Things to minimise ( not stop distortion )
Pre-heating of the base item / items - this minimises the heat differential between the base & weld metals, thus the shrinkage upon solidification of the weld is reduced along with a massive reduction in shrinkage stress, the stuff that make thing break for no apparent reason.
Jigs & fixtures, these restrain the job / items in place whilst the shrinkage of the solidifying weld / welds attempt to pull / distort the job
Small size weld beads - ie use a 3mm width weld instead of a 6mm wide weld bead, this benefits in several ways,
smaller weld beads = less heat, less distortion, yes you will need to do more weld passes but, each subsequent weld will have a nornalizing / stress relieving effect upon the previous weld if performed correctly. such as heat input, wait until the item has returned to you're initial preheat temperature before you run your next weld, before this next weld you should peen along the toes of the preceding weld bead, this is the area of most joint restraint/ shrinkage stresses
Slow cooling - preferably in a controlled manner / oven. If you have not completed the job but intend to take a break it goes in the oven to either cool out slowly or be held at the chosen preheat temperature for works to continue on.
These are the easy bits. The hard parts are how shapes, differing thicknesses, ambient temperature, draughts, etc etc effect the process / all of the above, this can not be explained here & only a really good operater even acknowledges this stuff & caters for it,
A back yarder just dose not have the EXPERIENCE, however nor does most others.
Just one more thing to think about.
Distortion or Shrinkage Stresses, what is the greater evil & how do you manage it to your advantage
Hope this helps.
Page 1470 ...... there has got to be some stuff in the last ten pages worth collecting here.
Originally Posted by MotleyCrue
Originally Posted by wobbly
As it stands I wouldnt use a Wiseco if they gave them away.
I've heard this a million times from different sources but I haven't heard a good explanation. What is the reason they suck ? They have been in business a long time and still sell lots of pistons, is it just certain applications they aren't good for ?
Originally Posted by Flettner
I used to buy a Wisco piston for my 350 Kawasaki, it was a prolite type, cost a bit too but it did the job. After a few pistons used (ordered on the same part number), a standard pistons turned up, not prolite, same price. Wisco said "get stuffed" thats all we will supply now and you will have to pay the same price, to bad. So I turned them into prolite myself with the milling machine. Then I find Wossner, only make prolite type, cheaper, available without waiting and seem to work well. I can order them from the factory in lots of ten, even cheaper still! Won't catch me dealing with Wisco again until they change their attitude, and make a decient product again.
Originally Posted by wobbly
The Wiseco Prolite range was a big step forward for the company, where they finally changed the forging material.
But the bottom line still is that they will 4 corner seize instantly if run at the minimum clearance recommended, and if run even slightly loose
they rock badly in the bore ( alot of taper,top to bottom ) then shrink insanely.
This then of course doesnt help the ring stay true in the bore and you quickly get blowby darkening the area under the groove.
Recently ( last 18 months ) the company has been groomed for corporate takeover.
The cash its worth comes down to the bottom line profit margin on sales, so they have deleted nearly all CNC ops on the basic forging.
The pistons are now way heavyer,more expensive and still have the issues explained above.
They used to do small run specials,but are now not interested.
Not even close to a Wossner in any respect.
Originally Posted by Grumph
Whilst I respect Wob's experience with Wiseco pistons, and agree broadly with what he's saying, I suspect the target market for Wiseco now is mainly 4T pistons. I've used a lot of their 4T forged pistons over the years and will continue to use them as long as the price stays reasonable.
I'd also suspect that Wossner and others have seen a vulnerability in the 2T market where Wiseco is concerned and jumped in with a more up to date product.
Fair enough, that's the American way of business. As consumers we should be aware of it and take advantage.
Originally Posted by WilDun
Are there any extra requirements (for a basic TIG welder) to enable aluminium welding to be done?
eg I remember being told way back that the old welders required a high frequency unit (AC I guess) and it was necessary to use a flat tip on the tungsten electrode, but I never see any of that mentioned these days, - I've really got behind here!
Originally Posted by mike schmidt
Over the years, I have funded my addiction (hydroplane racing) by welding. A few hints for welding aluminum that may or may not help...
