Lister Engine Forum

How to / DIY => Everything else => Topic started by: mikenash on August 24, 2019, 11:32:14 AM

Title: Welder
Post by: mikenash on August 24, 2019, 11:32:14 AM
I wonder if anyone has built a welder powered by a CS or similar using a Lincoln Tractapak or Hummel or PTO-drive welder unit?

I dunno if 6HP would cut it - but these old girls have a surprising amount of torque and might manage, say, 150A?

I'd be interested in any thoughts.  Cheers
Title: Re: Welder
Post by: ajaffa1 on August 24, 2019, 12:02:27 PM
Hi Mikenash,  No I have not tried this, however, many years ago I used to use a very old trailer mounted Lincoln welder it had a single cylinder diesel and belched smoke under load but it did weld well. It could also be used as a 240 volt generator. I think the important thing to consider is that my old Lincoln welder was close coupled to the old generating/welding equipment. I wonder if a belt driven unit off a CS might have too much belt slip and voltage variation make welding an exciting/difficult activity.

Bob
Title: Re: Welder
Post by: oldgoat on August 24, 2019, 02:49:43 PM
I think you might need a bit more hp than a CS has got because the welding generators seem to run about 1800 rpm. You might get enough output to tun a 12 gauge rod but that is about all. My Lincoln has a perkins 3-152 but it is 400 amps max. The perkins is about 40 hp I think.
Title: Re: Welder
Post by: BruceM on August 24, 2019, 03:50:47 PM
I concur with oldgoat.

For my battery welder, I recently measured stick welding voltage at between 24 and 28 V at the electrode, for 3/32 to 5/32 rods for up to say 220 amps.  The higher end of that is over 6000 watts so the CS isn't going to make it.  At the low end, 3/32 rods and say 25V/100A  (2500W actual, before wire/cable losses) the CS 6/1 isn't quite going to to make it.  Some propane in the intake might help.  An 8/1 might do 1/8 rods.

As for a direct driven setup I'm not sure how the 10Hz power pulse frequency/voltage sag will affect arc stability.  Given the  low cost, small size and efficiency of modern switch mode DC stick welders, I wouldn't bother with a directly driven welder.

My 30V battery welder is working nicely for me.
 
http://listerengine.com/smf/index.php?topic=8654.msg101247#msg101247

It gives me the needed peak power but lets me charge it at a slower rate off my PV/inverter system.  My neighbor did welding on about 26 fence posts a couple days ago with it.  That did not deeply discharge it and in an hour of charging at 15A they were nearly full. This was tack welding with zinc removal via air grinder, so low duty cycle.  From my own work I know 7 rods doesn't faze it much, so for repairs and small projects I see no issue.  I'm thinking of building a carry all for my tractor's 3pt hitch which would let me roll the battery welder up onto the carry all and then strap it securely to the back of the carry all for field work.  With three batteries, it's hefty. 
Title: Re: Welder
Post by: mikenash on August 25, 2019, 04:38:15 AM
Hi guys, sure.  I sort of have a handle on that - if the Tractapak runs at maybe 32VDC then, say, 250A is (32 X 250 X 120% for losses) = something like 13HP nominal

I have a 13HP chinese genset & it runs the 220A welder OK.  But the welder makes funny noises - because it doesn't like the ugly square-wave power I would guess

And I know when I have hired large single-phase petrol gensets from local hire companies that they say "You're not allowed to use this to run a welder, it'll wreck it".  The only reason I ever hire a genset is to run the welder just in case it decides to wreck it - better than wrecking mine . . .  They want you to hire the trailer-ised diesel genset or generator-welder; but it'd be cheaper to pay a mobile welding man to come do the job . . .

