Shrinking Tissue 101
If done the right way, applying tissue on balsa wood wing structures and other parts of model airplanes can be the most rewarding part of the build.
This article deals with the shrinking phase of the tissue applying process—but before we start, here is Tip Number 1:
Learn to put on tissue the right way here:
First of all is a shout out to a page on the Volare Website that has a list of videos that are really worth your time if you want to learn how to put tissue on a model aircraft. There are 5 separate videos in a series called: Ronny Gosselin’s How To Cover a Model with Tissue Videos. They are EXCELLENT! You can find it by clicking on the 4th button from the left on the navigation bar on the Volare web site, or directly HERE. Halfway down the page you will see a section called “External Pages — pages and videos created by others. It is here that you will find links to the Videos. Or you can access them here:
If you watch these you will be a master of the craft in no time!
Tip Number 2:
After applying the tissue comes a critical part of the process — The Shrinking of the Tissue—here’s how.
Shrinking the tissue is done by misting the tissue lightly with either water or 70% or 91% isopropyl alcohol. Which ever one you choose is a matter of preference. Water is the more aggressive of the three but I believe it produces the most shrinkage, which is good in most cases but can be to your detriment, depending on the project. 91% is the least aggressive, and with my experience you can re-mist the process several times to get the desired tautness, each time it seems to get a little tighter. If you believe your structure is strong, I usually will go straight to water if I believe the structure will take it. If you get too much liquid on the tissue, which is easy to do, I have taken Kleenex or toilet tissue and carefully swabbed the tissue to take up most of the water. What you don’t want is pools of water sitting on the tissue. Most tissue will handle this OK but you need to be gentle, remembering that in this state it’s not very strong.
When the tissue is dry, if you notice a spot that has a wrinkle, chances are that it can’t be helped, but I have found sometimes that if you re-mist the spot and let it dry again, that the problem area goes away. It won’t hurt to do this several times—and sometimes your insistence will pay off . If the wrinkle doesn’t go away, you will know that you need to improve your tissue applying skills. Practice is the word of the day here. The above videos will help with this.
As you might know, Esaki has shut down production so Mt. Fuji is a great alternative IMO.
I’d like to point out here that it’s not a good idea to try to shrink tissue on delicate indoor models as the process of shrinkage can easily warp these structures, as some modelers unfortunately have found out about this the hard way.
Study the picture at the top of the page and the picture at above right. Half of the wing in the picture at the top of the page has been held down flat on top of a piece of plate glass by metal rulers (stainless steel only—because of rust concerns) weighted down with sockets from a socket set. Plastic rulers work well also. You only want to do flat sections of the wing at one time so each part of the dihedral or multihedral is worked on separately.
Tip Number 3: Use glass for your work surface
A glass plate is used in this process because you know it is perfectly flat. While we are on the subject I should also note here that it also makes for a perfect work top surface to do modeling on as a razor blade and Windex for the most part removes any glue or spills. Even drops of CA come up relatively easy. Tempered glass shelves with smooth edges are what I use. I have three 8″ x 24″ glass shelves that I picked up at a ReStore inexpensively that I place top to bottom on my desk as shown at right. I can slide the first one over to install my portable vice and when done I can slide the glass back and place a cutting mat over everything when I am cutting tissue or other modeling.
If you don’t already have a cutting mat, I urge you to get one. The process of cutting tissue to size works infinitely better using the inch marks and grid of the mat in concert with a straight edge and Exacto knife. A great quality Fiskars 18 x 24″ cutting mat is around $16 at Walmart. Works great.
Next if you look closely under the wing there is a plastic ribbed shelf liner. This works extremely well to prevent the glued tissue from permanently sticking to anything. The author in the past has used Popsicle sticks to do the same thing, however they seldom are truly flat and they are a nightmare to position.
Tip Number 4:
In addition to placing a piece of glass underneath your part, use a product called:
I bought my shelf liner roll in the housewares dept at Target for around $8. A little goes a long way so it is entirely possible that it could be shared with other model builder friends. Cut it in convenient strips several inches wider than the cord length of the wings or parts you pan to use it with and make sure when you use it the ribs of the liner are parallel with the ribs of your airplane wing, and that the “pointy” parts of the shelf liner are face up as shown in the photo above. This allows air to circulate under the part as it’s drying. The nice thing about using this product is that it doesn’t stick to the tissue, and together with the piece of glass underneath makes it super flat—which is exactly what you want. Because it’s held down with the rulers and weight there is no warping.
Tip Number 5:
Let the part dry thoroughly—Overnight if possible.
After misting the wing with water or Alcohol (mist both sides) allow it to dry thoroughly — preferably overnight. You want not only the tissue to dry, you want the soaked balsa wood to dry under the weight of the rulers holding it down to keep it nice and straight. If you rush this step you risk introducing warps into the wing or any other part you are working on, if the balsa is still damp. If there are 2 sides to whatever you have like a fuselage for example, mist both sides so they dry evenly together.
The finished wing at last—ready for its final clear coat.
For the final tissue’s coating, instead of the traditional dope method, the author likes to use a product called Krylon Clear Spray Satin. It also comes in a matte finish as well. If applyed properly it offers a mostly water resistant finish and is IMO easier to apply. You will find that Easy Built Models and others endorse this way to go as well. It can be purchased at several stores including Walmart and Ace Hardware. Some projects I use satin but others I prefer matte. Try both to arrive at what you like. I like to put on a very thin but even 1 coat. You can easily overdo the paint which only adds unnecessary weight to the plane. If at all possible, it is advisable to pin down the part to keep it flat similar to what is shown above. In some respects it’s less critical IMO because the balsa is not dampened with something that will warp it as easily. Do your test spraying on something other than your model to get a feel for the way the finish lays down and the resultant finish you are after.