+David Wolfenbarger Hi David Thanks for your kind words I assure you that there's lots of fun ahead for you. Even though my naivety has led me astray at times, it's all there for you to see and steer round the problems. Good luck and remember, don't be lured over 60% power until you have an ammeter fitted and know how your tube performs. Russ

Hi Jadan I suspect we are several thousand miles apart so I'm unlikely to get that beer!!!! Thanks for the kind words Best wishes Russ

Yes we are several time zones apart so the beer would be quite warm by the time it reaches you :) I imagine you might just get a kick out of some of my own machinery videos I`ve posted. Thank you and best wishes to you also Russ.

Hi Be very careful when you buy, It's a jungle out there and most machines are not what they seem. If you wish to choose something that suits you and contact me via the you tube messages with your email, I'll be happy to pass comment Regards Russ

+Rik Kroon Hi Rik Thanks for your appreciation. I like the idea of your pin table. As your saw from my video on reflectance, it's not essential to paint the steel table as it has low reflectance and produces rapid beam divergence. However, BBQ paint is a good idea to stop it tarnishing. I hope I explained the reason for developing the flexible pin table arrangement. My machine is running with a 1.5" focal length lens and I only have a 6mm gap between nozzle and work. I have to be careful when cutting shapes that they either remain fully suspended on pins or are allowed to drop down. If they are the wrong size and pivot on a support pin and the edge sticks up, a collision with the head will disturb the sheet and wreck the job. In general I use minimal support and let parts drop but for paper and card I need lots of support in specific areas and this flexible approach allows me to deal with both situations. However, I'm using my machine for an infinite number of projects not as a production machine like yours so our needs are different My projects to date have generally been selfishly dealing with MY problems. However, as you will have seen from my recent work I have nearly "sorted" my machine (just waiting for a tube upgrade to fix the final issue) and now have a pretty good understanding of what makes it tick. The possibility of looking at setting the table level is a good subject for a future session. Although my lens has a very narrow usable "in focus" range, my table is reasonably true to the nozzle and I have not experienced any focus issues. A more in depth examination would not be a waste of time. Thanks for the suggestion (I shall mention you in despatches....unless you want to remain anonymous) Finally, I'm having the most fun ever with this little toy. I used to run a laser profiling business cutting metal with 3kw CO2 crossflow lasers. This is NOTHING like that. It's a whole new learning experience. My other hobby is video so documenting my adventure with this little Chinese Dragon has been a win, win for me. Everything I do is selfishly for me and my learning, but because you can come along and look over my shoulder, the unintended bonus for me has been to find out, from all the kind feedback, that it stops other people making the same mistakes and gives the knowledge that I have acquired in the same simple way that my mind likes to absorb it. Thanks again Kind regards Russ

+Carbon - G10 - FR4 - CNC Routing - 3D Design & Printing - Online Shop Hi Thanks for your appreciation. As I have told many people, I'm a retired engineering designer that has always had video as a hobby. Learning about this little Chinese dragon was the perfect subject for me to mix both passions. What you see is me "playing" and learning. It's all very SELFISH because I do and learn about things the interest ME. I dig into corners that are not well documented because without that understanding I could not have achieved the efficiency that I have arrived at or the knowledge and confidence to go out and buy a more powerful system. If I had the benefit of more power from day 1, it's unlikely that I would have pushed so hard to find that extra few % of efficiency. It's great that a few interested people with similar passions are finding it helpful, that's a pleasing and unintended bonus for me. If you check out the answer to Bradley all the contact info you need is there. On your potential machine purchase. 50 watts would be fine but make sure it is truly 50 watts. The tube will need to be at least 1000mm long so if the dimensions of your machine are less than 1150mm wide then it will NOT be fitted with a proper 50 watt "running power" tube. Most Chinese machines are sold on "peak power" which if you try to run at those values will invalidate the tube warrant because your are "over-driving" the tube. No Chinese machines are fitted with ammeters (an absolutely essential extra that you can buy from Ebay for almost nothing)probably so that it's easy to duck any warranty claim. DONT run your machine above 60% until you have fitted an ammeter and you also have a recommended max running current. I suspect that your vendor will not want to supply this but as a rule of thumb 18mA for 40 watts, 20mA for 50 watts and 22mA for 60 watts. Exceed these values and you will shorten your tube life. If you visit the RECI website and read about their tubes, they actually recommend engraving with this pre-ignition condition. My PSU is on 50watt rated so it's going as well. Remember my machine is fitted with a 1.5" focal length lens. Most engravers are fitted with 2" lens and you may not be able to replicate my results. So, this is another detail for you to check out when you buy a machine. People like Thunder laser sell you something called a Hi Res head as an expensive option, but it's only a special head with a 1.5" lens. You can see how easy it is for me to change my lens to anything I want and I don't need an option head. If you haven't seen it check out my lens video kzfaq.info/get/bejne/jchyg9OkmZjNeJc.html As for the temperature control on my water system, the meter I am using is a leftover from a project and is a rather expensive programmable unit. It's over-spec for the job it's doing but go to the message section and send me your email and I'll put some info together for you Regards Russ