In the US they sell an automotive cleaner called Superclean. Purple squeeze bottle. I run the hot water in kitchen sink and get it as hot as it will go. Shut the water off, put the part in the sink and spray it down with Superclean. Only let is soak for a minute or so. Then spray it with the hottest water you can. Works great. Do not ever use brake clean / carburetor cleaner to clean parts prior to welding. Bad gasses are created and bad things happen to the guy welding.
Complex casting repairs / additions are going to warp. Simple fact of life. If you are building parts to add on, leave stock to machine off. If you are going to have to machine a surface near where you are welding, run a bead on it.
Peening the weld makes the weld material denser / stronger. More like billet than cast. One of the places I use this is, is on cracked lower units on outboards. I have found that by peening the weld on both sides of the skeg, the repair lasts far longer. I use a simple air chisel set up like used for cutting off automotive mufflers. I cut up one of the chisels and sanded a big radius on it. The other place I use it is when the weld bead is on a mating surface. Machines much better.
Most aluminum repairs that require structural strength, you just have to preheat the whole thing, weld it and let it cool off slowly. I have used my wife's oven for years, but recently have switched over to using our gas grill on our back deck. Put the part in, turn it on and when it gets up to 350-400 F pull it out and weld it. Then throw the part back on the grill and turn it off.
DC straight polarity and medical grade helium works. All the Top Fuel Dragster blocks are repaired with this set up. No pre heat and you can penetrate over 1/2" with no weld prep. The helium and regulator is not cheap, but it works.
Take an HW-20 torch and using silicon carbide wheel (green) on a bench grinder, shorten the gas lens as much as you can. Then take the shortest "tail" and cut it down to about 1/4" long. Use some good 2 part epoxy to fill in the hole where the tungsten goes. Use about 1" long tungsten and you can get down inside a 125 cylinder. Not an easy job, but worth the effort.
Heat treating aluminum works. Most billet is heat treated to a T-6 condition. After you weld it, it goes back to T-0 (dead soft / weak) Having it heat treated back to T-6 is huge. In the US it is very expensive to have a single piece heat treated because of the time it takes. I have found that by going to a foundry that does their own heat treating, you can get parts done for far less money.
Steel, stainless and titanium you can get away with welding "cold". Weld a short bead (1/2") and let it cool back to room temperature. I even use compressed air to cool then off between beads.
Hope this helps a few of you. Again, this just a great thread / website for two stroke races.
Originally Posted by WilDun
Thanks Yow Ling / Wobbly, for the info, video etc. I will have to spend some time digesting it all.
A whole new world for me, I bought a small 160 welder about 2 years ago but had no idea of the cost of Argon (it was a bargain and that's all I could see at the time!) - now I have Argon I'm just setting up to learn it all from scratch, but I'm a pensioner and it will be a limited effort of course. I do want to try my hand at pipes as well as casting ally + machining (which I know) - no need to specialise in anything anymore as it's all a hobby and not for profit just very interested in all the processes. - still trying your hand at casting Yow Ling?
It's all learning at the moment, no particular project to work on but that's not the way I want to be in the future.
Good thread and I am learning - well at least as much as I am able to digest, much of it goes over my head!
Originally Posted by wobbly
Yes, cold wire over TIG has a small wire feeder that runs a spool of the filler thru a sheath that clamps to the top of your torch.
The normal TIG tungsten heats the weld pool and then the wire is fed into this pool.
Thus if you run the spool very slowly a tiny seam of weld is created, and this will easily fill small gaps,or ripples in the segments where they are not
aligned well.
Here is a pic of a stainless pipe I did with that gear.
The segment seams are normal tig, with the cut joints you can see the tiny raised bead.
I sold the setup, as I only really got the feeder to do Ti pipes for the factory teams I worked for, and both Ti and stainless take so long to roll/form/hand work
into segments that its impossible to charge out the time and make any money from the exercise ( unless you work for a cup of rice a day in Thailand ).
Also you MUST use Argon purge inside the pipe as its made ,and Argon isnt cheap enough now to use huge amounts of it.
The factory team engineers use an argon filled chamber, and weld the pipes inside this box with sealed gloves thru the front and a plexiglass lid.
