Black Iron can I weld it?

[hit_em]

the boat is only used in freshwater, but the engines are chevy 350's older ones, as for hp I have no idea, I had thought about using copper but they will be along the bottom of the boat and the guy had said that he runs it in shallow water and runs into objects the odd time so that made me change my mind with the copper. theres half of the old set still there I was going to use the parts that were there to give me an idea of how long and how many, but if you could give me a number that would be greatly appriciated.
Thanks
Jay

[aametalmaster]

Don't weld the hardware store version fittings as they are junk steel. You want socket weld fittings from a place like http://www.mcmaster.com/ and they can be welded to your black pipe...Bob

[hit_em]

how would I be able to tell the difference between the good and the junk?

[phaxtris]

thanks for the help guys, I gave it a try and it seemed to weld fine, now I'm going to get some end caps and pressure test it tommorow. How can you tell if it's cast iron or forged steel?

when you grind cast iron it gives off red sparks vs bright yellowish sparks that carbon steel gives off, or try to cut it with a torch, you can only cut carbon steel with a torch

[aametalmaster]

The forged ones will be smooth, the cast hardware ones look like junk to start with and will bubble up when hit with the mig...Bob

[hit_em]

the one I welded today didn't bubble or anything i thought it actuall welded pretty good, but I'm still learning. I'll try the griding thing and see what happens, but what would happen if I did use the junk steel one"s

[SundownIII]

I would think that about three lengths of 15'-20' 3/4" pipe would be the gracious of plenty. The normal heat exchanger for the 350cid chevy block (used by mercruiser, omc, volvo, crusader, etc) is only about 6" in diameter and 24" long.

Is the owner planning to just use the built in circulating pump mounted on the engine or does he use an aux. pump to circulate the water thru the keel/hull coolers. On most inboard installations with "freshwater cooling", there is a separate pump which moves the raw water thru the heat exchanger.

The reason I asked about gas/diesel, is that diesels generate much more heat and therefore require more cooling.

Still think that I'd use copper and maybe build a shield to protect the cooling tubes from grounding.

Just my .02.

[SundownIII]

After going back and reading my last post, I had to smack myself on the forehead. Not trying to cut you out of a job, but if the barge is operated only in freshwater, why does the owner want closed system cooling?

Here on the Chesapeake Bay, most of the gas boats are raw water cooled anyway. The engine will wear out before it rusts out.

If, like you say, the barge is going to be operated in fresh water only, drop the pickup over the side (with an inlet screen) and be done with it.

[hit_em]

I didn't really look at the engines too much just the plumbing on the exterior of the boat, but I would think he just uses the engine to pump it through. they are gas engines. But wouldn't copper corride quicker because it is a softer metal, and boats put off electrolises thats why they have the pads on the drives, I forget what there called. this barge is used in a marina so theres boats all around it, thats why I would think it would corrode quicker.I could be wrong it has happened before

[hit_em]

I asked him this too, but there not marine engines there out of an old pick up trucks. he uses anti freez in the cooling system. Thanks for the numbers I appriciate it.

[SundownIII]

Hit Em

Been around boats and marinas all my life. 50 years ago nearly all the deadrise boats built here in Deltaville, VA were powered with converted gas truck engines. Only keel coolers you ever saw were on the diesel engines.

I assume the owner is using a "dry stack exhaust", ie. a muffler like on a truck, rather than a marine exhaust, because if he's using a marine exhaust system, he has to pump water from the lake/river to cool the exhaust manifolds anyway. Most of the corrosion (rust) will occur in the elbows rather than in the engine.

With all that said, the best/easiest/quickest solution which meets your owners needs is go to HD or your local plumbing supply outlet, buy 20' lengths of 3/4" galvanized pipe, 4" galvanized nipples, and 90 degree galvanized elbows, screw it all together, wire brush the threads you can see left exposed, apply a heavy coat of zinc chromate and be done with his external cooling system.

Quick, clean, and cheap. Will last a lot longer than black pipe.

Just my .02.

[hit_em]

I dont know too much about boat motors so that kinda suck about this job, but I never turn away work. maybe thats what I will do thanks for the input, I'll go take another look at the job a make a final decision Thanks again

[TomVeatch]

I dont know where t get 90 degree angles or else that is what I would do. the only thing close I have found are the quick fab squaretubing elbows, but the guy wants round tubing and I dont kow where to get elbows and I dont have a bender. I'm openedto suggestions I was just considering this way as an option.

Oops. Sorry. I misinterpreted prior posts, thought you were using black pipe like that used in plumbing air/gas lines.

[hit_em]

That is what I am talking about is black pipe.

[Fat-Fab.com]

come on guysI need to have an idea to present to the client tommorow, looking for some good suggestions. he want this done right away.

Help would have come much faster if you would have laid out the whole project in the beginning

You are not talking about "black iron" pipe
You want to be using steel pipe as "black iron" pipe is cast and will not hold up to much impact


Steel pipe and weldable fittings are available at your local plumbing store.
The fittings are forged and prepped at each end with a bevel for welding.


TJ