RDWorks Learning Lab 59 Marking Metal 

Lol, I was like "wow, russ, to lazy to move your camera for a second?"

yes! You don't want any lube on the rails. it might lessen the wear on the bearings!!!!

Hi That sounds like a brilliant idea, however, can I ask you to firstly take a look at the table of properties for metals at 4min 30 into this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-zF9nQHlvGkc.html The second coulumn is what should interest you because it shows how much IR laser energy is absorbed by various metals and then watch ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sIlXSZhgbe4.html to see this in action. Let me know your thoughts after understanding what you see Best regards Russ

+Mid-Florida Tactical Me too, been use Moly spray for years too.

Mid-Florida Tactical What's the mix ratio of plaster and alcohol? Also do you know if this would work with low power lasers, 1.5 watt for instance ?

Ged Reilly 40 watts and greater

+Abraham Saenz I'm yet to find out how to grill steaks on it........eventually maybe!!!

+SarbarMultimedia , LOL I'm pretty sure steaks would come out great, but now that you mention it, food etching can become a thing. I wonder if the thickness of the sprayed layer would be a variable to consider. In the video the "expensive" material seems a lot thicker.

+Abraham Saenz Hi Abraham Possible yes but could I ask you to read the reply I made to himlegorush below Thanks Russ

Hi Some one else reported that he has been mixing plaster of paris with isopropyl alcahol with great success. Please report back because I'm a squirrel for new ideas. To get Cermak in the UK is like hunting for the end of the rainbow but a kind soul from US sent me a sample for marking glass and ceramics. Your idea may work for that as well. Best regards Russ

@@SarbarMultimedia hi was the ipa plaster mix then added to the moly?

@@mrdavidmelvinable Hi David I have not used it but, but no, the IPA and plaster slurry is just used on its own. You may be interested in this unpublished video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BWo_au1TPL0.html Best wishes Russ

Cermark does paint on but it also leaves a raised surface This seems to indicate that there maybe two processes taking place . The clue may be in the name CERamic. There is a chemical in Cermark that reacts with one of the elements of stainless steel (probably the nickel) and then also fuses a thin ceramic/glassy layer on top. The MoS2 ony does the first stage chemical reaction where the sulphur content bonds with the nickel in stainless under the action of tremendous heat, to make a black chemical called nickel sulphide. I investigate this further in a later session where I use MoS2 to engrave on glass and as I explore more about 3D engraving. See 7 to 14 min of ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0E6VfQD9n2o.html Many people have had success with a paste made from plaster of Paris and isopropyl alcohol Best wishes Russ

Hi Scott Slow down and pay your wife some attention....this is not a box set!!! The end is not in sight yet. Best regards Russ

I had to hurry as my machine was on its way. Besides, I have been captivated by your tutorials and had to binge watch ALL of them.

That is good to know. getting to the exact levels will be my conundrum. These videos have a very patient man doing it on various material. Each wood product I am engraving with our logo (not listed here ) will need most likely a different setting. Why, because we will need it deep enough to fill in some inlay stone. I hope this works out. The standard method of engraving using a toll to punch the logo out is not practical when you have hundreds if not thousands of product planning on running through the machine. Which is my next long term question. What part and pieces will need replacing at that point. So far noting has really failed here or lost too much tolerance, except for self inflicted manipulating of really everything by the producer RD Works.

