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Swede
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Exposed Ti is not a problem with a decent quality MMO mesh.
As for cutting, the best I've found is a metal-cutting bandsaw, or a wood cutting bandsaw if you can find a really fine toothed blade. The next
choice will be a jig saw, again with as fine a toothed blade as you can install. An angle grinder will definitely work, but watch out for excess
heat, and wear a dust mask.
After cutting, it will be burred, and a benchtop sander is handy to clean it up.
One last way to possibly cut it is with powerful aviation shears, or maybe potent wire cutters, working each of the mesh components individually.
It'd be slow but decently clean.
For welding, it can be welded, but the only form of welding I've tried other than spot welding is TIG. To do a good TIG weld requires a respectable
machine that can hold an arc at a low current. My very first anodes I TIG welded, and they did warp a bit from the heat. Not pretty, but functional.
Try to protect the surrounding areas and back of the weld with argon as much as possible, and I'd definitely scrape the MMO at the weld spots, and
wear a fume mask.
You can use Ti wire as fill, or possibly a section of the MMO mesh taken apart and stripped of MMO with a sand blaster or similar. Or use tin shears
to cut a really fine strip of Ti from a piece of Ti sheet. Ti welds much like stainless steel. It's hard to make aerospace quality welds, but very
easy to join just for mechanical connection and current flow.
Given the cost of the laserred mesh, I've always thought you could cut the anode AND SHANK from the same piece of material... no welding required.
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dann2
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Hello,
"...........At the other end, install a plastic plug inside the tube,............."
Just wondering would this leak if the plug is not a perfect fit and allow salts to slowly creep up the inside of the tube to your connection. Perhaps
pouring some resin (or something that will set) into the tube would do instead if you do not have a piece of plastic dowl of the exact correct
diameter.
The compression fittings are a nice professional touch.
You could put a large amount of spot welds on the flattened tube (effectively a continous weld) end and perhaps that would seal it instead of plastic
plug.
I often wondered would a few Ti bolts do instead of the welds to connect the Anode to the Anode shank? Would the junction between the Anode and the
shank form an Oxide coating that would stop current flowing? Ti bolts can be had on ebay.
Might suit those who do not have a spot welder.
Dann2
[Edited on 5-9-2009 by dann2]
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watson.fawkes
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Quote: Originally posted by dann2  | | I often wondered would a few Ti bolts do instead of the welds to connect the Anode to the Anode shank? Would the junction between the Anode and the
shank form an Oxide coating that would stop current flowing? |
Basically no, for the exact reason you mention.
The more complicated answer is that it would work if you had geometry at the point of contact that made an oxygen-excluding contact, such as a
specially toothed washer that pierced both conductors. The high pressure formed by the combination of a piercing point and a bolted connection can be
sufficient to exclude oxygen. The problem with just a bolt is that the pressure at all the points of contact just isn't high enough.
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12AX7
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I bolted copper to titanium anodes. The copper corroded and the bolts rusted but it kept on dumping amperes just fine.
Tim
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watson.fawkes
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| Quote: Originally posted by 12AX7 | | I bolted copper to titanium anodes. The copper corroded and the bolts rusted but it kept on dumping amperes just fine. |
I still worry about long-term function, but I doubt that matters, since you can just recondition the contact faces if they fail.
Your note points out to me that my comments are specifically for the "never think about again" scenario, which may be overengineering for a
hobbyist-level apparatus.
All said, I still prefer welding.
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dann2
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Hello,
Welding is definately the best job. It is probably the only way to do the job properly.
When you say that you "bolted Copper to Ti Anodes" I presume you meant it was all above solution surface (obviously). When you go under, things get
difficult and the Ti passivation (at contact point) now makes the whole idea unworkable.
When joined by a bolt (under the solution surface) the Anode shank at the point of contact is an Anodic surface (bare Ti remember) where you DO NOT
want it to be Anodic. The MMO, at the point of contact with the shank is a Cathodic surface.
My own opinion is that the Ti shank will passivate at the point of contact BUT perhaps it will not? I would be inclined to put my money on the fact
that it will but not my bottom Dollar. You could seal the joint but this would be very difficult to do and you would be back to square one messing
with sealents etc which never seem to work medium to long term anyways.
Dann2
[Edited on 5-9-2009 by dann2]
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Swede
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If the question is, bare Ti in solution on the anode side, I have never had the slightest problem. All of my fabricated anodes have a bare Ti strap
at the weld spot, and the worst they suffer is a bit of unidentified white smut. They do seem to passivate effectively. I am not 100% sure that
commercially pure is required. The alloys might be fine. But the Ti alloys are much harder to work than the pure stuff, and I suspect the tendency
of the alloys to crack will be much higher.
