Posted by pd1 |
Apr 19, 2011 @ 08:09 AM | 6,757 Views
Japanese Tissue is the lightest covering I know of.
It has a few quirks when covering so I'll try to remember all of them.
It is easier if you give the structure or sheeted area to be covered a couple of coats of dope first.
The dope under the covering helps to adhere the tissue to the plane.
Two methods of covering ; dry, wet.
Dry is only good over open framework.
You have to wet the tissue with water after covering to shrink it.
If you try to cover large sheeted areas dry, the tissue will have puckers that won't go away.
Wet will work over open framework and over sheeted areas.
1. Size the piece you're going to use about a half inch to one inch larger in all directions than needed.
2. Determine the shiny side.
One side is glossier than the other. The glossy side is out.
3. Determine the grain.
If you are going over open areas the grain goes the long way. Span wise, not chord wise.
If you try to tear a piece of tissue, it will tear readily in one direction only, This is the direction of the grain.
It doesn't want to tear across the grain.
4. Lay your sheet out over the area to be covered.
Wet the sheet with water, an atomizer works well.
You can wet the sheet then place it on the area to cover.
I have great difficulty doing it this way.
5. Once wet, work the wrinkles and excess water off the surface with your fingers. Use them like a squeegee.
Be careful, once wet this stuff can get very fragile.
1. Cut tissue. Grain goes lengthwise, not chord wise.
Tear a corner to check grain direction.
Cut tissue about 1 inch over sized.
2. Adhere tissue to the structure.
This is more personal preference, or what works for you.
I have heard people using thinned out white glue.
Cellulose based glue (Ambroid, Duco).
And a new possibility, Min Wax and an Iron.
Ron, Skysharkster is using this method on his Waco with a different material. http://www.wattflyer.com/forums/showthread.php?t=41555
I don't use Nitrate anymore, too flammable for me.
So it's butyrate this time.
3. Prep. At least two coats of clear on the structure with sanding between. I use 50/50 thinned clear.
4. Lay the tissue over the area to be covered. Wet the structure with a fresh coat of dope and lay the tissue on the framework.
Try to get the wrinkles out, but don't go too crazy.
I cover the whole bottom of the wing then the top.
Once the tissue is stuck to the frame, trim the edges and add more dope to the perimeter .
If there are a few big wrinkles on the woodwork, you can flatten them with more dope and your fingers.
Try not to get any dope on the open...Continue Reading
Posted by pd1 |
Apr 19, 2011 @ 07:53 AM | 6,761 Views
Working with silk.
Silk is a natural fabric It is woven and will cover around compound curves very well.
I've covered foam planes with silk, and balsa too.
This will be about covering open areas of a balsa structure or a solid sheeted area.
Minimaster build thread: http://www.wattflyer.com/forums/showthread.php?t=35712
First prepping the wood.
Balsa is cellulose based and it absorbs colored dope/paint like a sponge.
The faster you can seal the pores of the balsa, the less coats of paint you will need.
Dope, both clear Nitrate and butyrate, fills the pores in balsa well and stops the wood from sucking up paint.
The better the finish of the uncovered wood, the better the overall finish will be.
A few coats of clear will seal and then start to fill the grain of balsa.
Some people add talc powder to the dope so it fills the grain a little faster.
Some use a product called sanding sealer to fill the grain rapidly.
I prefer thinned dope. Thinned dope fills pretty fast and doesn't get too thick over the high spots.
Then I dry sand with 180 to 220 grit sandpaper using a block to get all the high spots down.
The goal is to get an even smooth surface, before you cover.
A lot of people use nitrate dope for the first steps.
I feel butyrate works just as well.
But remember nitrate and butyrate are not the same.
Nitrate can't be applied over butyrate. It will react and ruin your finish.
Nitrate is very flammable compared to butyrate. ...Continue Reading