Originally Posted by Yow Ling
Hi Will , it seems to be TIG with a wire feeder
In the case of an automatic supply a distinction is made between hot wire feeding and cold wire feeding. When feeding cold wire, the filler material is led to the welding spot without current and molten in the arc of the main process. So the TIG process creates very high-quality, spatter-free weld seams.
ya i have a oven for cylinders and small stuff. yesterday i seen a video and distortion on a flat plate was reduced alot by increasing travel speed
Originally Posted by WilDun
Wobbly,
What is the "cold wire over TIG" you mention?
Just starting out on TIG and need to understand the different processes etc.
Originally Posted by RAW
Things to minimise ( not stop distortion )
Pre-heating of the base item / items - this minimises the heat differential between the base & weld metals, thus the shrinkage upon solidification of the weld is reduced along with a massive reduction in shrinkage stress, the stuff that make thing break for no apparent reason.
Jigs & fixtures, these restrain the job / items in place whilst the shrinkage of the solidifying weld / welds attempt to pull / distort the job
Small size weld beads - ie use a 3mm width weld instead of a 6mm wide weld bead, this benefits in several ways,
smaller weld beads = less heat, less distortion, yes you will need to do more weld passes but, each subsequent weld will have a nornalizing / stress relieving effect upon the previous weld if performed correctly. such as heat input, wait until the item has returned to you're initial preheat temperature before you run your next weld, before this next weld you should peen along the toes of the preceding weld bead, this is the area of most joint restraint/ shrinkage stresses
Slow cooling - preferably in a controlled manner / oven. If you have not completed the job but intend to take a break it goes in the oven to either cool out slowly or be held at the chosen preheat temperature for works to continue on.
These are the easy bits. The hard parts are how shapes, differing thicknesses, ambient temperature, draughts, etc etc effect the process / all of the above, this can not be explained here & only a really good operater even acknowledges this stuff & caters for it,
A back yarder just dose not have the EXPERIENCE, however nor does most others.
Just one more thing to think about.
Distortion or Shrinkage Stresses, what is the greater evil & how do you manage it to your advantage
Hope this helps.
Originally Posted by seattle smitty
Peewee, you asked about peening the bead (you wrote "pinging" but I assume you meant what I know as peening), and yeah, that's always a stress reliever (though it is unlikely to remove visible distortion). The metallurgists say you want to mostly concentrate on the outer edges of the bead, more than the center of it. There's a device called a needle-scaler, usually air-powered though sometimes electric, which is ordinarily used mainly for fast removal of slag during stick-welding. But if you take the needles out and round off their working ends, the tool then becomes good for bead-peening.
You're right about sequencing the weld, and dividing the circle into four (eight, if there's room) segments and welding them criss-cross fashion, another technique worked out long ago by the metallurgists.
You're having a blast with that new TIG machine; cool!!!! I can't say anything from personal experience about pulse and so forth, because my poor old transformer TIG welder pre-dates not only inverters but square-wave, too.
Originally Posted by wobbly
Pulsed TIG will do nothing much to help distortion.
What it does do is allow you to use a higher base amperage to speed up the M/min welding rate and not create holes or
a big lumpy mess on the inside of a pipe for example.
The jump in amps allows you to move quickly, then the amps drop off, stopping the weld pool from getting to large.
It creates the scallop effect without you having to pulse the pedal, or move the tungsten back and forth to make a "pattern ", that looks nice.
Cold wire over TIG is by far the best method to weld thin sheet, but is idiotically expensive, and takes alot of slow practice to master.
Originally Posted by jasonu
You can get good results by 'pulsing' the pedal (I am assuming you are tig welding). If done correctly your weld will look like a stack of pennys pushed over.
