Brass or Ally

[bl4de-rr1]

Reading on the forum in different places that the Brass Valve is superior to the Aluminium one.
Why is there such a difference beteen the two, Surely they would be made to the same Spec ?

Ian

[DIAMOND]

A professional will be a long soon...but for now, you get me. 

From my understanding, they are made by two different companies, so not the same specs per se.

Aluminum is not as tough as brass, so it can wear out faster.

Hope this helps.

[quickster47 †]

Good question.  Personally, I think it might have something to do with the weight of the brass valve.  No hard proof, just a hunch.

Carl

[Madkoifish]

I will second  the weight thing. But also alum will corrode. Remember all those alum windows from the 70s and all that white crud. Well imagine that in your valves and crap of your gun. Being coated in pel should protect it. Brass will get that green slime, my hb 17 had a little of that inside since I put all sorts of lube into that poor gun before I knew any better. But it is not as bad as some alum parts I seen come off airguns and compressor related stuff like airbrush fittings.

[eric]

it 's old skool and about heat --- folks say the brass won't heat up as quickly as alloy but alloy will cool down quicker --- you can go from there

[proudhon]

Without getting into thermo dynamics or physics
an object will shed heat at  the same rate as it absorbs it
sooooo. can't heat up faster and cool down slower
second
any object can only give off the same energy it takes in. 
So the material won't matter to actual energy.
speed maybe (alumin. is lighter (less dense) therefor to give off the same given the same energy it will have to be moving faster.


Brass probably absorbs heat slower
I don't have the hand but as I remember it does.
Brass is less abrasive than aluminium
so more friction with alminium
which would heat it up faster.
and as the wears into the bore (esp with high pressure)
you would get bit of aluminium rubbing on embedded bits of aluminium
more friction and slowing it down (heat created less energy transmitted to object moved)
Brass embedded would be brass against brass
much better.
What the expansion rate for both is I don't remember either
but I'm guessing (and could very well be wrong) alum expands faster
so your fit would probably have to be a bit looser.

Maybe less bounce back or some such thi


Brass is sexier though.
joe

[arkmaker †]

my 2 cents worth.

Aluminum is cheaper and easier to machine. Not much easier,  but easier (and don;t forget cheaper or should I say less expensive and be politically correct ;-)

Both disapate heat well, but is that really a problem on the valve? Just for reference, we use brass inserts in our molds, not so much so that they will cool down or heat up faster, but because they have a stable composition and do not distort as much as aluminum. The expansion factor is higher with aluminum under varied temps as is brass. Just that brass is a bit more predictible. That and we use a very tightly contolled manufactured brass. Everything has a tolerance, even the quantities the ingredients in brass and aluminum. Reducing and then controlling the tolerance gives you better predictibility with what the expansion rate will be at a given temperature. Pretty important when molding optics (which I do). Not so important in a 13XX.

Another thought is that for as long as I can remember in molding shops, we use a big block of aluminum to place HOT parts on. The aluminum draws out the heat fast. So there is a vote for AL. AL is lighter....another vote as the 1377 is a pretty heavy pistol anyways.

I like the brass vavle in my 2240's, but have no problem with the aluminum one in my 1377. Oh, and aluminum is CHEAPER, something I'm thinking Crosman may have saved a bunch of money on by switching to.

So now "Mr. Know it All" has spoken! 

Have a great Memorial Day while I'm stuck at work 

Rich

[eric]

is it a problem for the valve --- heat ? that could depend maybe . the internals could deform and cause a leak .holding heat longer could help fry an oring on your piston if flat topped . i did a 12 shot string with my C9 {8 pumps max (9 -12 just for giggles)} .each shot represented how many pumps 1=1,2=2,.. 12=12.by the end the C9 was pretty warm --- sure not a 13xx gun but both are msps so you figure there is a heating issue if shooting a msp without letting it cool down

[arkmaker †]

First off, let me say that the boss sometimes surprises me! He came in and sent us home, so I'm in a better mood now.

I guess heat could be an issue, but I'm stickinging to the valve material would be a very low priority between brass and alumimum. As far as heat and FPS....anyone one have a take on that?
Rich

[bl4de-rr1]

So, after reading through the posts, in everyones Opinion as i have 1 of each, Brass and Ally which would you fit

[NorthStaR]

I think I read on a page somewhere was that Crosman make parts from what's stock is available? Or once did...?
Maybe it was someones post I read on here?  

Brass is traditionally used in guns due to the lack of spark - it doesn't.
That's possibly a transitional usage put to airguns and that its soft/easy to work plus doesn't rust.

Anywho I prefer the extra weight a brass valve brass adds to a gun. Go brass! Its airgun gold!

Jibber....

[arkmaker †]

So, after reading through the posts, in everyones Opinion as i have 1 of each, Brass and Ally which would you fit

Even with all I said and done........ go BRASS if you have the choice, I'm partial to it and I like the weight!

[eric]

Even with all I said and done........ go BRASS if you have the choice, I'm partial to it and I like the weight!

Xs 2

[quickster47 †]

^^^ X3

Carl

[bl4de-rr1]

Thanks fellas, will put the Brass back in and do some testing when i get the chance !

ATB  Ian.