Sanitary tube welding -- a few questions

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I'm looking to possibly take on a local sanitary tube tig welding job for a small craft brewery, but only if I feel I can confidently deliver a high quality finished product. I have about 6 years of tig welding under my belt but mostly on automotive performance parts that don't have as strict of a process as sanitary and other types of welding jobs, so I want to be sure I'm approaching this in the right manor.There's a quick initial job this brewer would like done and that's welding on a tri-clover flange to a brew kettle. Now this item can be cleaned inside pretty easy it looks, but I'm looking for tips on how to approach the job after what I've been reading in regards to sanitary welding. On to the questions I suppose....-Cutting the hole for the flange, can I use a regular cutting/lubricating fluid, or would it have to be something of an organic type? What also would you guys consider an acceptable means of cutting the hole? I have a ton of bi-metal hole saws as well as some step bits, but this looks like it'll be a job for a 1.25" hole.-Prepping the cut hole, and radiusing the end of the tri-clover flange tube--carbide burr use only, or can sanding rolls, sanding discs, and/or 3m "cookie" wheels also be used for finishing? -Cleaning up the metal after cutting and prepping but prior to welding, can I use acetone still or does it have to be something else like denatured alcohol, etc.-Wire brush -- use a dedicated sanitary stainless brush only I believe I read-Gap or no gap between flange tube and kettle? A local fabricator that has done sanitary work did suggest to me that he gaps his .065" tubing at .035" and then uses that size filler. I was also told to cover up the 3/4 of the joint in some manor so as the keep the back purging gas from escaping. If I can get away with no gap, .035", and full penetration then should I try it? Something to keep in mind, my tig is very basic and does not have any pulsing features. Not sure if that would change the opinions or suggestions to the last question above.In the meantime, I'm currently doing practice welds on some scrap .065" stainless tube, although the ends, while cut flat, do have a roughness left to them from the bandsaw and I'm sure aren't allowing my best attempts to shine through.Last edited by 91TSiGuy; 07-07-2011 at 10:38 PM.
Reply:I have never tigged stainless but I have done sanitary stainless on our dairy with a mig running .030 stainless.  I have used a holw saw for cutting holes and it works. Depending on the grade of stainless it can drill hard. Stainless is not as touchy as aluminum for contamination. I like to use sanding disks and flap wheels for prep and polish. A mounted stone or carbide works if you need to take alot off. Just remember  you need to polish everything so dont get carried away eith the grinder. I also like to "tape" off around the area to keep dingle berriers from sticking but with tig that shouldn't be a problem.  I welded a 2" triclamp onto a 6000 gal milk tank this way cause the dairy equip guy wouldn't lay on the floor.Millermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:The stainless I'll be working with will be your basic 304. At work, we use a lot of that and 304L in custom turbo exhaust manifolds I make. It's mostly been schedule 10 weld els I've been using in the past years, but more recently I've done a few in tube and have back purged them which is also why I feel I might be able to tackle this local job. The schedule 10 type manifold we never really purged or have had any problems (yet) from not doing that.I think when it comes to the prep and polish, I'm just over worrying about how "polished" it needs to be. Say, is the suface texture left from a 120 grit sanding drum going to be too rough and leave a spot for bacteria to form? I don't expect to  be running the sanding drum around the inside of the tube to clean it up and leaving marks like that inside of it, but I do want to make sure there aren't any burrs left inside the just-cut tube.
Reply:For 3a dairy I use scothbrite wheels on a die grinder and polish to match surrounding area.Millermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Cutting the hole in the tank, a hole saw will work, drill slowly with oil and lots of pressure, stainless work hardens, hence the sharp tools, low speeds, and pressure.I dont recommend a 1/2" stub ferrule as they will warp if the hole isnt prepped well.To install a 2" fitting I first cut the hole 1 1/2" prep it with no burrs then pull it out to 2" using a homemade puller (cone shaped with a hole for a pull bolt) this expands the hole to match the ferrrule ID and leaves a nice radius on the tank to match the fitting.Then reprep the hole, try to get the hole and ferrule to butt up with no gaps.Tack on the ferrule, I used aluminum foil taped inside the tank to cover the hole and retain the purge with the tape far enough away that it doesnt get too hot. I used a matching fitting on the outside clamped or screwed onto the fitting for my purge hose, then weld it up hopefully to get 100% penetration, if not, grind it smooth then finish with sanding bobs or 3 m wheels.Use only dedicated grinding wheels, polishing wheels, if they have been used on steel it will contaminate your weld or surfaces finished with it.The final finish should be smooth with no pits or craters. I liked the 3m 2SFN wheels to finish with.These are the basics of it, I could show you a lot easier than trying to tell you how to do it..........I used an abrasive cut off saw for the most part.If you have questions just ask and I will try to answer them the best I can........Last edited by popspipes; 07-08-2011 at 01:38 AM.Reason: more infomike sr
Reply:I really like the sound of the cone puller tool you made. Not sure if I have the capabilities to make one of those up in the time frame I have, but something to think about down the road. Do you pull it out far enough take your weld off of the tank and more as if it were part of the tube? We're currently waiting for a longer ferrule to show up because the current one the brewer has places the tri-clover clamp too close to the kettle and you can't use the thumb screw.Great info so far otherwise, thanks guys.