Originally Posted by peewee
I use clamping fixtures when ever possible as they help hold its shape and can provide some what of a heat sink but its not always possible to use such fixtures. I think this weekend ill give the pulse a try as ive heard quit a few times that it can help with distortion.
welded some alloy bungs not long ago and they ended up like eggs afterwards . I think what I did wrong is I tried to weld continuously around the circumference. what I probly should of done was put four tack welds at 3-6-9-12 oclock positions then just weld alittle at a time . going from 12 to 6 to 3 to 9 if that makes sense. then maybe the pulling force from each side of the bung would be more evened out
Originally Posted by peewee
hey wob I did a bunch of welding recently and wondered if you've found a way to keep distortion to a very minimum ? my machine has pulse function but I haven't bothered to try it yet but I wonder if that may help. ive put items in the oven after I was done welding so they didn't cool rapidly but I cant say for sure if this helped or not. also I heard pinging the weld with a small hammer could help but I haven't tried it yet
Those who have perfectly sound and logical reasoning behind a belief or statement that is published on here, find quite quickly that most of those who then disagree, simply cant provide a sound and logical reasoning for THEIR position. So what do they do - invoke a validation of themselves by promulgating a personal attack. There is no real defense against this " flaming " as its called, except to lower oneself to that level, or walk away. I tried both a while back, and got no satisfaction from either.
Wob, I don't feel that 'most of those who then disagree' resort to flaming. But I agree that it can be annoying, although I have nothing to complain about, compared to what you have to put up with.
Whatever your approach, there is no satisfaction to be found in the way you handle the situation. But I try to look upon it as an opportunity to work on my character. Walking away or ignoring the aggro can be considered Zen. Lowering oneself to the level of the flamers would be like barking back at a dog that barks at you: daft.
Originally Posted by lodgernz
Aren't the KTM SX65 and SX50 motocross bikes? That would invalidate them from buckets. I don't know about Freetech50 though. Might be legal there.[/
Yes, those KTMs are MX-bikes. By the way, KTM prefers to mention an engine's cylinder capacity first and its intended use second: 65SX instead of SX65.
A KTM 65SX with a 50SX-cylinder (smaller bore, same stroke) is a good tool for 50 cc racing. One drawback: it has no balance shaft, so the way you mount the engine will influence the life span of the frame, the functioning of the carburettor and the amount of numbness in the rider's hands and feet.
The latter may sound futile, until you've experienced the difference between engines without and with a balance shaft. Vibration costs concentration.
Freetech is like the name says: almost anything goes. Nitro is a no-no but if you want to play with a 50 cc V-8, a 40 mm carburettor, a twelve-speed gearbox, a variomatic or a turbo, go ahead. For a turbo the total cubic capacity should not exceed 25 cc though.
But if you look at ancient Formula 1 engines (1500 cc BMW 4-cylinder with 1350 hp during qualifying) a blown 25 cc foul-stroke could become a real thread. Eh, threat.
Things to minimise ( not stop distortion )
Pre-heating of the base item / items - this minimises the heat differential between the base & weld metals, thus the shrinkage upon solidification of the weld is reduced along with a massive reduction in shrinkage stress, the stuff that make thing break for no apparent reason.
Jigs & fixtures, these restrain the job / items in place whilst the shrinkage of the solidifying weld / welds attempt to pull / distort the job
Small size weld beads - ie use a 3mm width weld instead of a 6mm wide weld bead, this benefits in several ways,
smaller weld beads = less heat, less distortion, yes you will need to do more weld passes but, each subsequent weld will have a nornalizing / stress relieving effect upon the previous weld if performed correctly. such as heat input, wait until the item has returned to you're initial preheat temperature before you run your next weld, before this next weld you should peen along the toes of the preceding weld bead, this is the area of most joint restraint/ shrinkage stresses
Slow cooling - preferably in a controlled manner / oven. If you have not completed the job but intend to take a break it goes in the oven to either cool out slowly or be held at the chosen preheat temperature for works to continue on.
These are the easy bits. The hard parts are how shapes, differing thicknesses, ambient temperature, draughts, etc etc effect the process / all of the above, this can not be explained here & only a really good operater even acknowledges this stuff & caters for it,
A back yarder just dose not have the EXPERIENCE, however nor does most others.
Just one more thing to think about.
Distortion or Shrinkage Stresses, what is the greater evil & how do you manage it to your advantage
Hope this helps.
ya i have a oven for cylinders and small stuff. yesterday i seen a video and distortion on a flat plate was reduced alot by increasing travel speed
Wobbly,
What is the "cold wire over TIG" you mention?
Just starting out on TIG and need to understand the different processes etc.
