Sent my wife to get a 151,got a new version

[nhorvath]

I think I'm going to get these:

CAP ALUM 100000UF 50V (63V Surge) 20% SCREW
http://search.digikey.com/scripts/Dk...73388166754715
RES 50 OHM 50W 1% ALUM WW
http://search.digikey.com/scripts/Dk...73388166754715

I did some math and if it really is charging to about 50V you will need a 50W resistor.
W = V^2 / R

With this mod does the tip really stay hot until the cap is discharged? I thought the torch switch controlled a relay.

[Galaxieman]

I did some math too....before I bought the 63v capacitor:

The no load dc output voltage with capacitor calculates be 59.81 volts dc (that is why I bought a 63 volt capacitor)

After modifying my 151, the actual measurement on MAX 2 at the 100,000uf capacitor with bleed resistor connected was 55.3 volts dc.

I can sleep at night with a 63 volt rating on the capacitor....

[Bluewelders]

"With this mod does the tip really stay hot until the cap is discharged? I thought the torch switch controlled a relay."

The voltage while you are welding is on average about 18v depending on what range you are in.
The only time the resistor will have have maximum voltage on it is in the instant before the wire touches the work.
The relay controls the input power (240v),so when the torch button is released the capacitor stays charged,depending on the leakage of the circuits,sometimes a charge will last for weeks.

[Galaxieman]

"The only time the resistor will have have maximum voltage on it is in the instant before the wire touches the work"

AND the entire time you are holding down the trigger to feed wire through the torch cable....

"The relay controls the input power (240v),so when the torch button is released the capacitor stays charged,depending on the leakage of the circuits,sometimes a charge will last for weeks. "

That's for sure! When I received my 100,000 uf capacitor in a direct shipment from Hong Kong I opened it and found that it was charged with 34 volts! That's a lot of energy for free!

[jdchmiel]

dang, you should go into business shipping electricity from hong kong to the US then!

[Renron]

Very first thing I did when I got my 100,000 cap was to short the outputs. Capacitors tend to "recharge" themselves when left alone for a while.
Ron

[Bluewelders]

It finally got time to put a capacitor in mine.

All that I did to make extra room for the capacitor was to re-route the negative output cable,and move the power wires around.
I pushed some extra power cord into the case, removed some of the outer sheath of the power cord, and shortened the ground wire.
Seems to work fine with just the capacitor and bleed resistor.
Extra hot as always.

[Spar-X]

Now only if "someone"...... would make a video of the before and after mod, welding, that would be great.

[woi2ld]

Originally Posted by Spar-X

Now only if "someone"...... would make a video of the before and after mod, welding, that would be great.

spar-X , member SDPAULIE posted some pictures of some welds he made with the new black welder in stock form. I kinda like it just like the way it is.. Im guessing the cap melts/wets the weld in alot more like the newer welders . He posted in this section> MIG, TIG, Stick, And Oxy/Fuel Welding > Mig like Tig > Page 23> Post#559

[Spar-X]

Originally Posted by woi2ld

He posted in this section> MIG, TIG, Stick, And Oxy/Fuel Welding > Mig like Tig > Page 23> Post#559

Thanks woi2ld, found it HERE, but a video of the differences would still be nice between cap and no cap. Seems theres allot of spatter with it right out of the box.

[takirc02]

Hi all, first time poster here. I recently got my first welder, this "new version" 170, and have been having lots of fun learning to weld, so far just fluxcore but I have really dove in and have been through almost 10 lbs. After reading about the largely positive results with the mods, I decided to give it a go myself, but I am a bit nervous about firing it up for the first time. Would you all mind taking a quick look and just verifying, at least on the surface, I didn't do something stupid. Everyone's amazing input on this forum has seem to have made it dummy proof, but I have been know to mess the simple things up. Thanks in advance!

Edit: It would help if I told you what I did...messing up the simple things... I added a 100000uF 50v Cap, a switch (10 amp, 240v, ac...couldn't find a sufficient dc switch, a little nervous about this but it won't get flipped when welding obviously) on the positive side leading to the rectifier, and a bleed resistor. All 10g wire. Also a small cap on the feed motor. no close-ups of this, but I'm not overly worried about that one.

Tim

[jdchmiel]

you put a switch inline with the cap? I think you will burn it up. I did a mod with a bank of smaller caps to a different brand welder, and I had unacceptable heat in the wire I used- I think it was 12 guage stranded, but it could have been as small as 14. Either way, that means the 90 amp unit I modded was passing a whole lot more than 10 amps that your switch is rated for. I predict switch will melt.

[takirc02]

Originally Posted by jdchmiel

you put a switch inline with the cap? I think you will burn it up. I did a mod with a bank of smaller caps to a different brand welder, and I had unacceptable heat in the wire I used- I think it was 12 guage stranded, but it could have been as small as 14. Either way, that means the 90 amp unit I modded was passing a whole lot more than 10 amps that your switch is rated for. I predict switch will melt.

Yep, that is definitely the weakest link in my mod... there will be more than 10 amps flowing, but not of the full 240 volts. my switch is rated at 48 amps at the constant 50 volt rating of my cap (38 at the surge rating of 63 volts), but I'm still not sure that is enough. I considered a beefy circuit breaker for absolutely no concerns but space is awfully tight in that box and I was a little concerned about aesthetics and mounting/access from the exterior too.

What is the potential damage if the switch isn't up to the task? are we talking fire, or smoke...could I destroy more than just the switch? I have no further uses for the switch so if that is the only thing I might hurt, I'll go for it and try to monitor temperature, but really don't want to toast my welder.

A little comforted by this post where Renron used an identically rated switch on a 151 and then monitored temperature...got good results...

[Bluewelders]

The switch should only have about 30amps at most across it,and that would be intermittently,I am not sure if switches have a duty cycle or not.
If you check the heating of the thing while in use a few times, it should tell the story.

[takirc02]

Thanks all! I feel a little better if the switch is the only concern. I'll give it a go this weekend...If you don't hear from me, at least I died having fun...

[takirc02]

Originally Posted by takirc02

Thanks all! I feel a little better if the switch is the only concern. I'll give it a go this weekend...If you don't hear from me, at least I died having fun...

Well, I am still alive! And my welder didn't blow up. I did a quick test with the cap turned off, and then on, and wow is there a difference in how it sounds and feels. I honestly wasn't sure what to expect but...wow. I snapped some photos of the test, and may even try a video as requested above, but think I am going to start another thread for searchability.

[Bluewelders]

Almost a scary change,very noticeable.

[SuperNinja]

Originally Posted by nhorvath

I was browsing at harbor freight and have been looking at them off and on but I keep seeing things about how you get what you pay for

The term "you get what you pay for" is just something that a lot of people like parroting.
It is only generally true, and is definitely not absolutely true.
If the term was true, then shopping around, and getting good deals would simply not exist for anything, anywhere.
Also, I would suspect that a fair amount of the people that use that term never even bothered to personally try out the particular lesser brands or models in question, before forming their opinion.