Anyway . . . it's all very well to talk about 220A, 250A.  What are we doing, building bloody bridges with 4mm iron-powder rods?  Mostly we're doing shit like repairing the trailer, or making a frame for a 'Roid out of 10mm RSJ & plate.  The former is either 3.2mm rods at 90A or, more likely, 2.5mm rods at 70A.  The latter maybe 3.2mm rods at 130A

And, anyone who spends a few hours looking through a welding helmet knows that, if you have to, you can repair/build most anything with multiple runs of light rods - AS LONG AS YOUR PREP IS GOOD
Title: Re: Welder
Post by: mikenash on August 25, 2019, 05:03:31 AM
Hi guys, sure.  I sort of have a handle on that - if the Tractapak runs at maybe 32VDC then, say, 250A is (32 X 250 X 120% for losses) = something like 13HP nominal

I have a 13HP chinese genset & it runs the 220A welder OK.  But the welder makes funny noises - because it doesn't like the ugly square-wave power I would guess

And I know when I have hired large single-phase petrol gensets from local hire companies that they say "You're not allowed to use this to run a welder, it'll wreck it".  Except they don't say "wreck".  Now, the only reason I ever hire a genset is to run the welder just in case it decides to wreck it - better than wrecking mine . . .  They want you to hire the trailer-ised diesel genset or generator-welder; but it'd be cheaper to pay a mobile welding man to come do the job . . .

Anyway . . . it's all very well to talk about 220A, 250A.  What are we doing here, building bloody bridges with 4mm iron-powder rods?  Mostly we're doing shit like repairing the trailer, or making a frame for a 'Roid out of 10mm RSJ & plate.  The former is either 3.2mm rods at 90A or, more likely, 2.5mm rods at 70A.  The latter maybe 3.2mm rods at 130A

And, as anyone who spends a few hours looking through a welding helmet knows that, if you have to, you can repair/build most anything with multiple runs of light rods - AS LONG AS YOUR PREP IS GOOD - as every welding instructor will SHOUT at you over and over.  Sure you'll do stuff like leaving a small burn-through gap between initial set-up components, and turning stuff over so that you can always do your weld slightly uphill to better manage the puddle, and using 7018s - which you should be anyway . . .  All of those things are good practise anyway

In an "off grid" situation where you have a 6HP diesel sitting doing nothing, and where there's room on its frame to mount some sort of DC head . . .

So, if you had some DC device that ran at, say, 25VDC, and you accepted that you'd end up using 2.5mm rods at, say 80A - all of a sudden it's:

25 X 80 X 1.2 = 2.4kW

Just kicking it around really.  I'm gonna keep an eye on TradeMe for old PTO-drive type heads.  Who knows, I might find an abandoned Miller or Licoln diesel one cheap anyway?

Cheers
Title: Re: Welder
Post by: BruceM on August 25, 2019, 06:26:25 AM
Yep, on small rods you should be able to do it.  A trickle of propane in the intake does clean up the exhaust on a moderate overload (I've tried it), and does nothing but good for the engine.  Alas, unlike methane, it can only replace about 20% of the fuel (max).

For an Ufer grounding system at my house I had all my rebar tack welded together and my helper used his small flux core MIG rig on my 4000/4500 (peak) Watt cheapo gas backup generator.  No troubles, though he did jack up the rpm a bit which helped with the surge load greatly.   So a modest MIG rig might be a good lower power welding choice.  They are fixed voltage, from low to high 20's volts. I'd guess 70-90A.  CS 6/1 territory.

I would guess your welding rig is not great power factor, which is why the generator is stressed.  Waveform is irrelevant to the welder, which would likely saw the top off of the nicest sine. Welders stress generators because the poor PF and big surge loads means guys are often trying to run over the capacity of the electronics, which were rated with the wild optimism of marketing fairy dust.  The standard modern practice of grossly oversizing the genhead on CS engines should solve that.  The other issue is that welders generate massive EMI- lots of nasty spikes on the power, which may fry an AVR.  A cheap commercial power filter (dual stage CM choke and small caps) would likely stop that.

I decided not to try a battery DC MIG setup because of a couple reliable sources of welding literature  stated there is a strong AC interruption of current (5-100Hz) when using the normal MIG shorted wire welding method. The wire extends into the puddle, shorts out, melts off a blob, open circuit, repeats as the wire is fed. Frequency depends on set voltage and wire feed rate. It's the source of the frying bacon sound of MIG.  I thought that would be a bust, health-wise for me.  It helped explain why I have to stand back a LONG way from MIG welders.

