Is TSP/90 as Good as TSP for Anodizing?

December 13, 2010
TSP90
TSP 

James asked, “Will the TSP/90 Phosphate Free products work as well as the standard TSP brands?”

An excellent question. My first impulse is, “I doubt it.” But I am not sure. The folks at ReactiveMetals.com might have some insight (that I would share here if passed along).

TSP/90 is made with Sodium metasilicate and pentahydrate. So it is an alkali electrolyte with plenty of oxygen carriers in it. So far, so good. But as a cleanser it appears to suffer from leaving behind a film; a bad sign.

If you are concerned about the potential harm of artificial phosphates in the environment, anodizing is not a significant supply. I have been using the same 8 oz. box of actual TSP for the last dozen years. That’s equivalent to a few weeks of laundry. The same batch of electrolyte can keep on going for months, by adding distilled water (the part that is used up) and an occasional pinch of TSP crystals (to keep up the concentration from the drops removed by pulling out pieces). Occasionally, I filter out the dust and bring it to a boil to make sure it stays sterile.

If you want to be even more environmentally correct, use ammonium phosphate (lawn fertilizer) and then dispose of your old electrolyte by spraying it on your lawn. I used a box of this through the 1980’s and 1990’s.

One of these days, I’ll probably expound why the lingering phosphate meme of the 1970’s was somewhat misguided in the first place.

Advertisements

Titanium Grinding vs. Tumbling

May 1, 2008

Harbor Freight bench shear

I’ve tried a few different methods over the the years to reduce my hands-on time in getting rid of those razor-sharp fresh-cut titanium edges. I started doing this with essentially no tools or money to buy any. I first bought tin snips, and then a small bench shear something like the one pictured.

Polishing MotorThe merciless edges on fresh cut titanium encouraged me to buy leather gloves. To remove those edges, I first used emery paper (wet/dry sand paper) to smooth them. But the tedium soon urged me to learn that a motor, a couple of taper spindles, and Cratex wheels (rubberized carbide) were much faster and spit few sparks. I put my grinder/polisher together from a salvaged ΒΌ horse motor and parts from a mail-order catalog (this was around 1980). Now there is website: www.RioGrande.com and you can get everything there. But grinding small parts ended up using up finger tips; both gloves and my own.

Harbor Freight Cheap Rock TumblerOn a whim, I tried out my childhood rock tumbler. I just cut up a bunch of pieces, and threw them in with some rocks, and let them go for a week, then three weeks. There was some rounding of the sharp edges, but not much nor fast. I then ordered abrasive ceramic media from RioGrande, and tried that in place of the rocks. After a couple of weeks, nice, smooth edges. The ceramic media lasts for many uses (I have yet to reorder). You can also get it cheaply from HarborFreight, here or at your local Harbor Freight shop. You can also try rock shops, craft stores, or online.

Lightweight vibratory cleaner/polisherBut, c’mon! Weeks? So (many years later) I went to eBay to find a vibratory polisher. I wasn’t ready to spend $500 on a name-brand one at RioGrande. So I found one specified to clean shotgun shell casings for about $60 delivered. It has a clear top, so I could watch the pieces and media do their thing. It reduced the time to about 4 days. I ran it with a dry load, with no water or agents. Amusingly, the dust that grinds off from the media is hydophobic! Water runs right off of it, like mercury on glass. I found that adding tap water at the end and vibrating for another hour suspended the dust in the water and didn’t darken the titanium too much. Anyway, I etch after I tumble.

But I never did manage to get a shine with this machine. I tried ceramic media and porcelain media, I used polishing compounds, ran it wet, ran it dry, and still my best was a matte finish. My worst was that the titanium turns almost black in water with porcelain.

Harbor Freight Vibratory PolisherSo I thought I’d try another type of vibrator. I got it from eBay, and then found that I could have driven across town to HarborFreight and gotten the exact same unit for about $25 less. I first tried running it wet with porcelain. Blackish titanium, eww. I etched the titanium clean, and then tried dry with ceramic media: Shine! Trumpets and doves and a beam of light from above. The gray ceramic media turned dark and shiny in 24 hours, as the titanium deburred and gleamed.

Had this not worked, I would have finally bought a professional (expensive) circulating fluid vibrator assembly (Raytech). But I’ll hold off on those.


Hypoallergenic: Titanium versus Niobium

April 2, 2008

There is a bit of confusion about which of these metals is safer for sensitive ears, or wherever. Niobium is generally available only in a chemically pure form, whereas titanium is available both pure and in a bewildering list of alloys (such as many surgical implant grades).