Hi Will , it seems to be TIG with a wire feeder
In the case of an automatic supply a distinction is made between hot wire feeding and cold wire feeding. When feeding cold wire, the filler material is led to the welding spot without current and molten in the arc of the main process. So the TIG process creates very high-quality, spatter-free weld seams.
Yes, cold wire over TIG has a small wire feeder that runs a spool of the filler thru a sheath that clamps to the top of your torch.
The normal TIG tungsten heats the weld pool and then the wire is fed into this pool.
Thus if you run the spool very slowly a tiny seam of weld is created, and this will easily fill small gaps,or ripples in the segments where they are not
aligned well.
Here is a pic of a stainless pipe I did with that gear.
The segment seams are normal tig, with the cut joints you can see the tiny raised bead.
I sold the setup, as I only really got the feeder to do Ti pipes for the factory teams I worked for, and both Ti and stainless take so long to roll/form/hand work
into segments that its impossible to charge out the time and make any money from the exercise ( unless you work for a cup of rice a day in Thailand ).
Also you MUST use Argon purge inside the pipe as its made ,and Argon isnt cheap enough now to use huge amounts of it.
The factory team engineers use an argon filled chamber, and weld the pipes inside this box with sealed gloves thru the front and a plexiglass lid.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
Hi Will , it seems to be TIG with a wire feeder
So the TIG process creates very high-quality, spatter-free weld seams.
Originally Posted by wobbly
Yes, cold wire over TIG has a small wire feeder that runs a spool of the filler thru a sheath that clamps to the top of your torch............
Also you MUST use Argon purge inside the pipe as its made ,and Argon isnt cheap enough now to use huge amounts of it.
Thanks Yow Ling / Wobbly, for the info, video etc. I will have to spend some time digesting it all.
A whole new world for me, I bought a small 160 welder about 2 years ago but had no idea of the cost of Argon (it was a bargain and that's all I could see at the time!) - now I have Argon I'm just setting up to learn it all from scratch, but I'm a pensioner and it will be a limited effort of course. I do want to try my hand at pipes as well as casting ally + machining (which I know) - no need to specialise in anything anymore as it's all a hobby and not for profit just very interested in all the processes. - still trying your hand at casting Yow Ling?
It's all learning at the moment, no particular project to work on but that's not the way I want to be in the future.
Good thread and I am learning - well at least as much as I am able to digest, much of it goes over my head!
Over the years, I have funded my addiction (hydroplane racing) by welding. A few hints for welding aluminum that may or may not help...
In the US they sell an automotive cleaner called Superclean. Purple squeeze bottle. I run the hot water in kitchen sink and get it as hot as it will go. Shut the water off, put the part in the sink and spray it down with Superclean. Only let is soak for a minute or so. Then spray it with the hottest water you can. Works great. Do not ever use brake clean / carburetor cleaner to clean parts prior to welding. Bad gasses are created and bad things happen to the guy welding.
Complex casting repairs / additions are going to warp. Simple fact of life. If you are building parts to add on, leave stock to machine off. If you are going to have to machine a surface near where you are welding, run a bead on it.
Peening the weld makes the weld material denser / stronger. More like billet than cast. One of the places I use this is, is on cracked lower units on outboards. I have found that by peening the weld on both sides of the skeg, the repair lasts far longer. I use a simple air chisel set up like used for cutting off automotive mufflers. I cut up one of the chisels and sanded a big radius on it. The other place I use it is when the weld bead is on a mating surface. Machines much better.
Most aluminum repairs that require structural strength, you just have to preheat the whole thing, weld it and let it cool off slowly. I have used my wife's oven for years, but recently have switched over to using our gas grill on our back deck. Put the part in, turn it on and when it gets up to 350-400 F pull it out and weld it. Then throw the part back on the grill and turn it off.
DC straight polarity and medical grade helium works. All the Top Fuel Dragster blocks are repaired with this set up. No pre heat and you can penetrate over 1/2" with no weld prep. The helium and regulator is not cheap, but it works.
Take an HW-20 torch and using silicon carbide wheel (green) on a bench grinder, shorten the gas lens as much as you can. Then take the shortest "tail" and cut it down to about 1/4" long. Use some good 2 part epoxy to fill in the hole where the tungsten goes. Use about 1" long tungsten and you can get down inside a 125 cylinder. Not an easy job, but worth the effort.
