A short center section Lanzo Bomber built by former SAM president Tom McCoy. Presently powered by an Ohlsson Sideport/Large Exhaust c.1947.   Sorry again for the vertical orientation of the video.

Covering with Polyspan

For a more comprehensive video, order Dave Platt's Back to Basics DVD

Polyspan and Spunbonded Polypropylene From Mike Myers. 

Rudy Hewert asked: Gents; In following this discussion, I am getting somewhat confused by the names of the vari- ous products. Anyone know who actually makes "Polyspan Lite"? Polyspan, Polyspan Light (sold by Larry Davidson and maybe Mike Woodhouse), Salzer Tissue, and SAMSpan (polyspan sold by SAM 27 in Northern California) are all vari- ants of the same thing - spunbonded polypropylene. It is an industrial product and it's made by a lot of people. (In my old work life I was a lawyer who helped form a joint venture and gave ongoing business legal advice to a world scale polypropylene plant that was built in Southern California.)

Here's what Dupont has to say about "Spunbond Polypropylene": DuPontTM Spunbond Polypropylene is a non-woven fabric composed of thermally bonded, continuous polypropylene filaments. The structure gives it good filtration properties and tensile strength even in diagonal direction. In addition, it is made of 100% polypropylene, which makes it resistant to moisture and chemical attack. It is a unique composite media that combines polymer technol- ogy with DuPont nonwoven manufacturing expertise. The polypropylene based material is an exceptionally strong yet light, pleatable material with excellent drainage and permeability properties. It is manufactured by a unique inte- grated process in which continuous filaments of polypropylene are spun and then immediately formed into a multi- directional arranged web that is heatbonded at filament crossover points.

Polypropylene comes out of the reactor in the polypropylene plant as a white plastic pellet about the size of large rock salt. It's then shipped to fabricators. Fabricators melt that plastic pellet and do lots of different things with it by running it through extruders, moulding machines etc. It shows up in plastic deck chairs, flower pots, medical trays, in a clear film wrapping cigarette packs and CD's - and in various "spunbond" forms. That spunbonded polypro- pylene is a fabric. It's made in as many different weights as there are manufacturers and end users. We sold a lot of it to people who made disposable diapers. It gets rolled up and used in filters - cigarette filters, water fil- ters, automobile oil filters, for all I know. It also gets used in sheathing or interlining or facing material that you can buy at your local fabric store. In thicker fabric weights it gets used to make disposable lab coats, Hazmat suits etc.

The manufacturers have large capital investments in these machines - one of our customers was making clear film in China. He had the film coming off the machine at about 2,500 fpm - or close to 30 miles per hour in a roll that was 10 feet wide. You'll note on Mike Woodhouse's earlier post that when he got some light polyspan from a manufac- turer in Austria, he had to buy a 2.5 kilometre long roll of the stuff.

Since spunbonded polypropylene is a plastic, it doesn't react to water - and so doesn't shrink when you spray it. It does react to heat, so you can shrink it or set a different warp in a wing through use of a heat gun. And because it doesn't react to water, it doesn't sag on a damp morning.

For our modelling purposes, we want it in the relatively lighter weights. You can buy "Polyspan" from the usual sup- pliers - Woodhouse, Davidson, some of the local hobby dealers and cottage industry people. That stuff is all good, and a lot of us use the material in just a single coat with nothing but dope.

But if you can't find a polyspan supplier and you're in a pinch you can go to the local fabric store (they still have a few of those around) and look for dress interlining or interfacing. That material is spunbonded polypropylene. The sewing and tailoring folk use this stuff to thicken up colours, cuffs, coat lapels etc. It comes in white - any colour you want, so long as it is white because after all it's going to disappear inside the finished article of clothing.

It comes in several different weights so you need to look around. The lightest stuff is probably not useful, so go for the medium or heavier weights. Most of the stuff that I've seen is light - a bit lighter than Larry Davidson's "Light Polyspan", and would take a lot of dope to fill. But if you are going to double cover with tissue or silk over the material, then there's a lot to be said for it. The polypropylene fibres run in all directions and are bound to each other by heat - so you add tremendous tensile strength to whatever you already have in the tissue or silk where the fibres tend to run at right angles to each other.

