Which to use?

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Hello all, this is my first post on this forum. I am not a welder I just play one in my basement, but I do enjoy it a lot and want to learn all I can about it. I have a miller 110v  gas shielded mig that I have used a good bit on vehicle body work/rust repair. It is rated to weld 1/4" I believe. I also have a Miller suitcase tig that can stick weld as well. It can run on 110v or 220v and I dont remember how thick it supposedly welds. I have TIG welded a little on fair amount on stainless frames/machines for my work,  ususally cosmetic nothing structural.     So, what I want to do is build my very own custom BBQ smoker on a little trailer. It will not be big, trailer and all maybe 8-10 feet long and 4-6 ft wide. Smoker will be out of an old 250 gallon propane tank and the rest of the smoker's fire box will be 1/4" mild steel. Also mix in various angle iron and expanded metal for racks and suck. The trailer will be 3" and 4" channel and angle iron, nothing over 1/4" thick.    My question, after all that info, is which process would be the best to use for this size material and for this application. I obviously want the strongest yet easiest for me to "master" enough to do this project. And I dont want to have to bevel the steel to weld it (or is this even necessary for what I am doing?) I will really be practing a lot to make nice looking welds so which process should I be practicing most? If I dont feel like my welding is capable of being safe for the trailer part then I may have to get someone else to do this but if I can really practice on it then I may be able to do it.    SO, what say Ye? I know the knowledge is vast on this forum, so please, tell me your thoughts.ThanksJason
Reply:For your skill level, buy a trailer and then build the BBQ smoker to fit on it. Trailers are not learning projects.For the smoker, any of the units will most likely work. I'd either mig or stick weld it, depending on how thick the material you are going to build the smoker out of.Despite what the literature might say, that 110v mig tops out under real world conditions at 1/8" steel. Trying to weld thicker material will not work for critical welds like on a trailer, but you should be good on the smoker for the material I'm guessing you might use. If you were to go with heavy steel, say 3/16"-1/4", then I'd use the stick machine on 230v power to deal with the thicker material.Most people pick up mig a bit faster than stick, but that really depends on the person..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:As a rule of thumb you should never MIG weld anything thicker than 3mm (1/8"), unless you have a machine that provides at least 250 amps output. (There are some exceptions to this rule but they don't bear mentioning. ) With a 110volt machine even welding 1/8" would be questionable at best. It's a poorly known fact that MIG requires at least 2 times more output current than stick or TIG. This is because MIG has faster travel speeds, while using lower on-arc voltages.Many major manufacturers are in the habit of selling severely underpowered MIG machines, and then wildly exaggerating their capabilities.So yeah. In conclusion you want to use stick welding for this kind of project. I like the previous poster's idea of buying a small used trailer and converting it. Many of the welds on trailers are safety-critical. Not something for a beginner to mess around with. It hardly bears mentioning that you don't want something important breaking free when you need it most-on the road. Visual appearance of welds can be deceptive, since what matters most is what lies in the root, which cannot be seen. In particular this is one of the risk associated with MIG welding, the ability to make welds that superficially look great, but contain severe lack-of-fusion and lack-of-penetration defects.beveling the edges of joints depends on a lot of things. It may be a good idea if you're welding thicker than 1/4" , or if you can't weld both sides of the joint with a "full seal weld." That's a specific engineering question and it would depend a lot on the nature of the loads imposed on the part. I'm not the best person to give you advice on the subject.Be careful with the propane tank. Remove the valve stem, fill it completely with warm soapy water. let it sit for a few hours, drain and repeat. Do this before you start cutting it up.Last edited by Joshfromsaltlake; 02-25-2012 at 01:54 AM.
Reply:Thanks Josh and DSW. I copy on the trailer. I found one this weekend that will work, I'll prob have to cut it down and take it to a pro to put it back together at the length I want.I got some practice also today and yesterday with the stick welder but have many questions. My welds are not the prettiest but when the material was put in a vice and beaten with a small sledge the welds held so I think I am on the right track. Does anyone have any suggestions on books or videos that would help me to see what proper welding should look like, proper technique, how to tell if the weld is penetrating, and other learning tips. I dont really know anyone that can stick weld any better than myself  to ask if they could show me some stuff so i am just shooting in the dark.
Reply:Post up picts of your practice work with all the settings, rod used, material thickness etc and we'll try to help where we can. There are any number of help threads on stick welding here that you can find and read.As a basic, I'd suggest starting out with 7014 as an easy rod to learn with. Size would depend on what thickness you need to weld, probably either 3/32" or 1/8". For 1/8" you probably want to be at about 125 amps and you will get about 6-8" of weld from one rod. If you find you go farther than that you need to slow down. A good practice material is a 12" length of 3" angle iron 1/4" thick and a couple chunks of scrap you can tack on as "feet" you want to set the angle so it sits like a V, and then weld stringers one right next to another so they over lap by 1/2. You can do the same thing with flat plate as well. this saves you material and lets you get the basics down before starting on joints. These are a few picts of practice pieces a friend of mine was working on off the scarp pile.You might look and see if any of the local tech schools or community colleges run night welding classes. When you sit down and add up what it would cost you in material, rods/wire, gas, electric etc, not to mention the instruction, a class is usually stupid cheap. You also usually have access to better equipment than you normally would have at your level, plus other shop equipment like OA, plasma shears, etc many times. Most instructors will actively encourage students with projects once you get the basics down. It shows the student has a real desire to learn.Miller has some good info on stick and mig welding in their student pack. You can download the material from their site or purchase the pack.http://www.millerwelds.com/resources...-skills/stick/http://www.millerwelds.com/pdf/guidelines_smaw.pdfAlso the hammer/ vise test really doesn't show you much. There are better ways to test your welds. Once you get decent we can go over some of them later..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:DSW thank you so much for your time to share some info. I stopped in the store today and picked up some new rods but I thought I remembered 7018 so thats what I got instead of 7014, so I'll stop back in tomorrow I have been using 6011 cause thats what I kept around here and I will post pics after a few more passes of straight weld. I jumped right into joining stuff but I see where doing multiple runs will benefit me.If using 1/8" 6011 on 1/4" steel, should I have heavy discoloration or complete penetration on the other side or does this even matter. Also whats a general setting for the 1/8" 6011.
Reply:Originally Posted by jascoltIf using 1/8" 6011 on 1/4" steel, should I have heavy discoloration or complete penetration on the other side or does this even matter. Also whats a general setting for the 1/8" 6011.