A CS based welder is most interesting project.  A guy who thinks- "hey, I think can do what I need with less power" is well suited to practical off grid living. 









Title: Re: Welder
Post by: mikenash on August 25, 2019, 08:59:21 AM
Hi again Bruce

See link?

https://www.trademe.co.nz/business-farming-industry/industrial/manufacturing-metalwork/welders/listing-2286611569.htm?gclid=CjwKCAjw44jrBRAHEiwAZ9igKPI02lL3j7TSYNqgnOtuedtdw50aanM8AlGSOFfpMhhfoPK0_1SpFBoCxToQAvD_BwE&gclsrc=aw.ds

The single-phase welder I use for everything is a close cousin of this - couldn't find the exact one, but it'll be functionally identical

They're cheap, about $400.  I first bought one maybe 15 years ago when the expensive $2500 Italian unit I was using blew up for the second time (first time repair bill was $1500).  I get four or five years out of them (I'm on my third)  They're super-portable and have enough of a duty cycle (80%-odd maybe? I forget) that the downtime between electrodes for scraping, wire-brushing, occasional grinding and, of course, swapping rods is enough to make the duty cycle effectively 100%

I once built a big steel frame in the sawmill out of 12mm wall 150 X 160 SHS (half-inch wall, six-inch square tube)  and,once it was all tacked up, spent maybe four hours burning a packet of 4mm rods - you might call them 5/32"? maybe - to stick it all together.  My hands overalls & gloves were smoking and every bit of my beard that stuck out anywhere outside my mask was frazzled off - but the welder didn't give a toss.  I still got another couple years service out of it . . .

So they're cheap.  But not nasty

But for some reason, when you run it off the generator, it makes an odd noise.  Kind of a whine?  hard to describe.  I don't have any way of knowing if it's bad for it and I don't much care cos if it dies the boss will just buy me a new one

Anyway,  that was the basis for my ill-informed assumption that maybe it didn't like the non-sine wave

Re off-grid?  Yes, I have always been "less is more" with woodstoves, LPG hobs, wetbacks, solar hot water, gravity-generated water pressure . . . all that stuff

I just planted 100 coppicing gum trees near my shed so I can have close, convenient firewood (think chainsaw + wheelbarrow lol)

Just cos I'm gonna be broke in retirement doesn't mean I'm gonna be miserable lol

Cheers
Title: Re: Welder
Post by: dieselspanner on August 25, 2019, 09:36:21 AM
Two great quotes in the last two posts.....

A guy who thinks- "hey, I think can do what I need with less power" is well suited to practical off grid living. 

Just cos I'm gonna be broke in retirement doesn't mean I'm gonna be miserable lol.

Sums up exactly where my (and, I'm certain lots more guys on here) head is at!

Cheers
Stef
Title: Re: Welder
Post by: ajaffa1 on August 25, 2019, 10:43:26 AM
Hi Stef, when I am broke after a lifetime of work and paying taxes and etc on the promise of a pension in my old age, I plan to shoot a politician of my choice for having lied to me and stolen my money. I then plan to surrender myself to the authorities, they will try me for murder, to which I will plead guilty. I will then spend the rest of my days in prison where I will have a roof over my head, three good meals a day, air conditioning and all that free health care that is not available to the average civilian. This plan also comes with free internet access, education, television and treatment for depression (free happy pills).

Australian prisons now have a total no smoking ban, which caused terrible problems when it was implemented. As a lifelong smoker the first few weeks could be difficult , however I like the idea of a thirty year jail sentence that starts with me having to quit smoking. This will probably extend my life expectancy considerably and cost the government hundreds of dollars a day for as long as I can keep going.

If after many years of this comfortable retirement plan the parole board decide to release me back into society, I plan to go and shoot another useless politician of my choice.

