03-02-2015, 04:46 AM
https://www.youtube.com/watch?v=v8mMQbEkr8w
Here is a good video from Yoshimura on how they hand bend the pipe using heat. You will note a plug in the end of the pipe which is to retain the sand in the pipe that is used as a "mandrel".
As to "machine bent" pipe...this can be done with and without a mandrel, but generally, for the purposes of headers, a mandrel is not used on typical tube benders. The complex bends would make it difficult to remove the mandrel.
Here is a good video from Yoshimura on how they hand bend the pipe using heat. You will note a plug in the end of the pipe which is to retain the sand in the pipe that is used as a "mandrel".
As to "machine bent" pipe...this can be done with and without a mandrel, but generally, for the purposes of headers, a mandrel is not used on typical tube benders. The complex bends would make it difficult to remove the mandrel.