pre/post gas - upslope/downslope ??
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  1. #1
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    pre/post gas - upslope/downslope ??

    Hey all,

    I just bought a new (to me, second hand) TIG - Kemppi Miniarc TIG Evo 200. I printed out the manual from online, but no explanation of what the upslope/downslope actually do?

    so, what are some basics of pre/post gas and up/down slope.

    Most of my welding is mild steel in the 1/8-1/4 thickness range.

    cheers
    Serg

  2. #2
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    Re: pre/post gas - upslope/downslope ??

    You won't need upslope or downslope, forget them, unless it's a lift TIG machine. post flow is how long gas flows after arc is extinguished, it should flow until tungsten cools down

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    Last edited by MetalMan23; 08-19-2019 at 10:35 PM.

  3. #3
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    Re: pre/post gas - upslope/downslope ??

    That's not right at all. There's a very good reason why they are included on any half decent TIG machine.

    Pre-gas is before arc ignition, set this very low, like 0.1-0.2 sec, you barely need any.
    up-slope - most machines have a time, some have a start current as well. 20% start current is pretty decent, and a 1 sec upslope is enough. It makes
    down-slope - more important than up, it stops craters at the end of the weld. I usually have a 2sec downslope, and a 20% end current.
    Post gas is very important for stainless especially, usually 6-8 seconds for most work.

    Only time i wouldn't use these features is for quick tacking up. My welder has a quick downslope on/off feature, but I leave everything else the way it is.

    EDIT: I've just realised that metalman is probably saying that because he has a foot pedal, not a torch button... which is fair enough, your up/down slopes do nothing with a pedal.

  4. #4
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    Re: pre/post gas - upslope/downslope ??

    I like 0.4-0.6 seconds of pre-flow to get past the initial surge of shielding gas that is expelled at high rate due to the flowmeter calibrated to 50psi. Any half-decent tig will come with a foot-pedal, so unless you absolutely have to use a torch-mounted button, all "slopes" should be done with the foot-pedal.
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  5. #5
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by Oscar View Post
    I like 0.4-0.6 seconds of pre-flow to get past the initial surge of shielding gas that is expelled at high rate due to the flowmeter calibrated to 50psi. Any half-decent tig will come with a foot-pedal, so unless you absolutely have to use a torch-mounted button, all "slopes" should be done with the foot-pedal.
    Very few people use foot pedals in the UK... they are just a pain when you can use a torch button to do 90% of what a foot pedal does.

    ONLY time anyone will use a foot pedal is on aluminium! Absolute waste of time on steel.

  6. #6
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by Munkul View Post
    Very few people use foot pedals in the UK... they are just a pain when you can use a torch button to do 90% of what a foot pedal does.

    ONLY time anyone will use a foot pedal is on aluminium! Absolute waste of time on steel.
    Last I knew 90% was less than 100%

    Further, I don't agree that you can directly compare a foot pedal to a torch with an on/off switch. If you want to compare a foot pedal to a torch with an amptrol built in they are close to the same other than cost.

    If your torch just has an on/off switch I don't see how you're able to adjust the heat as the work piece gets hotter, or if you're welding an irregular shape that isn't a constant thickness. With a pedal those things aren't difficult to adjust for, and only take normal practice to be able to master.

    I'm a fan of roughly .5 sec of pre-flow because all the regulators I've used (maybe only five or six) start out with more pressure/volume for the first couple of tenths of a second. I like the arc to initiate after that has stopped.

    Now that I think of it, you guys spell vise wrong and drive on the wrong side of the road so this really should be a surprise to anybody
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  7. #7
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by husq2100 View Post
    Hey all,

    I just bought a new (to me, second hand) TIG - Kemppi Miniarc TIG Evo 200. I printed out the manual from online, but no explanation of what the upslope/downslope actually do?

    so, what are some basics of pre/post gas and up/down slope.

    Most of my welding is mild steel in the 1/8-1/4 thickness range.

    cheers
    Serg
    Slope function: when you do not use a foot pedal
    To increase/upslope or decrease/down slope the power, you need a way to control that part of the welding process.
    You adjust the slope parameters on the machine so that when you initiate the arc buy a simple on off switch on the torch or Lift arc, the machine takes care of the increase in power and decrease in power.

    If you use a foot pedal then you do not need to worry about slope setting on the machine as you'll do that manually with the foot pedal.
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  8. #8
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by MetalMan23 View Post
    You won't need upslope or downslope, forget them, unless it's a lift TIG machine. post flow is how long gas flows after arc is extinguished, it should flow until tungsten cools down
    Not really anything to do with lift. A lift only(non HF) machine would most likely never even have upslope or downslope settings.

