Avoiding rust

[AMALGAM]

Hey you guys,
I know that there are a bunch of primer and paint products to avoid rusting in metal pieces. But, what about when one works with pipes or tubes? How to avoid the rusting coming from inside out?
Thank you
Alfredo Alamo

[Sberry]

Most of the time when that is an issue the ends are capped, or if joint design permits its seal welded so no moisture can enter. No water, no air, no rust.

[Roger]

Steel tube air frame they put tube seal oil in tubes then seal tubes with final weld.
Here is more information.

http://www.aircraftspruce.com/catalog/mepages/tubeseal.php

[vipermanz]

i have thought about filling tube with expanding foam , doesn't add much weight and would keep it dry

[echo8287]

Toxic foam

Contray to that belief the foam will not keep it dry on the inside and it will make a huge mess. Also if you had to re-weld or add a weld the heating of the foam will be quite toxic. David

[vipermanz]

true, that stuff makes a choking black smoke!!