Using mylar to wrap diy fiberglass

[RocketSquirrel]

Ive had issues with pulling the mylar off after its cured, what is the ideal time to take it off? Should i coat it with something? Its so tedious to scrape off the pieces that want to stick with a dentist tool.

I use west system slow cure. I measure how much i need for the size tube and apply on the tube first. I saw this method on a RocketVlogs youtube video. He then drapes the cloth and lets the epoxy wet the fabric with the leftover epoxy on the brush. Then wrap it with mylar pushing out bubbles as you go. Tape the edges then squeegie out bubbles with plastic flat edge. I let it sit the first time 24hr but it took me hours to get all the mylar off. Second time i waited maybe 12h and same thing. Then 3rd time i let it sit 48hr and again it stuck and took hours to remove.

Any advice on your method would be good to know!

 

[SolarYellow]

Are you using a dull-surfaced mylar or shiny mylar?

 

[Tractionengines]

"Mylar" can be a VERY broadly applied term. Often miss-applied to other materials...

Were all of your attempts with the same material? If so, can you let us know what you have? (Link to exact material and your supplier, would be best.)

 

[RocketSquirrel]

Are you using a dull-surfaced mylar or shiny mylar?

I think shiny, i purchased the same product shown in the video i watched from RocketVlogs. This was the one

 

[RocketSquirrel]

"Mylar" can be a VERY broadly applied term. Often miss-applied to other materials...

Were all of your attempts with the same material? If so, can you let us know what you have? (Link to exact material and your supplier, would be best.)

I got the same product from the RocketVlog video, he had a link to it. He has good luck with it so i feel like im doing something wrong. Its called duralar

 

[SolarYellow]

That is polyester. Epoxy sticks to polyester, hence why polyester fiberglass things can be repaired with epoxy.

 

[Upsrocketman]

I have used the same mylar to wrap glassed tubes. Sometimes it peels right off, sometimes I have to work at it. I've used it with a couple different epoxies as well and there seems to be no consistent result. I have noticed that some epoxies will form an oily layer on the surface as they cure, which may aid in the removal of the mylar.

 

[Zbench]

I got the same product from the RocketVlog video, he had a link to it. He has good luck with it so i feel like im doing something wrong. Its called duralarView attachment 635022

I bought some of this same stuff and it’s impossible to remove. It tears before it releases. It’s not what you should consider for wrapping tubes.

 

[RocketSquirrel]

I bought some of this same stuff and it’s impossible to remove. It tears before it releases. It’s not what you should consider for wrapping tubes.

That's annoying... what would you recommend that works?

 

[reddrock]

One can paint PolyVinyl Alcohol (PVA) on mylar as a release.
I paint one layer with a chip brush and let it dry. Thoroughly. Paint another layer at 90 degrees to the first layer. Let it dry. Then laminate with FG, CF, or whatever you are using. After curing, the mylar and laminated tube slides off the mandrel and the mylar then can easily be peeled off the inside of the tube. Any residual PVA on the inside of the tube is water soluble and can be washed off. Works with polyester and epoxy resins. Also works with oven curing.

 

[John Kemker]

One can paint PolyVinyl Alcohol (PVA) on mylar as a release.
I paint one layer with a chip brush and let it dry. Thoroughly. Paint another layer at 90 degrees to the first layer. Let it dry. Then laminate with FG, CF, or whatever you are using. After curing, the mylar and laminated tube slides off the mandrel and the mylar then can easily be peeled off the inside of the tube. Any residual PVA on the inside of the tube is water soluble and can be washed off. Works with polyester and epoxy resins. Also works with oven curing.

I like this.

I just received a bottle of PVA specifically for mandrel release agent (Tripoli Research) and vac-bagging release.

 

[pathtouch]

I like using porous Teflon as a peel ply. Minimal sanding needed after.

I talk about it a bit in this video:



Get it from aircraft spruce.
https://www.aircraftspruce.com/catalog/cmpages/vb7025.php

 

[lr64]

In general, epoxy doesn't stick to polyethylene. Maybe wrap with that. Ditto polypropylene. Test first. I've heard of waxing Mylar.

 

[shockie]

You can buy very thin Teflon film :

https://catalog.cshyde.com/viewitem...n-products-ptfe-teflon-films/ptfe-skived-film

It can be used as a non+stick film over a mandrel or wrapped over the outside of a tube as a release film and then use some Dunstone heat shrink tape to compress it and squeeze out the excess resin from the ends.

 

[cbrarick]

use real release film from here https://sollercompositesllc.com/product/silicone-coated-release-fabric-60-inch/
this is one of those places where saving a couple of bucks can cause disaster compared to the good stuff.

 

[JohnCoker]

That's annoying... what would you recommend that works?

Mylar® is a brand name, so I meant it literally. Not every plastic film will release from epoxy. I got mine from Tap Plastics, but it is widely available.

 

[lr64]

I've read that Plexiglas will release from epoxy, but I bet it depends on which epoxy. And if using some other acrylic sheet, which acrylic sheet. Alex Strojnik built at least one airplane with fiberglass sheets laid up over Plexiglas.

 

[cwbullet]

I've read that Plexiglas will release from epoxy, but I bet it depends on which epoxy. And if using some other acrylic sheet, which acrylic sheet. Alex Strojnik built at least one airplane with fiberglass sheets laid up over Plexiglas.

I cannot confirm that 100%, but I use a sheet on my desk top and it is easy to remove epoxy to date.