cast iron to copper air lines

[pillguy]

Hi all,

I have a question on connecting black iron pipe and copper together. Can I do it or is there anything special I need to do?
I sear he'd but could not find anything spe ific on the forum.
The reason I am doing this is to make a cast iron manifold to dissipate heat and moisture right out of the compressor.

Thanks

 

[BADSIX]

they make copper ******* that are NPT on one end and soldered on the other.

 

[38Chevy454]

Copper is a much better heat conductor than iron. Iron is good for vibration dampening vs copper, but I would just use copper for the whole thing.

 

[Bobdog]

Of course you can.

You just need to thread the end of the pipe and use a copper sweat x pipe thread adapter. In the case of big pipe, you would use a companion flange.

 

[awdblazer]

you need a dielectric union between the two

 

[CNGsaves]

Sounds like you're trying to re-invent the wheel in terms of making your own Franzinator.

Use GJ black line at top for Search, then scroll down to Advanced Search, and put in Franzinator airline and you'll find lots of threads.

For DAYS of reading, just Google as follows:
> > > > Google > > > Franzinator

 

[larry_g]

you need a dielectric union between the two

You sure? I've never seen one for any copper tube that runs from the cast iron pump head to the steel tank. Never seen one on a cast iron engine block either.

Can you provide a recognized source for your statement?

lg
no neat sig line

 

[pillguy]

Hi Guys,

Thanks for all the comments. I ended up finding the franzinator threads and was able to pick up parts yesterday. Worked on putting it together, but one challenge has been installing pipe on either side of the double tapped bushing that goes into the mallable T fitting. The thickness of the casting limits the length of the threads for installing both pieces of pipe. I will put up a picture or two.

Thanks for your help.

Saved me about $150

 

[pillguy]

Here are a few pictures

Here is the other showing the inside of the double tapped bushing and the lack of threads to install the remaining components.

This is what I cannot install

Sent from my Nexus 7 using Tapatalk 4

 

[onewaydave]

Grind back a few threads on the male end and reinsert.

Dave.

 

[Bobdog]

you need a dielectric union between the two

No, you don't.

 

[Alchymist]

you need a dielectric union between the two

Dielectric unions are meant for electric water heaters.

 

[RPH]

Dielectric union are used to stop the galvonic reactions between dissimilar metals. Has nothing to do with the electric versus gas. Plumbing code requires them when going from one metal to another. Iron to copper or galvinized to copper.

 

[Alan Douglas]

I have a forced-hot-water heating system with copper pipes and 12 cast-iron radiators, installed around 1950. It has never leaked.

 

[Alchymist]

Dielectric union are used to stop the galvonic reactions between dissimilar metals. Has nothing to do with the electric versus gas. Plumbing code requires them when going from one metal to another. Iron to copper or galvinized to copper.

Used on electric water heaters because of the potential for stray electric currents through the pipes, which causes the galvanic reaction. If there is no electrical force, no reaction. Very unlikely in a compressed air system. Most compressors use a flex hose of some type between tank and piping anyway, lessening the chances of galvanic action even further. Never ran across a dielectric union in an air system. YMMV.