Rice paper purge dam techniques?

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heywell right now i have the luxury of using rubber dams and inflatable bags to purge the pipes im welding and its very convenienti havnt used rice paper at all really, ive seen it... i kind of know that you make a dam, wet some paper to seal the edges on the inside and your done, plus your vent hole etcBut my question is, has anyone here used rice paper to make dams? and used it well? if so, i was wondering if youd like to share your techniques either here in public or thru a PMor a link to a website that describes the process?ty in advance for any information
Reply:I used it quite a bit back in the day. The best way we got it to work was to cover the whole thing with a layer of the tape, otherwise the argon just goes right through it.We would cut a piece larger than the pipe, hold it up against the edge of the pipe and tap it all the way around so that a little indent formed showing you the ID. Then cut it about an inch or so past that indent. Put the layer of tape on, then cut slices about an inch wide from the indent to the edge. Then go around and bend those slices up 90 degrees, that gives you a fringe to tape to on the inside of the pipe. Of course, the pipe has to be clean or the tape won't stick.It actually worked pretty well.
Reply:Originally Posted by TimmyTIG to cover the whole thing with a layer of the tape
Reply:yes, water soluble tape. Seems like we used to use a wet rag and dampen the tape with that. It was a long time ago, back in the 80's, I can't remember exactly. I do remember the helper licking the tape to make it stick better, then we started using the wet rag.I've done the needle purge, too. Never did like that much. We always tried to get a hose in it if we could. Needle purge worked better with two hoses on big pipe.
Reply:white bread...
Reply:I remember some nuclear work with rice paper and Elmer's glue back in the late 70's early 80's.  I've built some dams using those materials,   How about a freeze seal / plug?  Any one here ever work up against one of them?