Bob
Title: Re: Welder
Post by: glort on August 25, 2019, 01:54:01 PM

Water/ methanol injection is a lot easier on engines than LPG to get more power.
Title: Re: Welder
Post by: BruceM on August 25, 2019, 05:11:35 PM
This was an interesting and enjoyable thread on welder and welding tech and very positive self help now gone to threats of murder and derision of people who want to reduce racist mass murders.  I'm just going to speak out and say please stop.  I'm not well myself so I understand depression, anger, loss, pain and misery and being marginalized.  I'd be very grateful if this forum could be a positive place.
Title: Re: Welder
Post by: sirpedrosa on August 26, 2019, 12:03:37 AM
Hi Everyone

I am self-taught in welding, that is, if it looks good in the first run I do not need to grind, if it does not go well, grind it and put a second run.

But, of course, to make a welding worthy of the name, I still have to burn a lot of welding rods. As many of us (excuse me if i'm wrong) at this days you must  have a cheap 120A inverter to do light job on shop. MIG's and TIG's are other championship (yet for me).

Giving a hand to Bob: What can I do to divert you from that ideas of shooting liars. There will be a dozen of others waiting for it's velvet seat chair. Sorry if I'm saying, or said, something that disregards you!

You don't need to go to jail to quit smoking. Just exchange it to a bootle of the same price and have to last the same time as the packet.

I stopped burning them in 5out90, and I still have the empty packet with lighter in it. It was a packet a day - if I slept - otherwise it was almost two.

Have all of you a safe week
VP

Ps: I also feel marginalized, no longer reminds me why, but I have this feeling.
Title: Re: Welder
Post by: mikenash on August 26, 2019, 07:43:22 AM
Hi Bruce

I'm sorry that light-hearted stuff has caused you distress

As an American It might be hard for you to understand antipodean humour?

That comment was an example of the black humour common in NZ and Australia, and the joke about shooting a politician or two to gain oneself a warm retirement with healthcare etc . . . . it's a bit hard to explain but it's an old, old, joke

It has nothing to do with shooting politicians, it's a commentary on the way politicians run things so that a working man, having toiled all his life, and now in his twilight years, cannot afford healthcare, or to get his rotten teeth fixed, or his worn-out hip replaced, or somewhere warm and dry and safe to live with central heating and three square meals a day, or even somewhere warm, dry and vaguely hospitable where he might feel comfortable having his grandkids visit . . .

Whereas a criminal, never having done an honest day's work in his life, is rewarded - by said politicians - with the tenure of a warm dry cell, with three square meals a day, an out-of-the-weather exercise yard, first-world health & dental care, free clothing. bedding, laundry, library service, TV etc etc, plus visiting rights for his family, the prospect of government assistance to allow them to move house to be closer to him so as to support and visit him, and the congenial company of like-minded others

Since all one has to do to move from private poverty to government-funded luxury is to commit a substantial crime - then the politician (the cause of the problem in the first place) is an ideal target

That's the short version lol
Title: Re: Welder
Post by: ajaffa1 on August 26, 2019, 12:21:24 PM
Hi BruceM, I apologize unreservedly if I caused you offense. I would like to point out that I was only joking and have no murderous intentions. As an ex military person, trained to kill people, I can honestly say that there is no blood on my hands, nor do I intend there to be.

Thank you Mike and VP for standing in my corner and trying to explain Australian humor. Bruce and I are more than able to sort this out in a civilized and adult fashion, perhaps he is right in suggesting we stick to topic and stop getting sidetracked. I disagree, but am willing to accept his criticism.

So back to welding using a Lister CS as the primary mover. In my limited experience, I have always found that welding using any sort of generator setup is problematic because of the sudden load when striking the arc and the lag associated with the governor mechanism trying to deliver more fuel to counter that sudden load. I have seen and experienced no end of invertor welder failures when connected to slow responding petrol generators. My Lister ST2 startomatic produces 7KVA but struggles to keep up with any welder I have used with it. That said if I load up this generator with the motors for my surfacer and thicknesser, it improves thing enormously. Back EMF and extra mass, I guess.

I believe that a CS driving a 48 volt alternator charging a 48 volt battery setup would provide a very satisfactory welder as the batteries would reduce the sudden load effect, allowing the governor to catch up. That said, modern batteries do not go well with high loads for extended periods, so you would need a large battery pack. Probably cheaper to look for a second hand Lincoln welder.

