Resistance Welding of Butted Rings.
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Joined: March 27, 2009
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Posted on Wed Aug 04, 2010 4:53 am
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lorenzo wrote:
Well I was wrong, it does weld aluminum in a very similar way to how it welds silver. You just need to use a variac to get the voltage right. It's a bit tricky to get the settings but there doesn't seem to be any problem with the HAZ.

Of course the standard problems with aluminum welding still apply. The welds are a bit brittle which seems to be an oxide problem. Right now I'm getting maximum 60%-90% stength welds. Rings need to be welded within about 1/2 hour of being cut to prevent oxide formation but it might be possible to use some sort of flux or inert gas to help with that.

Ok, for those of us who aren't welders, here are a few questions. First, what is HAZ, and do I need to care? Second, when welding the aluminum rings, are they dead soft afterward like you had originally thought? Third, can the rings be cleaned and/or tumbled to remove the oxide so you can weld them (if it's been more than 30 minutes since cutting)?

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Posted on Wed Aug 04, 2010 5:24 am
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Vorondil wrote:

Ok, for those of us who aren't welders, here are a few questions. First, what is HAZ, and do I need to care?


HAZ=Heat Affected Zone. This is the area of the ring that is hardened or softened by welding, it's in the article.

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Second, when welding the aluminum rings, are they dead soft afterward like you had originally thought?


No. The softened area can be made small enough that it doesn't affect overall ring strength.

Quote:
Third, can the rings be cleaned and/or tumbled to remove the oxide so you can weld them (if it's been more than 30 minutes since cutting)?


I don't know yet, I'm still working on that. You can weld them anyways but the welds are more brittle.


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Posted on Wed Aug 04, 2010 8:10 am
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lorenzo wrote:
HAZ=Heat Affected Zone. This is the area of the ring that is hardened or softened by welding, it's in the article.

So it is. I either missed that on my first time through it or just didn't understand it enough to remember. I'm leaning towards both.

lorenzo wrote:
The softened area can be made small enough that it doesn't affect overall ring strength.

Awesome.

lorenzo wrote:
I don't know yet, I'm still working on that. You can weld them anyways but the welds are more brittle.

Hmm, ok. Well, it'll be a while anyway before I can afford this welder. I look forward to hearing what else you come up with in the mean time.

Joined: February 24, 2010
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Posted on Wed Aug 04, 2010 11:56 am
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could you try etching the very ends of the aluminum rings? would that help prevent oxidation enough for this, or no?

I'm not exactly sure how etching affects it other than the color change and stop of the aluminum oxide. (otherwise i understand most of it rather well, surprisingly... thank you Mr. P from physics for rambling off about past machining jobs you've had Razz)

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Posted on Thu Aug 05, 2010 3:06 am
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I tested a few more things today.

The recommended aluminum welding procedure is degreasing, followed by a base etch, followed by an acid wash, followed by a rinse, followed by fluxing, followed by a preheat and finally welding. I consider most of that to be unnecessary and impractical for our purposes.

If you are using old rings tumbling in a fine abrasive media followed by ultrasonic cleaning and then a rinse gives very good results, equivalent or better than freshly cut rings.

Tumbling in fine abrasive media followed by washing in detergent then a rinse gives a small improvement in weld quality.

Tumbling alone without washing and degreasing afterwards results in rings that won't even weld.

Washing and rinsing alone without tumbling has little to no effect.

Most common and relatively non toxic fluxes have no effect, or a detrimental effect on weld strength.

The last option I haven't tried is specialty aluminum welding flux.

http://www.tinmantech.com/html/aluminum_welding_supplies.php#3

The most active ingredient is NaFl. Even if it works, I'm sure that the risks of working with such a toxic substance are not worth it. Let's face it, if you really needed really strong welds you could use steel. There's no sense risking your health to get that extra 20% strength out of aluminum.


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Posted on Thu Aug 05, 2010 5:56 am
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lorenzo wrote:
If you are using old rings tumbling in a fine abrasive media followed by ultrasonic cleaning and then a rinse gives very good results, equivalent or better than freshly cut rings.

Ultrasonic cleaning, huh? I'm guessing that is expensive and/or requires specialized equipment.

Joined: June 21, 2010
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Posted on Thu Aug 05, 2010 6:36 am
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To true, to true.

but even still, welding Stainless can have harmful effects also.
especially grinding it, its cancer causing.

u want to weld any thing its all about safety, safety, safety.

Respiratory
Burns(u, table, floor, curtains)
Shock's


sorry guys but I'm stepping out on a limb here, but i need to clear this up,I am a welder 7 years, top of my class,Lead-hand for 2 years held 14 People under my responsibility(health&saftey to).....

