By Ondrej Mitas and Wout Moerman
9 April, 2006
This article was originally published on article section of the small Flying Arts website.
Wout: As my re-entry in building stick-and-tissue models takes place on the dining table in the living room, I soon was trying to find a substitute for dope. When browsing on the internet I found a possible substitute: Future Floor Finish, which is sold in the Netherlands as Pledge Parket Plus.
Andy: I’m on a perpetual quest to find chemicals that allow me to build good models without the headaches I always get from dope, acetone glues, and even Krylon spray. For a covering sealer I wanted something that I could brush on, thin and dissolve with water, and use to good effect on models that required additional strength from their covering, like light Dime Scale models.
Wout: "Future" is a water-soluble acrylic floor coating which dries into a completely clear, waterproof, tough and flexible layer. As it does contain ammonia it is not completely odourless, but the smell is less annoying than the smell of dope. Brushes can be cleaned with water directly after use. Hardened Future can be dissolved in an ammonia solution. More info on Future and its different names can be found at:
In this article we will show different techniques to use Future:
- dry covering
- wet covering
- Dried tissue
- pre-shrinking and pre-doping
- tissue over tissue
- tissue over foam
Wout: The balsa frame is coated with diluted PVA-glue, and a slightly
oversized piece of tissue is put on the coated frame. The tissue is pulled taut
to remove wrinkles. The excess tissue can be removed after the PVA has dried.
The tissue is coated with Future, which contains enough water for a moderate shrinking action. If the tissue is very sloppy it can be watershrunk before applying Future. Normally this will not be necessary.
Wout: When tissue is used for covering complex forms it is better to use wet covering:
- coat the frame with diluted PVA,
- coat the rear of the tissue with Future,
- place the tissue on the frame and try to smooth as much as possible,
- the remaining wrinkles should disappear when the tissue dries.
In this example green Esaki tissue is used which has been sprayed with Tamiya spray paint (rattle can) before covering. The sprayed tissue can be used as regular tissue. If dope is used over spray paint it will smear the paint, but Future can be used without problem.
|Coat with Future||Cover wet. The curved surface can't be covered without wrinkles||Dried the covering looks perfect!|
Andy: I now use wet covering on everything except the most fragile structures (indoor models and tail surfaces). My procedure is a little different from Wout’s. I cut each piece of tissue to the size & shape needed and dip it in water. While it dries from wet to damp, I brush Future on the frame. Then I place the damp tissue on the frame, starting in a corner, and take advantage of its wet strength to pull it tight. If it is a wing, it is advisable at this point to pin it to the board in a jig to keep it flat or even warp in a little washout.
Covering fragile structures with pre-Futured tissue
Andy: Light indoor models do not require any kind of sealer for the covering, as the structures are not dependent on the strength or water-repellance of the covering. The tissue should, however, be pre-shrunk, so that the humidity in the air does not warp it over time.
On the other hand, on the fragile tail surfaces of an outdoor model, you may want to seal the tissue for reasons of strength or appearance. I’m going to explain a procedure that will allow you to either pre-shrink or pre-seal tissue with Future, then apply it to get a tight, attractive finish without warping. I use a Styrofoam meat tray as a shrinking frame.
The meat tray sits right side up on my workbench. I brush full strength Future over the edges and apply the tissue, as if I was gluing a covering to the top of the meat tray to cover its contents.
After the Future dries, I now have a sheet of tissue loosely covering the top of the meat tray.
If it’s sprayed or brushed with water at this point, it will sag, then shrink and tighten. Peel or cut it free and let it “breathe” for a few hours before covering an indoor model with it. It won’t be perfectly smooth once cut off the meat tray for a while, but it won’t warp your model.
|Rand insmeren met lak||Droog papier eroverheen leggen||Na het drogen met lak bestrijken|
For tail surfaces of outdoor models and other applications where very slight tension and strength is needed, I paint the tissue with thinned 50% Future (instead of spraying with water) while it’s stuck on the meat tray frame. It will tighten as it dries. The key to a tight covering job with such pre-doped tissue is to cover immediately after you cut it off of the meat tray. It will maintain its smooth, tight finish but shrink very little. My Nickel Scale RWD-5, published in the Tissue in 2006, flies with Future pre-doped tissue on wings and tail surfaces.
Wout: When tissue is used over tissue, the new piece of tissue can be placed dry in the right place and Future can be applied directly on top. The Future will be absorbed by both layers of tissue, which will bond together when the Future dries. In the meantime you have a few minutes to make adjustments or to correct mistakes.
Wout: Future is completely friendly for all types of foam. In the example, tissue strips are used as canopy frame over foam and clear plastic. Don’t try this with dope!
When to use Future:
- normal covering jobs
- tissue over foam: Future is completely foam friendly
- as a sealer over decals
- as a topcoat over acrylic paints
- when the smell or high of dope is prohibitive
When to use dope:
- tissue over Mylar, because dope gives a better bond between tissue and mylar film
- tissue printed on an inkjet printer, because most inks will dissolve and run when in contact with water, but are safe in contact with dope
The DoodleBug in the picture is finished with cocloured tissue, Future and acryllic artist paints.