Commercially, sheet MMO is cut and installed into pool chlorinators and the like without recoating the cut edge, and the electrical contact leading to
the cut sheet is plain Ti. So if they do it commercially, I think we're OK, and observations confirm this.
I definitely over-engineer, but I also try to think of ways that improvements can be done when tools like lathes and spot welders are not available.
I chose the plastic plug because for me it would be easier, but some sort of poured resin would be satisfactory. My gut feel is that the flattened
end of the tube, once welded, is not going to allow much trespass of liquor, but it has a tendency to find its way into the tube regardless, so I'm
thinking you may as well drill a pair of 1/16" or so drain holes in the shank so that you won't have trapped liquor for weeks while the anode is in
storage.
One method to make a mechanical connection that might work would be a pair of Ti bolts, a strap, another small sections of moderately thick Ti sheet,
and you form a clamp-sandwich with the MMO between the strap and the other Ti piece. Drill through all 3 layers, and torque the bolts down to 90% of
yield. I think you'd get enough deformation of the mesh and the Ti sheet to form multiple contact points that should exclude liquor or oxygen.
Everything would need to be abrasively cleaned and degreased just before assembly to strip the oxide layer. It might work, but the torque required
would need to be very high, I think.
Even small towns have professional weld shops. I'll almost guarantee you could find a guy who will weld 2 or 3 anodes/cathodes for you over a lunch
break for little money. Professional TIG welders are wizards with their tools. I've seen a guy TIG weld two razor blades at 90 degrees, and another
weld two beer cans together.
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Swede
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I am about 1/2 done on a "How To" document on the basic chlorate process for the amateur. It is at 45 pages now and will include much info from here
and dann2's site - not copied verbatim but simply incorporated into the doc in my own words and within my own experience. When it is done, I'll
convert it to PDF and hopefully some guys will find it useful.
I did some additional experimentation with the n-phenylanthranilic acid (NPAA) chlorate detection test. Of all the things I've done within this
discipline, I think I am proudest of this simple test, a 2-dropper bottle cold test for the presence of chlorate contamination within perchlorate.
The original test called for NPAA (a grey powder with the texture of corn starch) dissolved in sulfuric acid. The improved test was 3% tincture of
NPAA in 99% isopropanol, and a separate dropper bottle of concentrated sulfuric to acidify the precipitate and develop the purple color. It turned
out to be reliable and easy to do.
For the new test, I tried methanol and ethanol as carriers of the NPAA, and at lower concentrations, and other acids besides sulfuric. The best
combination was 2% NPAA in methanol, and plain HCl to develop color. HCl is superior to sulfuric in that it is easier to obtain, and colorless,
whereas crude sulfuric often is dark and also more dangerous to handle.
To test, a pinhead (less sample is better) of the sample is placed in a test tube, 2 drops of water added, and swirled. 3 drops of the NPAA tincture
is added. A grey/white precipitate forms. Concentrated HCl is added dropwise, and 5 to 10 drops will strongly acidify and bring out an unmistakable
purple color when chlorate is present. 3 drops of the 2% tincture will detect 0.03 grams per liter chlorate; 6 drops will detect 0.01 g/L chlorate,
or 10 PPM. More NPAA makes a more sensitive test, but for everyday use, 3 drops is adequate.
ANY purple color indicates the presence of chlorate. A good quality commercial perchlorate sample will have no color, and remain white or possibly a
very slight gray coloration. If you can find a source of NPAA, 10 grams will last a lifetime and should cost no more than $10 or so. It's not an
expensive chemical, simply hard to source. Polyethylene dropper bottles are great to make a test kit, or you can simply use a pair of traditional
amber glass bottles with dropper caps.
I cannot imagine 10 PPM chlorate causing problems with a batch of perchlorate in terms of pyrotechnic sensitivity. If you clean your perc with SO2
gas and it tests clean, use it with confidence.
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dann2
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Hello Swede,
Looking forward to reading the doc.
I have still not gotten around to some the Lead Dioxide stuff put I am getting there. Intend to make a good Anode.
I think the notion that LD will stand up to a non-pH controlled cell all the way from Chloride to Chlorate to Perchlorate is a bit of a pipe dream.
The pH probably needs to be contolled to keep erosion at a sensible level.
Or probable better to keep the precious LD (all the trouble of making) for Perchlorate making only.
Then there's always the Tin Oxide + Bismuth Anode to be checked out.
