Bought a new to me Airco Dip/Stick 160 multiprocess welder

[Aeronca41]

Ryan, I've been called a lot of things but very seldom distinguished...... :-)

H80N,That pic of the mica cap did dredge up old memories. I think I still have some of those in the drawer next to 50 year old Sprague Orange Drops. And I still have my old Allied Radio (from their first instantiation before Radio Shack) book with all the handy color codes, wire tables, and even tube characteristics.

[ryanjones2150]

nice!

[H80N]

ok, now you're just showing off....

...old guys...uh hem, I mean, distinguished gentlemen.

....

https://www.youtube.com/watch?v=G0kVgSPAkcg

l

[ryanjones2150]

ok, now you're just showing off....

...old guys...uh hem, I mean, distinguished gentlemen.

[H80N]

Aeronca41.... think we are both also experienced (old..??) enough to have learned the color code jingles for resistor stripes & dot colors for "domino" mica bakelite caps

remember

B-B-R-O-Y-G-B-V-G-W

[H80N]

Yep-we're right on the same page. Couldn't agree more. I just can't get used to paying $27 for a cap I used to buy for $3-$4 "back when". However, I suppose in the perspective of wages then and now they're not that much more expensive. My wife says I'm just cheap. But I still don't buy Chinese welders-the old "cheap does not always mean inexpensive". That's why it's so great to see people fixing up these old dinosaurs-quality stuff if you can do without the new bells and whistles.

Cheap..?? you cared enough to invest in a Dynasty 200DX... the pinnacle of TIG machines as far as I am concerned... and not inexpensive...

would maybe call your spending guidelines....as being "Prudent"..... and value driven...

[Aeronca41]

Yep-we're right on the same page. Couldn't agree more. I just can't get used to paying $27 for a cap I used to buy for $3-$4 "back when". However, I suppose in the perspective of wages then and now they're not that much more expensive. My wife says I'm just cheap. But I still don't buy Chinese welders-the old "cheap does not always mean inexpensive". That's why it's so great to see people fixing up these old dinosaurs-quality stuff if you can do without the new bells and whistles.

[H80N]

Can't argue very hard with you. They fail because they dry out, and you don't know how they were stored. If stored in a hot place they will likely go bad faster. I suggested the surplus only for price and good past experience with reasonably recent dates from Surplus Sales but there's always the risk. Prices he found don't look bad so I'd go with new ones.

am not trying to nit pick... just trying to cover all the bases...

This is a welder designed & built 40 plus years ago when 20% tolerances were the norm... (and it has performed admirably)

What we are NOT dealing with... is a critical milspec gadget in the avionics bay of a B-3 bomber...

so we need not be overly critical of tolerances....

I say this because I come from that "Weapons Grade" world and need to keep real world perspective...

[Aeronca41]

Can't argue very hard with you. They fail because they dry out, and you don't know how they were stored. If stored in a hot place they will likely go bad faster. I suggested the surplus only for price and good past experience with reasonably recent dates from Surplus Sales but there's always the risk. Prices he found don't look bad so I'd go with new ones.

[H80N]

I think all that I would add is to again ask that you check the date code on the Electrolytic Capacitors that you purchase..

Do not have an "official" shelf life figure... but my seat of the pants feeling would have me buying caps that are no more than 5 years old...
avoiding NOS or surplus made before 2011.... maybe I am being too picky... but they do have a shelf life...
Am open to input on this... maybe I m being too strict..??

In "CRITICAL" applications I have seen an estimate of a 2-10 year shelf life

http://digital.library.unt.edu/ark:/67531/metadc3104/m2/1/high_res_d/thesis.pdf

... Soooo... I arbitrarily picked 5yrs

[Aeronca41]

Not sure-need someone with more direct welder repair experience, but since there aren't really a lot of parts in there and you know the caps are bad, seems you're starting at the right place.

[Hondacivic247]

I'm only going to put in the same cap that was in there a 10000mf 50vdc. Prolly the cheaper of the 2 by a few bucks as I'm unsure if the caps are the only issue.

Does it make sense that if the caps are bad I would experience this on high voltage were I get a lack of penetration were as on low voltage it works great, cause the caps aunt storing a large enough charge?

[Aeronca41]

FWIW, A bit of geeky tech info on electrolytic caps. The life expectancy is defined at the rated maximum operating temp. For each 10 degrees C you can lower the temperature inside your welder, you approx double the cap's life expectancy. (This is all within limits-caps don't like extremely low temps either). There is also a school of thought that if you need a 50V cap and choose one with a higher rating, say 75 or 100, it will last longer. There is certainly data to back this up, which is why H80N and I have said its OK to go to a higher voltage rated cap. The "lifetime gain" is not nearly as dramatic as temp reduction gains you, but there is some improvement. However, as in every electronic design decision, there is a negative, and every single component choice is a compromise of some sort, which is why you have trust the decisions of experienced designers (and why I only buy brand name welders, designed by competent people, working for companies with good engineering process controls-while they clearly have some very smart engineers in China or wherever, there is no substitute for institutionalized design quality executed with quality parts). Electrolytics have a physical property known as equivalent series resistance, or ESR, which tends to make the cap run a little warmer internally. ESR increases with cap voltage rating in general, so in identical circuits the higher voltage rated cap will run just a bit warmer, with some small reduction in life expectancy. Thus, you don't want to put in, say, a 150 V rated cap where you only need 50 v. It will work fine, but will operate at a slightly higher temp, with some lifetime reduction, which plays against the lifetime increase you get from the higher voltage rating. There's still a net gain but not as large as you might hope. So, in choosing a cap, get the voltage rating you need, or just a bit above, but don't go too far. Also, depending on your shop temp and how much you plan to use the machine, it may be worth while to invest in a cap with a higher max temp rating. If operating in an un-air conditioned shop in the south, as opposed to the far north, it may well be worth it. Cap makers have graphs and charts for all this stuff, but in general: buy a cap with the needed voltage rating and keep it as cool as possible without freezing it. The single biggest life factor is operating temp; all the other variables have MUCH less effect.

[Aeronca41]

My hands-on bench experience is now a bit (actually a lot!) dated but Sprague and Cornell are both big names in this field. Like Ford and Chevy. Probably each have their following. Either should be fine in my estimation.

[Hondacivic247]

Found out mallory is now cornell dubilier so it comes down to cornell vs sprague, the sprague are a little cheaper. What would you guys get that know more then me?