+Kris Kumaroo Hi Kris First your concerns about failure. From the many conversation I have had with folks around the world with these machines and from my own personal experience/assessmen, there are only a few "at-risk" items. The tube itself must be considered a consumable item. A typical cheap tube will have a life expectancy of 1000 to 2000 hours and that will depend on how you are working the tube. Run it at it's max permitted current and it should make at least 1000 hours. However, if you are running with the original factory fitted tube it MAY be bad news. Firstly the machines bought via ebay or amazon and even through a US company called Light Object, have over-rated tubes fitted ie you buy 80watt but get what is actually a 60 watt tube. Apart from the disappointment, this is not in itself a problem, where the issue becomes important to someone like yourself who is using this for business, is the fact that from the experience of many, including myself, the factory tubes appear to be B grade and of very variable performance and life, sometimes less than 100 hours before experiencing loss of power or complete failure. I compare this to the practice of inkjet manufactures who now supply full size cartridges with their machines that are only 10% full. You can buy High quality replacement tubes directly from China, Reci being the most famous, that are high quality, long life (8 to 10000 hours) but quite a high price. There is a mid range vendor that I bought my tube from who's "cheap" product is high quality, excellent performance and rated at 4000 hours, They also make 8 to 10000 hout tubes . The extra life being achieved by various more expensive manufacturing techniques like gold anode/cathode and microscopically thin vapor deposited gold film on the wall of the central laser tube to aid recombination. So number one priority, get yourself a spare tube on order form China. Mine arrived by DHL (who charged as much for a 5 day delivery as I paid for the tube!!)but others come by normal 3 to 5 week mail . The other parts I have known to fail are the air assist pump, which is an oil-less aquarium system that will not contaminate your lens. Again, easily and cheaply available from China but an essential part of your machine. I have quite a few instances of the flow protection switch not working or working intermittently. The easy fix is to short the wires to the switch as a temporary fix while you find a replacement (or carry a spare) Mirrors and lens? Well it depends what you have fitted already. If its got a gold look to the mirrors that may be bad news. Cheap crown glass is often used because it can be easily polished flat and then gold flashed for reflectivity. The gold flashing is thin and very prone to damage especially during cleaning, the glass underneath is highly absorptive to IR and will soak up your power. If they are silver, it could be good news. They are probably very robust molybdenum mirrors. Ideal for your situation. Not the highest transmissivity but will stay stable for long periods between cleaning. No panic but worth having a set of these in reserve. The lens is slightly different. The zinc selenide that the lens is made from is only about 70% efficient in it's raw state. It's surface crystal structure REFLECTS the other 30%. So all lenses are coated with an anti-refection coating. Normal cheap chinese lenses work well enough at about 95% transmissivity but a patented US coating can get this above 99%. They normally go under the heading of HQ but are generally more than twice the price. I think in your situation where a few extra watts of power at the work surface is not essential, then a handful of cheap lenses of various focal lengths (1.5", 2" and 2.5") would be a sensible precaution. Belts and bearings are a really long term issue that I anticipate will eventually ned attention but I would expect slow degradation and will give you plenty of warning that attention is needed. So, not that much which is risky really. You other point about stone inlays and logos is an interesting topic that you may wish to write to me about it off line. If you wish to send me your email via the private you tube messaging system there may be methods of exploiting the machine's capability to speed up production because wood carving deep grooves can be quite time consuming Best regards Russ

Hi Ben, what size/watt chinese laser did you use for this job?

gemrough I was abt to type the exact same thing lol

Your suggestion sounds perfectly logical and at one stage I would have thought likewise. It all come back to a clear understanding of what our laser beam is and how it works in different situations. First the beam. It is a beam of LIGHT, yes it's in the infra red region and is invisible to our eyes but non the less it is LIGHT. Only when this LIGHT hits a surface does something happen. If it hit's a metallic surface then it will be rflected. Different metals reflect with different efficiencies and in different ways. Metals such as gold, silver, aluminium ,copper are almost 100% reflective, stainless stell is about 90 % and mild steel about 60% but with scattering. Non-metallic materials will absorb the LIGHT fairly efficiently. When I say absorb you may think of the light penetrating into the body of the material. Wrong. The light interacts with a few surface molecules and atoms stimulating them to a more excited energy level. It's the same priciple by which your microwave oven works. What happens next is very dependent on the heat conductive property of the material your are firing at. This SURFACE energy transfer causes the receiving atoms to vibrate more. If they cannot transfer some of that vibration to surrounding atoms then the light energy stimulates even more vibration in those local atoms. Vibration in atoms means heat. More vibration= higher temperature. OK , so that's the heating mechanism explained. If the beam stands still then heat will build up in one spot. If you hold a piece of paper in a candle flame it will catch fire, but if you MOVE it through the flame it will not Move it slowly and it will scorch, move it fast and the energy available at the flame will be spread so thinly that it will not damage the paper. So now we have 3 factors to consider when we address your proposal.. Light absorption, thermal conductivity and energy density per unit of time. Can I be facetious and compare your proposal to trying to commit suicide by jumping from a ground floor window. You have to find the right balance of power and traverse speed for the beam to heat the Mos2 to a point where there is sufficient heat to cause a chemical reaction between the stainless steel (I think it's the nickle content that's reactive, but don't quote me because I'm not a chemist) and I believe the sulphur content of the MoS2.. I have achieved similar results with neat flowers of sulphur powder but it's a VERY messy and impractical way to mark stainless. I hope that my explanation makes sense and you can now see that multiple passes will not be the answer. My problem in this video was using a very thin piece of stainless. As I have moved on and marked many stainless objects, I realized that these parameters only applied to this thickness and that as the stainless got thicker the thermal conductivity of the steel was sucking heat away from the heat zone and I needed to up the power or lower the speed to get the same heating effect at the beam contact point. Thanks for the comment because this may help others understand the nature of our laser beam. Best wishes Russ

