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Tiny anvil knob for forge. By ArmaBianca creations. 6:50 video:
https://www.youtube.com/watch?v=QNhNDFwGe2w
Previously:
Homemade Forge Build Guide
https://www.homemadetools.net/forum/...252#post141955
https://www.homemadetools.net/forum/...240#post121457
https://www.homemadetools.net/forum/...2459#post96368
How do you like japanese knives? Homecrafted
https://youtu.be/sc7eKI10m-Y
I turned my AC stick welder into a DC welder with only bridge rectifiers!
Has anyone tried it?
https://youtu.be/eXlOomQyy80
OH! You can overclock those welders for free!! I had one of those welders years ago. Well, a very similar rebadged version of that welder. There were two versions, a big one and a little one (they looked identical, but one had more amps). Turns out the good welder and the lesser model are the exact same welder, and you can easily unlock the extra amps.
I was a broke high school student I couldn't afford the good one, so I had to buy the poverty version. There's a plate that decouples the primary from the secondary which you operate by turning the handwheel. That's how you adjust the amps. There are two sets of holes to mount the transformer, and one set of holes won't let you pull the decoupling plate out all the way. That artificially limits the maximum amps. Just unbolt the transformer then reinstall it on the other set of holes. Congrats. You just gave yourself an extra 30 amps.
I think there's a 150 and a 180. Anyway check the bottom. See if there's an extra set of holes in the sheet metal for the transformer. You might be able to upgrade this welder even further.
waooo, that's quite promising.
I guess this can be put externally if I want to try it without being intrusive to the welder ?
Shouldn't be a problem.Quote:
Originally Posted by Christophe Mineau
A friend of mine down in dry gulch Tx. sent me a DC converter for my Lincoln 225. It was a nice self-contained unit that could be mounted on the top of the machine I connected it one day to see how it worked, which was great someday though I want to remove it from its case and install it inside and add the connectors to the front of the machine so I can have either AC or DC by simply changing the leads' location
I'm glad you guys like the project.
The most effective change that I've noticed is the amount of the metal that melts from the stick and thus the thickness of the weld bead.
As far as I know, with DC current, electrons move more easily from the stick to the base metal.
To nova_robotics:
I am willing to try this hint of yours, do you think the welder (cables especially) would stand that higher current? 30 Amps more don't seem too much for the cables, actually.
To Christophe Mineau:
Sure you can put it externally. Since the output coil it's directly connected to the cables I guess you want to mount it right before the cables to avoid the soldiering part and stuff, right?
To Frank S:
What were the results, what change did you see in the welding?
With the DC you get a smoother more stable arc with low hydrogen rods like 7018, you can buy 7018 rods that say they are ac or dc but the formula that make them able to be run on AC machines is all in the flux coating, even those run better on DC current.
most people who run AC machines shy away from low hydrogen rods anyway. and run 6013 or 6011 either of these will run on either AC or DC-or DC+ you will see about the same penetration at ever so slightly lower amps with either of these on DC current6011 will run a little better on reverse polarity. 6010 or what pipeliners call 5P runs on DC reverse only, 6011 being the most common rod for beginners and still quite popular for veteran welders since it has a violent deep penetrating weld and a fast-freezing puddle it will weld through rust and even paint. Higher amperages for horizontal lower for vertical and still lower for overhead. 7018 even if not specifically labeled AC DC will run on AC it just requires strike start to get it going but it likes to be run on reverse polarity electrode positive best.
I found that my machine ran quite smooth with the converter on it which also allowed me to run Nickle rods for welding cast iron
IF you bump your machine up the extra 30 AMPS be aware you should practice a lower duty cycle. if it is now a 40% duty cycle drop down to using it as if it were 30%. a 100% duty machine would know no difference. Most people unless they are like me who welds a lot of 1/2" and thicker stuff will hardly ever exceeded 60 to 80% duty. for materials in the 1/8 to 1/4" thickness using 1 rod size smaller than the machine is capable of 40 to 60% If your cables heat up you have 1 or more things going on exceeding the duty of the machine and or cables or loose connections. Hope this helps.
Mine ran fine for about 10 years until I gave it away to my brother-in-law. It's a free 30 amps. If you get nervous you can always adjust it down with the handwheel.Quote:
Originally Posted by ArmaBianca Creations
Hi, It's just to give it a try before cutting the wires, if satisfied, I could put it internally just like you, I'm not afraid with the soldiering :)Quote:
Originally Posted by ArmaBianca Creations
Congratulations ArmaBianca Creations - your AC/DC Stick Welder Conversion is the Homemade Tool of the Week!
Clever, useful, and the suggestion for externalizing this modification is a good next step.
