Best way to clean old aluminum for TIG

[Oxide00]

I have never had any good results trying to clean aluminum and then trying weld on it. Always looked like a disaster for me (maybe it was because I was relatively new to ac tig welding when I tried it )

[jakeru]

Charlie - if I were in your shoes, I would mechanically clean the diamond plate aluminum for welding with one of those bristle brushes. The bristles will conform and clean around the "raised diamonds". You only need to clean the area you are welding (unless you want to clean a larger area, for aesthetic purposes.) But hey, this is just a foot pedal... it will be "living" on the dirty floor of your welding area, and you'll be often stepping on it with your dirty welding shoes, right? (So maybe it doesn't need to be sparkling clean. )

I tig welded some used, aluminum diamond plate (1/16 and 1/8" thicknesses, not counting the raised diamond shaped) together recently. I prepped it pretty quickly, just using an old, cruddy 4.5" flap wheel I had nearby. I tried to get the edge of the flap wheel into the grooves near the raised diamonds, which kind of worked but not all the great. I had to move it around in different angles to get around the surfaces, and didn't try to achieve perfection, but it worked out well enough. I just posted up a project write-up about it, check it out:
http://www.everlastgenerators.com/fo...t-(jakeru-s-10)

The abrasive impregnated plastic bristle cleaning things however, work very well to conform to irregular surfaces (like up against raised diamonds, would be perfect.) Harbor freight sells some cheap versions in "cup brush" and "radial wheel" versions. I have a red colored cup brush with 1/4" shank, (and probably 2" or a little greater OD) and it worked pretty well. It does not work super fast (you don't want to overheat and melt the plastic bristles) but it does work well. It will leave a "scratched look" but they will be pretty fine scratches. Here is a link:
http://www.harborfreight.com/2-inch-...ush-91367.html

[EricCox]

I'm a welding noob, so I don't know how nitric acid cleans aluminum, but when I worked for an electronics manufacturer we used to use it to burn holes in the cases of silicon chips so the wafers inside could be examined under a microscope.

Be CAREFUL with nitric acid. Do it outside with a fan blowing the fumes into your neighbor's place. If you smell it at all, you're doing permanent damage to your lungs.

[Mike J]

I.e. Do not use brake cleaner!!

[scootarida1]

I.e. Do not use brake cleaner!!

Is there a reason not to do this? Will it react when welding?

[Mike J]

Is there a reason not to do this? Will it react when welding?

Check this out: http://www.brewracingframes.com/id75.htm

Scared the hell out of me!

Cheers,

Mike

[Wookie]

If it were me i would just toss it in the electropolisher depending on the parts size

[everlastsupport]

Is there a reason not to do this? Will it react when welding?

There should be a sticky here somewhere, but search for "brake cleaner" on the forum. Certain types can kill you. Avoid them all to be safe.

http://www.everlastgenerators.com/fo...r-Phosgene-Gas

Acetone and Denatured alcohol is a better way to go.

[Ifixjets]

This is what we use in the aviation industry for prepping aluminum. http://www.aircraftspruce.com/catalo.../alumiprep.php

[Jake98]

Welcome to the forum Ifixjets, we need more aviation talk here!

[hooda]

I have tried many things, including a trip to the local hydroponic growing store (Gee, wonder what people go there for?). They sell a product called "pH down" which is basically food-grade phosphoric acid in a decent concentration. They have really diluted it in recent years, as back in the day when I was an actual customer of this place (YEARS ago), the directions called for like 20% of the recommended application that the newer formula does. But, I bought a pint, just to see. I applied it with a clean cloth, and it INSTANTLY brightened the surface to a shiny finish. On deeper oxidation, a little help from a red scotchbrite pad helped, but the key was to keep the solution moving, not just wet it and let it sit. Then rinse thoroughly and immediately. You're doing yourself no favors by letting the stuff dry on the part. Another product that I've had great results with is Kleen-Strip's "Concrete Prep n Etch". It's a phosphoric acid-based etchant for getting old concrete ready for over-coating. The product cost was to the best of my recollection, less than ten bucks for a 3-quart jug. It gave good results FOR ME, and before any further action was taken, I RINSED thoroughly with plain, hot water. You want to get ALL remaining product off the base metal, as it will keep on working as long as it's on the metal.

I must put a disclaimer here: Neither of the products mentioned above is labelled as an aluminum cleaner, my experiences may be different from yours, the whole of my intent is to relay my personal experience using different products for different applications. Should you decide to experiment with the above mentioned products in any way not specified on the label, you do so at your own risk, and without any endorsement by me whatsoever. See, that wasn't so bad, now was it

[Joe from NY]

Same problem here Tom. Nothing leaves the yard that comes in through the gates. It drives me crazy to see a huge pile of stainless steel I could use to build my ethanol plant but can't buy, beg, borrow or steel (pun intended).

Thurmond

It might be a local law issue. Over here, you need a "second hand dealer" license to resell things you purchased from people who walk in from the street, to other people who walk in from the street. My local scrap yards have such a license, because i can always walk around to see what i need. They are glad to sell it to me, as what they charge me is more than scrap value. If they could sell a whole dumpster of scrap to people at higher prices, they would love to do it. If they dont let you buy stuff there, they are either piss-poor businessmen, or dont have the correct license.

[Jason]

All the places I have gone around me wont give anything away. I think they make up the prices for each purchase made. I got some round bar one day and ended up short so the very next day I went to get some more and the rate had gone up over night.