As long as you're down at the dress or fabric shop, you might also look at the coloured dress sheathing material. A lot of this stuff is made from polypropylene or other plastics. I covered a Peerless Panther in red and silver grey dress sheathing in the late '80s, and flew it with a Mills 1.3. The red and grey was heavier than silk, but it was hell for stout and that was just fine for a sport model. Unlike silk the colours never seemed to fade much in the sun.

You have to be careful with the coloured dress sheathing when you put it on, because it doesn't shrink with water, or much with tautening dope for that matter. It does shrink with heat. I still have some of it - as I recall it was like $3 a running yard of material that was 50 inches wide - when I was paying $10 a square yard for Esaki silk. Cheap is good!

Covering a Wing with Polyspan

Particular attention is paid to the undercamber.  

Miss San Diego

The aeroplane is a Miss San Diego designed by Elbert Weathers in 1936. In the Air Age Gas Models book, it is referred to as the Westerner, which is really the title of the article. Here are some early photos of my Miss San Diego, lacking some trim, ignition system and servos/receiver. Powered by an original Elf Model 1 serial # 117, it will come out at the recommended weight of 18 oz. even with 2 channels for R/C. It is covered with Polyspan which I dyed with Idye-Poly before covering. Available in a number of colors, it looks the same as colored silkspan and eliminates the tedious spraying of tinted clear dope.

The engine has a displacement of .13 cu.in. All the newer Elfs had a cylinder displacement of .098 cu. in. I also have 2 Elf Twins. Ask Gil Morris about them as he told me that a friend of his won A gas in 1941 with a Zipper with a twin. I'm gonna fly it in fuel allotment, because it runs 43 minutes on 1 oz. of fuel; turns that 12X4 at 3500 RPM!

Dave Acton
Brooklyn Skyscaper

Earl Stahl "Gypsy" 8 Ounce Wakefield, covered entirely in regular polyspan, Higgins Fade proof ink used for the color. Site is a little over 7 minutes from my house

I did not have anyone with me to take a launch picture. I weighed the motor, 36" long, 24 strands of 1/8 FAI Tan II from the 90's and it was (I think) 2.83 ounces. I put in a little over 200 turns on the first flight and it flew well actually getting up there to my surprise. My second and last flight showed 472 turns on the winder and it got up quite high, picture in the air to follow. The glide can best be described as "floaty" or superb. Cheers, cccnh out in the Rural American West, Lewistown, Montana, home of The Greater Central Montana Co-Prosperity Sphere p.s. this model was built in about 1997 or '98 and this is the second prop which is much better than the first one. Very little vibration. Having a swell gin and tonic and basking.

The "Gypsy" still climbing, the air was dead calm

Karl Gies

Pair of Tomboys by Karl Gies

This is my just finished Tomboy built from a Bob Holman laser kit and Jim O'Reilly plan. They both did an excellent job on this model in all respects. This is the second one I have built as the first one was built 44 years ago and is still in service. I recently converted it from a Cox Baby Bee .049 to an MP Jet Classic .040 and it is a 44" ws version.  This is a 36" wing span version powered by a CS Boddo Mills .75cc. The fuselage is covered with Japanese tissue over polyspan and the black trim is black tissue. The flying surfaces are Japanese tissue over 1/4 mil mylar and black Japanese tissue trim. The tyres, and this is a British model and correct spellings are in order, are not the tyres going on the model --- I have some coming on back order that will be much lighter. I am also going to build a 44" wing for it to see how much different it flys. 
Cheers,
Karl Gies

Bomber

Larry Davidson's Free Flight Bomber as seen in the pages of the SCAMPS newsletter.

Bucky's Latest Project IV

Hi Tom,

Finally completed the 1/2 A Texaco Lanzo R/C Cabin Stick.
It weighs 16 ounces with the tracker transmitter installed.
Wing area is 288 square inches or 2 square feet.
It is covered with Polyspan and trimmed with Jap tissue and silkspan.
I doped 2 coats of 50% nitrate dope and 50% thinner, follow with five coats of butyrate 50 - 50 thinner.
Due to the high humidity the doped blushed.
Gene Wallock told me to use 50% retarder and 50% dope to slow down the drying.
It worked!
Hope to fly it soon.

