. But occasionally you would catch the wood a mar it.

Instead of scoring with a knife to create a line I like using pencil soldering iron. Have use a light touch but you assured no cut.

Great article. Thanks for sharing.

I've scanned this article and saw nothing about working on stick & tissue models with SILKSPAN covering. This covering may have been adhered using dope or water -based polyurethane (WBPU)

It seems to me that there is no truly satisfactory method for such removal. Any help?

I enjoyed reading the article and the helpful hints good ideas.

Good info.

I found this basic instruction very helpful, thank you!

Thanks for article that was great, I always wondered how to get old covering off

Add your thoughts to the article

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.