Glass Tape Backing Vs Ceramic

Date 07-23-2007 15:17

Question, I have never seen or worked w/ "Glass Tape Backing". We do use ceramic at times. Is this the same thing, just w/a different name? The ceramic comes adhered to a sticky tape so that makes me wonder if it's just a terminology thing.

FYI This is for a D1.6 Pre-qualified WPS for a S/S project we have coming up.
D 1.6 Pg 61 3.29 Part H (10) "Roots of groove or fillet welds may be backed by copper,flux,glass tape, or backing bars of pre-qualified stainless steel to prevent meltthrough". It doesn't list ceramic, that's why I thought it might be the same thing.

Thanks in Advance as usual, Chris

By hogan

Date 07-23-2007 15:38

i've was going to post a similar question. i noticed in one of the last couple of issues of either the welding journal or inspection trends that there was an add for a fiberglass roll of backing. has anyone ever used this? anyone run a pqr with it? what caught my eye was that it looked like it would work like ceramic, but it was thinner and it came on a roll. it looked like it was form fitting to a degree, unlike ceramic

By Joseph P. Kane (****)

Date 07-23-2007 17:41

Hogan
I tried it back in the middle 80's for GMAW (Spray Transfer), FCAW and GMAW Aluminum. I had porosity in all three on the root pass (All open root welds). The GMAW (steel) root condition was ragged and unacceptable. The Aluminum Root pass appearance looked just like an open root joint (without backing), that I couild do any day of the week I was trying to get more melt through on the root pass, but it was not satisfactory. I also tried to make a root mold for the TYK 6GR test on Aluminum Pipe, but could not get rid of the "Heart Shaped Groove" on the inside root face.

I probably still have the balance of that original roll.

I also used a fiberglass backed tape with Sub Arc flux piled on it. That worked real well, after I got used to staying on top of the molten puddle using hand held SAW.

By eekpod

Date 07-23-2007 18:08

Interesting, so it sounds like they are not the same, and thus not interchangeable for a pre-qualified WPS.

Anyone have any thoughts why "Ceramic's" can't be used on pre-qual s/s WPS's??

Thanks Chris