Stainless repair on sailboat (underwater)

[pucketprutectah]

Hiya,
First post here. Just got my Miller mig after 20 years of waiting, and I've got to repair my little darlin'. Thought I'd ask here about it.

So, the bottom shackle on my rudder is apparently weathered and busted apart. I don't have the money to buy new parts, so I'm gonna weld her up myself. I'll be welding stainless, and as soon as I'm done with it she's going back in the water. What kind of gas/wire combo should I use in order to retain the best possible corrosion qualities for salt water immersion?

Thanks in advance!

[yorkiepap]

Hey pucket,
You really need to describe, with pics, the part to get good repair suggestions.

1) What is the power output of your welder?

2) What is the thickness of the repair part.....solid or hollow?

3) Is it steel or a casting?

Your weld area has to be clean & bare. Beveling if necessary to insure a good bond & strength. Wire could be 309/309L or 312 or possibly 316 for optimum corrosion resistance. Gas mix would probably work well with Ar/CO2 not more than 5% CO2. I use 98/2 generally with superb results. Member SundownIII has a lot of experience with boats & marine welding & I'm sure he will offer your best options for success..... give us as much info as possible.

Denny

[pucketprutectah]

Aargh. I won't know the exact nature of the repair until I pull her out of the water. And, unfortunately, I will have a limited amount of time to have the proper materials available and do the repair. Can't afford dry storage for more than a day or so. I apologize for being vague, but that's all I've got.

[ubnoxus]

I do not think Yorkie caught that you were welding stainless, you need a trimix gas, helium, argon, co2. Other than that I cant tell you to much without knowing thickness and all of that.

[JSFAB]

I'm pretty sure yorkie caught the stainless thing, all the alloys he mentioned are stainless. The gas mixes he specified, are also commonly used for stainless.

[yorkiepap]

Hey noboxus,
You apparently did not follow the order of my response as to suggested procedure. Quote: "I do not think"....... correct, you did not think. Quote: "you need a trimix gas"...... that is incorrect. There are very few applications that a tri-mix is needed or required..... a waste of money. Also, SS can be forged or cast just as carbon steel. The OP's indication that he is "welding stainless", also did not clarify if the part he is going to weld is stainless, or he was going to use a SS filler for the repair w/SS wire, thus his comment of "welding stainless" was not entirely clear.

To you & all others, especially the newbies/youngsters learning stainless, who really need to do some homework on gasses, here's the site that will enlighten you regarding gasses, fillers, & applications that are proven & work extremely well. The information from Ed Craig is from years of experience & the science of metal & metal fusion.

Denny

http://www.weldreality.com/MIG_welding_gases.htm

[ubnoxus]

I'm pretty sure yorkie caught the stainless thing, all the alloys he mentioned are stainless. The gas mixes he specified, are also commonly used for stainless.

actually that gas combo is never used for stainless if you have any real background with stainless. 98% argon 2% O2 and trimix are the only gases to be used on stainless and you better be on top of your welding game if you go with 98/2. If he is new to welding stainless it is very smart to use trimix as it gives much better results and is more forgiving.