Reply:Originally Posted by 91TSiGuyI really like the sound of the cone puller tool you made. Not sure if I have the capabilities to make one of those up in the time frame I have, but something to think about down the road. Do you pull it out far enough take your weld off of the tank and more as if it were part of the tube? We're currently waiting for a longer ferrule to show up because the current one the brewer has places the tri-clover clamp too close to the kettle and you can't use the thumb screw.Great info so far otherwise, thanks guys.
Reply:I do a ton of sanitary at work, all tools are dedicated to just that not to be used for anything else. This is how we cut itAll cuts are square and burrs removed with a file, burr, or scotch briteAs far as fitting in to a vessel or doing a stab in we use hole saws and we have a nifty Ridgid stab in toolhttp://www.ridgid.com/Tools/HC450-Ho...l/EN/index.htmAll of our fittings, piping, vessels, and filler is 316, when welding no gap, and a good purge.I will get more pix when I go back to the plant.Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:I like the cold saw mounted on a ridgid vise, the Fischer saw that DSI used was so heavy and cumbersome that one man would have trouble getting it loaded and unloaded....... it is the best way to cut stainless though.That pile of fittings and valves sure brings back memories.....I built several turntables to rotate fittings for repetitive shop work.Last edited by popspipes; 07-08-2011 at 10:04 AM.Reason: grammermike sr
Reply:might want to find out if passivation is required after welding.
Reply:Originally Posted by boatbuoymight want to find out if passivation is required after welding.
Reply:What cutter is that Tozzi? That looks sweet, I built a custom one, but it is bulky and when i leave it on job site, their employees have no problem playing with it.
Reply:Here is some mere stuff, this is the cutter we haveWelding machines, my Syncro 250The lunch boxPurge set upsBuffung when doneInstalledDisclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:any time you can plug the pie/tube you're working on and perge it with argon you're welds will stay clean and pretty on the inside, very little color will and no nasty sugary welds will result.  Just a suggestion.  i tig up stainless steel manifolds for natural gas pump substations, we purge everything out with argon.
Reply:I stopped in yesterday to speak with the one owner to verify a few things about the project.... -if pasivation was needed afterward-verifying that everything was 304, 316, or a mix match for filler selecting-if the longer ferrule ordered had come in yet or not....but he was on vacation this week so I settled for just having my 2 growlers filled.So I had a few  more questions on my mind about the project. First, what is the preferred method with attacking this type of thin tube weld?  Should I be attempting a non-stop weld around the entire ferrule hoping I don't end up in an awkward position or snagging the torch cord on something, one where I'm taking cooling breaks every 3/4-1" of travel and slowly easing off the pedal at my stops preventing cratering, or one where I'm jumping around from side to opposing side to keep warping to a minimum? Walking the cup is something I haven't had time or a need to gain experience with, nor do I think I'd be using it on such a small job as this (I am open to be educated however, and am curious if anyone would recommend that). Second, what differences in prepping and welding would there be depending on the kettle needing pasivation afterwards or not?Third, where can I pick up one of those orbital saws for the low low price of on the house?
Reply:I have used orbital welding on sanitary tube fittings.  If the joint is a butt joint with at least .5" clearance on each side it can be welded inside a closed tube head autogenously.  If less some clever clamping needs to be used.Orbital tube heads and power supplies can be rented weekly and most power supplies will automatically generate the correct welding program for an inputted diameter and wall thickness.Wachs and Tri-tool make decent tube prepping machines which I have used on multiple jobs.