Heat treating aluminum works. Most billet is heat treated to a T-6 condition. After you weld it, it goes back to T-0 (dead soft / weak) Having it heat treated back to T-6 is huge. In the US it is very expensive to have a single piece heat treated because of the time it takes. I have found that by going to a foundry that does their own heat treating, you can get parts done for far less money.
Steel, stainless and titanium you can get away with welding "cold". Weld a short bead (1/2") and let it cool back to room temperature. I even use compressed air to cool then off between beads.
Hope this helps a few of you. Again, this just a great thread / website for two stroke races.
Are there any extra requirements (for a basic TIG welder) to enable aluminium welding to be done?
eg I remember being told way back that the old welders required a high frequency unit (AC I guess) and it was necessary to use a flat tip on the tungsten electrode, but I never see any of that mentioned these days, - I've really got behind here!
Over the years, I have funded my addiction (hydroplane racing) by welding. A few hints for welding aluminum that may or may not help...
DC straight polarity and medical grade helium works. All the Top Fuel Dragster blocks are repaired with this set up. No pre heat and you can penetrate over 1/2" with no weld prep. The helium and regulator is not cheap, but it works.
Thanks Mike - I'll pass this one on to a friend here in NZ if I may. Every time I'm in to see him, he's got at least one drag or speedway block or head there for repair. He's always complaining about the preheat time too....
So I have made a start on the next phase of the NSR300 development which is to stroke the crank out to 59mm which will give me square bore and stroke and also a capacity of 322cc To do this I will be designing and manufacturing a custom crank.
Also part of this project is to maximise the potential of the NSR150 barrels that we use so I have got myself a seat of Engmod2T to entertain myself with.
I am in the very early stages of entering data at the moment and am working on modeling the exhaust port. I've taken a paper copy of the ports and brought this into solidworks to create a 3D barrel to use in my crank assembly.
But when modeling the ports in Engmod are they modeled as a flat pattern
Or as viewed in the barrel as curved ports?
Either way using this method of measuring the ports in solidworks makes it very easy to get accurate geometry.
Below is the crank assembly in its very basic design stage.
Below is the stock dimensions of the original NSR300 setup as raced last season
Stock Specs
Stock Stroke: 54.5mm
Stock Rod Length: 105mm
Piston Diameter: 59mm
Compression Height: 35mm
Deck Height: 0.00mm
Ex Duration: 194.7 Degrees
Trans Duration:123.1 Degrees
Capacity: 298.0cc
And this is the first pass at what we will be running in terms of rod length, capacity and Stroke for the coming season. (ignore port timing TBC with Engmod)
Upgrade Option Five
Stroke: 59mm
Rod Length: 118mm
Piston Diameter: 59mm
Compression Height: 32mm
Deck Height: +2.0
Ex Duration: 194.5 degrees
Trans Duration:129.4 degrees
Capacity: 322.6cc
no,no,no,no,no,NO.
In Engmod all the port dimensions are normal to the flow direction, or simply chordal width.
Anything ( paper or Solidworks unroll feature ) is nothing like what is needed, as this is circumferential width.
In most all cases the A port is flow direction, the B and C are chordal as is the T port.
Dont forget to calculate the T port pocketing correctly as well.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
Basically you have two options for stroking the cylinder. (please note I am not calculating the longer conrod as it boils down to adding a spacer below)
with the longer stroke the piston will go 2.25mm more up and 2.25mm more down.
1) you leave the cylinder as it is, provided you have enough deck height for the piston ring to stay into the cylinder, and do the porting for the new stroke
this is not optimal because you will have the lower part of the transfer ports floating 2.25 mm above the piston at BDC.
You loose piston cooling and time area.
You could work the ports down but this is very difficult to do correctly, it is easy to break the inner radius of the ducts.
2)you take away 2.25mm from the bottom plane of the cylinder, AND add 4.5mm of deck height. If you have enough, great, otherwise you have to weld a slice on the deck and redo the plating.
Or does it have an iron bore?
In this case there's also a lot more porting job to do, but it would be the nicest way.
I did a couple as in case 2).
The cylinder i'm using currently is both bored from 47.6 to 52 and stroked from 39.3 to 46. totally worth it.
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