food grade stainless steel project

[greenthumb]

I am not ready to attempt it yet. However, a goal project of mind i to build a maple syrup evaporator with a stainless steel pan on top and steel fire arch. the arch would be made out of maybe 18 ga steel. the pan on top is stainless steel about 2feet by 4 feet. with divider's in it to seperate freash sap from sap that is cooked down. Well my question could I even attempt this with arc welder. Can you weld stainless steel that would be of food grade with an arc welder. thanks

[Hobart Expert Rock]

GREENTHUMB..........FOOD GRADE STAINLESS IS TYPICALLY 304..... I THINK THE BEST WAY TO DO THIS IS WITH TIG......... ROCK...
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[morpheus]

Dan works at that food place. didn't he post some pics of some projects from work that he welded with MIG ... let me see if I can find that post.


edit: Dan's project from work http://www.hobartwelders.com/mboard/...&threadid=1207

- jack

[Guest]

Yes you arc weld food grade stainless, use Solar "B" flux on the back side if you want 100% penetration and clean it real good after welding. If you don't need 100% penetration, you can weld it without flux, just don't penetrate, or make any 'sugar' on the inside. Welding narrow gage stainless is a blast with stick arc, you just have to do it by Braille, cuz ya can't see the puddle very good.

[Dan]

Arc welders (stick) aren t the best choice for welding thin gauge material. For 18 ga and thinner my first choice is TIG and then MIG. I honestly wouldn t even consider stick welding thin ga material myself. On the stainless steel you will either want to back purge, use back up bars or the flux that Rocky mentioned. My first choice for food grade stainless is 304L and then 304.My choice of filler metal for either one of these is 308L.

[JTMcCracken]

Having worked a lot in food plants, I'll throw in my .02, On something like the pan you describe, the welding process used isn't as important as the design and execution. Any process you can get an acceptable weld out of will do. More critical is that you leave no cracks or crevices that are hard to clean and will hold bacteria. The pan would need to be welded on the inside, and most likely, the weld bead would have to be ground to a smooth profile, and the ground surface buffed smooth with a flapper disc even tho it would be hard to get to. Most would require the outside of the seams to be welded also, and most likely buffed to a smooth finish as well. At one place I used to work quite a bit, the inspector would put on a cotton glove and rub hard all over the fabricated piece, if he could snag his glove on your work, he wouldn't buy it. Company policy was if an employee got cut or scratched and drew blood they got the rest of the day off with pay. You guessed it, anything they could cut theirselfs on, they would. Also consider if 18 ga. will warp in the heat and design accordingly. Long winded I know,
regards,
JTMcC.

[Thomas Harris]

I have made some handcrafted finishing pans for myself. I used 304 stainless steel in 24 guage and silverbrazed it together. I also welded some with a mig in 20 guage. And the first one I made was tigged by a pro after I did the cutting and bending. A simple flat pan is quite easy to make. For lack of the box brake I simply notched the rectangular piece of stainless,(hand shears and much effort!) clamped some boards onto it securely, and bent and beat that sucker really hard with a rubber mallet. The one the pro welded is by far the best. It has a nice draw-off fitting on it too. One thing about silver soldering stainless....joints must be secure before the heat is applied or it will warp and cause the joint tolerances to be way to large. The solder will not flow if this happens. The mig method is possible, but I had a tough time getting four watertight welds on the outside corners of the pan. Finally did though. Now for the arch part. This is actually my pet project now. I have been making syrup with propane stove for awhile and want to increase my number of taps and gallons of syrup. Propane will be way too exspensive at this scale, except possibly for finishing purposes. If you are thinking of making a true evaporator consider that commercial units have convulated flue pans in them. This would be very difficult for a home workshop to fabricate. On the other hand, a flat-pan evaporater is not out of the realm of things. Are you planning on just making syrup for personal use? If you sell and produce for the general public there are some special considerations. As far as baterial build-up in the unit is concerned, the boiling nature of an evaporator sterilizes the unit quite continuely. One last thing if you do fabricate yourself a unit. Make sure you use safe materials. That means watching out for cadmium, lead , etc. This is really important for the arch too, if you will be buning those hot fires inside an enclosure or anywhere you could inhale metal vapors. Good luck next spring!