Hi Bill I think the following video will answer all your questions kzfaq.info/get/bejne/hKeZgNV-rLqVf2Q.html Best wishes Russ

Hi Hector I have severarl Mk 2 designs . Which item are you interested in? Best wishes Russ

+Bradley Mohr Hi Bradley, I looked long and hard and made quite a few enquiries. Apart from the gold-standard RECI (too expensive for hobby use) and who don't produce tubes below 100watts anyway, it's a bit of a jungle trying to read the Chinese specs and getting straight answers to questions. I encountered this small company who want to provide a top quality product and service. I got honest and simple answers to my questions. Their specifications were all "up front". Like RECI they declare their peak power but sell on the "running power". Their normal tubes have a claimed "running power" life of 4000 hours (twice that of most other cheap tubes) and after that their words are "the power will decrease". With my usage, I shall probably be shaking hands with St Peter before that happens!! They were very quick with their communications and although I had to communicate and buy through AliExpress, I asked them a for a direct email contact....and got it. Now that I have ordered, they have asked for my controller information and are preparing a connection diagram for me.....that sound more like really good service to me. From what I can see they make all their own tubes and power supplies. I'm paying little more for a 60watt tube AND power supply ' than I paid for my second, cheap, over-specified and erratic tube. However, DHL are doubling the price for their 5 to 7 day delivery service!! I will obviously be recording my fitting and first test experience but so far it's got that "good" feeling. Here's the company website www.mactron-tech.net/sdp/819105/4/cp-4811529/0/Homepage.html All their products and prices are at www.aliexpress.com/store/group/Co2-Laser-Tube/321243_252074840.html?spm=2114.12010108.0.51.UDXo0H They do sell machines as well but cannot find prices for them. If you have special questions or enquiries, the email I have is for Gelly Dung in the Service Department sales02@mactron-tech.com However, this is not publicly available and out of courtesy, if you use it, please advise that Russ Sadler was the source Thanks for your support Russ

+SotirisG Hi Sotiris Thanks for your words of appreciation. Your last question first about fibre optics. Although IR is classed as light, in the overall electro-magnetic spectrum, this is a bit misleading. Glass is very absorptive to IR and it will not transmit. Remember its HEAT energy. Secondly your major concern about smoke particles on mirrors and lens. It's more of an imagined than a real problem. If you have good through flow ventilation the smoke and fumes will never get near your mirrors. The only risky area is the lens, BUT the air assist that is keeping your cut zone smoke-free is also providing positive pressure inside the nozzle where the lens is, so that is not at risk either. The machine I have is basically very sound but I have modified it to suit my lazy ways and to fix a few small design issues. Most Chinese machine vendors are selling on ebay as private listings and there appears to be no link to the company making the machines. When you buy one don't expect any help or after sales support. I know that the company I bought from have warehouses in the UK and Germany so I would expect yours to be shipped from Germany. You will almost certainly be asked to pay by Pay Pal. If you have an account don't use it. Make sure you pay by CREDIT CARD. PayPal and Ebay protection is almost worthless, you will be much better protected by your card company. Good luck Russ

+SarbarMultimedia Hi. Thanks for the advice. Also about using a credit card instead of paypal, I'll keep that in mind. About the mirrors and the lens, I overestimated how much smoke they get, but still they are consumables because of the dirt that gets burned on them by the laser. I searched about CO2 laser fiber cables and they do exist, they're called IR-transmitting hollow silica waveguides (HSW), and Polycrystalline InfraRed (PIR) fibers. I have no idea how much they cost but they're mainly used in medical surgery and everything tagged "medical" is usually too expensive. Imagine though how much better everything would be without mirrors, complex mounts and alignments, and all the power losses!