Bucky

Covering With Polyspan

Some advice from Larry Davidson on using Polyspan:

Excerpts from Larry Davidson's article for Sam Speaks

"I can tell you that this is a great covering material..."

After seeing several ads for Polyspan, I decided to order a roll and try it out. I also ordered some of the analine dye that Sal Fruciano (owner of Starline) sells. So far, I only used the Polyspan on a 1/2a Country Boy free flight and the results are as follows: The first thing to know is that this is a polyester material and impervious to water so don't try to shrink it with water. The Nitrate dope will shrink if fine and any wrinkles left can be taken out with a MonoKote iron. I started on the stab first and proceeded to follow the brief instructions which came with the product. He recommends pre-doping the frame outlines in the usual method used for Japanese tissue or silkspan which is two coats of Nitrate Dope. I then cut out the Polyspan 1" larger than the outline of the stab and doped it with Nitrate Dope thinned 50% through the material. So far everything went well and the material went on easier than Japanese tissue. Naturally you try to put it on by getting it reasonably wrinkle-free. Then I cut the material flush with the framework with a NEW double edge razor blade. So far so good. I then applied the Polyspan on the top in the same manner and trimmed it leaving the usual 1/8" for overlapping. Then came the problem. The material does not want to be rolled over the edges in the usual doping down method. It kept trying to straighten out the overlap and no matter how hard I tried, it would not roll over. I called Sal Fruciano and asked him for a remedy to the problem and he said that using a Monokote iron to crease the material should help. Well, he was right and the following was the method which worked great for me. Before putting the dope on the edges to be rolled over, I used the Monokote iron and creased the edge as Sal suggested. Then I put the Nitrate Dope under the overlap and rolled it over with my fingers in the usual fashion. It will still try to come up and by running my fingers around the edges until the dope is almost dry to the touch, I then took the MonoKote iron set at about 325 degrees and rolled over the edges to stutter when I use the "M" word. That is because as many know I am a religious silk and dope man. The next step was to brush some of the analine dyed Nitrate Dope on the bottom of the stab. It was difficult for me to believe that you could get the wrinkles out and make the covering tight with just putting the dope on. Well I can tell you that it tightened up great but I did not like the way the color came out on the bottom or the top. It was streaky and I did use a foam brush. Then I noticed that the top looked like the Chia-Pet that is advertised on television as it seemed to sprout fuzz and hair on the top. I wondered why this did not happen on the bottom and finally realized: IMPORTANT: There is an inside and outside to the covering. There is one side to the covering that is more glossy than the other and you MUST put the glossy side on the outside. On the roll that I used, the glossy side was on the inside of the roll and when placing a cut piece on the bench it would try to curl the edges up with the glossy side facing up. I removed the top covering from the stab and put another piece on with the glossy side up. As I said before, I was not satisfied with the orange tinted dope finish which I had brushed in my usual fashion with a foam brush as it looked streaky and mottled. The answer was to spray the dyed dope on. This would not be necessary if you left the material white, which is the only way it is available. Don Reid, after seeing my Country Boy at the GGG decided to try Polyspan and then called me to say he had recovered his house including his wife, Cynthia. Obviously he was impressed with the Polyspan. One of the members of our SAM 75 chapter, John Sullivan asked me for a piece of the Polyspan so he could experiment with the dying process and at our next meeting, he had produced the following results: He felt the best way to dye the material was to use a powdered analine dye. You also may buy the liquid dye 10 parts of nitrate dope to 1 part of dye, however I found that with the orange dye, a 20 to 1 ratio worked great. John says to mix a 2 oz jar of the powdered dye with one quart of methyl alcohol (methanol) and spray it on the material before covering the model, otherwise the dye will also color the rest of the wood of the frame work. You can also use the dye, both powder and liquid in nitrate thinner and spray this on Polyspan before covering the plane. If you use the powdered dye, be sure to use cheese cloth to filter the dyed thinner after mixing it thoroughly. Because this plane had to be fuel proof as I use 40% nitro fuel in my Cox TD .049/.051, I continued with my customary finishing technique of spraying K&B Super Poxy over the two coats of nitrate dope. The fuselage came out fine, but the wing was a disaster. The Super Poxy would not fill the pores I the Polyspan on the bottom. I decided to spray one coat of butyrate dope on the top of the wing to fuel proof it. I assume that if I applied several more coats of the nitrate dope to really seal the Polyspan, the Super Poxy would have worked well. I can tell you that this is a great covering material and I expect that on the next plane I use it on will work well with the techniques I learned on this plane. It really gives tremendous strength to the framework, probably as much as silk does and it surely is a great improvement in strength and puncture resistance over Japanese tissue and silkspan even though it is a little heavier.

