brass tubing

[hoppercar]

seems like I read somewhere one time, not to use brass tubing on model boilers?...something about about the zinc can leach out over time? can anyone shed some light on this? I have used brass tubing from pm research for years, they have pipe nipples of various lengths at very good prices. ..I have never experienced any trouble with them?...

[gwrdriver]

The generally accepted rule is no brass in the pressure vessel structure (shell, stays, bushings, etc), for the reasons you state. For external renewable/replaceable components (tubing, fittings, gauges, etc) brass is acceptable although bronze is preferred. The exception is low pressure, low volume, low service time "toy" boilers (Mamod, Wilesco, etc) where exposure to harm is relatively low and which fly under the radar.

Whether the use of brass in toy boilers suggests that brass in other boilers should be acceptable is a conversation for another thread.

[SteveM]

You can get copper tubing, so if you can use that, you should be good.

Steve

[hoppercar]

where can I get hard drawn copper tubing with a wall heavy enough to thread for m.t.p.

[Builder01]

Copper tubing should probably be terminated with a silver soldered cone union, rather than threaded with a MTP. PMResearch can supply you with either heavy wall brass tube that can be threaded for MTP, or, cone unions for use with copper tube.

David

[Glenn Brooks]

Any good plumbing supply store will carry thick wall copper tubing. Most hobbyists use type L tubing. This is the medium thickness pipe. Plenty heavy and strong for hobby work. hardware stores that cater to industry (not the Home Depot style DIY blister pack merchants) also often carry it.

Generally one doesn’t thread copper pipe. Better to buy or make brass or bronze threaded fittings and sodder them on.

Glenn

[ccvstmr]

When in doubt, search McMaster-Carr. While they carry some straight copper tubing, you'll find a better selection of brass tubing with various wall thicknesses. Call in the morning...usually get next day delivery. Carl B.

[Rwilliams]

I spend many hours each week working with full size steam locomotives. More than once I have been called upon to machine bronze fittings that are then silver brazed on the end of the copper tubing to complete the new steam line. Have yet to see threads on the copper tubing in full size steam locomotives. The bronze fittings allow for use of proper size wrenches instead of the hack damage of a pipe wrench. The end result of application of pipe wrenches to fittings designed for a flat jaw wrench has caused me much work. Some shop crews should not be allowed to go near a pipe wrench without supervision.