welding chainsaw piston

[razor]

hi all,

ive got a jonsered 621 chainsaw which has a chip in the skirt of the piston its about half inch squared sort of size. i have had a look for a secondhand piston but cant find one and as far as i know aftermarket pistons are not available for this saw . so i was thinking is it possible to weld it? i only have a arc welder , we have oxy acetylene for cutting so could get set up for brazing ?

 

[Rig Pig]

I would think that it would be best to price up a new piston, husqvarna are fairly good on parts. It may be possible to tig weld the piston but it would really need a visit to a lathe afterwards to clean it up, by the time you have payed for all that on a worn old piston a new piston starts to look attractive!

 

[the snooper]

Not worth the risk of it falling apart later on, it will cause a lot more damage

 

[razor]

thanks for the replies,

yeah if i could get a new piston for it that would be ideal , do husqvarna supply a piston that will fit this saw?

 

[Rig Pig]

Husqvarna own jonsered, they are a decent make so parts are available for most of there machines, I rebuilt a chainsaw that had a tree land on it a few years ago, no problem getting the bits from the local agent.

 

[hotrodder]

Might not apply to something like a chainsaw but pistons typically aren't round or cylinderical, they usually taper from skirt to crown to account for the temperature differential from top to bottom and are ever so slightly oval for similar reasons i.e. narrowest at the pin boss where the wall is thicker

The internet suggest Husqvarna use AlSi18CuMgNi to make pistons from which is a hypereutectic aluminium alloy and probably not very weldable although 4047 and TIG probably standas the best chance

 

[razor]

so husqvarna own jonsered well i learn something new every day. it is a cracking saw, would be good to get it running again, sounds like welding the piston could be abit risky then. i will try my local dealer see if they can find me a new piston.

thanks for your help everyone

 

[wristpin]

so husqvarna own jonsered well i learn something new every day. it is a cracking saw, would be good to get it running again, sounds like welding the piston could be abit risky then. i will try my local dealer see if they can find me a new piston.

........ And Partner!

Between Husqvarner and Jonsered there is usually an equivalent model in each range.

 

[outofthefire]

where's the bit that broke off? if its dropped into the crankcase you could do with stripping it down to get the bits out.

 

[rich r]

Might be worth asking the guys on www.arbtalk.co.uk, there are lots of people who repair and rebuilt chainsaws on there. You may find the piston is an aluminium alloy that won't be easy to weld anyway. There are certainly aftermarket pistons for Stihl and Husqvarna, it's possible there's something that'll fit yours.

 

[razor]

and partner too , i dont think ive heard of them before.
outofthefire theres no sign at all of the bit that broke off, ive had a good look in the crankcase and its spotless no tiny metal fragments nothing. so weather it shot out the exhaust port in one piece or broke up i dont know. all the bearings seem fine no play or binding at all, the cylinder is in good condition also.
thanks for that rich, i have asked on arboristsite.com if aftermarket pistons are available for it and there was someone on there with good knowledge of this saw that didnt think there was. i will ask jonsered see if they can find me one

thanks all