Reply:When I weld thin stainless steel tube, I tried out many different ways of welding to see what works and what warps. I found that if you are welding 1/2" ferrules like I do mostly, you will warp it if you don't keep the heat flowing in one direction.
Reply:I ended up starting the project tonight and welded the 1.5" long ferrule on. I didn't end up with 100% penetration while following the steps of butting it up to the kettle and fuse welding it (had the machine set to 50 amps max but must have been too light on the pedal). Luckily I was able to sit the kettle on its side and put my upper body inside of it and fuse the remaining spots of the joint. I think this ended up putting too much heat into it and ended up warping the kettle some directly on the left and right of the ferrule. I'll try to post up pics of the progress tomorrow or the following day if I can. If anyone has some tips on fixing the warping areas, that would be great as well.While that was a bummer for me, I did end up picking up some dedicated abrasives for this and future sanitary jobs, including some 3" unitized discs for weld polishing, some red scotch-brite style wheels for the die grinder, and some smaller unitized style cylinders
Reply:Here are pics of its current progress:The warping:
Reply:post 13 last foto..i  see one pipe hanger.......
Reply:So what are you going to do about the warping?  Does the customer care?I only ask because I've done a lot of 304L exhaust (and 321) and never had an issue with warping.  Mostly 16 gauge.Anyway, I got a  couple of sheets of .035 thick 304 - nice polish on one side.   For the life of me, I cannot weld that stuff without extreme warping.   Even butt weld, with tacks every 1/2"...   I think I had it down to 28 amps.  I tried quenching and air cooling.  Didn't seem to make any difference at all.Just curious if you have suggestions or came up with a solution.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Ill have to speak with the customer when I'm done with some other small welding things for them and see what they say. It may be fine, or it may be a new ketlle for them out of my pocket. Hopefully not the latter. I haven't had a chance yet to see how I can massage it out if possible
Reply:The customer was ok and understanding with the warping issue, although I'd like to prevent that from happening again. I picked up a Miller Diversion 180 for home use and used it for this project, knowing that I was just going to sell it later down the road for at least a 250amp or larger inverter with the additional features that could have probably helped me out with the heat issue here. Go figure, just yesterday I found a local friend with a Dynasty 200 that they're looking to sell with the variable voltage input I needed for here at my house, but I don't think they'd take "plastic" for payment.Anyway, here's some more pictures of the project. Any and all input is appreciated. I spent a hair over 4 hrs on it with cleaning up and polishing-to-match the welds. The inside of the one pickup tube had the weld sanded down after pics were taken since I was able to reach in there with my long sanding mandrel.
Reply:tozzi that cutter is sweet. the coolest thing i got to cut with are the cutting guides you clamp over the tube and run the porta band trough... just a couple thoughts..... im suprised to see guys running machines with the pedals on... i see it on the kettle to ferule but .065 to .065 sanitary ? the sweetest setup ive seen running around the dairies right now are the miller maxstar 150 on a hand truck with a full bottle of argon a 10/3 extention cord a spot for filler tube and the purge fittings in a tackle box. super mobile to move around and 15A of 120V will get-er-dun. plus lift arc is the coolest thing known to man at this point.. foil tape and foil is your friend! when you are not on tube only welds the ability to "tent" the back purge is key. "flaring tool" for the tie ins sounds cool id like to make on my self. you got pics?
Reply:I've done a few more jobs for this local brewer, learning things as I go and understanding more of what was previously posted above.Now I'm at a point where I'm looking to save time with weld clean up and polishing so I can get these projects done faster and cheaper. I'm having a little bit of a tough time grinding down and polishing the welds at, say, a kettle to tube joint....at least with my current regular and 90* die grinders. I'm using 3" unitized wheels and then a 3" red scotch bright wheel, approximately 3/4" in width trying to get in the tight corner while also keeping the mandrel end from bumping off any of the tank or tube. I'm thinking maybe a larger 5" or 6" wheel would suite me better, and an electric die grinder to save my wimpy 5hp air compressor.Any suggestions on what abrasives to use for my situation?You really need a big end grinder with a scotchbrite on it, you can get in close to the vessel with that big wheel.Disclaimer; "I am just an a$$hole welder, don't take it personally ."
