Welding nuts and bolts

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I know I am about to lob a stupid question out here, but here goes (please be gentle :P )How do I tell what kind of metal a particular nut or bolt is made of or treated with, and what kinds are unsafe (like galvanized)  or just a pain to weld? For reference, I'm an auto-mechanic and I like to fabricate alot of my own specialty tools if I can, as well as tinker around as a hobby machinist. I'm currently running a Lincoln weld-pak 175hd with flux-core  I know this is really basic, and I know some of it already BUT, I'm self taught and I don't want to make an assumption and learn my ignorance the hard way. Any advice would be appreciated, especially a "idiot, go read this link, or google XXX"Thanks guys
Reply:what type of tool are you making? i actually had to make on last week to do a t belt on my sisters mitsu. :/ if you will be using it to do anytype of prying or pulling, i would stay away from galv. i've welded galv. before, just make sure you clean it before welding and do it in a well ventilated area.if possible, use a bolt that came off the car, they are very strong. there should not be any galv.
Reply:This time around, I'm making a boot-leg smart-strings for doing alignments. Its really basic, but SO usefull. I was rooting through my bolt bucket that I toss my extras in for nuts to use when I realized that half the time, I dont know EXACTLY what kind of metal or coating I'm dealing with and which one can put off something nasty.
Reply:if you going to use it for alignments then i'd honestly just use a tape measure. not as easy but will be accurate every time.
Reply:Stay away from welding anything that has a yellow-tinged plating on it...it might be cadmium and its fumes are super toxic!
Reply:I own a plating company.  My point of view is the "yellow" is a chromate conversion coating (like a top coat on top of zinc, cadmium...etc).  Without having an "eye" for different types of plating, the general "joe" wouldn't be able to tell the difference between "yellow" zinc or cad.If the vehicle you're going to weld on is not older than say 10 years, there probably isn't any cadmium plate on the vehicle.  Nuts and bolts on most vehicles are are either zinc with powder coating, "yellow" zinc with the chromate conversion coating, or "Tin-zinc" with a dull flat grey color that's lighter than regular "galvanized."  Straight  "galvanized" is not used on a modern vehicle because the needed tighter thread tolerances are crap.  the nuts/bolts that are galvanized wouldn't be conducive for a vehicle's purpose.  If you see a bolt that looks dull and gray, chances are its "Tin-zinc" or "zinc-nickel.".  Those last two plating processes are starting to phase out regular zinc plating.  All plating can be welded over IF need be. Just use common sense. If its zinc or cadmium plated, just make sure you have plenty of outdoor ventilation and just do NOT breath the smoke plume. To weld a small bolt, it's going to be a rather quick tack like weld. You can hold your breath in that short time period while placing a bead down on a nut or bolt. That's what I do.  I've also used a small fan set up outside the weld pool that sucks (not blows) the smoke away from me without disrupting the shielding gas.Last edited by SuperArc; 04-09-2012 at 03:23 AM.Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member
Reply:Have a bench grinder?Use some locking pliers, like vice-grips or similar. Grind the coating off the head of the bolt, as best you can. Never weld through coatings unless you have no choice. It's rare for cadmium plating to be used these days, except for aircraft parts.
Reply:it might be cadmium and its fumes are super toxic!
Reply:If I need to weld some bolts or nuts, I usualy burn the zinc coating with oxy-acetylene torch. I'm not worried about safety, because I weld only few nuts and bolts monthly.
Reply:Originally Posted by ravseljIf I need to weld some bolts or nuts, I usualy burn the zinc coating with oxy-acetylene torch. I'm not worried about safety, because I weld only few nuts and bolts monthly.
Reply:I keep my head out of the smoke, AND have good ventilation, AND wear a respirator.  I figure the $30 something for the respirator is a very cheap cost to avoid health problems.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Originally Posted by AndyAI keep my head out of the smoke, AND have good ventilation, AND wear a respirator.  I figure the $30 something for the respirator is a very cheap cost to avoid health problems.
Reply:Damiens I cant help you with your question, BUT, welcome and no question is stupid (although the person answering it can think it is).The guys can get a bit too upity sometimes but don't be afraid of asking. I'm a smart guy but I must admit (seeing no one is listening) there is a little bit of stuff I dont know soooo dont be intimidated. If some one carries on as if your stupid, politly tell em to f themselves and then go into the settings at your end and block their posting. Thats what I have done and you never see any more of their crappy attitude (cause life is too short). As far as making tools and stuff, we all do it and I for one never thought to ask what those coatings were either, see your not alone. thanks you have contibuted to me being ALL KNOWING.Last edited by dumb as a stump; 04-10-2012 at 10:03 AM.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:bolts have a coded stamp on the top of them,for exmple 8.8 or 12.9 the first numbers are relative to tensile yield,8=800kpa 12=1200kpa,the second number is to tell you what % of the tensile yield the bolt will exeed its elastic limit.if a bolt has A2 on it its stainless steel,watch out though they look nice but have no where near the same tensile or shear strengh of high tensile steel (12.9).These codes can help you if you want to weld them,depending on the application, it can tell you what rods or wire to use.the higher the tenacity the more ductile the rod needs to be to accomadate shrinkage and heat stress.whenever i have been welding high tensile steel bolts ive used 307 stainless,its strong and ductile,good enough for most applications when welding them to mild steel.