Dann2
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Crest21
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The disadvantage of the "Salchlor" anode is the length; at 12 inches long, it is hard to find suitable containers that can accomodate the whole
electrode. In retrospect, I think it would have been better to go with the "Autochlor" AC-20 or AC-25 chlorinator cell assembly.
Regards
Crest
_____
dossier surendettement
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Swede
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dann2, I am definitely reserving any likely LD anodes created for chlorate --> perchlorate only. I have committed myself to potassium, which
forces a two-step process (Cl to chlorate, harvest/clean, chlorate to perchlorate) due to the crappy solubilities.
I am communicating with a very knowledgeable guy on APC who is going to attempt a one-pass system - a KCl reservoir will feed a small, possibly
insulated electrode cell (similar to what I tried except mine recirculated), which will in turn feed a chilled crystallization/collection chamber.
I thought about the math behind this concept. A typical KCl starting liquor will be 14% chloride ion, or 4 moles of chloride. Most guys will
terminate a run at around 8%, or 2.25 moles chloride, thus converting 1.75 moles of chloride to chlorate. At 161 Ah per mole, to convert a liter
would require 282 Ah.
Let's say your electrode chamber can run at 60 amperes. Therefore, a flow rate of 60/282 = 0.21 liters per hour (assuming 100% efficiency, bulk
conversion) should have the effluent at 8% chloride. Upon chilling, the xtals would rain out in the collection vat.
If we assume 60% efficiency, then the flow rate drops to 0.128 liters per hour, of 128 ml/hour. A peristaltic pump could do this easily. It is an
interesting thought and something that I have never attempted. At such a low flow, heating could be a real problem. Inevitably, too, you would have
some xtallization inside the EC despite the high temps, so jamming of the EC with xtals might be another problem.
The effluent port would need to be placed above the electrodes, be wide-bored, and well-insulated to prevent premature crystallization. The fumes
from the collection vat would need to be properly vented, or the room would become uninhabitable.
Overall, there are technical issues to work out, but it would be very interesting to give such a device a try. The enormous advantage would be the
fact that you could have a 100 gallon KCl reservoir, power the system on, collect chlorate as needed, then power off.
[Edited on 5-10-2009 by Swede]
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hissingnoise
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| Quote: Originally posted by Swede | | I have committed myself to potassium, which forces a two-step process (Cl to chlorate, harvest/clean, chlorate to perchlorate) due to the crappy
solubilities. |
Why not NaCl Swede? It has advantages over KCl besides better solubility. . .
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Swede
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| Quote: Originally posted by hissingnoise | | Quote: Originally posted by Swede | | I have committed myself to potassium, which forces a two-step process (Cl to chlorate, harvest/clean, chlorate to perchlorate) due to the crappy
solubilities. |
Why not NaCl Swede? It has advantages over KCl besides better solubility. . .
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You know, I have never adequately answered this question beyond a sort of lame "no worries about Na contamination for pyrotechnic use." I started
with it because it is easy to separate and clean the potassium products due to decreasing solubility, and made up for the solubility issue with raw
cell volume.
Straight K does make recycling easier. Wash water and used liquor is good to go after recharging with chloride, while executing a conversion is going
to leave a hash of potassium and sodium ions behind.
But the reality is, I have no good answer beyond that I am comfortable with it.
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hissingnoise
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Each to his own, I guess. . .
With K though, you could have a situation where the oxidised salts precipitate onto your electrodes, adhering in large crystals, with a potential to
damage your hard-won LD anode. . .
IIRC, sodium seemed to be less erosive than K on graphite.
And I never had a noticeable problem with Na contamination.
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astroturf
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swede wrote:
| Quote: |
I had a PM from a nice guy in Australia who had his eBay MMO cut with a cutoff disk, and he said they now have a POTENT smell that gave him a
headache. I found this to be really odd. Any theories?
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that nice guy is me!!! Thanks swede 
The smell went away after about 2 weeks. I think the smell was due to the anodes being cut with the abrasive wheel probably immediately before being
put into the bag for postage. I could cut a bit of anode to test this.
Since then I have cleaned a piece in HCl and used about 6" submerged in a KCl cell at 30A with a PC power supply. It works well.
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Swede
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Hi Astroturf! Good to hear from you!
I have been haunting eBay, and the Laserred material is apparently gone - or, he is sitting on a hoard, and waiting a bit to let the market
"recharcge." For those that have some, I would really recommend cleaning by soaking in concentrated HCl for maybe 15 minutes. There is definitely
some sort of smut on there that turns the HCl bright yellow, and while I have no idea what it is, the potential for toxicity certainly exists.
What metal ions would dissolve in HCl creating a bright yellow coloration? Any ideas?
