Keeping mylar straight

Some years ago I saw a magazine article (or reflector post) containing
some advice on what seemed a very simple means for keeping everything
absolutely straight in the spanwise direction when replacing mylar
seals. For the life of me, I cannot now find that information (which
I recall -- although not confidently -- involved using masking tape as
an index).

Can anyone help me find what I need or, alternatively, weigh in on
what has worked for you?
Thanks.

Mark -- B9

I've found the best way to keep mylar straight is lots of firm
discipline at an early age.

Fred

I'm assuming standard 38mm curved Mylar for ailerons etc.

1.Mark a line using a sharp chinagraph pencil and STRAIGHT edge where the
leading edge of the Mylar needs to be - make sure you get this bit right.I
use a steel straight edge.

2.Lay the Mylar out and tack it in place using the line as a reference and
small pieces of masking tape.Then when you're happy,run a full length
piece of masking tape along the edge.This then positions the Mylar.Do this
as many times as it takes to get it straight and in the right place.

3.With the Mylar still just laying under its own weight on the wing/tail
surface,remove the pink adhesive strip backing tape at 45 degrees away
from under the Mylar.Do this slowly,a bit at a time, and just touch it to
the surface as you move along pulling the pink strip away.

4.When the whole strip is tacked in position you can go back along it and
roll the adhesive strip down.

5.Use white Tesa capping tape to finish it off.Always cut small 45 degree
corners off tapes then the corner point won't get snagged and start to
peel - a round curve is even nicer if you have time and/or care!

TIPS.

1.Ensure the surface is perfectly clean with no lumps that could cause the
Mylar to go away from true.The cleaning part takes most of the time but is
very important.

2.NEVER force the mylar - the curve in it gives it a natural straight
lay.There IS a small amount of tolerance but it IS small.

3. Take your time - you only have to do this once every several
years.Allow at least 2 hours per control surface.

4.Some gliders have a recess of about 10 thou for the adhesive part of the
tape to sit in - don't assume it's straight - don't ask!

5.Enlist a friend who's as keen as you to see that it gets done right -
you may need another pair of hands although I managed alone using this
method.Worked ok on my Libelle which didn't have recesses for the aileron
Mylar, and Discus which did.

GOOD LUCK

On Mar 22, 12:00*pm, Pete Startup wrote:
I'm assuming standard 38mm curved Mylar for ailerons etc.

GOOD LUCK

Thanks, Pete. Looks familiar.

Regards,

Mark -- B9

On Mar 22, 1:00*pm, Pete Startup wrote:
I'm assuming standard 38mm curved Mylar for ailerons etc.

1.Mark a line using a sharp chinagraph pencil and STRAIGHT edge where the
leading edge of the Mylar needs to be - make sure you get this bit right.I
use a steel straight edge.

2.Lay the Mylar out and tack it in place using the line as a reference and
small pieces of masking tape.Then when you're happy,run a full length
piece of masking tape along the edge.This then positions the Mylar.Do this
as many times as it takes to get it straight and in the right place.

3.With the Mylar still just laying under its own weight on the wing/tail
surface,remove the pink adhesive strip backing tape at 45 degrees away
from under the Mylar.Do this slowly,a bit at a time, and just touch it to
the surface as you move along pulling the pink strip away.

4.When the whole strip is tacked in position you can go back along it and
roll the adhesive strip down.

5.Use white Tesa capping tape to finish it off.Always cut small 45 degree
corners off tapes then the corner point won't get snagged and start to
peel - a round curve is even nicer if you have time and/or care!

TIPS.

1.Ensure the surface is perfectly clean with no lumps that could cause the
Mylar to go away from true.The cleaning part takes most of the time but is
very important.

2.NEVER force the mylar - the curve in it gives it a natural straight
lay.There IS a small amount of tolerance but it IS small.

3. Take your time - you only have to do this once every several
years.Allow at least 2 hours per control surface.

4.Some gliders have a recess of about 10 thou for the adhesive part of the
tape to sit in - don't assume it's straight - don't ask!

5.Enlist a friend who's as keen as you to see that it gets done right -
you may need another pair of hands although I managed alone using this
method.Worked ok on my Libelle which didn't have recesses for the aileron
Mylar, and Discus which did.

GOOD LUCK

One more useful technique. Procure your seals without preapplied
transfer tape. In many cases(most from my experience) the preapplied
type is not as straight as the plain type. If it comes preapplied in a
big roll, it likely will be curved , warped and go on hard. The
exception would be if your supplier stores seals flat and straight,
and only rolls when shipping. I know John Murray does this.
Straight seals are easy to apply, curved ones are hopeless.
To install. Tape one end in position with tape on end of seal. Unwind
and cut to length. put tension on seal lengthwise to straighten and
tape other end. Add hinge tapes every 8 inches or so from center out
watching for signs of curve or waviness. Scuff, clean, peel, apply,
burnish, safety tape, enjoy.
Good luck
UH

On Mar 23, 8:39*am, wrote:
On Mar 22, 1:00*pm, Pete Startup wrote:



I'm assuming standard 38mm curved Mylar for ailerons etc.

1.Mark a line using a sharp chinagraph pencil and STRAIGHT edge where the
leading edge of the Mylar needs to be - make sure you get this bit right.I
use a steel straight edge.

