Peel Ply Cotroversy?

[noodles]

Alright,

 

I was using the Rutan composite tutorial Moldless Composite Sandwich Homebuilt Aircraft Construction 3rd edition August 1983 composite kit from Wicks. Rutan, says to only use peel ply where necessary.

 

He indicates that this adds unnecessary weight and should only be used when you are bonding two fiberglass components, because peel ply removes the shiny top layer.

 

He states, “Another thing to remember is that peel ply adds weight. It fills the weave 100% with epoxy so it should only be used where it will serve its purpose of bonding of transitioning plies. Do not get carried away and peel ply any more than necessary.”

 

Mr. Nat Puffer stated in his Cozy Newsletter #80 Jan. 2003 in his Weight Saving Column “Don’t add extra layers of glass and don’t use excess epoxy. Peel ply everythin and use a hair dryer when you squeegee, to remove excess epoxy.”

 

I’m not trying to split hairs here but Rutan say peel ply only where necessary and Puffer say peel ply everything.

 

So which one?

 

 

Nathan,

[Marc Zeitlin]

Originally posted by noodles

I’m not trying to split hairs here but Rutan say peel ply only where necessary and Puffer say peel ply everything.

 

So which one?

See:

 

http://www.cozybuilders.org/mail_list/topics95/peel_ply.txt

 

and

 

http://www.cozybuilders.org/mail_list/topics96/peel_ply.txt

 

For discussions of this topic from both sides.

[ErlendM]

If I am to peel-ply everything (Cozy IV) - could someone please give me a roughly estimate on how many yards or meters I would need? My local supplier can deliver peel-ply in 1,6 meter wide rolls (63").

[Vacabrava]

Erlend,

I peel ply all my Cozy parts. I don`t build the wings nor the turtleback.

I bougth 83sq.yrds. and have yet half of the roll.

I think 100sq.yrds. you do all the work, but is better to buy until you need.

Read the other post about peel ply being in the laminate.

I used two tipes of peel ply, one was very malleable, like pure fin cotton, that one is not good.

The other is nylon tipe. Good stuff. Get out of the laminate very easy.

Check the properties here:

http://www.barracudatec.com.br/produtos-vacuo-peelply.htm

 

So check the cloth quality to not have the unhevelled concern.

Cheers.

[Big Steve]

I tried a test on my elevators to see if peel ply was heavier. I had one elevator peel plied and the other with no peel ply I sqeezied them and tried to put as littl epoxy on them as I could. The peel plied elevator was heavier. I now only peel ply where things will join and I sand that area also. STeve build on

[TMann]

I vacuum bag as much as possible so everything has peel ply.

I guess a better measurement would be to determine what the approach is at Scaled Composites.

 

Times change right along with research results and materials. Obviously we are not using the same epoxy that Burt used when he wrote the book on it.

[schmeddz]

In the aerospace industry, everybody who manufactures parts uses peel ply. They don't always use vacuums or autoclaves, but they liberally use peel ply. (Without the peel ply, those tools don't work at all.) And if there are no secondary bondings being planned, you will see fiberglass or reinforcing weave. Look closely at the tail plane of an F-18 up close next time you are at an airshow. You will see the carbon fiber weave in the stabilator.

 

Most of the layup ratios by weight are 35-40 percent epoxy to the reinforcing materials for ideal strength of the total structure.

The best hand layups are usually around 50/50.

Using peel ply always takes off a few grams the more you use it. Unless you just like wet layups and sanding a lot! Take off several hundred grams and you get several ounces and then several pounds. It all adds up.

You never have to sand into major structural fibers when you use it liberally. If your part is straight to begin with you will sand and fill a whole lot less. Look closely at Burts old airplanes in the museums. They are really rough looking compared to all the show planes out on the flying circuit!

[Big Steve]

schmeddz says:

 

 

Look closely at Burts old airplanes in the museums. They are really rough looking compared to all the show planes out on the flying circuit

Look at the weight difference in the planes. Burts planes are a whole lot lighter than those show planes. Those really fancy super smooth airframes generally weigh a whole lot more. STeve build on

[Edge 513]

If you think one way or the other will save resin weight or not, dont worry about the 4 pounds on the airframe...lose it off your gut. Net result is your planes gross weight is the same.. and you will live longer and be happier.

As a sidenote. Nobody is going to notice your plane is 4 pounds one way or the other...but 4-10 pounds off YOU, and you will look and feel better.

[CBarber]

YEAH, What Edge said. Funny how we will major in the minor....now, that being said, if you can loose both places all the better. Hmmmmmm, I wonder how much me droping abut 40 lbs AGAIN (can we say yo-yo ) would be worth in the aviation market......not to say in the Nutrisystem market.

 

I did use a lot of peel ply, especially in the beginning. I am about to go read the links Marc posted in 03. When I starte I was told the peel ply soaked out the extra epoxy, so I was always under that impression until I read otherwise a few years ago. Now, I don't really kow.....but I just keep building and trying to progress. I don't want analysis paralysis to over burnden me (I really need a spell checker on this thing)

 

Oh well, back to serving and protecting tonight til 0300 hrs, saving folks from themselves and others....but tomorrow I should be starting the new year back out at the hangar. I sooooooo hope this plane is an "09 model". I started in 02....geesh, where does the time go? It is fun though.

 

Back out to turn Dino's into decibls as I tweek my rotary.

 

Happy new year.

 

All the best,

 

Chris

[schmeddz]

schmeddz says:

 

 

 

 

Look at the weight difference in the planes. Burts planes are a whole lot lighter than those show planes. Those really fancy super smooth airframes generally weigh a whole lot more. STeve build on

 

Yeah, I agree. The extra weight comes from the bondo, bondo, bondo, micro, paint, and all the extra stuff we put on to make it purdy! Things like starters and stuff to make it all work in IFR, and cushions, and extra's....

Look at the bottom of Voyager in the Smithsonian and it's not even painted on the back two thirds of the wings.

But, peel ply and a heat gun will remove some of those ounces...

[Lynn Erickson]

Yeah, I agree. The extra weight comes from the bondo, bondo, bondo, micro, paint, and all the extra stuff we put on to make it purdy! Things like starters and stuff to make it all work in IFR, and cushions, and extra's....

Look at the bottom of Voyager in the Smithsonian and it's not even painted on the back two thirds of the wings.

But, peel ply and a heat gun will remove some of those ounces...

If you could add an extra 2 gallons on micro to get a good surface, you would be adding only 10 lbs. to the plane. its not the good finish that adds the weight. its all the extras that you think you need to fly the plane.

[Big Steve]

its not the good finish that adds the weight. its all the extras that you think you need to fly the plane.

I think this is where it all really lays just like Lynn has said above. Auto pilots, oil heat, Electric nose lifts and Massive instrument panels, bigger motors, variable pitch props, Leather, or full interiors, Electric trim, Extra layers of glass to "make it stronger" This is the kind of stuff that make a 750lb Longeze weigh 1,000 lbs. My .02 STeve build on