+SotirisG Hi Sotiris Because the IR energy is rapidly absorbed by water to a depth of less than 0.5mm (human tissue being mainly water) it is widely used for medical purposes where little power is required and the damage to tissue is very shallow. The power limitations of the technology will limit its use in the sort of machines the Chinese are mass producing. Certainly for multi kW industrial lasers they use fibre optics but at a completely different wavelength. As you say, this is not normal glass fibres as used in light transmitters but a special crystal structure material. The "glass " lenses used for focusing the beam at the final stage are made of a special IR transmitting crystal material called zinc selenide. In its raw state it only transmits about 70% of the energy. Not because its being absorbed but because 30% is being reflected. They have to apply special light absorbing coatings to it, and good quality coated lenses are more than 99% efficient. Back to mirrors. Most mirror materials that you will encounter have better than 98% reflectance. Typical 50 and 60 watt machines will therefore lose about 1 watt per mirror. The beam is 6mm diameter so the energy density is insufficient to even scorch a piece of paper let alone burn anything onto the mirror. The only mirrors that are sensitive to heat are what they call K7 mirrors. This is basically gold plated glass and if the surface coating of gold gets damaged in any way at all ( just a few microscopic scratches) the highly absorptive glass behind will suck in energy and break. You might be able to buy some old medical equipment to play with but I'm afraid that you are likely to be buying a cheap Chinese machine like the rest of us. Best regards Russ

+Daniel Ennis I was disappointed at not getting what I was "promised" but not unhappy with what I got. It was good value and has forced me to learn huge amounts about these little Chinese dragons. The fact I have been able to share my adventure will hopefully ease the pain for those that follow Thanks for your kind words Russ

Will this fit through a door ? No side entry :-)

+Daniel Ennis www.ebay.co.uk/itm/350B-50W-CO2-Laser-Engraving-Cutting-Machine-Auxiliary-Rotary-Device-0-60000mm-/111694615353?hash=item1a01849339 Width of 25.6" should pass through a standard 27" door. You may have to take it off the hinges depending on how far the door swings open. Russ

Hi Michael The power you choose depends on what you wish to mainly do with the tube. If you are wanting to cut mainly 8 and 10mm material then the more power the better BUT the more powerful the tube the less control you will have at the low end if and when you want to do photo engraving. A 40 watt tube is great for this sort of work but is limited to cutting 3mm material (as a guide) The 60 and 70 watt tubes are jack of all trades. They will have enough low power control and adequate top end cutting power to still cut 10 and 12 mm material....but slower. So the first decision is to decide on your application to best select a tube power. Remember that the cost goes up disproportionately as you choose more power. You can safely run your tube to certain current limits without the fear of over driving and shortening your tube life. Typically you can expect a tube to last for anything between 3 and 5 years So here are some typical max running current guides 40 watts =18 mA 50 watts = 20 mA 60 watts =22 mA 80 watts = 24 mA 100 watts = 26mA Best wishes Russ

Did you try the antifreeze? How did it work out?

+Martijn V Yes , that would be a great upgrade, but then there would be very few problems to solve and all the fun would disappear!!! I have a colleague who still runs a laser profiling business and he has a 4kw fibre laser machine for metal cutting. Wow that's amazing to see. I did a little video of with my phone as it was cutting some 1.2mm thick zinc plated steel. kzfaq.info/get/bejne/jsmkbLurrberoGw.html (the green hue is because we are looking through a guard system) Best regards Russ

+SarbarMultimedia yes you are very righ about that that would take away a lot of the fun and co2 tubes are a factor 10 cheaper :)