Bob
Title: Re: Welder
Post by: BruceM on August 26, 2019, 04:08:01 PM
Sorry I completely missed the boat on Au politician murder/prison benefits black humor.

I've not seen any listed PF ratings for cheap inverter/welders- so it is likely 0.6 for those surge loads starting the arc; meaning they are simply rectifying the AC to DC into capacitors on the front end of the inverter-welder. That lops off the top of the sine.   PF correction requires an active buck- boost circuit to take smaller gulps of power throughout the sine, boosting the AC voltage when it's lower than the  DC being created. The PF correcting controller tries to make the load current look like a sine in phase and proportional with the incoming AC voltage. It's much more sophisticated circuitry and also more susceptible to electrical interference; which would be a serious design problem for welder designers. 

There are PF corrected welders out there- for more $.  That might make a CS directly powered MIG welder viable. 

There are MIG spool gun welders sold for direct battery operation; the direct battery voltages are 24-30V, or a MIG wire feed could be used direct off 24V batteries.  If 24V AGM  batteries were used (high charge and discharge current capable) they could be modest size if fed by a high current charger during operation.

That might make a decent automotive alternator type welding setup that a CS could handle.

There are also "portable" battery powered DC inverter welders (MIG).  Here's one:
http://www.weldingtipsandtricks.com/hobart-trek-180.html
This one is for 115VAC charging, and has a small lithium battery.  Spendy at $1200., but would certainly fill the bill for a CS powered welder. 

48V from batteries is too high voltage for useful direct MIG or stick welding and would have to be down (Buck) regulated. 

Budget wise, my 30V ($300 for new batteries) battery stick welder with 3- 15A battery chargers ($45 each) is looking pretty good. The arc stabilizing choke cost me nothing but the 1000W transformer core I gapped would run about $50. new. 
Title: Re: Welder
Post by: ajaffa1 on August 26, 2019, 11:44:03 PM
Hi BruceM,  I agree that 48 volts is a bit high but 24 is too low, 30 volts is better but how are you achieving this, five six volt batteries and how do you use three battery chargers to charge them?

Perhaps what you are using is three 12 volt batteries each with a charger which would give you a welding voltage of between 36 and 40 volts.

Bob
Title: Re: Welder
Post by: mikenash on August 27, 2019, 02:15:32 AM
Hi Bruce and Bob

I was thinking of you guys today as I was doing some flanges

Firstly - you're right, there's not enough juice in one of the old CS's to drive a useful welder - it'd be a bunch of compromises.  I'll see if I can find a cheap Lincoln (although I think that might be like a warm icecream or a partial pregnancy . . .)

It's always interesting to hear other folks' takes on settings:  electrode selection, sizes and current . . .

So here's what I would think of as a bog-standard reference piece of work in terms of what I normally do:

It's welding a piece of 12mm wall pipe (half inch in the old money) to a piece of 20mm flat in the form of a flange (3/4 inch).  It's done using a 7018 (my old favourite, which is a Low Hydrogen rod with a bit of an iron deposit action in its flux makeup).  The rod is 3.2mm (I think you'd say 1/8") and it's running at 120A on that little single-phase welder I mentioned yesterday

The comment I would make is that it's hard to imagine a situation - in normal work - where you couldn't get most stuff done with 120A?

That's a single pass and the work is nominally rated at 70,000 PSI test

It's not a particularly pretty weld as I never do pretty fillets - but you could easily achieve the same strength - or functionally close-enough to it - with a root run using a 2.5mm rod at, say, 80A and then a couple of runs with the 3.2mm rod at perhaps 100 or 105A

Although we talk about 220A welders, I don't know where we would use one in what is effectively our "hobby" situations

Just my $0.02  Cheers
Title: Re: Welder
Post by: BruceM on August 27, 2019, 03:04:49 AM
Bob, my welder uses 2- 110AH, Group 29 marine batteries, and one 200AH 6V floor sander battery. All from Walmart, all $90 to $100 each. The 3 chargers I use are automatic, 6/12 volt capable, 15A max chargers and I have a charge plug with 6 Anderson/Sermos type connectors so each battery is charged separately.  They don't have to "match" that way; one of the 12V batteries is 3 years old, the others are new but obviously grossly mismatched in capacity. It gives me the flexibility to use what's on sale come replacement time. The galvanized steel strip resistor gives me the ability to adjust current; open circuit voltage is the battery series voltage. As the battery charge level lowers I just move the connector down one notch to compensate.  A big 800uH toroidal choke acts as an arc stabilizer, which helps greatly at lower current levels where starting and maintaining an arc is otherwise a real stinker. 