Larry seen here with his Polyspan covered Pacer and the designer, Sal Taibi

And also from Don Typond

(Reprinted from Flying Models, December 1994)

Wouldn't it be nice if there were a covering material that's strong and stable and just about puncture-proof, and not any heavier that what's being used now?

Polyspan, a modern covering for traditionalists. Looking very much like the more transparent silkspan of 30-plus years ago. Polyspan is made of non-woven polyester fibers randomly intertwined, but with a definite grain running lengthwise along the sheet. It isn't as stiff as silkspan or tissue, but rather feels "floppier" and is soft and silky to the touch. Like silkspan and tissue, Polyspan is porous, and needs to be filled with dope. It's perhaps best described as a "paper" made with polyester fibers instead of wood fibers. But unlike paper, Polyspan is waterproof and doesn't absorb moisture. Which means it won't sag and change the airplane's trim on those dewy early morning flights or rainy day flying sessions. And it is tough! Trying to tear it across the grain takes more force than you'll ever put on a model in normal use. It does tear more easily with the grain, but is still much stronger than silkspan, and probably even stronger than silk. Let's put it this way; if you dropped a quarter on it from two fee up, it'd bounce off. Yes, sharp objects will puncture it, but the polyester fibers will resist the puncture growing into a tear. Polyspan is made in Germany, and imported by Sal Fruciano. A roll measures 12 feet by 20 inches, and sells for $15.00. Polyspan is available only in white, but can be colored by mixing dye into clear dope and spraying it on. (The old method of dyeing in colored water before covering doesn't work because Polyspan is waterproof.) Starline by FAI Model Supply sells 2 oz. concentrate dyes in red, yellow, blue, orange and black, at $5.50 per-ounce bottle, which will dye a lot of dope at the recommended one-to-ten ratio. Polyspan can also be painted with opaque dope, of course, or with other compatible paints once it's been sealed with a few coats of nitrate dope. Okay, how heavy is it? I weighed one-square-foot samples on my balance scale (which I'm sure is accurate, but even if not produces usable relative weight comparisons). Polyspan weighs 2.25 grams per square foot, Japanese tissue ("Esaki" white, from Oldtimer Model Supply) weighs 1.125 grams per square foot. Thus, Polyspan is twice the weight of silkspan, and slightly more than twice the weight of Japanese tissue. But raw weight doesn't mean much since these coverings require dope to seal them, and Polyspan is said to need only two coats of 50-50 thinned nitrate to fill it. So I made a 12 x 12-inch balsa frame, and doped the Polyspan to it. Then I thinned Sig nitrate clear dope 50-50 by volume could result in a more full-bodied material, requiring fewer coats.) Two coats began to produce a gloss, and filled most of the grain, but there were still a few small pinholes that could be seen when I held the panel up to the light. It took five coats to completely fill all the pinholes, and by then the surface had become attractively glossy. Obviously, applying many coats to the entire surface just in order to fill the pinholes is overkill, and were I covering a glider or rubber-powered model I would consider two or three coats sufficient (maybe dabbing a little more on the pinholes), especially since the dope isn't needed to make the covering moisture proof. I then removed the Polyspan from the frame and replaced it with a sheet of silkspan. Painting silkspan is like painting a blotter, and the first couple of costs used a lot of dope as it soaked in. By the time the silkspan was sealed and the surface no longer fuzzy, I had applied six coats. Lastly, I repeated the procedure with a panel of tissue, which required three coats to fully seal it. After allowing 48 hours drying time, I weighed each panel. The Polyspan weighed 3.6 grams, the silkspan also weighed 3.6 grams, and the tissue weighed 1.8 grams. In short, Polyspan ends up having the same finished weight as silkspan, but with much more strength, moisture resistance, and longevity. Yes, it's twice the weight of Japanese tissue, which is still my choice for small, light rubber models, but Polyspan is perfect for larger, heavier freeflight, control line, and R/C models.

