How to tell what covering

[tangocharlie123]

How do you tell what covering you have on a plane. Dope Stitts etc.

 

I need to do a small repair job on both wings and dont want to mix systems.

 

Cheers

 

 

[Guest Maj Millard]

tangocharlie123, There are several ways of telling, but differ with each covering type. Most 'aircraft grade' fabrics have a stamp on the fabric, and this can usually be seen on the non-painted side by looking into the rear fuselage or inner wing. Another way is to refer to the aircraft specs, they should tell you what type fabric is used. You can on some types try rubbing the finish with various types of solvents, to identify the finish mediums used to seal and finish the fabric. This may lead to identifying the fabric type.

 

Failing all that, dig up an old fabric man and he should be able to help you.

 

Most common these days is Ceconite, either Stits or other brands. The Rans series aircraft use another type that is characterized by it's glossier smooth finish. Not much 'Grade A' cotton (linen) around anymore but you may come across it on Tigermoths or DC-3 control surfaces, and other older aircraft. etc.

 

 

[Yenn]

Stits finish will dissolve with Methyl Ethyl Ketone (MEK), just get a small amount of MEK on a rag and rub a hidden part with it. If it is Stits you will see it begin to dissolve quite quickly. Can't help with the other methods.

 

 

[pylon500]

There is the fabric and it's associated systems, and then there's the final surface finish (paint).

 

These days most people are painting aircraft with two pack paints that are virtually impervious to most chemicals.

 

If you try MEK, Acetone or GP Thinners on the surface, you can get a few results;

 

Does nothing, most likely two pack paint.

 

Softens the surface slowly; possibly an enamel paint.

 

Takes the top surface off quickly; either an acrylic paint or a coloured (butyrate) dope.

 

If you have a two pack paint finish, it can be very hard to 'blend' in the repair.

 

You will have to mechanically remove (scrape or sand) the paint off as if you use most chemical paint strippers, they will also melt the fabric!

 

Most fabrics these days are synthetics (polyester), cotton is really rare.

 

Sometimes you can get lucky and the paint stripper will stop working at each layer, just be careful.

 

Once you're down to bare fabric, it doesn't really matter which process you use, they will all stick, just be aware of the weight of fabric used in the local area and provide enough overlap, 2" is good depending on location/type of repair.

 

Would need to know more about the nature of the repair to give any more advice...

 

Arthur.

 

 

[Yenn]

I was reading up on Stits repair procedures and while the normal Polytone will dissolve with MEK, the shiny finish which Stits produce and which I have forgotten the name of doesn't dissolve with any solvent. You can dissolve the undercoats from the inside though and that is the method they recommend for repair.

 

If you need further info I can post part of the stits manual here.