I don't use over 1/8" rods myself, and 3/32 is my most commonly used welding rod.  For thinwall (1/16") tubing or sheet I use 1/16 inch rods and suffer with the greater difficulty in arc starting and stability of low amp welding.  Below that, I must braze since I can't use MIG.

I'm only doing hobby work so battery capacity has not been an issue.  The big deal for me is that I can tolerate using it pretty well outdoors with good ventilation, on a good day.

I found the ideal voltage by cutting up a retired Optima yellow top battery.  What I found is that just one additional cell made 24V (+2v) way better for 3/32 rods.  Two cells extra (24+2+2) was plenty hot enough for 1/8 rods.  I couldn't find a source for 2V 100AH batteries in the US and China manufacturers wouldn't sell less than pallet loads, so I opted for adding a 6V battery and a big power resistor.  The galvanized sheet/strip resistor on the side of the welder has worked out well- stays cool and has good increments of adjustment while dirt cheap.  It saved me having to design, build and test a linear regulator for up to 160A and seems to work adequately.  Arc starting at low currents would be better with an active regulator, and it would automatically compensate for battery fade but I like the utter simplicity of zero electronics.

A 160A adjustable current buck converter on 36V batteries would be perfect if one wasn't impaired by EMI.  The battery interconnects and leads could be #4 AWG since a little loss is OK. 

Mike, I'll be some generator will turn up to operate your nice inverter type stick welder if you just keep your eyes out for it.  7-10KW is a common capacity and might be useful as occasional shop power to supplement a CS for day to day operations.








Title: Re: Welder
Post by: old seagull man on August 27, 2019, 07:15:26 AM
Sort of on the subject of welders. I have got sick of waiting for the welder. To make my generator frame. For the mighty ZS195  and its 5kw friend.
So i went a bought myself one.  https://www.tradetools.com/product-range/welding-equipment/welding-machines/renegade-140-amp-inverter-arc-welder-20-duty-cycle
 140 amp inverter 10amp power point operastioon gloves, auto dacking mask, an d chipping hammer.
All for $200. even though in a pack of 6018 and so old bits of plate for me to start practicing on.
I last welded in 1975. so this might be entertaining, im thinking.

So all your welding talk has fired me up to have a go.So were do i sign up for lessons.
Title: Re: Welder
Post by: sirpedrosa on August 27, 2019, 08:17:18 AM
Hi OSM

Welcome to the classroom. Take a seat and enjoy the welding masters lessons.

Have you all a nice day
VP
Title: Re: Welder
Post by: mikenash on August 27, 2019, 08:21:52 AM
You will be staggered at how much easier starting & holding an arc will be with the new machine compared to one of forty years ago

There are several hundred experts on Youtube lol

But this guy is great :)

https://www.youtube.com/watch?v=8veisgOaHUg
Title: Re: Welder
Post by: ajaffa1 on August 27, 2019, 01:28:18 PM
Hi Guys, when I was welding regularly to meet aircraft standards in the RAF, we had top of the range equipment. The Tig welder I used maxed out at 500 Amps, I doubt I ever took it over 400 Amps, but it was faultless. The trouble with it was that it was bigger than an office filling cabinet and not very portable, much easier to move the airplane than the welder!  :laugh:

Bob
Title: Re: Welder
Post by: BruceM on August 27, 2019, 05:43:21 PM
Bravo, Old Seagull Man.

I concur with MikeNash, weld.com's got lots of great videos by a pro.  I also hadn't welded (stick) since about 1974.  The  area fence/steel/welding shop sold me a car trunk full of scrap for $10 when I told them I was re-teaching myself to stick weld and needed some scrap for practice.  Nice bunch of guys.