[Spike]

Rather than messing with acids and chemicals and all the mess that goes with safety, cleanup, and disposal of hazmat chemicals... i just mechanically clean aluminum. I invested in a big variable speed buffer and just polish large oxidized or pitted aluminum areas. Where i'm going to weld i use a scotch brite pad on my angle grinder.
And then, i turn the 'clean width' way up on my welder and make a couple of quick passes over the weld area (no filler, and not at full heat) to bring contaminants up to the surface. If there's a lot of contaminants i will knock them off with the scuff pad again, but usually i don't have to. The little contaminants will float on the surface of the weld puddle. After welding, hit it with a stainless wire brush.

If you're going to weld a plate with lots of porosity, or contamination thats been absorbed into a porous aluminum casting (like aluminum engine parts) a good trick is to either set your welder to 100% clean width, or switch over to DCEP and run over the area you're working on with light heat. It will bring porosity and the contamination to the surface and you can knock it off with the scuff pad or wire wheel. I use this when working on vintage aluminum pieces like aluminum cast engine and motorcycle parts (even from back as far as the 1900's - 1920's).

[jakeru]

Regarding using low-current TIG torch cleaning: lately I haven't been bothering to move the AC Balance knob. It seems to work just as well, even with 20% EP (minimum cleaning setting) on my machine, and even with a Helium mix (the Helium content further reduces the cleaning action compared to pure argon.) It seems like the real "cleaning" action happens from heating the surface (without melting it, at least not excessively deep puddle.)

It's even OK if the surface melts slightly during cleaning (as if often does for me with 20% EN and a Helium mix), just as long as the puddle doesn't melt very deep, that works well. I like to see a smooth-frozen surface ideally after it freezes.

If there are any hydrocarbon contaminants in or on the surface, you don't want to just form a deep puddle because then, that it what causes porosity to be frozen down underneath the surface and it's not easy to "cure" once it's there. Heating the surface sufficiently often causes the hydrocarbon contaminants (e.g., water, oils, grease, etc) to vaporize. When I weld two sides of something, even when I find cleaning the "front side" is very helpful and important, I almost always find cleaning the "back side" accomplishes little because the heat from welding on the first side vaporizes the contaminants off the back side.

A lot of the above relates to weld-repairing cracked aluminum automotive wheels. Usually, some nasty contaminants are embedded down into the crack. Even welding new materials, some etching is useful to "test" the cleanliness of the metals that you think are clean, (before you really weld them.) I like to see no blackish or discolored looking deposits around the etched area. Whitish to grey etched area color is perfect - it means it's perfectly clean, and going to weld up beautifully with a glassy puddle (and look really nice too.)

[Wookie]

I'm a welding noob, so I don't know how nitric acid cleans aluminum, but when I worked for an electronics manufacturer we used to use it to burn holes in the cases of silicon chips so the wafers inside could be examined under a microscope.

Be CAREFUL with nitric acid. Do it outside with a fan blowing the fumes into your neighbor's place. If you smell it at all, you're doing permanent damage to your lungs.

nitric acid works well we use it at work to prep alum to be welded removes the oxide layer and cleans it

[fdcmiami]

nitric acid works well we use it at work to prep alum to be welded removes the oxide layer and cleans it

this is real easy if you let it be.

1. if the metal is really dirty just weld it the way it is.

2. if dirty aluminum is not going to work for you then order some new aluminum and weld it up.

3. or, spend all your time trying to devise a new way to make your welds look better without actually practicing the welding part.



the long fillet was done as a test after i had drained, cleaned and refilled my cooler; as well as cleaning the torch head and installing a new power cable.

there are two tie ins, i took the pic while testing my camera.

just checking for leaks basically. that aluminum has been in bin since 2008 and it was dirty when it went in.

[Wookie]

this is real easy if you let it be.

1. if the metal is really dirty just weld it the way it is.

2. if dirty aluminum is not going to work for you then order some new aluminum and weld it up.

3. or, spend all your time trying to devise a new way to make your welds look better without actually practicing the welding part.



the long fillet was done as a test after i had drained, cleaned and refilled my cooler; as well as cleaning the torch head and installing a new power cable.

there are two tie ins, i took the pic while testing my camera.

just checking for leaks basically. that aluminum has been in bin since 2008 and it was dirty when it went in.

that would not work for me at work with our WPS's and those are there for a reason Engineers make those for what we work on ..
sounds to me like you work at a hack shop... i hold numerous nuclear certs number 2 is a good idea but seriously you can clean it up with nitric acid with 10% hydrofluoric and be good to go

[fdcmiami]

yes, WW i am aware of your numerous nuclear certs since you never miss an opportunity to remind the reader of the fact that you possess them. in this case you might take a moment to read the posts on this thread. no nuclear welder's here just a group of poster's that believe that chemical alchemy is going to make their welds look better. the post and photos were for illustrative purposes only; you do not have to kill yourself with acids and cleaners to get a decent weld in place but you will have to take the time to practice welding. in most cases a ss brush and some acetone is all you'll ever need; if that. you are a little detached from the reality of working in non nuclear environments. perhaps a little time in a hack shop would suit you well. WPS? don't make me laugh.

[Cippee]

If your going to be welding something with a wps then I'm guessing it isn't going to be old or oxidized. Maybe some repairs might be. I always use a light duty wizz wheel and acetone it cleans the metal looking brand new. Not a wire wheel but the roll lock pads or flap wheel. It works great for me. As long as the pad is not contaminated and you use a stainless steel brush after it looks like new metal. I've never been a big fan of chemicals ever since I got some aluminum cleaner in a cut one day. I thought my finger was going to fall off. It felt like it was going to burn through to the other side of my finger.