Covering the Center Section?

[Ebby]

As I was varnishing the center section I began wondering whether it was finished smooth with varnish and sanding then painted or if it was fabric covered filled and painted. I just don't know.

If the center section is fabric covered, is the fabric glued directly to the entire surface and NOT heat shrunk or is it glued similar to a horizontal stabilizer at leading and trailing edges and then heat shrunk?

I'm using the Stewart System products to do the covering and also wondered if felt needs to be applied to the leading edge?

My gut tells me to make sure the center section is smooth and uniform with no dips or irregularities and glue the fabric directly to the surface with no ironing. Then use EkoFill brushed then 2 cross-coat sprays.

[JBMoore]

I'm not familiar with the Stewart system.. but here is what I did with Ceconite and dope.
Mine is fabric coveres. I glued the fabric on around the edges and not directly to the surface. I shrunk it per the instructions and applied the dope in the usual manner. I was afraid if I didn't shrink it, some fluke of nature would cause the sun to heat up everything and make the fabric do funny things.
I used Stits' leading edge covering... kinda like thin quilt batting and not felt. What ever you use, make sure the chemicals don't disolve it into a runny glob. I remember someone telling me the covering alows the fabric to move a little bit over the leading edge for expansion/contraction... plus it's a little padding to absorb small knocks without leaving dents.
Jeff Moore

[Clifford Hatz]

Ebby, Jeff did it right, somehow you're going to have to glue it to center section and shrink it. Call your Stewart system guy and see if there glue will soak thru the fabric and stick to the structure underneath. I never used this process so I don't know.

[womenfly2]

Here is what the Stewart System fabric manual states;

Fabric to Metal - EkoBond Cement (E610) is used in a different manner than most aircraft cements. Apply EkoBond Cement (E610) to the surface where the fabric will be attached. Let the cement tack up (tacky to the touch, approximately 5 minutes, depending on temperature and humidity). Apply the fabric to the cemented area. Using your hand, remove excess wrinkles, then with firm pressure rub fabric onto cemented areas. This will gently hold fabric in place. When fabric placement is acceptable, use a Close Quarter Iron set at 275 to 300°F and make a single pass over the cemented area, using firm pressure. This will heat the glue and hold fabric in place. You will see a glue bond of about 1/16” to 1/8” wide where the iron heat bonded the glue. Brush additional glue down through the fabric to the cemented area and wipe away excess with a blue Scott paper shop towel or equivalent while at the same time smoothing the fabric down. The cemented area should show an even color indicating a complete bond to the substrate. Drying time will depend on temperature and humidity. When installing inspection rings or reinforcing patches, use EkoBond Cement like contact cement: apply to both surfaces, allow to become tacky, and then press the surfaces together.

They also just came out with:

EkoBond - Glue and Sealer- "LINEN" ...The Lined colored EkoBond was developed for use in the cabin area of aircraft where there is no interior and you see the back side of the fabric. For antique aircraft and biplanes it gives the classic look of a cotton or linen covered aircraft when viewed from the inside of the aircraft. The fabric and tapes are applied normally with the linen colored EkoBond. Then you dilute the linen colored EkoBond up to 10% with distilled water and brush or roll a coat into the weave of the fabric from the out side. Then a x-coat of the White E620W EkoFill is sprayed on to lock in the linen color. The white EkoFill is followed up by 3 x-coats of Grey E620 EkoFill before the top coat paint is applied.

Sounds like you are really moving along Jeff. Please do post some pictures!

I too plan on using this painting system.

Blue skies,
Keri-Ann

[alvinsager]

Hi Ebby,
I asked Stewart exactly that question. They suggested pre-gluing the entire part. Felt was not needed. I did mine about 6 months ago and it was such a non-event that I don't remember the details. I probably adhered just the edges and shrunk out any wrinkles before working cement through the surfaces.
Al

[Ebby]

Thanks all. I get the idea very well now. I've watched the SS tapes at least a half a dozen times and understand the technique of applying Ekobond, placing the fabric then applying another coat of Ekobond to 'sandwich' the fabric between the glue layers. Much the same way the Piper's leading edge was treated in the SS video. As the fabric is directly glued to the wooden structure it would be best if the wood surface was smooth and uniform with no big dips or waves. I think I remember on another video the line 'If you can feel it you will see it in the final finish' or something like that. Thanks again and now with winter knocking on fall's back door, I hope to hunker down and do some covering in my basement.

[womenfly2]

Awesome Ebby, please do post lots of pictures for all of us still making ribs.

Blue skies,
Keri-Ann

[Ebby]

I'm covering wings now...major wooohoo for me at least and am saving the center section until the four wing panels are done. I'll take representative photos and post at that time. I have lots of photos of the build if there is anything specific you would like to see let me know and I can PM them.

[Ebby]

Covered the center section and I agree, it was a non-event. I'm pleased with the results. Thanks for the tips.