Mastermind Meets The Dolmar 7910

[Mastermind]

Will silver solder take the heat generated? I'm asking because I honestly don't know, not trying to be a smart azz........

Depending on the content it has a melting point between 800 and 1200° F.

 

[Mastermind]

Stolen from Tom Walz......

"Silver Solder Versus Silver Braze

I just got another call from somebody that had a lot of problems with brazing.

Once we got into it, it became apparent that the problem was that he was trying to use silver braze alloy with a silver solder flux. He wasn't clear on the difference between silver soldering and silver brazing. He went to a welding supply store where the clerk wasn't clear on the difference either and the clerk sold him soldering flux for a brazing application.

Flux does a lot of things but primarily it is an oxygen interceptor. It is designed to keep the materials from oxidizing during brazing. If you get an oxide layer formed the braze alloy and the two parts being brazed will not join together.

Silver solder is a solder which has typically 1% to 3% silver in it and melts around a couple hundred degrees Fahrenheit. Silver braze or silver braze alloy may have 30% and 60% silver and it melts above 1100°F. These are approximations but they serve to illustrate the difference.

Typically brazing takes place above 800°F and soldering takes place below 800° Fahrenheit.

Silver solder flux and silver brazing flux are two very different compounds. Silver solder flux is designed to become active at very low temperatures and to work at very low temperatures. Silver brazing flux becomes active around maybe 500°F or so and stays active up to maybe 1500°F.

If you use silver solder flux for silver brazing then the silver solder flux will be all used up before the metals get anywhere near hot enough. If you use silver brazing flux for silver soldering the metals will be heavily oxidized before the flux even begins to become active.

The term silver soldering is often used to cover all joining using silver of any the amount and thus covers silver brazing as well. I am as guilty of doing this as anyone.

I think it would be for the general good of the industry overall, and certainly the new people, if more care was taken in differentiating between soldering and brazing.

The latest guy to call was a nice young guy and he had messed up $50 worth of parts which was a lot of money to him. I kind of hate to see that happen to anyone."

 

[tdi-rick]

Will silver solder take the heat generated? I'm asking because I honestly don't know, not trying to be a smart azz........

Melting point is around or above 600*C so I reckon it's pretty safe.

The high silver stuff (>45%) should be good for well over 300*C service and you need at least that high silver content to work and wet out steels, otherwise it won't work.

 

[Jon1212]

I just started using silver solder........amazing how little it takes.

The other advantage over welding rods is you never get confused which one is your leg, and which one is the welding rod. If you wore shoes on occasion it could help avoid a serious injury. Just sayin'

 

[Mastermind]

The other advantage over welding rods is you never get confused which one is your leg, and which one is the welding rod. If you wore shoes on occasion it could help avoid a serious injury. Just sayin'

Muh wife bought me some shoes Thank You Very Much. :msp_mad:

 

[Jon1212]

Muh wife bought me some shoes Thank You Very Much. :msp_mad:

Wal Mart branded Crocs don't count. Even if you do fancy the pink ones.

 

[Mastermind]

Wal Mart branded Crocs don't count. Even if you do fancy the pink ones.

These are Garmont's :msp_sneaky:

 

[B Harrison]

I get fussed at for reading this stuff, I need to go cut firewood or something.

 

[shorthunter]

The inside of the muffler.......

Just curious here, did you measure the exit on the SLR insert? What about the inlet? Muffler canister exit?

 

[Mastermind]

Never bothered.....just chunked it.

 

[shorthunter]

Well damn. I don't really want to rip mine apart but I am curious about the dimensions.

 

[VINIFIREWOOD]

Randy
Between the 7900 and the 7910, which is the better ported saw?


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[Mastermind]

No real difference.

 

[VINIFIREWOOD]

I read something about the crank being different in the 7910, do you know what they changed or what is diff?


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[Mastermind]

Not that I see.

Same crank, piston, etc.

The jug is different at the exhaust flange....but the timing numbers are the same.

 

[cgraham1]

I read something about the crank being different in the 7910, do you know what they changed or what is diff?

http://www.arboristsite.com/community/threads/ps-7900-vs-ps-7910.202467/

Well the NEW PS-7910 are selling, and anyone that has bought them or tried them has been HAPPY. As far as NET Weight for Power Head Only as comes in the box here are the results...........
Stock Dry New PS-7900 per our digital UPS Legal scales 14.8 pounds
Stock Dry New PS-7910 per our digital UPS Legal scales 14.8 pounds
Hmmmm same weight, brattier exhaust note, NO CAT, Adjustable Carburator, 15% better on fuel, cleaner running to keep the EPA happy whats not to like??
as far as gross horsepower well I dont have a dyno But in side by side comparison cutting real Logs burring a 24" bar in hardwood 7900 vs 7910 the power and torque are very close!
The EPA Legal saw is still VERY EASY to Service, and do repairs to no major redesign to the saw..., it does have a SLR Muffler, new Cylinder with top side deco, the new lightweight piston same as late model PS-7900's New crank, new coil and a different flywheel. The carb has adjustment screws and a vent hose off the metering pump cover. So again Whats not to Like I ask?????
Both above models are less weight than the CAT equipped PS-6400
Scott

The PS-7910 coil is Limited to 12,800 in lew of the 13,500 on the PS-7900 But like I said side by side stock to stock they are VERY CLOSE I need to test with a broken in saw seeing when we tested them it was a year old 7900 vs out of box 7910. The crank is the same design I believe the timing changed and was told the crank also has been strengthened..
Scott

 

[Mastermind]

Cool.

I love to learn new stuffs.

 

[VINIFIREWOOD]

http://www.arboristsite.com/community/threads/ps-7900-vs-ps-7910.202467/

Nice. Knew I had read that somewhere
Thanks