I list a few of the more popular grades and designations of titanium here. Most of them are hypoallergenic. Most of the jewelry that I sell is pure grade #1 or #2 titanium. Some of my ball posts are an alloy, medical implant certified, and with no detectable trace of dreaded nickel.

The etching and anodizing process strip the few percent of non-titanium elements from the surface, and then create a protective shield of titanium dioxide.

Chemically speaking, titanium is less likely to be absorbed by biological systems than niobium. Neither should cause an immune response or allergic reaction.

But when it comes to piercings, part of the issue is abrasion. Titanium is a hard metal that could have a slightly rough surface on the microscopic scale. The act of putting it in might abrade a tight hole.

Niobium is a softer metal, so the surface will yield more to pressure. This might make it better for extremely sensitive skin. The same softness is why the initially brighter colors of niobium don’t last as long as titanium colors.

Whereas I am distinctly a titanium partisan, my colleague at Wear-Earrings-Again.com prefers niobium, from her personal experience.

When in doubt, try both. If both work, then choose only by price, color and design.


How can I build an anodizer for UK Current?

March 22, 2008

Another reader question:

I am thinking of making an anodizer based on your anodizer digram. I live in the UK but was thinking that the volts for your electricity is different from the UK’s 240 volts?
If so do you know any diagrams that can help me with this, what I need to change?
My first thought is: In the UK, you can use the same Variac circuit. I wouldn’t trust the dimmer circuit because of the instability at lower voltages.
The U.S. uses 110 vac (150 volt peak), so we use about 3/4 of the range of the variable transformer (less if it is wired to provide over-voltage).
In the U.K, you would just just use 3/8 or even half of the available range.

If you really want to use the inferior dimmer-switch design, you can probably find a simple step-down transformer to cut your voltage in half upstream of the rest of the circuit.

Then came a follow-up:

Thank you for your reply; it was a big help. I am going to be doing the variable transformer one. I have been looking for stuff, but wow its hard to find anything that is needed.

I didn’t like the idea of using light bulbs, so I wanted to get Power resistor 200w 100 ohm but no one sells them, any idea of other Power resistors that I could use?

Try eBay.

I found several by a simple search for 200 watt resistors on eBay. You could vary the search for whatever power and resistance values you want, or use a search to find a good seller, and then ask them if they have what you need.

There are also a wide variety of variable transformers on eBay. But these heavy items cost more to ship, especially internationally.

Before the internet, I always shopped an electronics salvage store in my county. Many cities have at least one of those. Some junk yards and metal salvage yards also have a room full of gizmos that seem too nice to melt down. Call around.

Note: If you are not comfortable rewiring a lamp or replacing an electrical outlet, then you are probably not qualified to build your own anodizer. Buy a read-made regulated 0-150 vdc power supply.


Getting started in anodizing: Mesh?

March 18, 2008

Here is a typical question that I get asked:

I would like your advice: Besides the plastic container, what else do I need to anodize titanium grade 23 or grade 5. I called Reactive Metals to buy the machine for $206 , they told me to buy a mesh but I do not know what or where to buy it. I am a little scared of getting hurt if I do not know how it really works.

Any help will be really appreciated.

Peter

The question seems to be, what is needed to get started. Peter has already bought an anodizer, a 0-150vdc voltage supply.

The “mesh” might be one of three things.

  • A large-area cathode (negative pole immersed contact) could be a mesh of titanium or even stainless steel. I use a coil of wire for this, but a plate of metal does fine. Ideally, you want to have a non-conductive porous material ( maybe a plastic mesh) between the cathode and the work piece, in case of contact. Rubber non-skid shelf liner mesh/screen is cheap and good for this.
  • A mesh basket made of niobium wire makes a good anode connection for loose parts. A titanium wire basket will work, too. Just not quite as reliable at higher voltages.
    Note: I haven’t tried this myself. I use a homemade titanium clip and the niobium clips that ReactiveMetals sells.
  • A plastic mesh basket such as a salvaged automotive windshield washer fluid filter can also be used on the anode side by running a niobium or titanium wire into the basket full of little parts.
    Note: I haven’t tried this myself, but have heard of it being used by others.

One can easily weave your own basket from titanium or niobium wire.

One important final note: If you are afraid of getting hurt, please do some more reading about electricity and safety precautions. Wear rubber gloves, and always double check where all the live contacts are when you are working. Read my old anodizing page over until you understand everything in it. It may not be complete, so do ask questions to help me fill it out.