Hi There may be slightly different (usually higher) max allowable tube currents from different manufacturers but these are the generally accepted maximums for each tube size 40 watts (800mm long tube) 18 mA . 50 watts(1000mm long tube) 20 mA 60 watts( 1200 mm long tube) 22ma 80 watts (tube diameters and lengths can vary) 24mA 100watts (tube diameters and lengths can vary) 26mA Typically if you do ny have an ammeter fitted then do not exceed a power setting of 65% An ammeter is an essential addition to your machne and simple to fit www.ebay.co.uk/itm/91C4-DC-0-30mA-Class-2-5-Accuracy-Analog-Ammeter-Amperemeter-Gauge-/351749565079?hash=item51e5e86a97:g:HjsAAOSwmtJXUVFu In case you do not have one see kzfaq.info/get/bejne/rqqKoNip1pumdYE.html Hope this helps Best wishes Russ

Hi Jason there are detailed instuctions on how to fit the ammeter on kzfaq.info/get/bejne/rqqKoNip1pumdYE.html The meter can be just a cheap DC ammeter because there is no high voltage involved at the cathode end of the tube. The line that connects between the output end of the laser and returns to the power supply is a fairly thin wire. It is nothing special because it's at virtually zero volts. You need to break this line somewhere and insert your meter as I demonstrate in the video. This is a typical meter description that you will be able to copy and put into your own ebay search if it's not .co.uk www.ebay.co.uk/itm/DC-30mA-Analog-Panel-AMP-Current-Meter-Ammeter-Gauge-85C1-0-30mA-DC-White-/281821569084?hash=item419ddfe03c:g:UTUAAOSwKsRWFfCz Is your tube marked KH Laser? If not, has it any markings? What are the tube diameter and length? Best regards Russ

Thanks Russ, machine was only ordered this morning so cant get those sizes or markings yet just trying to get all the additional things i will need ready. Thanks ill get on and buy an ammeter in readiness.

A little misunderstanding here. The mains and the current through the tube are completely unrelated. The hv power supply does two things. Very crudely the mains voltage powers something similar to the spark coil in old cars. That voltage which will be in the 25 to 30kv dc range will cause the nitrogen, in the gas mix within the tube , to break down and ionize. With loads of free electrons floating around this gas becomes an almost resistance free conductor capable of carrying huge currents. That is where the HV power supply does its second job of regulating the current flow though the ionized gas.. Best wishes Russ

@@SarbarMultimedia So a little like the starters on fluorescent tubes that provide really high voltage to create a conductive path?

@@ridley68 Yep. That is an example of another type of gas discharge tube, it's just that the excited atoms collide randomly with a flourescent material where the energy transfer appears as light.. Old radio valves and flash tubes are other variations of gas discharge systems Best wishes Russ

@@SarbarMultimedia I think in the tubes the light produced is ultraviolet which is absorbed by the coating and the coating fluoresces with a white(ish) light.

@@ridley68 My apologies I should have said photons not atoms .Different gas discharge tubes emit photons at different wavelengths and it is the energy transfer as the photons hit the fluorescent coating that stimulates the emission of white light. Thanks for the correction Best wishes Russ

I'll call them sunflowers and just hope you are not a botanist !

If you buy from China direct from a manufacturer ( you generally still have to do the transaction via Aliexpress or Alibaba) you will generally get what you ask for. The down side is that it costs an arm and a leg for special transport arrangements and then you will have to pay import taxes as well. It appears that Ebay is just a dumping ground for rubbish tubes and power supplies hidden in reasonable mechanicals.. If you accept that fact and take the cheapest price machine that is already landed and in a warehouse with all taxes paid, and then plan to replace the tube and PSU with reputable kit, it will probably work out considerably cheaper. As a hobby machine that's probably the best way to go but if you need it to start a small business then it's not. There are a few large export companies selling these machines but most are being sold on Ebay by a guy ( or woman) from their kitchen in China for some small commission. They know nothing and care nothing about the machine they are selling Regards Russ

SarbarMultimedia Well, the prices seem to be fixed within a few dollars of each other but if that one guy just received a really nice unit with a tube that measures a true 40 watts maybe there is hope but I doubt it. If I found a machine for 100 less knowing I would have to pay 200 for a real tube replacement then alright but that isn't the case sadly.

Hi Ron A couple of your posts went into the youtube comments "holding" bin which I didn't notice for a few days. All your comments and posts have now been released by me and are there for all to read. Good luck with your new venture Best regards Russ

Many thanks, ron