going to build a pipe for my 660

[timberwolf]

Yep, 13,000 is high, esp for a larger stock saw.

Also I don't think the stinnger diamiter is sufficient, I'd go bigger than that on a 60cc saw. Pipe has a fair volume, but still I would think another 5mm would be in order.

Serg, cant say as I have run vertical down pulling... not when I was thinking about it anyway... About the only time I think I would run MIG down hill is on sheet metal. Have to experiment with it some time.

 

[breymeyerfam]

he are some numbers I worked out by hand. rpm@12000

 

[breymeyerfam]

redone at 12000rpm with mota

which one looks better? after of course making the stinger dia. larger on the mota pipe(same as my figure: 22.26mm).

 

[breymeyerfam]

anyone care to chime in and tell me which would work better and why...

 

[snofrog]

If you tacked it all together and kept the purge in it could be done and certainly the backside on thin stainless need protection. Problem is keeping the sticky tape on when your welds are close together like that and the glue is a mess. Plan on using far more gas for purging than for the gun! I did virtually nothing else but for 14 months in a fab shop! Solar Flux paste can be brushed on inside of joints if you cannot purge but if floats on your puddle and the flare makes it hard to see fusion at the edge of the puddle.

You will find you have to backstep all your welds with tig or torch or warpage will haunt you on sheet metal! The sweep out of the exhaust will tighten up considerably unless you watch your direction of welding and have a bit more inches travel to the outside of the bends. Distortion is double with stainless what it is with mild steel and stainless work hardens which is the cracking problem. At 250 cps you accumulate a lot of fatigue in a short time. Cracking is a matter of when, not if!

a lot of it is due directly to the production of chromium carbide in ss from welding and can be greatly redeuced by choosing proper filler for the job , proper pre weld prep and proper back purge . chromium precipitation also follows poor welding technique and will lead to poor weld performance and appearance
imho it would be best to ceramic coat the pipe inside and out after welding is finished .the results are a pipe that comes up to temp quicker ,maintains a higher overall temp in the chamber that will also flow higher rates . jmho Mark

 

[Tzed250]

I pull MIG downhill tabbing parts at work. .045 wire @ 24-25V.

 

[Metals406]

a lot of it is due directly to the production of chromium carbide in ss from welding and can be greatly redeuced by choosing proper filler for the job , proper pre weld prep and proper back purge . chromium precipitation also follows poor welding technique and will lead to poor weld performance and appearance
imho it would be best to ceramic coat the pipe inside and out after welding is finished .the results are a pipe that comes up to temp quicker ,maintains a higher overall temp in the chamber that will also flow higher rates . jmho Mark

I mentioned the ceramic thing to him too... Too expensive with the ceramic coating he uses.

Do you have any experience using the 'weld hugger' at all?

 

[snofrog]

Do you have any experience using the 'weld hugger' at all?

no experience with it here

 

[timberwolf]

anyone care to chime in and tell me which would work better and why...

Ran a few quick numbers last night, they all will work, the first design produces a nice smooth wide powerband, Peek is about 9.5 hp, but torque is falling off well before 12,000, saw would likely cut just over 11,000 in the wood with just a little over 9hp.

Second design is peekier you get a little more torque, but it would not be as good a design for a bike.

Last one looks good, kind of between the two, but might be a little long, though I don't think you will get 12,000 RPM in the cut unless there is a fair bit more done to the saw.

Played around with a few multi stage designs, might be able to get close to 10 hp but thats hardly 5% over what the first design is at.

Whats you plan for metal and welding?

 

[breymeyerfam]

Ran a few quick numbers last night, they all will work, the first design produces a nice smooth wide powerband, Peek is about 9.5 hp, but torque is falling off well before 12,000, saw would likely cut just over 11,000 in the wood with just a little over 9hp.

Second design is peekier you get a little more torque, but it would not be as good a design for a bike.

Last one looks good, kind of between the two, but might be a little long, though I don't think you will get 12,000 RPM in the cut unless there is a fair bit more done to the saw.

Played around with a few multi stage designs, might be able to get close to 10 hp but thats hardly 5% over what the first design is at.

Whats you plan for metal and welding?

I would be willing to try whatever design you thought would be best, and 22ga and oxy is what I will be using. what more would you do to the saw without hurting it unpiped?

 

[blsnelling]

What sticks out to me here is that this 660 on pipe won't have any more HP than the 361 Timberwolf recently showed. That just goes to show that you have to port for a pipe to make it work. That would indeed be embarrasing to have a piped 660 beat by a piped 361.

Timberwolf, did you run the numbers to see what HP this 660 is making without the pipe? In other words, how much is the pipe doing for the saw.

 

[timberwolf]

I was going just with a stock 660, I don't know exactly what changes were made in this 660 so kind of hard to know, but likely with the porting and pipe the saw would top out over 10-11 hp. when I ran the 361 I was thinking the times were not very far off my work ported 066 with pipe. The race would certainly come down to chain and sawyer.

Same token though the 359 stock apearing gas I built a couple years ago would be a problem for the piped 361 and not far off the 066 work saw with pipe. There is a little stock apearing 50 husky out there I did up on alky that would clean them all up in 8x8.

 

[breymeyerfam]

What sticks out to me here is that this 660 on pipe won't have any more HP than the 361 Timberwolf recently showed. That just goes to show that you have to port for a pipe to make it work. That would indeed be embarrasing to have a piped 660 beat by a piped 361.

Timberwolf, did you run the numbers to see what HP this 660 is making without the pipe? In other words, how much is the pipe doing for the saw.

yeah, but that is one 361 I woulnt be embarrased to be beat by. the cylinder work on it is just plainly beyond me and I'm not afraid to admit it.

 

[breymeyerfam]

mocked up pipe

now I can't get the steel til monday... :censored:

 

[blsnelling]

Dude, you are serious aren't you?!!!

 

[breymeyerfam]

Dude, you are serious aren't you?!!!

gotta go faster

I'm going to give it a shot, now I just hope it all welds together this well.

 

[blsnelling]

Here's what I've been wondering about. So you have your lengths from the design. Once you curve the pipe, you have to either lengthen or shorten one side. Or do you split the difference to keep the distance down the centerline to the original design?

Also, how do you intend to support the pipe with it going out the left side? Most of them go out the right and are often supported from the bar studs. I've never made a pipe, or even run a saw with one. Just helping think with you.

 

[breymeyerfam]

Here's what I've been wondering about. So you have your lengths from the design. Once you curve the pipe, you have to either lengthen or shorten one side. Or do you split the difference to keep the distance down the centerline to the original design?

Also, how do you intend to support the pipe with it going out the left side? Most of them go out the right and are often supported from the bar studs. I've never made a pipe, or even run a saw with one. Just helping think with you.

i used a cone layout program that keeps the length the same with the angles added in. it will be supported by a triangular bracket to the lower two muffler bolts.

 

[blsnelling]

So the demo version of MOTA will do all this for you without having to buy the actual software?

 

[timberwolf]

I would put just a little more bend in the pipe and point it up a little. If the pipe is hanging out to the left too much it puts a torque on the cylinder and makes the chain wobble in the cut on changeovers. Nothing wrong even puting a little bend up in the 3rd stage.

Other than that, looks good, can't wait to see some welding pics and a grin on your face when you put it in the wood first time.