You can make a sturdy etching mask by spraying the metal with an outdoor paint like hammerite. You will need to scrub afterwards as lasering away the paint will leave a thin layer condensation on the lasered areas. But because the outdoor paint is so tough, you can even do that with a toothbrush and liquid abbrassive.

The only thing missing from that stupid label was "contains small parts that will be harmful if swallowed" I just couldn't be serious about that Regards Russ

I've tried using powder coating dust (with modest success) on my Epilog laser at work, the chief problem being the micro explosions created by heat expansion from the laser reacting with the dust can often "blow off" the dust surrounding the focus point. Maybe if a slurry can be created with a solvent/binder and the powder coating material, it will serve a similar purpose without the molybdenum safety fears (real or otherwise)? Regardless, once I get the K40 up and running, I'm going to try this dry Moly Lube approach...

Hi Sean I have gunsmith in your great country that tells me he has used plaster of paris mixed with denatured alcahol with great success. This is not something I have checked out. Powder coating is either epoxy resin or polyester resin. I would check for safety issues with both infohouse.p2ric.org/ref/39/38186.pdf Russ

You might like to look at this ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-mCQqn0kfvCo.html What do you think? Best wishes Russ ps I will be returning to glass engraving.

Having established that sulphur is the main magic ingredient I am currently awaiting delivery of some flowers of sulphur powder (its VERY cheap) to experiment with. Best wishes Russ

RobertWerden any molydisulfide "drylube spray". You want the drying type, not moly suspended in oil (no break free clp, etc). Most hardware stores and home improvement shops should carry similar. Just check ingredients, you want moly disulfide, some vehicle/solvent to carry it, and not much else (no oils gums Esther's you can avoid) but propellant.

Hi Michael I am not a chemist, but from what i see and feel I think Cermark has a double action in the way it works. Tht thixk nature of the material tells me it is loaded with some sort of ceramic filler powder as well as the other vital component ,sulphur, to cause the interaction with the nickle in the stainless steel. MoS2 is perfectly flat whereas the Cermark is slightly raised when nit's marking job is done , implying that something has been heat bonded to the surface. I have looked at this reaction again during this video see 9:13 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0E6VfQD9n2o.html Many people have reported success with mixing plaster of Paris with isopropyl alcohol into a paste. Best wishes Russ

Hi Russ, Thanks for reply. I’ve just discovered your series of videos as I myself have just taken the plunge into a China Red/Black machine (ordered and just shipped on a slow boat from China). I have just retired (in last 12 months) as an electrical (electronics) engineer. Thought I’d take the opportunity to do some of my own product developments (for my own entertainment only), and see a laser cutter as a great adjunct to this. I can see it coming in handy for all manner of things, including enclosures. My first project is a retro-computer in the style of the old 1960’s DEC PDP-8 computer and for that I will make some faux-NIXIE displays (link below). This will be a stack of 10 acrylic pieces each with an etched number, and LED edge lit from the bottom. The second project will be a Rubidium atomic clock with 10MHz output to calibrate my instrumentation (now that I can’t just send them off to a test lab like I could when in business $$$). For this project I will laser cut a custom enclosure (wood or acrylic, not yet decided). As I go through your videos, I’m picking up some VERY useful information and would like to thank you for the huge effort you have obviously put into them. I’ve also learnt a bit late that I should have gone with the blade table instead of the honeycomb one, but guess that will be the start of my mods :o) I’m kicking myself a bit, because I was offered the choice and it appears Murphy stepped in. I have been lucky in inheriting my son’s water chiller for a bargain basement price of $0, a S&A CW-5000 which I hope will be compatible. He used it on his CNC router, so expect will be okay. This will be a necessity, as we’ve just gone through a summer with temps ranging up to 44 C here in Melbourne, Australia. Freezing will never be a problem. Again, many thanks for videos and trust all well with you. Regards, Mike Sloane. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-miqN2gR1Zns.html On 9 Mar 2019, at 7:58 PM, RU-vid wrote:

Hi Toni That's a very neat trick that I will try. I will probably have to make a special lens holder because 3.5mm will focus INSiDE my existing nozzle. My existing 38mm HQ lens is producing dots just less than 0.1mm. Until I start experimenting with dot graphics (which is on my learning agenda) I wont be able comment on the quality untill I start trying very small pictures. What size do you call "small images"? Thanks again for your invaluable input Best regards Russ

The size of a small coins I guess.

And 3.5 mm from the top of the head not from the last lens, measuring from the opening where the laser beam exits the cylinder is 3.5 mm.

I am not a chemist but from what little I do know, I do't think suphur can ever be a gas. It easily and rapidly combines with oxgen to primarily produce sulpur dioxide gas. It is the sulphur content of the suphur dioxide that (when heated by the laser beam) combines with the high nickel content of stainlees steel to produce black nickel dioxide. IIn a later video I pulled lots of sulphur bearing products together to test the validity of my sulphur theory. See ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-whDqjIhRQ-o.html Best wishes Russ

+Kris Kumaroo Hi Kris nice observation BUT you will note that the head mirror is AWAY from the spray and the lens is 30mm up inside the nozzle that has a 4mm hole in the end. That would be some overspray miracle. I also know there were no ill effects because once a week I check the power at the workface to make sure I'm not losing beam power through mirrors/lens losses or misalignment. When I made and installed my own copper mirrors 4 months ago, the doom merchants were forecasting almost immediate atmospheric tarnishing and that I would be soon be losing power and switching back to molybdenum mirrors. I'm still seeing no drop off in performance or reason the change them and if I can go 4 to 6 months without cleaning or re-polishing them, then I think the doom merchants were wrong and I can make superb quality mirrors for free. I obviously did not get the message over in my 3 part session on reflectance ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-kJe16YQlIM0.html that tarnished copper is almost reflective a polished copper. Thanks again for your input Best regards Russ

I would expect no less. I will use that Moly method. I investigated the properties of it and it is used quite a bit in the gun industry for coating parts to stop any corrosive effects. It is quite cheap here going to the local Home Depot. Usually less than 10.00 a can. I am only looking to etch a marking of my signature and a 1 of XX for specific pieces of product I am custom making in limited numbers. I want to engrave the bottom of the handle that is brass or silver. Using this product will be crucial, or it won't work at all. How much product are you running though your machine a week?

+Kris Kumaroo Hi Kris Very little. I am in this as a hobby not for any specific business purpose. I'm 80% retired now but still keep my hand in. Just at present the 20% seems to have all turned up together and I being PAID to work. It's getting in the way of me playing and producing videos. Really annoying as I was getting a nice pattern going. Best regards Russ ps note the precaution about good ventilation and extraction when using this moly.

Hi Rajesh This is not proper metal engraving or etching but some sort of heat induced chemical reaction with the surface of stainless steel. Cermark do manufacture products for marking many other materials but the products are very expensive. 60 watts is perfectly ok for doing this as you have seen from this video. My machine is a 70watt tube but I was not using full power. I did accidently discover that it was possible to mark raw stainless steel but I was using a 1.5" focal length lens. see ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-jP9ncWksEGw.html Best regards Russ

Stainless steel is so called for a very good reason. It requires a mix of some pretty nasty acids or other chemical compounds to etch into its surface. This is not man cave technology in my opinion and I would not want to encourage non-chemists to play with these dangerous chemicals But thanks for the suggestion Russ

