Welding Tips and Tricks

This was without a doubt the worst cast repair I ever have done. As the pics show, this exhaust manifold had a pretty significant crack. I was able to make homemade dye and find the ends of the cracks...then the fun began. This part is off a 20 year old boat so I knew it was going to be badly contaminated so I chose Sil Braze to repair it. The metal was so contaminated that it would vaporize as soon as I lit up on it. I went over the crack with the torch to try to boil out some crap and that seemed to make the braze stick a little better but when I water tested it, it leaked like a sieve around the edges of the braze. I tried to wash the braze out further and no luck so I ground out all the braze and tried Inconel. It didn't work because Inconel has a sluggish puddle and I needed to laywire this.. I had to keep the arc in one spot a little too long to advance the puddle and the cast was burning back and evaporating so I switched to N82. Much better puddle control and I was able to get it welded up and she held. I preheated for the brazing but I just said screw it for the welding and just kept ironing in the filler and she held up fine. Not my prettiest weld but it saved my buddy 5 large for a new manifold and it worked. God I hate anything from boats Sorry the pics aren't in the right order but you guys get the picture.

Cool that you were able to make that happen!

Consider trying 312 SS on CI of crappy, dubious condition, next time.
It wets out nicely, adheres better than 99 Ni, etc. Fire off on filler rod (lay rod as you mentioned)

Additional prep that works for any CI--fire off TIG torch on bare min amps, play the arc around
the beveled break. This vaporizes contaminants, de-gasses and with decent CI--makes a frosty,
white appearance. Play arc around more and little, chrome/shiny balls appear on surface. Some surfaces
may show a brilliant, chrome like, honeycomb-- pure iron cast structure minus all the casting additives.
This is elemental, close to pure iron. Whatever filler is then to be used, it will bond readily to these
little melt balls.

On heavier sections, like 1/4" +, well made CI can bond back to itself as the little chrome balls are coaxed into puddles.
I don't recco welding CI w/or filler, however.
Chronatron sells a hi-zoot, CI prep rod-stick use, that gouges, de-gasses and cleans in a similar way to
the TIG method. After seeing and trying a salesman's demo on this rod, I tried the TIG method.

Older mercury water jacketed ex. manifolds were cast with some not-nice additives/contaminants.
Those are well nigh impossible to successfully weld.

Thanks guys.

That came out really good. I notice most of the openings are taped shut, did you use a purge on the backside?

MarkL wrote:That came out really good. I notice most of the openings are taped shut, did you use a purge on the backside?

No Mark, that was for leak testing. I wasn't able to pressure test it but my friend came over and picked it up and was going to put on back on the boat last night and test it and said he would call if it leaked and I never heard from him. They had a boating trip planned that's why I did this on a Sunday and it was a bitch but I guess he's boating today and happy. I wish all jobs paid as well as this one did

That is a great repair on some tough material. Im impressed. Cast is a b word

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exnailpounder wrote:

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Didn't read...too many words. So by looking at the pics, you took a perfectly good welded/repaired manifold and ground off the weld, and then drilled two holes in it and beveled the crack you discovered?? What were you drinking? Were you just trying to see how it was repaired?

electrode wrote: Didn't read...too many words. So by looking at the pics, you took a perfectly good welded/repaired manifold and ground off the weld, and then drilled two holes in it and beveled the crack you discovered?? What were you drinking? Were you just trying to see how it was repaired?

Judging by Jeff's recent "behaviors" perhaps there's something wound a little too tight?

electrode wrote:

exnailpounder wrote:

20170528_143046.jpg

20170528_082250.jpg[attachment=0]20170528_084143.jpg

Didn't read...too many words. So by looking at the pics, you took a perfectly good welded/repaired manifold and ground off the weld, and then drilled two holes in it and beveled the crack you discovered?? What were you drinking? Were you just trying to see how it was repaired?

I read about reverse engineering and had to find out for myself. I have actually been going easy on the drinking lately...can't you tell?

