Explain this

[mark tucker]

I have tottaly figured out what is going on and why. the tape was just sitting there minding it's own bizness when some hot 3m eazy release tape strolled by and...bing,bong boing!!!! and there you have it.

[Abscate]

[cdennisg]

So, yesterday morning I sat next to two retired 3M employees, one of which spent most of four decades working with adhesive tape production. So I posed this question to him.

His answer? The roll was wrapped too tight. Between that and what has been mentioned here (adhesive lubricity and temperature during storage) the rolls will "telescope". That was his term for a distended roll.

Not sure a more definitive answer could be had. Adhesive tape was this guy's lifelong career, he likely knows what he's talking about.
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[raygreenwood]

[56Cabrio]

[cdennisg]

[56Cabrio]

[raygreenwood]

Abscate is pretty close. He got half of it! There are two items at play here. Get there in a minute.

About 90% of electrical tape made is vinyl. Vinyl is insidious crap .....but sometimes useful....crap. Some hugh end tapes like class H are made of fiberglass cloth.

I see people trying to use vinyl for things they want a permanent solution for.....and the fact they are using vinyl 100% guarantees its temporary.

Vinyl begins outgassing solvents ....and therefore shrinking ....and eventually hardening up when there are no more plasticizers to make it pliable.....the very minute its cast, molded or extruded. Long term parts like fender beading are made of vinyl....and therefore guaranteed to shrink and distort.

So....the two issues:

1. Its vinyl.....so it naturally shrinks.....and as abscate noted.....squeezes the roll and csn eventually pump out the core.

KEY TO REMEMBER: the plasticizers that are outgassed by vinyl.....are SOLVENTS....VOC's

2. The adhesive on basic, cheap vinyl electrical tapes are rubber based.....either natural or synthetic. The rubber is dissolved in a very low flash point, fast evaporating solvent like methylene chloride (low corrosive) or ethyl acetate (eventually will become corrosive).....and then roll or slot-die coated onto wide sheets of vinyl .....and dried in an explosion proof oven.....and then rolled up into one big wide roll (may be upwards to 144" wide).....and sliced into narrow rolls.

The problems this causes:

The problem is that as you roll materials like this.....as the roll grows in diameter....the roll tension needs to be reduced as you go. This is hard to control. The material near the inner core is under more tension.....which = more compression, twist and shear. So thats an initial problem.

The next big problem is that the rubber in the adhesive....readily absorbs and dissolves in solvent. And.....REMEMBER.....vinyl outgasses solvents. And....vinyl accelerates ots outgassing of solvents.....with heat!

So the adhesive is "re-wetting" from the solvents comi ng out of the vinyl.....and getting "slimy" and starting to FLOW.......and.....between the shrinking of the vinyl.....and the excessive pressure/tension down near the core.....it can pump the core right out.

BETTER electrical tape....even made with vinyl material......will use an ACRYLIC adhesive. But acrylic adhesive has less initial tackiness so it has to be used more carefully....and....eventually....acrylic based adhesives as they age....will become permanent and you will have a very hard time getting them off.

This page has a good comparison chart of the three main adhesive types used on electrical tapes and their pros and cons.

https://www.can-dotape.com/adhesive-tape-consultant/adhesives-used-for-tape/

Yes.....the tape manufacturing industry and the methods they use for toll coating are part of my industry.

Ray

[Cusser]

[Abscate]

It’s temperature shrinking the tape and pushing the roll up to relieve the pressure

If you store it cool, it won’t happen.
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[mark tucker]

I thought that too but Ive had some that were flat and did it.I figured the outer portion was tightening up or the center was swelling thus forcing the tape to go somehwere...probably the center absorbing some moisrture and swelling along with a heat sorce weather sun it whatever and time. it seems many tapes get liquider the older they get.I thinks it's the rubber/plastic affecting the addhivsive and liquidfiying it. or just time it's self and the addhivisive breakdancing down and liquidfiying.possiably another could be the moons phase when it's in the orbit of chewing gum softening the gummy addhivsive till it's more like the dog drewuel from pluto. either way I hate effing with a wireing harness thats got degrading tape, that slimey shit gets everywhere and a booger to screw with and retape with new tape.I dont think the fabrick tape does it, but it can dry out...witch starts another issue when jupiter is in retrograde........ where is that emogie of somebody beating thier dead horse

[kreemoweet]

It's just gravity in action. Heat makes the glue (a sticky semi-fluid) less sticky and more fluid. The coils of tape will start sliding downhill. Tape stored flat on a horizontal surface does not do that. I have twenty-year old rolls of electrical tape in my toolbox, only the rolls that got dislodged and lay at an angle show any departure from flatness.
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[brando90gl]

I switched to Tesa brand wiring loom tape because I got tired of sticky rolls of regular electrical tape and I wanted to use what the OEM European manufacturers used on my bikes and cars. This stuff is made for high heat application and performs pretty well when handled correctly. It’ll definitely loose some adhesion if handled with sweaty hands at the ends. Scissors are also required to snip the length desired.

https://www.amazon.com/gp/product/B016ZMXLEI/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
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[Pez]

Now Cusser, there is a point in a little tapes life when it begins to experience changes. These changes may seem weird but are perfectly normal.

But in this case its totally weird, such a freak. Really though we see electrical tape do this in Texas too. From work we see trucks come in with tape everywhere, When used on the chassis it still sticks well and lasts a good while. In the engine compartment it appears larger and almost swelled up. So I'm no scientist and I have self respect so I'm not a engineer either, so our guess is the plastic tape expands and on a roll follows the path of least resistance thus pushing one side out. I feel like if it where the glue expanding it would just ooze out.

Or maybe they are just excited to see you
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[cbeck]

You are the one who posted about a hole with sticky edges.
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[Cusser]

[mark tucker]

turner over.

[finster]

I think mrs cusser has been trying to fix the shelves in the fridge/freezer with it!
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[insanitize]

This thread made me think of the old RAMVA days and so I checked and it is still there

https://groups.google.com/g/rec.autos.makers.vw.aircooled

[Cusser]