Hi Dermot try www.ebay.co.uk/itm/DM-90-Dry-Film-Molybdenum-disulphide-lubricant-dry-moly-spray-500ml-lasercutter-/263190992940?hash=item3d4767d82c:g:4eEAAOSw0yxZsCP2 Best wishes Russ

That would be mild steel then? and less than 1.5mm thick? It's certainly quicker and easier than a jig saw. Best wishes Russ

Great humorous explanation thanks. That probably also explains the success of plaster of Paris as an alternative to moly sulphide? Thanks again Best regards Russ

SarbarMultimedia sure, plaster is calcium carbonate, so you're depositing metallic calcium, and liberating CO or CO2, depending on energy excess pumped in. My bet is higher power settings for equiv mark over moly however. Copper sulfate, baking powder, washing soda, maybe even talcum or fine sand too. Most Clay's, probably. Sand or clay would probably need lots of power, the copper sulfate could well actually "acid etch" into the surface as well as tint/deposit. Might be fun to try galvanized steel, but I think the zinc would just vaporize. Rust might be worth a try, to deposit straight iron. Just a few ideas. I'd probably avoid sodium and potassium as they are so reactive, though that might well give better results. I'd say the lower on the periodic table, probably the more caution should be used. Higher atomic number means more energy wound up in it, though the "danger" will be more ugly work piece than some catastrophic event, but always some possibility of a vapor deciding your expensive mirrors and lenses are better company than the hip flask, lol

I have not personally tried the plaser of Paris method but it's good to know that there is a good logical chemical reason why it would work With moly, you will see from my results that that there is a fairly narrow range of heating that works best. I also found that as you increase the material thickness it takes more power to achieve the same success. So it looks like you are having to compensate for the greater heat loss through conduction/heatsinking to keep the temperature in the correct range. Kind thanks for your great contribution Russ

SarbarMultimedia my guess is the moly sulfur bonds are very energetic. It has been a fair chunk of calendar since high school chem, so bond Dynamics is a bit iffy in my cobweb trap above my neck, lol. Calcium is an alkaline metal, so reactive, and moly isn't. I'd say a really good bet is baking powder, sodium carbonate. Sodium is pretty reactive, so I'd do a very small test chip, like a disc or washer of stainless, just to minimize mass in case it goes feral. Washing soda is a boron salt (20 mule team here) if I remember correctly, so also a decent bet. What you are certain to find is some combos seem to genuinely desire to work, while others won't cooperate at all (like clay to carbon steel, as aluminum and iron seriously don't get along), but an alloy change in the substrate can make it work in some cases. For some reason though, instinct says "copper sulfate", it just seems just moly like enough, with a promise of some brown or green tint, lo!

I actually have some copper sulphate that I dissolve and use as a plant antifungal spray. How would your prepare it into a paintable paste? Thanks Russ

Hi Sorry to disappoint, it's only 73 watts at the 22mA current limit. Best regards Russ

I'm not sure which maths you are questioning but if it's to do with the power calculations then can I remind you that I work in degrees C and you may be working in degrees F?

72 watts at 22mA out of the tube.

@@SarbarMultimedia Do you think one could get these favorable black markings from this unit in it's original state? (original 50w tube, PS, lens ,etc)

@@kwhite002y Hi Keith if you buy the right machine (there are several variations) with good mechanical design and a Ruida controller then you have the basis of a good machine. The tube and power supply are always a gamble with Ebay machines. They are usually QA failures from main manufacturers that work but cannot be sold with a warranty. Your 50 watt tube is always a fantasy. It will at best be a true 40 watt tube 800mm long and probably because it will be B grade it may only output 30 watts. However This 30 watts is enough to do this MoS2 engraving. Sadly, machine build QA is not included in the price..... that is something you have to take care of yourself. These machines will work but not without some of your TLC. Despite these issues, they are excellent value for money. If you want a true plug and play machine you will be paying 5 times the price. Best wishes Russ

@@SarbarMultimedia Great info! Thanks for taking the time to share.

Panic not. It may look very gung ho but look carefully at the construction of my mirror assemblies. You will see that the one you may be concerned about is buried 2" deep into a 20mm diameter tube Perhaps your machine has the open type and would then be a real concern. My lens is 35mm up inside the nozzle which itself has a 4mm hole at the bottom. Be assured there were no ill effects Thanks for comment though Russ