Lanzo Swayback part 2

From Spirit of Yesteryear models....

First flights of the Lanzo Swayback,

a Chet Lanzo design, built by Bucky Walter. Power is an

original HP VT.21 4-stroke.

Wedgy part II

Hi Tom,

The Wedgy is very hard to hand glide and grab the transmitter to control the glide.

With the CG at 40 percent it drove straight into the ground, like I just held it by the tail and dropped it. With full up trim it did not make a difference.

Moved the battery back under the wing where it had a CG of 67 percent. With full up trim I was able to make a steep control glide to the ground.

I am going to make a battery box holder at the rear of the wing. Right now I am pretty beat from going up and down to the basement to make changes in the battery location.

I built the rear of the fuselage to match the plans twice so the stab location is as the plans show it. If it still wants to dive with the rearward location of the battery I will start raising the trailing edge of the stab.

The nose wheel sure takes a beating. It saved the model from some serious damage.

I also have to make a needle valve extension.


Hope to get the Wedgy to glide correctly by the time you are able to pick it up. I will also try to run the engine.

Bucky

Paul Plecan Tornado II part 2

Well guys:

The Paul Plecan Tornado II is almost complete. I have one rotten job to do - make a wind shield!

I have to be in a good mood to tackle that job. I am just about running out of steam on this project.

Bucky Walter

tissue
(note yellow & black is different)
decals

Goldberg Sailplane videos

We're still waiting on Tandy Walker's Sailplane. In the meantime, here are some built by other modelers.

Latest from Larry Davidson

Civy Boy 66 for Nos Gas. O.S. .29 MAX III from Gene Wallock's plans



Contact info and latest product list below: Larry Davidson
66 Casa Mia Circle
Moneta, VA 24121-5307
(540) 721-4563
samchamp@jetbroadband.com
Name_____________________ Phone#______________email________________3-17-09 List
Address_________________________________________________________________

____Champion Repro V Spark Plugs 3/8” X 24” (Check for Availability) @ $18.00

____Champion Repro V-2 Spark Plugs ¼” X 32” Long Reach @ $18.00

____Champion Repro V-3 Spark Plugs ¼” X 32” Short Reach @ $18.00

____ New “V” (3/8 X 24) Rimfire Spark Plugs, Great Plugs! @ $ 21.50

____ Rimfire V-3 (1/4 X 32) Short Reach Spark Plugs @ $ 18.00

____ Rimfire V-2 (1/4 X 32) Long Reach Spark Plugs @ $ 18.00

____Adaptor 3/8” X 24 To ¼” X 32 (Adapts V-2 & V-3 Size Plugs to Large 3/8” Threads) $ 3.75

____NEW! Coils, light and small, 30 grams. 2.4 to 3.6 Volt @ $ 25.00

____NEW! Solid State Ignition Unit, #SSIGN W/Instructions @ $20.00

____ Solid State Ignition Unit #SSIGN2 (TIM-4) @ $ 24.00
(Instructions Included for points or Hall Effect operation) W/SSIGN2

