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Melted and fused bump head "string"

#1

M

motoman

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.


#2

7394

7394

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..


#3

M

motoman

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


#4

Hammermechanicman

Hammermechanicman

If you soak that 25 year old roll in a bucket of water for a few days it will make it less stiff and brittle.


#5

J

Joed756

Hammermechanicman said:
If you soak that 25 year old roll in a bucket of water for a few days it will make it less stiff and brittle.
Click to expand...
Hammer is right, give a good soak in water and your life will be showered in goodness.


#6

C

Chevy S

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.


#7

7394

7394

motoman said:
Yep , my string is 25 years old off a big roll, but aged plastic not like a fine wine? What is the upgrade?
Click to expand...
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.


#8

M

motoman

Chevy S said:
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.
Click to expand...
Please help me with the physics of water migration into plastic. I know you can without the formulas!


#9

ILENGINE

ILENGINE

motoman said:
Please help me with the physics of water migration into plastic. I know you can without the formulas!
Click to expand...
Some of the polymers used in trimmer line are hydroscopic. So they dry out and get brittle. Nylon for one.


#10

M

motoman

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


#11

B

bertsmobile1

Chevy S said:
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.
Click to expand...
The difference between soft plastic & hard plastic ( of the same kind ) is what is used to keep them soft , funny enough they are called plasticisers .
Some are UV resistant as used in garden furnitures , some are petrol resistant as used in fuel tanks , some are water resistant as used in boat seats & kayaks .
Now to take the opposite tack, some dehydrate & crumble very quickly these are used in trimmer line and to make them "vanish" ever quicker most are also not UV stable either .
The idea is the bits you leave all over the yard fall apart quickly and become a sort of inert part of the soil pretty quickly
Trimmer line also has a low melting point which is why they will melt together in the head so not feed
The way to overcome this is to regularly feed fresh line or go down to the next smaller sized line .
have a lot of idiots who run 3mm line in their Honda line trimmers and they have to use the really expensive duel compound line because they think not having to keep on bumping more line trough is some how saving them time & money where as the opposite is true because they are always having to stop and manually pull out welded line from the spool .
Any type of heat will activate plastics so they will weld together and that can be an iron, hot air or plain old friction .


#12

M

motoman

bertsmobile1 said:
The difference between soft plastic & hard plastic ( of the same kind ) is what is used to keep them soft , funny enough they are called plasticisers .
Some are UV resistant as used in garden furnitures , some are petrol resistant as used in fuel tanks , some are water resistant as used in boat seats & kayaks .
Now to take the opposite tack, some dehydrate & crumble very quickly these are used in trimmer line and to make them "vanish" ever quicker most are also not UV stable either .
The idea is the bits you leave all over the yard fall apart quickly and become a sort of inert part of the soil pretty quickly
Trimmer line also has a low melting point which is why they will melt together in the head so not feed
The way to overcome this is to regularly feed fresh line or go down to the next smaller sized line .
have a lot of idiots who run 3mm line in their Honda line trimmers and they have to use the really expensive duel compound line because they think not having to keep on bumping more line trough is some how saving them time & money where as the opposite is true because they are always having to stop and manually pull out welded line from the spool .
Any type of heat will activate plastics so they will weld together and that can be an iron, hot air or plain old friction .
Click to expand...


#13

M

motoman

A great summary...and...BTW I missed your coronation into landscape royalty. Thanks for the info, King!


#14

B

bertsmobile1

motoman said:
A great summary...and...BTW I missed your coronation into landscape royalty. Thanks for the info, King!
Click to expand...
Just as long as you don't call me queen :eek:
IT was quite some time ago comes in around 10,000 posts I think
Funny thing is I had just finished editing a composting video setting a lot of people strait about what will compost ( everything other than bone ) and then this popped up after we had filmed a lot of tiny bits of trimmer line in the garden that had been there for at least 3 years and they crumbled to dust in my fingers


#15

G

GrumpyCat

motoman said:
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.
Click to expand...
Any chance it has this head?


#16

7394

7394

I believe that vid is referring to the new Speed Feed 500 head only.. Love my 400, old school.


#17

B

bertsmobile1

7394 said:
I believe that vid is referring to the new Speed Feed 500 head only.. Love my 400, old school.
Click to expand...
I am older school than that as I use either a Dranganfly head or a manual feed Tanaka head
Neither give a seconds of problems


#18

7394

7394

Cool..


#19

G

GrumpyCat

7394 said:
I believe that vid is referring to the new Speed Feed 500 head only.. Love my 400, old school.
Click to expand...
Yes but the O.P. said nothing about what model head.

And my point is that there possibly others which are melting.


#20

7394

7394

GrumpyCat said:
And my point is that there possibly others which are melting.
Click to expand...
Well mine is certainly not melting anymore.. Used to when I was using Echo orange .095 line


#21

M

motoman

Sorry, did not describe bump head. Do not know models. It is one with knurled round plastic , left hand threaded nut. The wrap direction is shown with an arrow. It has two string outlets of brass which wear out over time. The shaft is a hollow tube with a removable tension spring. I have found light greasing the shaft and the spool mating hole to be beneficial. I abuse the use of this tool to weed into dirt which causes frequent bind up and field disassembly, string loosening, and rethreading. The restring of the .090 " line when doubled is about 25 feet. The 2 stroke 31 cc unit has a click shaft which accepts hedge shears and a rotary 4 blade cutter useful on thicker branches. The last unit I bought has the "easy start" "elastic" pull cord which I hate. But I love this tool overall. Using sta bil and run dry for storage allows easy Spring startup. The Crafstman brand has changed hands, but these units were only about $125 a few years back compared to $300 up on othe brands.


#22

7394

7394

Very true.


#23

Avman

Avman

Hammermechanicman said:
If you soak that 25 year old roll in a bucket of water for a few days it will make it less stiff and brittle.
Click to expand...



#24

7394

7394

And after a while that old water gets moldy / funky.


#25

M

motoman

7394 said:
And after a while that old water gets moldy / funky.
Click to expand...
The "feel" of the string is "pliable" when wrapping, not brittle. The weather here is humid mostly which may have increased longevity. And...as I abuse the string against walls , fencing and dirt the tip of the string is narrowed to perhaps half its diameter of .090," also "curled." (How long can we milk this conversation on what I thought was a trivial subject? ha ha) We should offer the aged line in an IPO on the stock market. Doesn't matter that's it's worthless. We could sell shares at $29 .


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