MSDS for zinc oxides(ZnO)
http://www.numinor.com/files/MSDSZincOxide2010.pdf

it suck, it can give you the trots, shakes and nausea, but very harmless.
as a welder i have learned one trick. Drink milk, symptoms are gone in minutes, don't know why but it works. but look at the chemical make up of Galv Wire, Iron(Fe) & carbon(C), with a dipped shell of pure Zinc(Zn).
every bit of this is used in our Body, Zn and ZnO are used in tons of medicines. After a while of welding you can desensitize your self and no longer get sick.

Now
MSDS of Stainless Steel(in general)
http://www.h-b.com/images/msds/StainlessSteel.pdf

very bad stuff Chalk full of Carcinogenics and other stuff.
in very,very small amounts its mixed with Radioactive and cancer causing materials. In its Cold form it is Very Stable but when heated up can release very small amounts(not even noticeable or readable) of these metals and over time 10-20-30 years can build up to the point of Cancer some where.

to follow up on this....
if you do weld/fuse metal id trust Galv over Stainless any day.
But an air mover and/or respirator should be used at all times, cause its also whats on the wire to that can change your life.
soaps, waxes, grease, what it was dipped in, rolled in, sat in b4 you got it.


P.S.
Stainless is the Slow Silent Killer(you May Never Recover)
Galv is a Kick in the Pant(you will get over it)

sorry for the rant but i had to get this off my chest.

--------Some thing else to worry about--------
This article is the worst thing to happen from a simple situation.

http://weldingweb.com/showthread.php?t=32501

i have seen people use Brake Cleaner in stuff to give a quick clean.
maybe its in your garage beside u or 15 feet away.
(i hear the range for UV to affect chlorinated hydrocarbon is up to 20-50 feet, either way your garage is alot smaller then that)
if you try arc welding/tig welding(fine jewelry welders), the Ultraviolet light and chlorinated hydrocarbon =Phosgene Gas
this kills at 4PPM same rate as Sour Gas.
a respirator will likely not even help you in this case.
good news though resistance welding has no UV. Arc,Mig & Tig does.

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Posted on Thu Aug 05, 2010 5:27 pm
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Vorondil wrote:
Ultrasonic cleaning, huh? I'm guessing that is expensive and/or requires specialized equipment.


From a webpage I picked at random; A decent sized one for small batches of rings or finished pieces costs <$50. I'm sure there are better deals out there. You can get small battery powered ones on ebay for about $8. They are excellent for cleaning jewelry/rings and they seem to be able to break down the oxide layer on Al to some extent.

http://www.jewelsmall.com/cleaner.html?gclid=CNeklozpoqMCFRD75wod6FCM4Q


http://www.mailletec.com

Y'know, that might just be crazy enough to work!

Joined: March 27, 2009
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Posted on Thu Aug 05, 2010 9:26 pm
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That's surprisingly affordable. I thought it was much more expensive than that. Guess I'll add that to my list of things to buy along with the welder.

Joined: December 19, 2009
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Posted on Thu Aug 05, 2010 10:44 pm
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harbor freight has several affordable ultrasonic cleaners

http://www.harborfreight.com/catalogsearch/result/?category=&q=ultrasonic+cleaners

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Posted on Fri Aug 06, 2010 3:44 am
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Those harbor freight ones look like a real bargain, especially the largest one since it's heated.


http://www.mailletec.com

Y'know, that might just be crazy enough to work!

Joined: March 27, 2009
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Posted on Fri Aug 20, 2010 4:40 pm
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When using this welder, does one need the face mask/goggles one would normally use when welding, or is this one just not bright enough?

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Posted on Sat Aug 21, 2010 1:32 am
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No, you don't need anything, there's no UV rays or bright light emitted from resistance welding. Titanium is about the brightest metal when welding on this machine but even then it's not a problem.


http://www.mailletec.com

Y'know, that might just be crazy enough to work!

Joined: May 07, 2008
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Posted on Sat Aug 21, 2010 1:46 am
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...not anything besides normal protective goggles that should be always worn when mailleing, anyway...

-ZiLi-


Maille Code V2.0 T7.1 R5.6 Ep Fper MAl Ws$ Cpbsw$ G0.3-6.4 I1.0-30.0 N28.25 Ps Dacdejst Xagtw S08 Hip

Human societies are like chain mail.
A single link will be worth nothing.
A chain is of use, but will break at the weakest link.
A weak weave will have the need to replace weak links.
A strong weave will survive even with weak links included.
-'me

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