____High Tension Leads with 10K resistor & Clips (HTRC) For R/C @ $ 6.00

____ Hi Tension Leads (No Resistor) (HTFF) Free Flight & U-Control @ $ 4.50

____3/8” Rubber Bands for DT (Bag of 100) @ $ 1.00

____Plastic Fittings for Pacifier type Pressure use @ $ .70

____Surgical Tubing For Pressure (3/16” X 1/32” Wall) 2- 1 Foot pcs. $ 2.00

____Surgical Tubing For Pressure (1/4” X 1/32” Wall) 2- 1 Foot pcs. $ 2.00

____Surgical Fuel Line Tubing (1/16” X 1/32”Wall) for pinch off timers 10 ft. 6.00

____Dethermalizer Fuse (3/16” X 33’) (English Type) @ $15.50

____Polyspan Covering Material NEW SIZE AND LOWER PRICES!!!!
NOW 39” WIDE X 10’ LONG $15.00

____NEW! Polyspan lite Approx 15 Grams/per Sq. Meter, 39” X 72” @ $13.00

____Polyspan Instructional Video (40 Minutes) @ $ 20.00

____ Polyspan Dye ( Can Be Used for Most Coverings Too!) 2 Oz. Bottle @ $ 6.50
Red, Yellow, Blue, Orange & Black (use Butyrate dope with dyes)
____Polyspan Fluorescent Dye ( 2 Oz) Yellow Or Orange @ 8.45

____Glue/Oil Dispensers (Perfect for Thin CA Applications, Etc.) .010 Dia. Tip @ $ 3.50

____Glue/Oil Dispensers (Perfect for Medium CA Applications, Etc.) .023 Dia. Tip @ $ 3.50

____I Stock Many Small Parts for the Super Cyclone Engines (Inquire!)




____Anderson Spitfire Metal Tank & Gasket ( For Glow Or Gas Fuel) (Check Avail) @ $ 25.00

____Super Cyclone Original Type Plastic (Amber) Tank W/ Hdwe. @ $ 27.00

____ NOTE! I HAVE SOME BMJR LASER KITS IN STOCK. INQUIRE

____Super Cyclone Metal Tank & Gasket ( For Glow Fuel or Gasoline) @ $ 25.00

____NEW! AMA Bullet Shape Prop Nut (Uses 4 Way Prop Wrenches) @ $ 5.50
(Aluminum) ( 5.2 Grams) ¼ X 28 Thread

____NEW! AMA Bullet Shape Prop Nut “ (Brass) (15.3 Grams) @ $ 6.00
¼ X 28 thread

____ K&S Silk. *White, Royal Blue & Orange * Sq. Yd. $14.50
*(White Silk is 36 X 45”)

____Badge BL-7 Viscous DT Timer Super lite, great timers @ $22.50

____Badge BL-3 “ “ “ “ $22.50


____GLASS SYRINGES FOR FILLING PACIFIERS AND FUEL TANKS




____10 ML $ 14.00

____20 ML $ 15.00

____30ML $ 16.00

____50ML $ 17.00

Prices subject to change without notice!

SORRY, NO CREDIT CARDS

POSTAGE & HANDLING (USA DOMESTIC) $ 5.50. ADD $1.00 FOR PRIORITY 2-3 DAY DELIVERY IN THE US
PERSONAL CHECKS (USA), BANK CHECKS OR POSTAL MONEY ORDERS IN US FUNDS
(EXTRA P&H FOR FOREIGN ORDERS) PLEASE PUT PHONE # AND EMAIL ADDRESS ON ORDER
THANK YOU

Model Airplanes and Visibility

Personally, I'm partial to fluorescent orange and white (with a little strategically placed Skyshine/Skysheen). And, I've had no trouble with Serengeti sunglasses.

Others will object.

Working with Light Polyspan

LIGHT POLYSPAN

6’ x 39” $13.00

THERE IS A GLOSSY AND LESS GLOSSY SIDE. THE SMOOTH GLOSSY SIDE IS THE OUTSIDE (UP). Run grain spanwise!

APPLY AS YOU WOULD FOR SILKSPAN BY PREDOPING THE PERIMETER WITH TWO COATS OF DOPE AND MORE COATS ON THE BOTTOM OF THE RIBS IF THE WING IS UNDERCAMBERED. LIGHTLY SAND THE DOPED AREAS.