Reply:Well, you can weld just about any kind of nut/bolt.  It's just a matter of doing it without causing severe distortion which renders it useless.  The threads can be badly distorted where the nut/bolt won't thread properly anymore.Large nuts can be welded around the entire perimeter sometimes.  This is an acme thread, so it has a built in running fit.Smaller nut welded on two sides only.  This prevents distortion.  It's also a good idea to use a sacrificial bolt while welding.  Just run the bolt into the threads while welding, then remove when done.  Anti spatter on the threads protects them.As far as coatings go. Big shrug   If you have to weld it, weld it.  I had about 100 of these short welds to make, and I dogonne sure wasn't gonna grind the galvy off of every little area   The sky didn't fall in   (For you forensic detectives, this was an in position weld and the pic was taken while the weld was verticaly oriented, it is not a vertical weld, I just layed it on its side for viewing)As a practical matter, you really shouldn't worry about the coating on the base metal too much if there's some ventilation.  The chemicals in the weld filler are deadly enough Should you worry about changing the properties of the heat treated fastener?  Yes.  But when there's no alternative, you have to do what you can to build what you need.Most weld-on fasteners are either in the clamp mode (fastener on opposite of the steel, with bolt going through to the fastener), or where there's little anticipated stress on the fastener as a stand alone means of securing the bolted structure.Last edited by farmersamm; 04-10-2012 at 10:48 AM.Reason: spelling"Any day above ground is a good day"http://www.farmersamm.com/
Reply: Thanks for the replies, this is EXACTLY the kind of feedback I was looking for. Seriously, every one of you dropped great information. THANK YOU!  So, have any of you ever worked with an positive air supply? Any thoughts of the realities of doing actual WORK while using them? I know its overkill for this, but I've been thinking about a couple of simple designs for when I work with paints, urethanes, epoxies and other strong chemicals. SuperArc: Awesome tip for using the fans suction to clear fumes w/o disturbing your shield gas. I am SO going to use that. I've kept on using flux-core wire because I tend to set a fan up to blow across the work.FarmerSam I gotta ask, WTH are acme threads normally used on? I ask because the only time i've ever run into them, was for threads on an old r-12 manifold gauge set. And something tells me, they probably aren't the same as yours
Reply:Acme threads are usually found on most decent C clamps. You also find them on machines like lathes, mills etc for the table or cross feeds, leveling jacks, machinist jacks... usually anything that needs to have a load on it and still turn easily.As far as positive pressure masks, I've worked using them on several jobs. We used to do some confined space work when I worked for a commercial dive company. All dry work inside barges and compartments. The reason they had us do the work was due to fumes and such in some of the compartments. We'd do the work breathing off either the standard dive hat, or a positive pressure mask, depending on the job. I've also used a positive pressure hood to sand blast, and have a rig for painting..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:Originally Posted by JoshfromsaltlakeHave a bench grinder?Use some locking pliers, like vice-grips or similar. Grind the coating off the head of the bolt, as best you can. Never weld through coatings unless you have no choice. It's rare for cadmium plating to be used these days, except for aircraft parts.
Reply:Originally Posted by farmersammAs a practical matter, you really shouldn't worry about the coating on the base metal too much if there's some ventilation.  The chemicals in the weld filler are deadly enough
Reply:DamienS, I use a breathe-cool fresh air respirator  www.turbineproducts.com. It is a machine that sucks in air from wherever it is placed (like outside) and blows it down a tube to a hood you wear. I converted my welding helmet by drilling a hole in the top and putting the air tube into it. I clip the tube to my jacket to keep it from pulling. It blows cool air gently into the face mask but isnt disruptive or obnoxious. It also keeps your glasses from fogging. I feel better using this when the plume is in my face. See my leg leveler post from a few days ago, i made them of stainless steel and i was worried about that pesky hexavalent chromium or whatever it is in stainless thats bad. Im still alive today so that proves it works!Miller diversion 165Miller mig 211Hypertherm pm 30Milwaukee 6230 14 inch chop sawMd 45 mag drill (RIP; fell on its head)New MD 45! Thanks to the esposa!Finally got an O/A setup
Reply:Originally Posted by k45Are you talking about the metal in the welding wire?Ken
Reply:Look, it's rather silly if one thinks about it, but is any kind of smoke good to inhale? Nope.  So use common sense. Don't inhale.Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member