Reply:Originally Posted by 91TSiGuyI've done a few more jobs for this local brewer, learning things as I go and understanding more of what was previously posted above.Now I'm at a point where I'm looking to save time with weld clean up and polishing so I can get these projects done faster and cheaper. I'm having a little bit of a tough time grinding down and polishing the welds at, say, a kettle to tube joint....at least with my current regular and 90* die grinders. I'm using 3" unitized wheels and then a 3" red scotch bright wheel, approximately 3/4" in width trying to get in the tight corner while also keeping the mandrel end from bumping off any of the tank or tube. I'm thinking maybe a larger 5" or 6" wheel would suite me better, and an electric die grinder to save my wimpy 5hp air compressor.Any suggestions on what abrasives to use for my situation?
Reply:I'll most likely end up getting an electric die grinder and 6" disc then. I have a unitized disc at work on the bench grinder right now, but it's 1" wide and wouldn't work too well.......that and it's been used on other metals. I was wondering if something similar to this would work out nicely for filet weld polishing. I just can't swing that price at the moment.http://www.lehighvalleyabrasives.com...ctronic/DetailI'm all for the puller idea, and could use it on the current mash ton job I'm doing. I was looking at these dimple dies to use, but again funds don't allow me to buy this at the moment, http://www.vansantent.com/sheet_meta...imple_dies.htmand two, I'm limited on material thickness on that tool. The last jobs were 18ga, and this mash ton is 16 or 14. It's pretty large, about 3' diameter and 4' tall on its legs.
Reply:I wouldnbt have bought those as the cost is too high period!I used standard B&D4 1/2" grinders with the homemade adapters, the 8" 2sfn wheel from 3m approximately 50 + dollars.The pullers I made out of regular steel, tapered with various holes thru them for the appropriate size bolt. 3 and 4" pullers I used a 1" bolt prefferably grade 8 and fine thread. I used pipe couplings for the outside part with a plate on top of it with the appropriate hole for the puller in use.I used my impact wrench to draw them thru the tank, 10 gage is a bit tough but on 16- 14 gage it was relatively easy. I used a large 1/2" impact and at times I could have used a bigger one ha!  I think all of it didnt cost more than 300 hundred dollars.You dont need that fancy grinder, the 100 dollar versions work just fine with homemade adapters, I use the 2SFN x 1/2 x 1/2" then cut the center out to 1" to fit the adapters, this wheel wont come apart with the extra rpm of the grinder. The 5ACRS 6" wheel will come apart if used over 6000 rpm. I did use a speed control as the wheels last much longer at lower rpm.mike sr
Reply:Originally Posted by TozziWeldingYou really need a big end grinder with a scotchbrite on it, you can get in close to the vessel with that big wheel.
Reply:Originally Posted by popspipesI used standard B&D4 1/2" grinders with the homemade adapters, the 8" 2sfn wheel from 3m approximately 50 + dollars.
Reply:Originally Posted by 91TSiGuyWait, here I'm thinking you guys were referring to straight die grinders and not angle grinders. Which one is it, just to be sure? I'm going to have to make up one of those sheet metal pullers one of these days. Just need some spare time, but I know exactly what you're describing to do.
Reply:These are a couple of the grinders I used, I used this basic setup for several years. I did use a speed control with this as well.mike sr
Reply:My competitor went to this setup but they had to use guards on the angle grinder so they cut the wheel down to fit under the guard. I just wore my safety glasses and used the wheels full size.This setup is much easier to handle than the large straight grinders especially when on a lift andin a tight spot.mike sr
Reply:Originally Posted by popspipes(Second pic)
Reply:They are two piece, the cup part is placed on the shaft then the wheel is placed between the two pieces and it tightens up on the wheel of choice. The outer piece is tapped 5/8 x 11 to screw onto the spindle, that doesnt show in the pictures.mike sr
Reply:I'm with popspipes. I worked at Dupont for 7 yrs. They required a certain RMS finish.I swear by those 3M wheels. We use to have to polish everything to a 2RMS finish which is close to a mirror. Removing scratches is a tedious process.We would start out with fine grit tiger paw on a 4" or 6" grinder.Then use the 3M brown (Medium) pad, then the black that he shows (Fine)Then use a cotton wheel with rouge to get the final mirror finish.It takes a lot of practice to get everything even; smooth and 'not' wavy looking.We would make a lot of special arbors and hole punch those pads to get into tight areas.Edit: Electric tools work better than air, the discharged air would blow contaminants into the work area.Last edited by skelley521; 09-10-2011 at 09:34 AM.Semper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:The 3M wheels and related products are the best in my opinion. The 2SFN on the angle grinder gives a near mirror finish.In the old days we used sanding bobs obtained from Ladish, I used those for years, they were fine till the sandpaper broke then it would put deep scratches in the finish, that was a real pain, also you couldnt get into a tight angle spot with them either. The difference was night and day when I switched over to the 3M wheels, they are expensive but work better than anything out there in my opinion.mike sr
