Important....husky 350 loctite 518 vs 1184 vid

[cedarshark]

I cannot help but wonder if the Huskie 450 has gone to rubber gaskets on the cylinder to plastic case seal because of the difficulty in making a liquid sealant which will perform well between 2 different materials(aluminum & plastic). There is no mention in the 450 service manual to use any sealant at all.

 

[Tor R]

Tor,

Very interesting. This is the first I have seen this Dow/Corning 7901. It appears that this is a Husqvarna part. Am I correct ?

Edit: After research, this is a Husky part suitable for the aluminum to aluminum pan on Huskie 141,41,136 and 36 clamshells. The Dow Corning website rates it as an adhesive/sealant rated stable at high temps and low temps. It is not rated for certain types of plastics. $44/tube.

the only number I have found in Workshop manual for 340/345/350 is a silicone 03-7062, I dont know what their full part number is.
Their sealant from factory is a silicone type.

The one I posted is a Husky one that is recommended on 550 from gasket to crankcase, I didnt pay 44$ for my tube, it was more like 20$ from my nice dealer

Here's another unhappy customer with both 518 and 1184 on plastic. The pic below is a Husky 450 that is apart for the 3rd time in 2 weeks. It developes an air leak, wont idle down and races. The cylinder does not have an aluminum crankcase cover that bolts to the cylinder bottom. The cylinder sits directly on the plastic case. Note that Huskie now uses the small rubber gaskets(pictured on the notepad) . The first time this saw was rebuilt, I re-used the old gaskets and supplemented with 518. Air leak, so I took it apart and there was no evidence of 518 on the plastic. Repeat the above and used 1184...same result. Its now apart again and I have ordered new OEM rubber gaskets ($7/ea). When this saw is fixed, it going to spend Xmas under someones elses tree.

View attachment 540994

I have several 350s that do not have a problem sealed w/ 1184 but the bases are flat by sanding on sheet glass and 400 grit paper.

those two is the one you have to purchase.

 

[blsnelling]

How long would you let 3bond 1184 sit before putting the jug on ?

I don't think you want to let it dry. Wet sealant is going to stick better. This is the main reason that I prefer 518. It doesn't tack.

 

[Tor R]

Tor,

Very interesting. This is the first I have seen this Dow/Corning 7901. It appears that this is a Husqvarna part. Am I correct ?

Edit: After research, this is a Husky part suitable for the aluminum to aluminum pan on Huskie 141,41,136 and 36 clamshells. The Dow Corning website rates it as an adhesive/sealant rated stable at high temps and low temps. It is not rated for certain types of plastics. $44/tube.

I read a bit more about it. Your 450 is different and cant be compared to those other clamshell designs from Husky

There has been silicone used by Husky earlier.
504 98 26 01 -> 36,41,40,45
503 26 70 01 -> 136,141
Both those sealant is NLA and is substitute by 503 26 72 01 ie Dow Corning 7091

It's true that there is limitation when it comes to some type plastic like polyethylene and PTFE.

 

[cedarshark]

I spoke to friend of mine in the pipeline leak sealing business for over 30 years. Its his opinion, based on my description of the problem, that the problem may lie in the porosity of the surface of the hard plastic case. The slick hard surface of the plastic may prevent effective bonding of the sealant. He recommends roughing the surface of the plastic case before applying the sealant. I wish I had a 350 apart to test his theory.

 

[Andyshine77]

I spoke to friend of mine in the pipeline leak sealing business for over 30 years. Its his opinion, based on my description of the problem, that the problem may lie in the porosity of the surface of the hard plastic case. The slick hard surface of the plastic may prevent effective bonding of the sealant. He recommends roughing the surface of the plastic case before applying the sealant. I wish I had a 350 apart to test his theory.

This is common practice when sealing or gluing plastic, it will most certainly not hurt. This design doesn't sound like it was made to be easily serviced or all that durable IMHO.