    They are settings to use when using a switch instead of a pedal. It just allows amps to ramp up when starting and to taper off when your down while controlling machine with momentary swicth.


    Quote Originally Posted by G-ManBart View Post
    Last I knew 90% was less than 100%

    Further, I don't agree that you can directly compare a foot pedal to a torch with an on/off switch. If you want to compare a foot pedal to a torch with an amptrol built in they are close to the same other than cost.

    If your torch just has an on/off switch I don't see how you're able to adjust the heat as the work piece gets hotter, or if you're welding an irregular shape that isn't a constant thickness. With a pedal those things aren't difficult to adjust for, and only take normal practice to be able to master.

    I'm a fan of roughly .5 sec of pre-flow because all the regulators I've used (maybe only five or six) start out with more pressure/volume for the first couple of tenths of a second. I like the arc to initiate after that has stopped.

    Now that I think of it, you guys spell vise wrong and drive on the wrong side of the road so this really should be a surprise to anybody
    Dynasty 280dx will give you a upslope to a start amperage and if you have it set you can click once and be at a different welding amperage. It will give more than one heat setting to use with just the switch while still having downslope to finish up with.
    Last edited by danielplace; 08-20-2019 at 02:41 PM.

  9. #9
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by danielplace View Post
    Dynasty 280dx will give you a upslope to a start amperage and if you have it set you can click once and be at a different welding amperage. It will give more than one heat setting to use with just the switch while still having downslope to finish up with.
    Interesting stuff, thanks. I'd still rather have a pedal that I can adjust continuously and not rely on fixed settings. I can see it would be handy in some situations, but probably not that often for most folks.
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  10. #10
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by G-ManBart View Post
    Interesting stuff, thanks. I'd still rather have a pedal that I can adjust continuously and not rely on fixed settings. I can see it would be handy in some situations, but probably not that often for most folks.
    I am sure anybody that has tig welded has found the pedal is hard to manipulate when welding on a lot of projects. The switch can be really handy to have.
    Found some steel welding to be more consistent when the amp setting is steady. I don't have a switch on my torch but sometimes set the machine so the pedal is just a switch. Also great for tacking(or welding)out of position.

    Sometimes setting it to just stay on but use the lift arc setting is a good way to start out of position without a switch or pedal. Just have to be careful with the torch you don't accidently strike a arc when/where you didn't intend to.
    Last edited by danielplace; 08-20-2019 at 05:44 PM.

  11. #11
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by danielplace View Post
    I am sure anybody that has tig welded has found the pedal is hard to manipulate when welding on a lot of projects. The switch can be really handy to have.
    Found some steel welding to be more consistent when the amp setting is steady. I don't have a switch on my torch but sometimes set the machine so the pedal is just a switch. Also great for tacking(or welding)out of position.

    Sometimes setting it to just stay on but use the lift arc setting is a good way to start out of position without a switch or pedal. Just have to be careful with the torch you don't accidently strike a arc when/where you didn't intend to.
    No argument there....I have a switch on hand for out of position, etc. I don't use it very much, but wouldn't want to be without one. I've also considered a torch with an amptrol for similar reasons.
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  12. #12
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    Re: pre/post gas - upslope/downslope ??

    When you are brought up on TIG without a foot pedal in sight, you soon realise you don't need one at all, really. I honestly think it's an American thing, since practically no-one buys a machine or torch without a built-in switch in UK or europe.

    Steel/stainless steel - you find the right amps, and stick to it. Why you'd want to be up and down on the amps for steel is beyond me. Use the machine programming to set slopes etc, and that's all you need. The even bead and perfectly straight HAZ along a weld is all the proof you need of this. If you can't weld steel without a pedal, you're doing it wrong.

    Aluminium - yes, it would be tricky with a single amperage, but this is where feathering on a 2T setting comes in. Also, some newer TIG sets (like my new one) have a second current setting on the torch handle - usually set this low, and feather the second button towards the end of a seam, or set it high, to initiate the puddle at the start, before the heat input reaches equilibrium and you can weld it on a single amperage. An amptrol would be way nicer, though.

    I agree, if most of your welding is small fiddly aluminium then a pedal will be best for perfect results, but it's surprising what you can manage with a well set up machine and buttons, especially if you're doing a lot of sheet metal seams. A pedal is on my wish-list, but by no means my need-list.

  13. #13
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    Re: pre/post gas - upslope/downslope ??

    The reason I said forget the ramp up/down, is that most of these questions come from new welders who think that fancy advanced square wave TIG machines are necessary to learn to TIG weld. They get so caught up with the settings, messing with the frequency, square wave triangle wave, parabolic wave etc... , that they're not welding. Just weld

    IMO the fact that he asked the question tells me he's not an experienced TIG welder, not an insult just an observation.

