Well i would not have believed it

[wigglesworth]

I'd give my eye teeth if Muh accent sounded that cool on a video.

I sound like a pre-pubescent school kid hopped up on helium and mountain dew.

Crazy bout ur saw though. Can't say I've seen one weld itself up. I wouldn't worry bout it though, cause you don't have to clean husky filters anyways...

 

[deye223]

I'd give my eye teeth if Muh accent sounded that cool on a video.

I sound like a pre-pubescent school kid hopped up on helium and mountain dew.

Crazy bout ur saw though. Can't say I've seen one weld itself up. I wouldn't worry bout it though, cause you don't have to clean husky filters anyways...

yep life of the party and no helium. my take on is it's the 1st time i ran 3/8 full skip and there was a noticeable
increase in vibes and dry redgum is HARD

 

[2dogs]

yea see it all the time
stick right on, gotta pry it off
after a few times and the clips wont hold it tight anymore
then a little duct tape is in order
i have no idea how it happens, and not every saw does it

Really? All the time? And the proof?

 

[nmurph]

I've never seen it happen on the nearly 100+ 346's I've had through the shop.

 

[fossil]

My guess is that the plastic in the covers is ABS which is a styrene. Many styrenes are ultrasonically welded together using some pressure on the pieces and applying a high frequency vibration.

The frequency rate starts for welding smaller pieces which the area of a cover on the mating piece here would be classified as.

The frequencies used start at 15000 Hz. (CPS)

It is conceivable with a tight fitting cover and the high frequency vibration in chainsaws that this could occur even though they don't hit 15000 Hz

Having pulled a lot of these welds apart welding styrene for games that looks like a weak ultrasonic weld.

I could sure be wrong but it makes sense to me.

 

[jaya]

you see that XP on the air filter cover?....that stands for "Xtra Prying"

 

[brokenbudget]

you see that XP on the air filter cover?....that stands for "Xtra Prying"

around here we say 'xtra paying' or 'xtra praying':jester:

 

[H 2 H]

you see that XP on the air filter cover?....that stands for "Xtra Prying"

Now that's funny right there :jester:

 

[Andyshine77]

In this video it shows how plastic is welded together with high frequency vibrations. Skip to the 2 minute mark on the video.

How It's Made-Echo chainsaws - YouTube

 

[Andyshine77]

Just watched the video again, that saw has an elastostart handle, I'm wondering if it vibrated excessively causing the plastic to also vibrate thus causing the weld. Add that the fact the other side of the cover was fine.

 

[SawTroll]

Just watched the video again, that saw has an elastostart handle, I'm wondering if it vibrated excessively causing the plastic to also vibrate thus causing the weld. Add that the fact the other side of the cover was fine.

I don't really like the elastostart handle, but that's for a totally different reason.

Your post actually makes sence, regardless of that - but it is of course a shot in the dark.....

 

[Naked Arborist]

I have seen this happen on cars and other equipment. It is rare and seems quite puzzling. I have to go with bad vibes :msp_scared: ...

Second thought, Do you use an aftermarket filter on it? The reason I asked is it may be dripping a type of oil that is not compatible with the plastic. It looks like you would have to be felling trees with the saw turned on it's side for that to have happened in just that area. Only other thing I can offer is the gas oil mix is not very kind to that type of plastic. You know some chemicals in certain combinations just do strange things to plastic.

 

[Rudolf73]

But I thought huskies were supposed to have really good AV...

 

[Justsaws]

He found the sweet spot, the 372 harmonic hole in one. Pry it off, sand it smooth and glaze it over with some light heat.

I think that it is caused by mal formed plastic pieces and the just perfect situation that transfers the vibes to the plastic.

After repairing then spend everyday from now on trying to do it again in the exact same spot.

 

[Justsaws]

But I thought huskies were supposed to have really good AV...

That is what they tell everyone. Of course it could be that springs only pass the high freq vibes and that is why people think they are smoother.

 

[tree monkey]

Really? All the time? And the proof?

the proof that it happens is in the vid

 

[deye223]

Just watched the video again, that saw has an elastostart handle, I'm wondering if it vibrated excessively causing the plastic to also vibrate thus causing the weld. Add that the fact the other side of the cover was fine.

yeah but the elastostart handle has it's own rubber AV haha

I have seen this happen on cars and other equipment. It is rare and seems quite puzzling. I have to go with bad vibes :msp_scared: ...

Second thought, Do you use an aftermarket filter on it? The reason I asked is it may be dripping a type of oil that is not compatible with the plastic. It looks like you would have to be felling trees with the saw turned on it's side for that to have happened in just that area. Only other thing I can offer is the gas oil mix is not very kind to that type of plastic. You know some chemicals in certain combinations just do strange things to plastic.

OEM filter on this saw

He found the sweet spot, the 372 harmonic hole in one. Pry it off, sand it smooth and glaze it over with some light heat.

I think that it is caused by mal formed plastic pieces and the just perfect situation that transfers the vibes to the plastic.

After repairing then spend everyday from now on trying to do it again in the exact same spot.

yeah but it's a 390XP

IT'S JUST THE AGRESIVE way brad ports saws haha

 

[Andyshine77]

the proof that it happens is in the vid

Then why is this the first time anyone said anything about it?

Man are the Stihlheads getting desperate.:hmm3grin2orange:

 

[deye223]

i've been waiting for someone to say if it had bologna!! it wouldn't have happend :big_smile:

 

[Justsaws]

yeah but it's a 390XP

IT'S JUST THE AGRESIVE way brad ports saws haha

I do not have any 390s, but I do consider them to be the very best Husqvarna 372 BIG BORE out there. Little bit more expensive than the after market piston and cylinder kits but a decent saw until they get the 372 death spin, usually preceded by the 372 harmonic hole in one.

:msp_w00t:

They do that without the porting just takes longer.

:msp_wink:

On a serious note I think that the amount of weld bonding that took place is proof that you need to spill more oil all over your saw. Lots of the top covers get "wear marks" but are probably to dirty to actually make a decent weld, they just get shabby and crusty looking.