Laser as a heat source

[Anousse]

Hi everyone,

first time poster here. I would like to use a laser as a heat source to start a chemical reaction (forming an alloy out of two metals). Having to heat it through quartz with a flame is not very efficient for large volume. The reaction is exothermic, so I just need to have it started somewhere and it will melt the whole thing almost instantly. I was asked to to find an optical solution to this and I went to a lab at a university to heat a thermocouple with a laser and see how well it would heat it. I used a 532 nm 10 W Verdi laser by Coherent (adjustable) and I could raise the temperature to 560 C with a 3.5 W output.

As you can see, I do not care about wavelength distribution width (or noise), the modes or anything, I just want energy, fast to avoid dissipation. What would you guys suggest to get? I looked at wicked laser's arctic 3.5 W and looked at aliexpress high power lasers. But looking at some threads here, wicked laser has bad reputation and aliexpress gives big numbers and the reality is "low" power output.

This is an R&D project so I want to be able to test it fast (fast shipping to Canada), be sure of what I get, and have something cheap (if it gives good reliable results, money will not be an issue).

Thank you!

 

[Alaskan]

Although, more and more we have members coming here who can answer such questions. Diachi, Cyparagon, H2Oxide, CurtisOliver to name a few, I'm not going to keep listing names, this is a laser pointer forum, not a university

OK, can someone help him anyway? Even though I highly suspect this is our friendly HMT in a different incarnation.

 

[Razako]

Try the Sanwu 5W spiker Perhaps. Better deal than anything from wicked lasers.

 

[Alaskan]

You come off as more advanced than most members here already Wicked Lasers, I agree, no.

 

[Anousse]

Hi Alaskan,

I'm not too sure I understand your answer, but I am not trolling or anything. I found this forum to be a good and reliable source of information on laser pointers, and this is exactly what I am looking for: a cheap, reliable, high power laser pointer! I've looked at the review thread, but most of them have too "low" power output for what I need. The "theory" part about absorption, diffusion, reflection, heat transfer, etc... I have it covered, don't worry!

Thanks Razako, I'll look it up.

Regards!

 

[diachi]

Hi everyone,

first time poster here. I would like to use a laser as a heat source to start a chemical reaction (forming an alloy out of two metals). Having to heat it through quartz with a flame is not very efficient for large volume. The reaction is exothermic, so I just need to have it started somewhere and it will melt the whole thing almost instantly. I was asked to to find an optical solution to this and I went to a lab at a university to heat a thermocouple with a laser and see how well it would heat it. I used a 532 nm 10 W Verdi laser by Coherent (adjustable) and I could raise the temperature to 560 C with a 3.5 W output.

As you can see, I do not care about wavelength distribution width (or noise), the modes or anything, I just want energy, fast to avoid dissipation. What would you guys suggest to get? I looked at wicked laser's arctic 3.5 W and looked at aliexpress high power lasers. But looking at some threads here, wicked laser has bad reputation and aliexpress gives big numbers and the reality is "low" power output.

This is an R&D project so I want to be able to test it fast (fast shipping to Canada), be sure of what I get, and have something cheap (if it gives good reliable results, money will not be an issue).

Thank you!

How cheap is cheap? How much mass do you need to heat up? What metals? Your thermocouple and a chunk of metal are going to give you vastly different results, unless the mass of metal is rather small.

Seeing as you're using metals, have you considered induction heating? That removes the need for any laser safety.

 

[Alaskan]

Hi Alaskan,
I think so, I also want a cheap, reliable, high power laser pointer.

I haven't found all of those in one pointer but so much of what you wrote is so sujective, what is cheap to you, what is high power to you? If you have access to all of those lasers coming here is scraping the bottom of the bucket my friend but happy we could help. HMT.

Regards![/QUOTE]

 

[Anousse]

Hi Diachi,

the equivalent of mass under the laser spot should be less than a gram. As I said, it is highly exothermic and as soon as a small amount melts, it reacts and the whole reaction is self driven. The material covering the thermocouple is stainless steel I believe (Nickel alloy inside). Stainless steel has a higher specific heat, but a lower thermal conductivity than the metal I want to melt. The absorption coefficient might be different, but should be high for both.

560 C is higher than what I need, so I guess that all those little variations can be tolerated in the experiment. At the moment, it looks like it will work, I just want to try it for real. This is why I want something cheap (less than 500$, but if I can get the test done for 100$, that's great)!

Thanks for your answer!

 

[Anousse]

Hi Alaskan,

from my experiment, 3.5 W will be ok. I tried 2 W and I have reached 350 C, which might be ok, but considering I was heating a thermocouple and not the material of interest, I would like some room. Just answered it above, but less than 500$ would be ok. Of course, the lesser the best since this is a test.

Regards!

 

[Alaskan]

450nm NUBM44.... I'm convinced now, HMT, have a nice one!

 

[CurtisOliver]

Although, more and more we have members coming here who can answer such questions. Diachi, Cyparagon, H2Oxide, CurtisOliver to name a few, I'm not going to keep listing names, this is a laser pointer forum, not a university

OK, can someone help him anyway? Even though I highly suspect this is our friendly HMT in a different incarnation.

Alaskan, lol.

Anousse, does the laser have to be portable?

Edit: I was just about to recommend a NUBM44, but as a lab.

 

[Anousse]

Thanks Alaskan,

I started to look at building one myself too, so I'll keep your suggestion in mind.

CurtisOliver,

preferably yes, it would be better to have it portable. Space is tight and there are many heat sources, so the less objects you have around, the better!

Regards!

 

[Alaskan]

Optlasers sells one all ready to go in a CNC head package.

 

[diachi]

Hi Diachi,

the equivalent of mass under the laser spot should be less than a gram. As I said, it is highly exothermic and as soon as a small amount melts, it reacts and the whole reaction is self driven. The material covering the thermocouple is stainless steel I believe (Nickel alloy inside). Stainless steel has a higher specific heat, but a lower thermal conductivity than the metal I want to melt. The absorption coefficient might be different, but should be high for both.

560 C is higher than what I need, so I guess that all those little variations can be tolerated in the experiment. At the moment, it looks like it will work, I just want to try it for real. This is why I want something cheap (less than 500$, but if I can get the test done for 100$, that's great)!

Thanks for your answer!

Less than a gram? I think 2W would manage it just fine then. I'd personally go with a laser module rather than a handheld/pointer. Plenty of 2W (or higher) blue modules to be found online for fairly cheap, with heatsink/mounts/driver.

Be wise to take laser safety into consideration as well, keep that in mind.

 

[Anousse]

Thanks everyone for all the info. I just saw that you have a guide on how to make a laser, so I might just do that based on your recommendations!

You have all been very helpful.

Regards!

 

[CurtisOliver]

If 2W is adequate then you would want to use a M140 diode. I also recommend that you make a lab rather than a portable.