A good tip (at least for me) by another youtube guy- for older, less steady hands, cutting the electrodes in half is a huge help in control.

Title: Re: Welder
Post by: mikenash on August 27, 2019, 06:33:17 PM
If you watch the good guys online - the have great gear and they know about setup

IMHO if you have good overalls & gloves and a beanie or some such so that you know your head's not gonna get covered in sparks where there's no hair (most) - that's a good start

Then you need to be set up right:  A folded up old pair of overalls where your elbow leans on the table; a bench at a comfortable height, an old office chair to sit on, your work positioned where the lean into it is as natural as can be . . .

Then you need to find mechanical ways to make your hand steady - one hand supporting the other?

If you hold a loop of the cable in the non-welding hand then you won't have a big, swinging loop of welder cable wobbling your electrode . . .

Simple mechanical preparatory stuff

I used to get told at weld school two big things:

90% of a good weld is preparation

(and) Don't set yourself up to fail

Cheers
Title: Re: Welder
Post by: BruceM on August 27, 2019, 06:46:19 PM
Any thoughts on welding tables?  I've been working on cinder blocks outside, usually under my trees for shade,  but it's hardly comfortable.  The inexpensive portable welding tables like Harbor Freight sells would be a step up, but they seem rather farcical in terms of not being heavy enough to clamp work to.  I don't want to spend a fortune, it's for limited hobby use only. I've thought about going to the scrap yard to see what I can find for a top.  Steel legs and rails I can afford but a heavy top is beaucoup $$$.   I currently often use my rolling table saw with cast iron top and wings as a work table for things I must do outside, and have thought about making a light (removable) gauge steel welding top for it.  I could then at least use welding magnets to hold pieces to it. 



Title: Re: Welder
Post by: glort on August 28, 2019, 01:39:00 AM


 I currently often use my rolling table saw with cast iron top and wings as a work table for things I must do outside,

Bruce if you are needing to get away from Fumes and the Like, have you thought about putting a fan or blower Behind you?
One of the New gun clubs I used to shoot at had the AC Blowing from behind the Line at the very back of the room.  Given the gun was in front of you and the significant airflow was always behind the shooter, the smoke was always moving away and the air was at the shooters position at least, always 100% Fresh.

I have done this with various things in the shed  Including welding.  I get a fan or a blower ( set up a couple of car radiator fans on a stand now) and put that behind me and If I stand toward the front of the shed everything is blown away from me and out the door.

I'm currently doing Kitchen Renos and yesterday had to cut a channel in the concrete slab.  I got the twin radiator fans and put them on a battery charger for a power supply and set them as I do in the shed, in the window and had them sucking the air out.  I opened the front doors and cracked the doors in the joining rooms and cut the cement.  There was a hell of a cloud of dust as one would expect but it went no where and the room was completely clear in under 30 sec.  I went outside and could see the dustcloud hanging in the still air except where it could be visibly seen to be rushed out by the fans.
Mrs came home ans was suitably impressed all the other rooms were dust free and there was bugger all dust in the kitchen more than about 3M from where I had been cutting and jackhammering.

I like the radiator fans because they move Huge amounts of air. I have one in the shed window powered by a couple od solar panels blowing in.  They keep that tin oven so cool and it's great to work in there in summer because even though the fans are at the back, the strong breeze comes to the front and can be felt anywhere in the shed.  I'm going to add another set in the other window shortly and put the panel to drive them over the top like an awning  to keep the rain out.

Having a fan behind you would allow you to work in your shed but keep your air clean and fume free probably better than being outside with no forced air circulation.  You could even mount radiator fans On your welding cart itself on a telescoping arrangement so you can get the right height and tap to one of the batteries.  Being you are doing stick you don't have to worry about taking the shielding gasses away . The fumes will be moved away straight from the workpiece and you won't get any exposure at all.

If you put the fan/ cart to the side of you and had it blowing out the shed door, that would work just as well.