Reply:Yep, I swear by them. We had several different manufactures send sales reps in to try out all kinds of their products. None could compare in my opinion.The plant tried 'many' outside 3rd party contractors. Some of them even used electroplating, but they failed to understand how critical the weld smoothness needed to be.We would weld all parts, then use the lay-wire technique to make the welds convex and cover up lacing/ripple weld finish. Then grind the weld smooth, blending it in and polishing to the required finish.We made all kinds of parts including shafts for mixers and agitators..Semper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:I'm going to have to pick up some of the 6" 3m wheels asap it looks.I did get this today however.Here's a quick test I did with it using a unitized 3" wheel and then 4" buffing wheel (a little too large for this grinder, at least at high speeds) I was also in dress clothes and didn't spend too much time working at it.My current enemy I'm trying to tackle, although the brewer doesn't care so much about the outside weld appearance.This is my current stash of sanding and polishing consumables--not too much, or great at the moment.  I need those larger diameter wheels next.The mash tun project that's getting leg extensions, a tri-clover w/4" extension coming out a foot up or so, and a false bottom.
Reply:Any thoughts on this particular wheel, or stick with 3m only products?  This looks to be able to fit on my angle grinder and has a narrow thickness to it for getting into tight corners. Plus I can get it next day.http://www.lehighvalleyabrasives.com...-4%22-x/Detail
Reply:If it works for you, go for it.They have the 2S fine also.You also don't want to remove to much weld and make the joint weak.If they don't care about the outside, just hit it up to give it a good looking finish and spend you time on the inside.Sometimes giving it that little extra in appearance will always keep them coming back for more Cha-Ching.......lolGood LuckSemper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:I kept 2 guys fabing & 2 guys polishing in the polish room year round.Sometimes the polishers would remove to much weld and bring it back to the fab area to get it built back up.It happens and it's no big deal, it's part of the process sometimes.It does take time and patients, but the more you do it the better you get at it.The different jobs may require you to get inventive with making arbors and such.We even made them for the dremel tools and would use hole punches; stack them and grind them to a cone shape. You can also get the barrel ones and do the same.Edit: It's the flat face that gives the best finish also, but don't let the grinder nut hit  Last edited by skelley521; 09-10-2011 at 03:03 PM.Semper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:Originally Posted by 91TSiGuyAny thoughts on this particular wheel, or stick with 3m only products?  This looks to be able to fit on my angle grinder and has a narrow thickness to it for getting into tight corners. Plus I can get it next day.http://www.lehighvalleyabrasives.com...-4%22-x/Detail
Reply:I went thru yur pictures, some very impressive stuff in there! You need to make up some homemade pullers for the tank ferrules, gets the weld out on the ferrule part and not next to the tank, makes it much easier to clean up.mike sr
Reply:Thanks. I've got a bunch more uploaded on my facebook page, rather than the photobucket page. If you guys want to browse, it's here: https://www.facebook.com/weldiddesignsI'm trying to get into more art type of work, but the sanitary side jobs are paying the bills and buying the tools so I'm not complaining
Reply:Originally Posted by popspipesThe price is right thats for sure, I havent used them, I tried some of the other brands, they didnt last as long or cut as well and some of them smeared if the wheel got too hot.3M wheels are the best but a bit expensive.........
Reply:Originally Posted by dmfa200Can someone please post a pick of this puller that's been talked about.Would a puller work on a sanke keg?I've been asked to weld a 1 1/2" TC ferrule on one.Puller sounds like the way to go, especially if I could clean up the root if doesn't suit me.
Reply:popspipes,Sorry to ask more questions, but I just need a little more info.Is the puller shaped more like a bullet, or is it triangular in shape? And how long should the taper be?Also, do you think this method could be used on a 1/2 barrel sanke keg?Thanks.
Reply:i have a question about sanitary welds.  i understand why you polish the welds,but what do you do about the inside of the pipe. isnt that where the product flows and where bacteria can grow.  i know how to not get sugary welds but, they still are ruff inside compared to how smooth you make it outside.