CUT THE MATERIAL OVERSIZE, PARTICULARLY AT AN ELLIPTICAL SHAPED TIP, ETC.

APPLY BY DOPING THRU THE MATERIAL. I NORMALLY USE THE MAIN SPARS FOR FIRST ATTACHING IT, THEN DOPE THE LEADING OR TRAILING EDGE. NEXT, PULL ANY EXCESS MATERIAL OUT. IT DOESN’T HAVE TO BE TIGHT AT THIS TIME. DOPE EACH UNDERCAMBERED BOTTOM RIB AND RUB DOPE THRU THE POLYSPAN, ADHERING IT TO THE RIBS .

CUT THE EXCESS AROUND THE PERIMETER SO YOU WILL HAVE AN OVERLAP OF ABOUT 1/8”.

USING A MONOKOTE TYPE IRON, ROLL THE EDGES TO HELP THE MATERIAL FOLLOW THE CONTOUR. THEN DOPE IT DOWN AND RUB THE DOPE IN.

DO THE SAME FOR THE TOP ON THE WING. WHEN DOING AN ELLIPTICAL TIP, TACK DOPE SEVERAL SPOTS ALONG THE TOP AS YOU WOULD FOR MONOKOTE. ADD WEIGHT OR HAVE SOMEONE ELSE HOLD THE WING. THEN WHILE PULLING ON THE EXCESS WRINKLE AND HOLDING IT OFF THE SURFACE OF THE WING, HEAT IT WITH THE IRON AND IT WILL STRETCH--AND THEN PUSHING IT DOWN WITH THE IRON, IT WILL CONFORM TO THE CONTOUR.

THEN DOPE AND TRIM THE EXCESS.

THE DOPE WILL SHRINK THE MATERIAL BUT I USE THE IRON TO TAKE OUT ALL THE WRINKLES BEFORE DOPING IT.

PUT TWO TO FOUR COATS OF DOPE, PREFERABLY BRUSHED ON With A Foam Brush!, Thinned about 50%. (DON’T THIN TOO MUCH FOR THE FIRST TWO COATS) THEN IF YOU WANT COLOR, USE THE POLYSPAN DYE, MIXED 1 PART DYE, 1 PART CLEAR BUTYRATE DOPE AND TEN PARTS BUTYRATE THINNER AND SPRAY THIS ON.

(NITRATE DOPE AND THINNER DOES NOT MIX WELL WITH THE POLYSPAN DYE) USE PARKS OR SUNNYSIDE EPOXY & LACQUER THINNER FOR NITRATE DOPE, AVAILABLE AT HOME DEPOT AND TRU-VALUE

SPRAY ON A SEALING COAT OF DOPE. JAPANESE TISSUE OR COLORED DOPE CAN NOW BE APPLIED FOR TRIM IF DESIRED. THEN I BRUSH ON AS MANY COATS OF DOPE TO GET THE GLOSS I WANT (USUALLY 6-7 COATS) TOTAL.

APPLY FUEL PROOFER IF NITRO FUELS ARE GOING TO BE USED.

I SELL THE DYE. SEE MY LIST, SASE OR EMAIL ME FOR IT: samchamp@jetbroadband.com

Larry Davidson

More Polyspan covering techniques are taught by Dave Platt in his B2B (Back to Basics video)www.daveplattmodels.com/Video/index.htm

Jap Tissue over Polyspan technique

Cover with Polyspan, shrink and apply 2 coats of dope.
Sand with 600 wet/dry paper to eliminate fur.
Attach tissue like the Polyspan wasn't there.
Use Acetone through the tissue and activate the dope on the Polyspan. Be very careful not to spread it all over.
Water shrink the tissue and let it thoroughly dry.
Brush on a light coat of Acetone to attach the shrunk tissue to the doped Polyspan. Use a Monocoat iron to eliminate any wrinkles.
Apply two coats of thin dope and re-check for wrinkles. Add a third coat of thin dope to finalize.
If you just want to add tissue letters, just tack them down with Acetone. If they're smooth, apply a light coat of Acetone and use the iron to eliminate wrinkles.

Thermals,
GOD Bless America

Gene Wallock