Applying New Seals

On 10/4/2011 5:44 AM, JJ Sinclair wrote:


After 30 years in the repair business, I found the only way to insure
the mylar didn't lift was to sand both the inside of the mylar and the
corresponding wing (stab, fin) with 220 dry, then wipe both surfaces
with acetone just before applying double back sticky. Keep the DBS
straight as an arrow and then follow it in order to keep the Mylas
straight without any kinks. Sand only the 10mm area where the DBS will
go. If you get a kink, make a cut to remove it and press on.
I believe a good mylar job is all that in needed (internal seals not
necessary).

I've always used Mylar that already had the transfer tape on it. It
saves me a lot effort and time, and I've never had the adhesive come off
the Mylar.

I prepared the carbon on my ASH 26 E by cleaning off the old adhesive
COMPLETELY, even scraping with a flat Xacto blade or single edge razor,
then sanding gently with a block and 320 grit as JJ describes until only
fresh carbon shows, then cleaning the residue off with acetone.

I apply the Mylar under a very slight tension. When it's all on, I rub
over the adhesive portion with a firm piece of balsa, rag, thumb, as
needed , then follow that with a hard roller, paying particular
attention to "white" places. That's probably easier to do when the wing
surface is carbon instead of gel coat.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

On Oct 4, 5:24*pm, Eric Greenwell wrote:
On 10/4/2011 5:44 AM, JJ Sinclair wrote:



After 30 years in the repair business, I found the only way to insure
the mylar didn't lift was to sand both the inside of the mylar and the
corresponding wing (stab, fin) with 220 dry, then wipe both surfaces
with acetone just before applying double back sticky. Keep the DBS
straight as an arrow and then follow it in order to keep the Mylas
straight without any kinks. Sand only the 10mm area where the DBS will
go. If you get a kink, make a cut to remove it and press on.
I believe a good mylar job is all that in needed (internal seals not
necessary).

I've always used Mylar that already had the transfer tape on it. It
saves me a lot effort and time, and I've never had the adhesive come off
the Mylar.

I prepared the carbon on my ASH 26 E by cleaning off the old adhesive
COMPLETELY, even scraping with a flat Xacto blade or single edge razor,
then sanding gently with a block and 320 grit as JJ describes until only
fresh carbon shows, then cleaning the residue off with acetone.

I apply the Mylar under a very slight tension. When it's all on, I rub
over the adhesive portion with a firm piece of balsa, rag, thumb, as
needed , then follow that with a hard roller, paying particular
attention to "white" places. That's probably easier to do when the wing
surface is carbon instead of gel coat.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)

Forgot one thing, I make sure the mylar is secured to the DBS and to
the surface by rolling it very hard with a roller that I made from a
30mm X 10mm bearing mounted on a 12" rod. I press down real hard as I
roll everything twice. I usually buff and wax the ship every other
year (wax every year), then replace the safety tape which is showing
some age (wax after replacing the safety tape). BTW, I believe the
pilot of Ventus that had tape lift on its elevator, had waxed the
surface, then applied the safety tape..........good point to remember!
Cheers,
JJ

Go to Lee Valley Hardware and buy the plastic Razor blades. You can
use these to remove the tape gunk and not damage the gelcoat or Mylar
while scraping.

http://www.leevalley.com/US/wood/pag...56,43407,53612



Dave
www.foxonecorp.com