Title: Re: Welder
Post by: BruceM on August 28, 2019, 06:17:50 AM
Now that I have the inverter with very low EMI AC, I have thought of getting a fan on a stand for the shop.   Fan motors are problematic when nearby, depending on the power of the motor and stray field of the motor design...so I tend to think of fans last.  The shop has a big doors and a big concrete apron and all my wood/air motor tools are on wheels so I can work outside.   The fan would be useful even outside on still days, though those are few. 

I still need for a welding table; I don't want to scorch and grunge up my main bench, which has a 3 foot by 8 foot maple butcher block top, nor my cast iron table saw top which I regularly use for soldering electronics outdoors.

Once I rebound from this summer's wildfires I hope to be travel worth again and get over to take a look around the scrap yard for something that might be used for a welding table top.
It's always demoralizing to go backwards, health wise.





Title: Re: Welder
Post by: mikenash on August 28, 2019, 09:03:32 AM
Hi Bruce

When I came to my current job eight or so years ago they didn't have much engineering/fabrication capacity on site - they just had the local engineers almost next door do almost everything; so over a couple of years I built up stuff so we had some capacity

My boss was sceptical so we sort of did stuff under the radar.  When I needed a welding table I bought a half-sheet of 10mm (3/8 steel). It was only maybe $300 for 1200 X 1200mm 4-foot square, and I made legs out of scrap 2" galv pipe offcuts

Eight years later it still serves as well as ever.  I am forever tacking a bit of something to it to act as a stand or a brace or whatever.  It is GREAT.  It will last for 20 years or maybe more

I reckon you could get away with 8mm (5/16") if you put a bit of reinforcing of some kind under it

This thing has had all sort of sledgehammer-based abuse etc . . .

If you make up a couple of cheap saw-horse style stands about the same height out of any old junk or wood or whatever so they can support longer stuff so that one end is on the welding table - then you are 90% of the way there
Title: Re: Welder
Post by: BruceM on August 28, 2019, 03:28:56 PM
MikeN- So you like the tack it to the table top method?  That's something an old woodworker doesn't think of...  I was liking the look of slat table top designs where I could employ my large supply of C clamps, but I have seen on youtube vids that some, like yourself, prefer to simply tack weld to the table top.  I have two adjustable height roller stands I use for woodworking, so that's covered. 

A 2'x4' sheet of 3/8 thick A31 hot rolled steel is under $200 online so I'll have to check with the local fence/steel shop to see what price they can get for me. 



Title: Re: Welder
Post by: mikenash on August 28, 2019, 09:59:39 PM
HI Bruce

I'm forever tacking something to the top and then just cleaning it up later

Purists will say it makes a bit of a mess of the surface and it does - still works fine

Besides - mid-job - he whole area is a disgraceful mess :(

I have lots of C Clamps too.  An important feature of the table is the overhangs - two or three inches out past the frame - which allows flexible use of the C-clamps

Cheers
Title: Re: Welder
Post by: BruceM on August 28, 2019, 10:13:31 PM
SImple and effective- I like it!   Just wondering-  how did you cut the tubes to fit tubular legs?
I see a very clean and tight fitting joint there! 
Title: Re: Welder
Post by: mikenash on August 28, 2019, 10:41:15 PM
Hi Bruce.

Thereís a couple of options: 

The rough & easy one is to smack the ends of the pipe flat so that instead of being a 2Ē circle itís sort of a 3Ē X  1/2Ē flattened ovoid.  Then itís easy to weld at a rightangle

The other option is to cut pipe to length - not inside-to-inside but a couple inches longer & then hold a bit of scrap pipe perpendicularly against the edge & just copy thecurve with a marker. Needs a bit of practice & the nicer you get it - the easier the welding

Also, if you can imagine using a, say, 3Ē holesaw to cut a, say, 2&1/2Ē pipe in half and if you imagine the curve that would leave?  Thatís an option that can be very tidy

If you can put yourself in a situation where you cut the horizontals all to identical length & tack them to the legs BEFORE welding the legs to the table -that makes them less length-critical. Thatís where it goes wrong - getting the length right

Itís all fun. :)

Any proper engineer would tell you my table is an abomination probably. But who cares if it works lol
Title: Re: Welder
Post by: BruceM on August 28, 2019, 10:48:11 PM
Thanks for the good rundown on round pipe fitting options!