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tentacles
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There has recently been some discussion on the passfire board, reminiscing about the somewhat legendary Swedish perchlorate. It is known to be the
absolute best perchlorate in pyrotechnic compositions - particle size shape and distrubution just perfect. At any rate, someone mentioned a typical
1992 assay:
99.8 % KClO4
0.03 % KClO3
0.01 % KCl
Insolubles less than 0,01 %
Moisture less than 0,02 %
Neutral pH
Particle distribution: 100 % passing 140 mesh, 65 % passing 230 mesh and 45 % passing 325 mesh.
It is purely anecdotal, but clearly swede's under 10ppm would be very suitable for pyrotechnic use. Here's something a LOT less anecdotal:
Barium and Chemicals and Hummel both distribute military spec. product and that potassium perchlorate spec. hasn't changed since at least Sept. 1962
and perhaps the early 1940s: It's not a hard spec to meet; purity of only 99.0% and 0.1% KClO3, -0-% hypochlorites with easily met particle size
standards:
http://www.tpub.com/content/MIL-SPEC/MIL-P/MIL-P-217A/
Swede, there has been some comparison testing between the various brands of perc, it might be interesting to send Dan C a sample of yours to add to
the test as an example.
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Sedit
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| Quote: | | What metal ions would dissolve in HCl creating a bright yellow coloration? Any ideas? |
When I dissolve rust in HCl it creates a bright yellow solution. It turns greenish as it gets more concentrated. Possibly some form of iron oxide
contamination.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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Swede
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Sedit - I think you nailed it. The smut on this MMO is definitely brown, and pretty tenacious except when immersed in HCl, whereby it comes right
off, leaving clean MMO behind. It's good to know it's probably iron and not something nasty like cadmium, lead, or chromium.
Tentacles - Awesome information! The "official" permissible amount of chlorate was always something I wondered about. 0.03% chlorate is LOW. The
Hummel figure of 0.1% to me seems more typical of what you'd find in a bulk, industrial process, and my own limited intuition says that 0.1% chlorate
is safe; the product can be considered perchlorate for pyrotechnic purposes.
That mil-spec page also has some excellent info.
I would love to have some of my perchlorate analyzed... and would gladly pay a reasonable price to have it done. Is Dan C. on Passfire? Does he have
access to analytical equipment?
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tentacles
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Not much of an analysis; more empirical testing. He's done a series of tests comparing various perchlorates in whistle rockets. Remarkable how much
difference there is. He's only done some preliminary testing so far, but I think he was planning on getting into it more this winter. It's Dan Creagan
on passfire.
http://www.wichitabuggywhip.com/fireworks/rockets/preliminar...
Have you thought of checking with a uni lab dept, maybe some students would be gung ho to do some testing? If not, a prof may be able to hook you up.
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Swede
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I'll look into it. I'll bet there are companies or universities that would do it at a decent cost.
On the tubular electrode shank concept - one thing that concerned me was heating. At 60+ amps, pure Ti heats pretty badly at typical cross sections
of 25 mm^2. A 1/2" dia (12mm) OD Ti tube with an average wall has a similar x-section, and will heat up in much the same manner, with the tubular
section being more difficult to affix to a heat sink vs. a strap, making it more difficult, and with the very real possibility that the Ti tube will
melt or deform the compression fitting that carries it.
I had a thought, and perhaps a solution. #2 or #4 Cu welding cable has an OD, when stripped of its jacket, such that the Cu bundle can be inserted
into the tubing to carry the current. With the bottom flattened and welded shut, similar to this picture:
It should be leakproof. From the top, open end, insert the Cu bundle with some force, creating a chisel-shaped deformation at the bottom where the Cu
is near the anode. Now, you cap the Ti tube with brass, bronze, or Ti, and the Cu bundle is internally filling the hollow void, with vigorous contact
on the walls and cap. You have instantly created a Ti tubular shank capable of carrying a couple hundred amps with little heating. 
Of course, the Cu will be 100% protected. Another option - use Cu round bar as an insert for 90% of the length of the Ti tube. At the bottom, fill
it with stripped Cu cable, or even jam in some Cu or bronze wool, very tightly. You'd get the same effect. Think of the Ti tube as simply an
insulator jacket for the Cu, rather than as a primary means to carry current.
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watson.fawkes
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| Quote: Originally posted by Swede | | Another option - use Cu round bar as an insert for 90% of the length of the Ti tube. At the bottom, fill it with stripped Cu cable, or even jam in
some Cu or bronze wool, very tightly. |
Why not just braze the copper rod in at the bottom? Not difficult,
although it might require a special flux to strip oxides off titanium.
