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Forum Index : Other Stuff : AC or DC welding??
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| domwild Guru  Joined: 16/12/2005 Location: AustraliaPosts: 873 |
My welding is really multi-point tacking so here is a thought how to possibly improve it: The cheap welder is just a transformer with fan, so the question is if I add a rectifier + heat sink to it will it make it easier for me to get a better seam or not? Because of my inexperience I lose the arc and must restart which is always difficult and leads to sticking. I may have put this question on before, my apologies as I cannot find it again. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
Whether a rectifier etc would work? Don`t know, but if you do a bit of welding get a MIG, you can go gassless to keep cost down, not as good as using gas but miles better for fine work then a arc welder. Although for me the arc welder is better for heavy strong joints. But with the MIG you can weld 1.6mm even thinner and do so without a lot of experience. All comes down to if you can justify the cost of a MIG, I know I hummed and haddd for years, once I had a MIG I wondered why I didn`t do so years back. I realise this is not an answer to you question, just my tuppence worth. We come from the land downunder. Vic |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
It depends what material you are welding, and the welding process. Both ac and dc are used, and dc often with either polarity. Some welding processes require a constant current, and others a constant voltage. Best join a welding Forum and discuss with professional welders what it is you are actually trying to do. They are a very friendly helpful bunch over there. http://weldingweb.com/ Cheers, Tony. |
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9306 |
I tried to learn welding, as my father was a professional structural welder. I sucked at it. It was suggested that I do a course, as they have better equipment, as the welder I was using was a three-phase 440v industrial transformer based beast from about 1950! You changed the current on these beasts by sliding a big lump into and out of the transformer laminations. They were semi-permanent units, needing a crane to move cos they weighed so much.(I am NOT kidding) It was a VERY powerful welder when set to high current, but I could never maintain the arc correctly, and the electrode just kept sticking to my work. My language and patience eventually were exhausted..... It was later suggested that these were not the machines to learn on, as they are good welders for people who have been welding for years and know how to control the beast a bit more because of experience. Smoke makes things work. When the smoke gets out, it stops! |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Probably the best welding technique for home and hobbyist these days is gasless MIG welding. That is constant voltage dc, with a motorised wire feeder. There was no such thing as MIG welding back in the 1950's. Its an easy and forgiving welding method, and the latest electronic welders are very readily adjustable, light weight, and portable. Probably about the best thing you will ever do learning to weld, is purchase an automatic darkening welding helmet !!!! A Tafe welding course might be well worth thinking about as well. Cheers, Tony. |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Thanks for many answers. The auto darkening helmets are great! As a former TAFE IT lecturer I am trying to stay away from TAFE but can only praise TAFE for the fencing course I did with them. For the wind mill I better stick with stick welding as suggested for the strong welds. I have no need to weld thin material. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| MOBI Guru Joined: 02/12/2012 Location: AustraliaPosts: 819 |
Another problem that afflicts us off grid systems is the use of brushless generators with either stick welders or gasless mig. Unless the generator is way oversize, when you strike an arc, the generator voltage momentarily drops by about 50 volts and the stick or wire grabs. I have found that using an invertor welder improves the situation a little. I keep an old petrol driven dunlite generator for welding although the fuel consumption is a bit high. (a ten man portable). David M. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All I have done a lot of welding over the years and the best welder I have is an old Lincon DC genemotor 3 phase motor driving a dc generator it generates fuzzy DC so is easy to start and good penetration, and I have turned it right back and used it to tig weld steel and stainless steel, I have had many transformer welders over the years some OK and some terrible the little ones are a waste of money and a frustration. Any of them that run off 240 volt power poind will be a source of frustration to the learner and professional, if you have one get a suitable rectifier and convert it to a battery charger. My Choice. The next best is the DC inverter welder an amazing bit of gear, also produces fuzzy DC and is very versatile and doubles as a battery charger. Mig is OK for light work but lacks penetration on larger jobs a Inverter one is a lot better than a transformer type, good for light metal and thin plate to 6 MM, gasless is cheaper to run but produces inferior welds, unless you have a larger machine 200 amp plus, but looks daggy and lacks penetration. Dollar for dollar the little inverter welder takes a lot to beat, but avoid cheap Chinese welding rods, the best for general use I have found are WIA 12P and 13S more expensive but a lot easier to use. All the best Bob Foolin Around |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
Thanks Bob for that. I do not mind paying more for rods and I will see if I can get the ones you are recommending here in Perth. Am using the cheap Chinese rods at the moment. I have also put this question to the recommended welding web site. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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Bryan1 Guru Joined: 22/02/2006 Location: AustraliaPosts: 1344 |
For welding rods I suggest WIA TC16 rods, these welding rods are in my opinion the best and they are not the easiest to use. My arc welder is a 140 amp Lincoln caddy welder that has a 100 amp duty cycle at 100% and drops to 60% at 140 amps. This welder is designed to run from a genset and for the last 10 years it has done many jobs flawlessly. I did find my 3kw inverter won't run the welder on arc welding but on tig it is fine. |
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| norcold Guru Joined: 06/02/2011 Location: AustraliaPosts: 670 |
One of the most useful additions, I found, to the auto-darkening helmet, is a magnifying lens that fits on the inside of helmet lens. Fitted a CIG one many years back. Well very useful for these old eyes. Believe you can get them in various magnifications. We come from the land downunder. Vic |
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| domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873 |
The US welding web site is also suggesting "dragging rods", i.e., rods which keep the correct distance of arc and can just be "dragged along". Sounds like the ones for a novice or "solderer". Have to talk to a specialised rod shop in Perth if they have any of the rods suggested in these posts. Thanks for answers. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Dragging just refers to the direction of welding with respect to the angle you hold the rod. The welding puddle is behind the direction of rod travel with the dragging technique. The alternative and exactly opposite technique is "pushing" where the weld puddle is kept ahead of the direction of weld travel. They almost certainly will not have the American rods, or even know what you are talking about. Its a completely different world over there. Cheers, Tony. |
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