AQUASOL Soluble Purge Dam Paper
How to make a Purge Dam

Picture A

For small diameter pipes, simply position a wad of ASW paper several inches down into each section to be joined.

Picture B

For larger pipes (4" ID. And larger) cut the paper to a circular shape whose diameter is several inches greater than the pipe ID. (eg. For 6" ID. Pipe, cut 8" diameter paper circle.

Picture C

Trace or impress the pipe ID. On the paper and fold on this line to form a 90d lip. Insert the dam into the pipe with the lip towards the weld prep.

Picture D

Peel tape from backing and use tape strip to fasten dam in place. It may be desirable to punch a small hole in the dam to facilitate the evacuation of air when purging.

Picture E

For pipe larger than 28" in diameter simply splice two or more sheets of Dissolvo paper together with Dissolvo tape, and proceed as in step B,C and D.

Picture F

After the dams are in place, Argon or another purge gas may be introduced through the root gap with a needle valve connected to the gas line.

Picture G

If one end of pipe is accessible, the purge gas may be introduced through a hole at the lower end of one dam. A vent hole should be made at the upper end of the other dam to allow air and gases to escape. It may be desirable to cover the open root joint on the outside of the pipe with tape to prevent gas leakage.

 

 

 

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