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dann2
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Another option might be to jam in some pieces of Copper at the bottom of the tube and fill up with melted Lead or melted solder.
About the yellow color in HCl. The yellow color that is sometimes in hardware store HCl is Iron contamination (I have read).
Dann2
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patsroom
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Hello to everyone, I was invited by one of your members to this site as I have some (hopefully) some exciting news. I found a company that will sell
to me Lead Dixoide Anodes at a size that will be useable in the home lab. If all goes well with this deal I am making I could get them out to the
those how are interested in having one. But I do need to know if there is a strong interest in abtaining them from those that are willing to buy one.
The following I place on another web site as to try and get a response.
I have been in talks with a company that is welling to sale me Lead Dixoide Anodes. The New Price that they well be to buy one is $135.00 USD plus
shipping and handling for type A anode and for type B the asking price is $105.00 USD plus shipping and handling. I would still have to buy a minium
of 20 of them at a time. This is for the first order as they wish for the samples to be seen. I do not known if they would increase the price after
but I would think not (I hope not).
I need the help of all of the members here to see what you think about this, please reply good or bad so I can decide if I should buy 20 or more.
My feeling is that the price is now so much better (than the price for Pt. coated Ti. at $80.00 to $90.00 for a .5" x 4" with a 3" hanging strap). And
theses lead dixoide anodes well do everything that we could want from chlorides to pre-chlorates of the salts.
I know that there is a thread within this forum that deals in the sale of pyro items, but as you can see this is not items for sale at this time. This
is a request for replies to see if this is a deal that everybody would be interested in. Like I said earlier I just think that this is a great buy and
the price is now so much better than their first go around.
There is not much more I can add with out Beating a Dead Horse on this one. Just one more kick at the horse I just can't help it- This would be a
great deal I know it would be.
This was my first offer recieved, But I found the price way to high. Then I got the next offer and felt that it was a price I could work with. I hope
to get a PDF in here as well to shown the size.
XXXXXXXX-XXXXXXXX-XXXXXXX
Titanium Products and Equipment Manufacturing Co.,Ltd Price list
Date of offer: October 24, 2009
Item :Lead dioxide coated Titanium Anode
Client name: Patrick
Email:
Address:
Item 1
Type A anode
Cost of material
36USD/piece
Cost of coating
152USD/piece
Unit price
36USD+152USD=188USD/piece
Quantity
20pcs
Total value
188USDX20=3,760USD
Item 2
Type B anode
Cost of material
28USD/piece
Cost of coating
131USD/piece
Unit price
28USD+131USD=159USD/piece
Quantity
20pcs
Total value
159USDX20=3,180USD
Remarks:
Quotation mode
CIF Oregon (Door to door)
Validity of offer
Within 20 days
Minimum of order
20pcs for each item
Coating contents
Lead dioxide(PbO2)
Thickness of PbO2
1.5mm
Lifespan of anode
=2.5 years
Delivery time
Within 3 weeks against Copy of Remittance
Packing
Export Standard Wooden case
Terms of payment
By T/T, 100% payment in advance against Proforma Invoice
XXXXXX-XXXXXXX-XXXXXXX
XXXXXXXX Products and Equipment
Manufacturing Co.,Ltd
Contact person: (Sales Manager)
Tel: 0086+512+6665 XXXX
Fax:0086+512+6536 XXXX
Mobile:0086+151 9568-XXXX(24hour)
Web:
www
Mail
Sorry about blank out the contact infor. I just don't want to sour the cream.
So the price will be $135.00 USD plus shipping and Handling to your door for the large one and $105.00 USD plus shipping and handling for the smaller
one. I would love to hear what others are thinking.
I Than all of you if you manage to read this far and I hope to hear from those how would like me to finish the deal........Pat
Attachment: Drawing PDF Anode.pdf (11kB)
This file has been downloaded 611 times
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Swede
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| Quote: Originally posted by dann2 |
Another option might be to jam in some pieces of Copper at the bottom of the tube and fill up with melted Lead or melted solder.
About the yellow color in HCl. The yellow color that is sometimes in hardware store HCl is Iron contamination (I have read).
Dann2
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Dann2, after much thought on tubular anodes, I think your idea is best. Create a hard Pb alloy, plenty of antimony and/or tin, fill the tube (after
crimping and welding at the bottom) with the molten alloy, and after cooling, drill and tap the end for whatever bolt you'd like, preferably a coarse
pitch. 1/4" X 20 would be excellent to hold the power lugs.
This does three things: It solves the power cable attachment problem, the Pb carries the bulk of the current rather than the Ti, and it does away
with any specialty tools like a lathe. All you need is a drill and a tap.
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