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Advice Needed Using Soller Composites Sleeve and Shrink Tube

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wonderboy

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I'm helping a friend fiberglass his airframe tubes using the fiberglass sleeve and heat shrink tube from Soller composites. I'd previously done this on my 7.5 LOC Doorknob without any troubles. However, this time the heat shrink is not coming off easily at all. It is tearing into many tiny pieces. He is unable to get a continuous piece removed without it tearing. So the task now has become picking off tiny little pieces.

There are more tube sections to do, but now I'm gun-shy about recommending this process again. It went fine for me, but not this time (batting .500 here).

Are there any tips or suggestions for removing the heat shrink after cure? Is there any advice about what we may have done wrong?

The process we used was:
-Glassine peeled 7.5 LOC Airframe tube
-West Systems 105/206
-Tube mounted horizontally on a mandrel
-Resin applied with chip brushes from center out towards ends
-Once fully wetted, squeegeed to remove excess resin
-Heat shrink applied and shrunk
-Cure

It did take 3-4 days to get to the peeling process. Is it possible that the longer the resin cures the harder to remove? Should the heat shrink be removed during the "leather" stage perhaps?

Thanks all
 

Troy3003

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Did you heat it lightly before removing? It looks like they did a light warming with a heat gun before peeling.
 

wonderboy

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I saw that on their helpful tips video. No, it wasn't warmed before trying to peel it. Maybe that's the key. I didn't heat mine when I originally did my tubes, but it was summer time and warm out. This most recent time when we had trouble was during winter and it was generally much cooler in the workshop.
 

thzero

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I didn't heat mine either. On my 3" tube, I did all the same steps as above but it I peeled off the shrink wrap after it setup overnight; it was passed the leather stage for sure.
 

Tractionengines

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In this case, extra time on the tube is probably not your friend. Epoxy "cure" is per the times for your epoxy of choice.... but that is just the initial phase. Over a few days/week the properties and bonds continue to change....on a microscopic level.
The "stuff" we use at work is a long cure. But for example: If we try to pull the wrap at ~12hrs, it will leave a dull / rough finish even though it "seems" hard. If we pull the wrap at 24 hours it will peel off clean leaving a smooth surface, while easy to peel. If it sits over a weekend...it "bonds" to the wrap and is a PITA to get off, sometimes needing some heat, and in pieces...ONCE it was left on over a 5-day long weekend : that tube got scrapped...
It's all a learning curve, and every epoxy and process will have its own nuances.
 
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