Lawaranceville E-Newsletter

[Joseph Chikva]

Thanks Joseph. I've posted it on the focusfusion.org forum.

Don't mention it.
Good luck.

[Giorgio]

For etching of deposited copper I can propose the following (sorry for Google translation from Russian):

If they really intend to etch the copper deposit there is no need for all of this complicated procedures. Is enough for them to go out and purchase a bottle of ammonium persulfate or ferric chloride (your recipe n.5) from any hobby shop.

[Giorgio]

PS: How you can provide vacuum tight (hermetic) joint between glass window and vacuum chamber? As I have no idea without elastomers.

You can avoid using elastomers by using gaskets done by metal Indium wire that are feasible for vacuum until 10-8 Torr between a glass surface and the vacuum chamber.
They can also withstand baking temperatures until 150C if needed (melting point is 156.6C).

[Joseph Chikva]

If they really intend to etch the copper deposit...

If?

Second, copper eroded from the anode gets deposited on our glass viewing windows. We can take these out easily enough but what is good to clean the copper off the glass that won’t scratch or harm the glass or the surrounding steel?

You can avoid using elastomers by using gaskets done by metal Indium wire that are feasible for vacuum until 10-8 Torr between a glass surface and the vacuum chamber.
They can also withstand baking temperatures until 150C if needed (melting point is 156.6C).

Thanks, I knew about indium sealing for low temperatures but did not hear about its possibility to be used for up to 150C).
But what advantage would have Indium vs. elstomer when seal works close to melting point? http://www.2spi.com/catalog/vac/vacleak.shtml Atom number of indium and carbon or/and silicium? Doubtful 150C vs. real 450C? Chemical inertness of metal vs. silicon elastomer? Especially when you propose discharge in O2 media (in which O2 dissociates into more active O)

So, I like more Dan's idea of labyrinth sealing - to design glass-metal interface in such a manner that minimizes but not zeroing its degradation and further vaporization into reactor cavity.

But designing ways when there are restrictions on high voltage for plastic insulator are very limited. Surely in any case insulator will directly be contacted with ionized gas. And I am sure that insulator should not be made from plastic/elastomer.

[Giorgio]

If they really intend to etch the copper deposit...

If?

I highly doubt that the copper residue on the windows are "fused" with the glass as to need etching for a complete removal.
That's why I used the IF.

Second, copper eroded from the anode gets deposited on our glass viewing windows. We can take these out easily enough but what is good to clean the copper off the glass that won’t scratch or harm the glass or the surrounding steel?

That is exactly my point, and I suggested before that to remove them you can also use a stainless steel pad with no sharp edge. This will remove impurities from glass and metal without scratching them.
http://www.opticsplanet.net/bel-art-cle ... 50000.html

Thanks, I knew about indium sealing for low temperatures but did not hear about its possibility to be used for up to 150C).
But what advantage would have Indium vs. elstomer when seal works close to melting point? http://www.2spi.com/catalog/vac/vacleak.shtml Atom number of indium and carbon or/and silicium? Doubtful 150C vs. real 450C?

To answer your questions we should know the exact working parameters of the FF experiments. I doubt that they reach high temperatures inside the reactor but this is a question that only FF people can reply.

Chemical inertness of metal vs. silicon elastomer? Especially when you propose discharge in O2 media (in which O2 dissociates into more active O)

I never proposed O2 discharge as cleaning method. I am suggesting Ar discharge.

So, I like more Dan's idea of labyrinth sealing.

Labirint sealing is an interesting option but requires machining of the surfaces that might be too costly. In the end the best solution will depend on the real need and the working conditions of the experiment.

I think that FF people have now a complete set of ideas from where they can choose the most effective solution for them.

[Joseph Chikva]

If they really intend to etch the copper deposit...

If?

I highly doubt that the copper residue on the windows are "fused" with the glass as to need etching for a complete removal.
That's why I used the IF.

Really? And from where did that copper appear if not "fused"?
Focus Fusion device is very simple: copper electrod/electrods in the center, insulator and stainless steel chamber. Between first and last discharge occurs powered by capacitor bank.
That's all.

I remember that you did not propose to use pure O2 but proposed glow discharge of mix Ar+O2. And for what that O2 intends? Not for oxidizing of impurities? What that will do with plastic?

"Expencive" machining?
Restrictedly you can protect the elastomeric gasket of window welding from the inside the stepped ring on perimeter. But it is necessarily to leave the backlash (gap). And so, gasket in any case will touch hot gas.

