Mylar Not Sticking

On Sunday, January 13, 2019 at 2:24:10 AM UTC-5, Gary Wayland wrote:
On Sunday, January 13, 2019 at 12:56:48 AM UTC-5, bumper wrote:
On Saturday, January 12, 2019 at 4:11:35 PM UTC-8, wrote:


Determine which side the transfer tape released from an you will know which side was not prepped right.

What UH said is important. If the double sided tape failed on the Mylar side, you can improve the bond to the double sided tape by roughing the surface of the Mylar. Use masking tape to protect the half that is not to be bonded and then give the surface some tooth with abrasive paper.

It's important to press the Mylar down firmly onto the adhesive. A ball bearing mounted in a notched wood handle makes a good roller. After rolling down, position control surface so it's not trying to lift Mylar. Full strength is gained over about a day with most tapes.

bumper

Thanks, bumper, I'm heading to the hangar today and pull the glider from the box. I will take a better look at what the issue is. So a ball bearing works as a good tool for this? It sounds like your getting pressure in a very small area to help seal it.

When I first flew it after the resurface, I heard some chattering outside.. Ok what's coming loose! And you can't blame high-speed pass since I hadn't done one yet! The new air duct that was put in made the sound more intimidating. The 27 sounds completely different from the air scoop behind your head. Ok, I'm ranting... See ya... Thanks again... Gary


Gary

I rub down seal as follows:
1) After seating seal in correct position, rub down with finger(thumb)pressure so it will stay put.
2) My rub down tool is made from a piece of wood 5/8 thick, 1-1/4 wide, and 9 inches long. It has a 1/4 inch radius sanded on the corner so contact angle is not critical. The length is so 2 hands can hold the tool. One controls the alignment, and one applies the pressure. It's hard to do this well one handed from my experience.
Good contact is visible through the seal as the color changes from cloudy to clear.
UH

On Saturday, January 12, 2019 at 5:05:39 PM UTC-5, Gary Wayland wrote:
The Mylar on the wings of my 27 or losing their adhesive. Can someone tell me what they would use to fix this, or should I just replace it all?

Thank You

A drywall tape roller is a good tool for applying pressure.

JMF

Temperature when applying the tape is also a factor. If it is winter when you attempt to replace the tape, try to at least get the surfaces warm so the adhesive has a better chance to "flow" and stick.

This thread seems an appropriate time to note that properly applied and cared for Mylar seals can last a LONG time. When UH helped me refinish my then-26-year-old ASW 24 wings last winter, it was REALLY difficult to remove the original seals. The toughest part was getting the adhesive out of the channel in the wings. There was no tendency to "just pull on the end of the seal and it will lift right off". I had replaced the safety tape once before and that was easier to remove (and the previous adhesive had, in fact, deteriorated into a chalky powder).

The seals seemed to have retained their curvature, too, with no apparent tendency to lift off the control surfaces when deflected. I'm speaking just of the ailerons. If you have flaps that deflect further, this might not apply.

I always install the control locks on the ailerons in the neutral position when the glider goes in the trailer so I think that helps.

Your situation may be different so check the seals carefully from time to time. A loose seal can cause serious problems. But don't assume you need to rip them off and replace them if they're working fine and still secure.

Chip Bearden