Welding 14ga 304 SS inside and out

By yojimbo (***)

Date 02-09-2013 16:28

Thorzeen-
When doing food grade 14 ga stainless 316L in similar applications other than tubing I have used a fusion technique with backing purge to get both sides of the fillet with one pass and avoid the hassle of over welding, using filer rod and sugaring. Visualize a small approximately 1" long 1/2" X 1/2" piece of stainless angle with the ends sealed by some small triangular pieces and a 1/4" hole drilled into the angle that has a short tube welded to the hole to take a purging hose. You can hold that to the inside corner and purge while fuse welding the outside corner and fusion weld both inside and outside in one pass. Sometimes it takes a second pair of hand to handle your purging tool if you can't co-ordinate the movements, but usually it's a one man job. I suppose you could also get the boxes tacked up with good tight, no/minimum gap and tape it all off to purge the whole box as well. As small as these boxes sound they should make a good purging chamber. My guess is 25-30 amps and find a slow steady travel speed for your tungsten and you should be able to eliminate the problems you're delaing with.

By thorzeen Date 02-09-2013 21:13

Thanks for the reply, yes should have purge welded it, but now that they are welded on the outside with a corner to corner fuse weld ( no sugaring on inside ) whats the best option? low amp small filler rod inside or higher amp bigger rod (keeping heat on rod puddle) and try to move like the wind on inside weld ?

By Superflux (****)

Date 02-09-2013 21:36

Might get by with painting some Solar Flux on the outside before welding the inside.

By Stringer (***)

Date 02-10-2013 01:37

Thorzeen, can you expand on the use? Trying to inside fillet weld 14 ga (somewhat dirty because of no purge, remember) will be difficult because the puddle will want more heat than you better give it because it will burn through and/or warp. Wire brush cleaning will help, as will smaller diameter tungsten, and maybe chill blocks or purge the outside. If it doesn't get too hot on you and you can live with your weld profile, then on to the problem of trying not to distort everything.

By thorzeen Date 02-10-2013 17:03

Hi Thanks for the reply! Company did not want to purge. Weld inside and out. Have done this in the way past and couldn't remember if i added rod to outside for build up or not. I did not add rod to outside weld i fused it using 1/16th tungston . First i spot tacked at around 70 amp, Then fused it at around 40 Amp. NO sugar on the inside. now am inside welding using 1/16 tungston .o45 or .o35 ss fill rod at about 30 amps.

Out of the 7 inside welds i have done so far only one pitted slightly on the outside ( i then lowered heat) it just takes along time!! and hope i can speed things up somehow since i have 76 more inside welds to do . This is for a food grade plant BUT these are mop buckets. I do not have accuse to the solar flux unless i want to buy it out of my own pocket and even then we don't have a sand blaster

TIA

By 46.00

Date 02-10-2013 17:20

Mop Buckets?

By thorzeen Date 02-10-2013 17:27

Yes 12x8x6 ss boxes that will hold water to use with a mop for cleaning up /shrug

By thorzeen Date 02-12-2013 22:31

All corners welded. Took 7 hours ( including wire brush ) 84 6 inch welds. Used .045 rod at around 30 amps 1/16th red tungsten. Bleed through on 5 very small spots ( grinder fixed that) . Thanks to those that responded.

By CWI555

Date 02-10-2013 02:14

That sounded like a candidate for surface tension transfer.
http://www.lincolnelectric.com/assets/US/EN/literature/NX220.pdf