[Giorgio]

Really? And from where did that copper appear if not "fused"?

The fact that impurities of copper are present because the copper electrodes melt during discharge does not imply that it will than FUSES WITH the glass.
The two are very different phenomena.

I remember that you did not propose to use pure O2 but proposed glow discharge of mix Ar+O2. And for what that O2 intends? Not for oxidizing of impurities? What that will do with plastic?

Again no.
I proposed Ar only, and I wrote that:

I have heard that lately Ar-O2 mixtures glow discharge are giving quite interesting results, but I do not know enough to offer an advice on this.

See, I already stated that I do not know enough about Ar-O2 mixtures to offer an advice, so I can't reply to your doubts. Maybe some else will.

But really, please try to put some effort in understanding one's post before replying.

[Joseph Chikva]

Really? And from where did that copper appear if not "fused"?

The fact that impurities of copper are present because the copper electrodes melt during discharge does not imply that it will than FUSES WITH the glass.
The two are very different phenomena.

I remember that you did not propose to use pure O2 but proposed glow discharge of mix Ar+O2. And for what that O2 intends? Not for oxidizing of impurities? What that will do with plastic?

Again no.
I proposed Ar only, and I wrote that:

I have heard that lately Ar-O2 mixtures glow discharge are giving quite interesting results, but I do not know enough to offer an advice on this.

See, I already stated that I do not know enough about Ar-O2 mixtures to offer an advice, so I can't reply to your doubts. Maybe some else will.

But really, please try to put some effort in understanding one's post before replying.

The fact in that they need clearing glass from copper.
The second fact is that copper electrodes are subject of frequent replacement. From where does copper appear on the glass?
Excuse for O2 if I have misunderstood something.
Good luck. Thanks for discussion.

[Giorgio]

The fact in that they need clearing glass from copper.
The second fact is that copper electrodes are subject of frequent replacement. From where does copper appear on the glass?

The need of cleaning copper from the glass does not imply that the copper is fused to the glass as to need etching to be removed.
Etching is really an overkill if a cleaning pad can make the work.
Anyhow, FF people have all the elements to choose the correct solutions now.

[Joseph Chikva]

The fact in that they need clearing glass from copper.
The second fact is that copper electrodes are subject of frequent replacement. From where does copper appear on the glass?

The need of cleaning copper from the glass does not imply that the copper is fused to the glass as to need etching to be removed.
Etching is really an overkill if a cleaning pad can make the work.
Anyhow, FF people have all the elements to choose the correct solutions now.

"Overkill" when you shoot at hares from gun for elephants?
Dr. Lerner asked chemists to advice fast and cheap chemical solution for removal copper from the glass without scratching.
What the name of such process?
Not etching?

[ladajo]

Elbow Grease.

[Giorgio]

Dr. Lerner asked chemists to advice fast and cheap chemical solution for removal copper from the glass without scratching.
What the name of such process?
Not etching?

Actually no, Dr. Lerner didn't ask for a chemical solution, he asked: "what is good to clean the copper off the glass that won’t scratch or harm the glass or the surrounding steel?"
A stainless Steel Pad like the one I indicated will remove easily any deposit without scratching the glass nor the steel.

If the copper was indeed fused to the glass than, even if you remove it by etching, the glass will probably be ruined and will need to be changed not cleaned.

[Giorgio]

Elbow Grease.

One of the best chemical process ever invented by mankind IMHO!

[Joseph Chikva]

Actually no, Dr. Lerner didn't ask for a chemical solution, he asked: "what is good to clean the copper off the glass that won’t scratch or harm the glass or the surrounding steel?"

Actually yes, as:

For the chemists out there, we have a few cleaning questions....Second, copper eroded from the anode gets deposited on our glass viewing windows. We can take these out easily enough but what is good to clean the copper off the glass that won’t scratch or harm the glass or the surrounding steel?

So, he asked for namely chemical solution.

If the copper was indeed fused to the glass than, even if you remove it by etching, the glass will probably be ruined and will need to be changed not cleaned.

Actually no. Unlike copper the glass withstands acidic media very well. I have extensive experience in working with chemical glassware and can answer on your

the glass will probably be ruined

Not "probably" but 100% you are wrong. Nothing will happen with glass after etching. Your assumption vs. my knowledge.

[Joseph Chikva]

Elbow Grease.

One of the best chemical process ever invented by mankind IMHO!

I have googled "Elbow Grease" and found out:

Elbow grease is an idiom for working hard at manual labour, as in "You need to use some elbow grease.

I do not understand what this phrase have to do with chemical process.