Nice save!

I've only done the one cast iron job so far (alum bronze) but I've done several cast aluminum ones that were dirty from years of use - so I feel your frustration on this one

MinnesotaDave wrote:Nice save!

I've only done the one cast iron job so far (alum bronze) but I've done several cast aluminum ones that were dirty from years of use - so I feel your frustration on this one

Yeah this was a royal nightmare. I have had alot of success with brazing but this piece just wasn't having it. My buddy called me today from the lake and told me it doesn't leak a drop. I was sweatin it. I couldn't have pulled it off without the knowledge I have gained from hanging around here. It's funny...you can even learn something from the noobs that come here with problems...they make you look for the answers to your own problems...and from the other life-long students as well.

I know the feeling well, I've sweated many times wondering if an odd repair will be ok.

I wouldn't be tig welding properly in general, or done that tig braze, if it wasn't for Jody's videos/website.

exnailpounder wrote:

MinnesotaDave wrote:Nice save!

I've only done the one cast iron job so far (alum bronze) but I've done several cast aluminum ones that were dirty from years of use - so I feel your frustration on this one

Yeah this was a royal nightmare. I have had alot of success with brazing but this piece just wasn't having it. My buddy called me today from the lake and told me it doesn't leak a drop. I was sweatin it. I couldn't have pulled it off without the knowledge I have gained from hanging around here. It's funny...you can even learn something from the noobs that come here with problems...they make you look for the answers to your own problems...and from the other life-long students as well.

Yeah, cast iron can be a pain but I have always had good luck with it either by oxy/acetylene brazing or SuperMissileWeld. As long as it is fixed it doesn't matter what you used and it looks like you did a great job.

electrode wrote:

exnailpounder wrote:

MinnesotaDave wrote:Nice save!

I've only done the one cast iron job so far (alum bronze) but I've done several cast aluminum ones that were dirty from years of use - so I feel your frustration on this one

Yeah this was a royal nightmare. I have had alot of success with brazing but this piece just wasn't having it. My buddy called me today from the lake and told me it doesn't leak a drop. I was sweatin it. I couldn't have pulled it off without the knowledge I have gained from hanging around here. It's funny...you can even learn something from the noobs that come here with problems...they make you look for the answers to your own problems...and from the other life-long students as well.

Yeah, cast iron can be a pain but I have always had good luck with it either by oxy/acetylene brazing or SuperMissileWeld. As long as it is fixed it doesn't matter what you used and it looks like you did a great job.

But doesn't oxy put in too much heat? Or is too much better sometimes? I was pleasantly suprised that it didn't crack because I didn't pre-heat it but I think the shape of the piece and the area of the crack worked in my favor. I'm going to get some 312 for the next one but I was really happy with the way N82 worked for me.

I almost had to do a cast repair with oxy fuel brazing and go out in a limb and try it on a vise base but some dumbly left the oxygen on one night and it all leaked out(little bastard ) but while we are talking about it, got any tips or suggestions for oxy fuel brazing cast?

Brazing works because the torch flame heats the material (and surrounding piece) at a proper rate to get up to temp for the flux coated brazing rod (or you can buy bare and dip it into some good flux). You just have to cook the crap out of the properly prepared joint without melting the base metal and then braze away. It is easy once you have some practice. Use a brazing torch and not just a cutting head and set the flame properly. Then either let the part cool on its own or put it in the oven and do some post heat cool down. Brazing will not melt when the manifold is put back into service either. I was taught how to braze from a guy that built/welded submarines in the Navy. I don't think they brazed anything on the subs but he was a very qualified welder and repaired cast iron machine beds when they got broke, in some cases rebuilding the missing chunk all out of brazing rod. And once you get good at it you should be able to lay a bead with a stack of dimes look. If the part is too hot you will have a puddle that goes everywhere and doesn't look so professional.

edit: I must add that a manifold repaired with brazing will not work on a race car or a leaned out engine climbing a steep incline (for example) if the manifold ends up glowing red hot! If the manifold is rusty brown looking you are most like going to succeed. If it is white, as in run super hot, do not braze.