Some more good builds from this week:
Drill Press Hole Locating Pin by Frank S
File Organizer by hwmrob
Tapping Methods by GBWM
Spreader Bar by Frank S
Lathe Spider by Dudley Toolwright
Power Tool Speed Controller by Mazay
Drill Press by Kwandotechnic
T-Nuts by Frank S
Air Compressor by Catfish
Tramming Standoffs by Frank S
Improvised Toolmaker's Clamp by Improvised DIY
Mill Head Bench Bracket by mylilmule
Collection of Machine Tools by Dudley Toolwright
Nut Extractor by diy creative crafts
Assorted Luthiery Tools by SculptyWorks
Tailstock Die Holder by winkys workshop
Adjustable Angle Plate by ttmrj
ArmaBianca Creations - we'll be adding your tool entry to our All Homemade Tool of the Week winners post. And, you'll now notice the wrench-on-pedestal award in the awards showcase in your postbit, visible beneath your username:
https://www.homemadetools.net/forum/...OfTheWeek4.pnghttps://www.homemadetools.net/forum/...eWeekIcon4.png
And, you'll be receiving a $25 online gift card, in your choice of Amazon (US-only), PayPal, or bitcoin. Please PM me your current email address and award choice and I'll get it sent over right away.
Nice work! :thumbsup:
Fit a couple of big capacitors across the diode output to smooth ripple also make it switchable - to + polarity plus AC. Reverse polarity is useful and some rods require it.
A word of caution. Using diodes in parallel to increase the current rating does not increase the rating in proportion to the number of diodes.
Diodes are not born equal and when connected in parallel some will do the lion's share of the work and some will just loaf along. So the one doing most work will get overloaded and fail, that will put more load onto the remaining ones and so the one that is now most heavily loaded will fail quickly and the effect will quickly cascade through the whole diode pack.
So to avoid these problems you have two options.
1. Use more diode bridges than you think that you need, I would suggest double. They are cheap so there is no need to skimp on the number.
2. Use diodes with a sufficiently high current rating. In the past these were expensive but now they are not. This would be the preferred solution.
I do not know if you are aware of it, but if you add an Argon bottle and a TIG torch you will have everything that you need for a scratch start TIG welder for steel. You could add a solenoid valve in the gas line for greater operational convenience.
40 or 50 years ago I bought a thyristor controlled DC only welder which I used for TIG welding. It worked well. HF or lift start would have been better but I put up with scratch start. That welder is still my favourite for stick welding
I would second NortonDommi's suggestion to be able to switch polarity. I would disagree with the suggestion to fit capacitors, instead use a choke (inductance) in series if you want to smooth the current more.
thanks Tony, that's really valuable information. It also opens perspectives ...
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Absolutely, but it's even worse than that. Silicone diodes have a negative temperature coefficient, so the impedance decreases as the temperature increases. So the second one heats up even a tiny little bit, it'll pull more amps, which will cause it to heat up, which will cause it to pull more amps.... and you get thermal runaway and let the smoke out. MOSFETs don't have the same problem with negative temperature coefficient. They (most, all?) actually have a positive temperature coefficient, so the resistance increases as temperature increases. If diodes did this, when in parallel they would naturally balance themselves out and everything would be great.Quote:
Originally Posted by tonyfoale
So why am I talking about MOSFETs? Because if you reverse bias them, or wire them backwards, you can use the intrinsic or body diode of the MOSFET as a diode, but one with a positive temperature coefficient. Anyway, a potential solution to the problem.
Thank you so much!! :beer:Quote:
Originally Posted by Jon
NortonDommi:
I totally agree with switching the polarity, however I'm not quite sure if the capacitors will make a relvant difference. Surely more amps would flow and more material would be melt.
tonyfoale:
First, the idea or turning it into a TIG welder is so exciting and no I was not aware of it. Looking back I could have put more diodes, totally agree with the fact that they don't work the same. They can take much more amps then they actually do. Consider that the connecting cables are not too big in size (but not too small either) and they are all the same lenght so that, in theory, they should kinda polarize the whole circuit so that the current will be spread evenly just like with a polarized transistor.
No as I mentioned before, this is not the application for capacitors and there are good reasons why you will see chokes in some welders for smoothing but not capacitors. Let me explain some more, for that we need to understand a bit about the electrical nature of an arc.Quote:
Originally Posted by ArmaBianca Creations
An arc has the property that for a given length of arc in a given environment (ambient pressure and temperature) the voltage drop across the arc will be close to constant regardless of the current. So putting a capacitor across the arc achieves nothing because the arc is maintaining a near constant voltage to a greater extent than practical sized and affordable capacitors could hope to. On the other hand there many be ripple on the rectified AC, pulsating DC, current through the arc, the way to smooth the weld current is with the use of a series inductor or choke. This is what we see in many welders.
The DC welder that I bought decades ago, which I used for TIG welding steel as well as stick welding, was fitted with a choke and it makes a big difference, particularly for TIG.