Melted and fused bump head "string"

motoman

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After 20 years of whacking...a first . High grass mixed with black berry , 31cc craftsman 2 stroke on wide open throttle for 5 minutes. Bump head bound up from the heavy work? Common as unyielding weeds do not all cut, but pull on the spooled .090" plastic "string" wrap inside the bump head. Routine to stop, pull on shorted 2-feed lines, then rethread.

Not this time. Found that one string end was bonded to its own wrap. A mess requiring "field stripping" and total rethread. Ambient temp 80F. The "weld" appeared as a white spot.
 

7394

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I had that issue on the old string I was using.. Too hot a load for the string. I upgraded string & haven't had issue since..
 

motoman

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Yep , my string is 25 years old off a big roll, but aged plastic not like a fine wine? What is the upgrade?
 

7394

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Yep , my string is 25 years old off a big roll, but aged plastic not like a fine wine? What is the upgrade?
I upgraded to "Husqvarna Titanium Force" line. Never had a weld issue since.. I do only buy 1/2 lb donuts of it at a time. Because this line is lasting for 1 year per spool load (20 ft).. So 1/2 lb lasts me about 3 or 4 years.
 

motoman

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I saw someone that left a roll of trimmer line in a bucket of water full time. They had the string run through a small hole in the lid & pulled out as needed.
Please help me with the physics of water migration into plastic. I know you can without the formulas!
 

motoman

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Some of the polymers used in trimmer line are hydroscopic. So they dry out and get brittle. Nylon for one.
Verry interesting. I will soak the spool . thanks
 
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