2.Lay the Mylar out and tack it in place using the line as a reference and
small pieces of masking tape.Then when you're happy,run a full length
piece of masking tape along the edge.This then positions the Mylar.Do this
as many times as it takes to get it straight and in the right place.

3.With the Mylar still just laying under its own weight on the wing/tail
surface,remove the pink adhesive strip backing tape at 45 degrees away
from under the Mylar.Do this slowly,a bit at a time, and just touch it to
the surface as you move along pulling the pink strip away.

4.When the whole strip is tacked in position you can go back along it and
roll the adhesive strip down.

5.Use white Tesa capping tape to finish it off.Always cut small 45 degree
corners off tapes then the corner point won't get snagged and start to
peel - a round curve is even nicer if you have time and/or care!

TIPS.

1.Ensure the surface is perfectly clean with no lumps that could cause the
Mylar to go away from true.The cleaning part takes most of the time but is
very important.

2.NEVER force the mylar - the curve in it gives it a natural straight
lay.There IS a small amount of tolerance but it IS small.

3. Take your time - you only have to do this once every several
years.Allow at least 2 hours per control surface.

4.Some gliders have a recess of about 10 thou for the adhesive part of the
tape to sit in - don't assume it's straight - don't ask!

5.Enlist a friend who's as keen as you to see that it gets done right -
you may need another pair of hands although I managed alone using this
method.Worked ok on my Libelle which didn't have recesses for the aileron
Mylar, and Discus which did.

GOOD LUCK

One more useful technique. Procure your seals without preapplied
transfer tape. In many cases(most from my experience) the preapplied
type is not as straight as the plain type. If it comes preapplied in a
big roll, it likely will be curved , warped and go on hard. The
exception would be if your supplier stores seals flat and straight,
and only rolls when shipping. I know John Murray does this.
Straight seals are easy to apply, curved ones are hopeless.
To install. Tape one end in position with tape on end of seal. Unwind
and cut to length. put tension on seal lengthwise to straighten and
tape other end. Add hinge tapes every 8 inches or so from center out
watching for signs of curve or waviness. Scuff, clean, peel, apply,
burnish, safety tape, enjoy.
Good luck
UH

Now for the advanced course !
How do you apply zig-zag turbulator tape ?
Any tricks to keep it from shrinking (spanwise) over time and
separating at the ends ?
Thanks, See ya, Dave "YO electric"

On Mar 24, 1:59*pm, DRN wrote:
On Mar 23, 8:39*am, wrote:





On Mar 22, 1:00*pm, Pete Startup wrote:

I'm assuming standard 38mm curved Mylar for ailerons etc.

1.Mark a line using a sharp chinagraph pencil and STRAIGHT edge where the
leading edge of the Mylar needs to be - make sure you get this bit right.I
use a steel straight edge.

2.Lay the Mylar out and tack it in place using the line as a reference and
small pieces of masking tape.Then when you're happy,run a full length
piece of masking tape along the edge.This then positions the Mylar.Do this
as many times as it takes to get it straight and in the right place.

3.With the Mylar still just laying under its own weight on the wing/tail
surface,remove the pink adhesive strip backing tape at 45 degrees away
from under the Mylar.Do this slowly,a bit at a time, and just touch it to
the surface as you move along pulling the pink strip away.

4.When the whole strip is tacked in position you can go back along it and
roll the adhesive strip down.

5.Use white Tesa capping tape to finish it off.Always cut small 45 degree
corners off tapes then the corner point won't get snagged and start to
peel - a round curve is even nicer if you have time and/or care!

TIPS.

1.Ensure the surface is perfectly clean with no lumps that could cause the
Mylar to go away from true.The cleaning part takes most of the time but is
very important.

2.NEVER force the mylar - the curve in it gives it a natural straight
lay.There IS a small amount of tolerance but it IS small.

3. Take your time - you only have to do this once every several
years.Allow at least 2 hours per control surface.

4.Some gliders have a recess of about 10 thou for the adhesive part of the
tape to sit in - don't assume it's straight - don't ask!

5.Enlist a friend who's as keen as you to see that it gets done right -
you may need another pair of hands although I managed alone using this
method.Worked ok on my Libelle which didn't have recesses for the aileron
Mylar, and Discus which did.

GOOD LUCK

One more useful technique. Procure your seals without preapplied
transfer tape. In many cases(most from my experience) the preapplied
type is not as straight as the plain type. If it comes preapplied in a
big roll, it likely will be curved , warped and go on hard. The
exception would be if your supplier stores seals flat and straight,
and only rolls when shipping. I know John Murray does this.
Straight seals are easy to apply, curved ones are hopeless.
To install. Tape one end in position with tape on end of seal. Unwind
and cut to length. put tension on seal lengthwise to straighten and
tape other end. Add hinge tapes every 8 inches or so from center out
watching for signs of curve or waviness. Scuff, clean, peel, apply,
burnish, safety tape, enjoy.
Good luck
UH

Now for the advanced course !
How do you apply zig-zag turbulator tape ?
Any tricks to keep it from shrinking (spanwise) over time and
separating at the ends ?
Thanks, See ya, Dave "YO electric"- Hide quoted text -

- Show quoted text -

Not sure what you mean. I install as 1 piece so have not seen what you
are describing.
UH