Farmwelding wrote:I almost had to do a cast repair with oxy fuel brazing and go out in a limb and try it on a vise base but some dumbly left the oxygen on one night and it all leaked out(little bastard ) but while we are talking about it, got any tips or suggestions for oxy fuel brazing cast?

I think this is an excellent video on oxy fuel brazing:
https://www.youtube.com/watch?v=OL-2yNndGC0

MinnesotaDave wrote:

Farmwelding wrote:I almost had to do a cast repair with oxy fuel brazing and go out in a limb and try it on a vise base but some dumbly left the oxygen on one night and it all leaked out(little bastard ) but while we are talking about it, got any tips or suggestions for oxy fuel brazing cast?

I think this is an excellent video on oxy fuel brazing:
https://www.youtube.com/watch?v=OL-2yNndGC0

Pretty much what I said only 100 times better! Great video, I couldn't have said it better myself.

Hello

I was "strongly" suggested to use nor 312 but 29/9 electrodes (inox repair electrodes) if stick welding cast iron.

just for you to know, I did not try at that point but the information comes from a retired professionnal that used it preferably to the 99 Ni, or bi metal FeNi .

he use them "cold" (only gentle heating to avoid thermal chock)

due to the ease of welding with inox electrodes I can understand that if it does the job it is preferred.

I tried 316 on grey cast iron and had immediate thin crack in the middle of the weld

All the best

Jeff,

I'd love to hear your thoughts on the homemade dye-penetrant. While Jody talked about it, he didn't demonstrate it.

Steve

Hello,

I missed that one, but before finally buying 2 spray for about 25 USD, (and no regrets) , I did have a thread on that subject of "old times crack control "

essentially the penetrant can be red gasoil as we use here for trucks, then 30 minutes later cleaning , and using talcum or any thin white powder with a good absorbtion capacity.

others use oil (for etancheity testing) dripping for 24 hours and using "silk paper" on the other side of the part"s wall .

I do not regret the specific products, they are very precise and allow to see bad "glued" weld ( no penetration)

as I had to file and get rid of all the bad weld until the white spray gives a white surface everywhere (if you leave it for long it
will detect finest cracks or spaces, it really seem to be a very thin powder that is very efficient to attract the dye.)

it should be easy to clean afterthat, due to multiple testing.

the less dye and the less revelation spray are used, the better the results (cleaner reading, easier cleaning)

worth the small price if you want my advice.

best regards

Olek,

I use the professional products, specifically the MagnaFlux brand, very often. I'm interested in how the "home-brew" version works, and from what you said, and what Jeff did, it seems quite successful.

Steve

it works certainly at an accepteable quality level, (some said they never used the commercial products, but other answered that they are available since 40 years at least

I suspect the size of the particle of the white "reader" spray is what ameliorate the precision.

I use different very thin powders as microfine Teflon, talcum, "diatomite (silicium dioxyde), and the powder of the white spray is really thinner when rubbed between fingers it is surprising (try it if you did not

so better readings probably with the specific products. I am no welder but did discover bad weld on weld joints that I did not see even with a magnifier.
The easy cleaning is probably also an advantage

btw a method was given where a white powder (calcium carbonate) is delayed in water , brushed, let dry. It makes a very thin coating as a "silk paper"

when dry , petroleum is brushed on the other face of the part. if it goes thru it makes very visible stain on the white coat



regards

exnailpounder Please forgive the stupid question I am about to ask.

Why, in the first place, would someone want to try to repair a merc manifold? They are ~$250 brand new and you dont need to worry about any internal cracks that you can not see? I can understand trying if it was your own time or you are doing it for free. These things only crack for two reasons...serious overheat, or freeze damage. Usually they go bad from sediment build up in the internal space.