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  14. #14
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    Re: pre/post gas - upslope/downslope ??

    For me, I do a lot of out of position TIG welding, in almost every instance I am able to make the foot pedal work, last time I was laying under a car operating the pedal with the back of my knee, time before that I was repairing a bread cooler conveyor support, I had to balance on a pipe rail and squeeze my knee against the wall to use the pedal, in hindsight for that particular job I should've brought my switch, but I made it work.



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  15. #15
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    Re: pre/post gas - upslope/downslope ??

    Thanks for the responses guys. Yes im self taught and new. My first machine is scratch start, no functions. This is my second machine. They dont come with foot pedals here in Australia. Yes they are available but not standard as far as im aware.

  16. #16
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by husq2100 View Post
    Thanks for the responses guys. Yes im self taught and new. My first machine is scratch start, no functions. This is my second machine. They dont come with foot pedals here in Australia. Yes they are available but not standard as far as im aware.
    If you can get a footpedal, try to, it'll make your life a lot easier. If not, then try to fool with the ramp down, honestly you probably won't need it unless you're welding aluminum

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  17. #17
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    Re: pre/post gas - upslope/downslope ??

    Quote Originally Posted by MetalMan23 View Post
    If you can get a footpedal, try to, it'll make your life a lot easier. If not, then try to fool with the ramp down, honestly you probably won't need it unless you're welding aluminum

    Sent from my moto g(6) plus using Tapatalk
    I can bearly get my filler hand to work...adding the foot pedal would make my head explode lol

  18. #18
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    Re: pre/post gas - upslope/downslope ??

    Imagine having a tool box full of welding tools. Not too hard to imagine. Now imagine having just an adjustable wrench, pair of pliers, a hammer and a couple of screw drivers. This is what having a basic TIG welder is like. Yes, you can fix stuff. Sure you can put things together. That's all you really need isn't it? Now imagine the magical tool fairy comes and delivers you a set of socket wrenches with both metric and standard sizes, along with a ratchet that has a flexible, locking head. You've just gotten another tool, or actually a set of tools to work with. Now, is that an improvement? Of course it is. You've just gotten more tools in your tool box. Now add in a full set of screwdrivers and an assortment of pliers, and now, get into hand wrenches. You have the choice of combination, double open end, double box end, ratcheting combination with flex head, etc. You get the picture. Each one helps you to do the job more efficiently, and better. But not every tool will fit all jobs or applications. If you've ever done mechanic work, you probably had a half dozen 10 mm sockets or wrenches, and at least that many 9/16 wrenches. Each one is dedicated to certain jobs where their performance was a tiny bit different, but enough to make it more suitable than another wrench. But it is possible to get by without them. NO, you don't ever need more than an adjustable wrench and a pair of pliers a couple of screwdrivers and a hammer for most general repairs. And people who have only used these few tools will swear by it...but people who have the others...well you get the picture.

    Tools like up slope/down slope with a remote trigger are valuable as having a foot pedal in the right application. A foot pedal underneath a chassis is not very convenient, but sure you can do it. But that's not the only, or best way to do it.

    I have a number of customers that are physically impaired, with amputations and even strokes, and they use these features to produce not only satisfactory, but beautiful welds after a little practice. Tell a guy in a wheel chair that a foot pedal is the only way to go, and you may just make him get out of that chair and he'll beat you with your own foot pedal.

    But it's not just people with physical obstacles that benefit from it. As said, most of the world doesn't use a foot pedal, but you see some magnificent products coming out of Europe and even some of the Asian countries that had no benefit of a foot pedal. Yet somehow, we try to press people with different ideas and way of doing something into a mold that makes them conform to our way of thinking.
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  19. #19
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    Re: pre/post gas - upslope/downslope ??

    Some have found a way to make tack welds with the pulse feature. By setting it for really slow pulse. You hit your switch and get full on but you can control how hot it welds for how long and what it ramps down to. Then you let off of course before it goes into another pulse. Really neat actually if you can wrap your head around what I am trying to say is being done. It was smart and makes perfect sense and just waiting for the next projects needing a lot of tack welds made consistently.
    You can control the initial time and then set the background amperage as your control for how it tapers off and time for how fast.
    Last edited by danielplace; 08-23-2019 at 06:49 PM.

  20. #20
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    Re: pre/post gas - upslope/downslope ??

    Explaining same thing. Just down the page.

    https://weldingweb.com/showthread.ph...ith-Pulse-aids

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