PetroStreet

First of all, thanks to all here for the invaluable information in the past!

We are finishing a SS vessel to a #4 surface finish and would like to limit the finished surface on each side of the welded seam to approx 2" or less.

My Q is is there a type of tape that will mask of areas that a buffer will not permeate?

Appreciate any comments,
Robert P.
QA Manager

1772 wrote:First of all, thanks to all here for the invaluable information in the past!

We are finishing a SS vessel to a #4 surface finish and would like to limit the finished surface on each side of the welded seam to approx 2" or less.

My Q is is there a type of tape that will mask of areas that a buffer will not permeate?

Appreciate any comments,
Robert P.
QA Manager

I gather that your major concern here is to remedy the discoloration caused by welding. If so, go for passivation using some pickling paste. You might also consider electropolishing. However I still cannot understand what is at stake wrt to this masking tape issue.

With a pickling paste, any strong, polyethene-based tape can do the job for you - you can apply that on the peripheries of the area you intend to pickle and get the job done. A more runny liquid will slip under any tape you apply.

The Client wants the outside of the vessel, vertical weld seams to cosmetically look good. Their definition of good is to have the weld seams polished with a straight line on either side of the seam.

1772 wrote:The Client wants the outside of the vessel, vertical weld seams to cosmetically look good. Their definition of good is to have the weld seams polished with a straight line on either side of the seam.

In that case, your weld area will have two clear zones - the HAZ which can be addressed by pickling paste and the weld which should be done neatly by a good welder and then given a dose of some plastic/nylon abrasive wheel.

1772,
I doubt there would be any such tape.
Use any of the thick masking tapes available and just place two layers each on both sides. Ask the guy who has to buff the area to do as smooth as he can while using extremely small tool for buffing when coming near to the mask off area.

You may consider using steel strips to fulfill client's wish.
I was thinking of a duct tape but even that would not serve the purpose as it leaves marks on the surface while removal although thicker than a normal masking tape.

Found it! It's inoxitape which is basically stainless steel shim stock tape.

Thanks for all the responces, great forum here.
Robert

Hi Robert,
Good to hear that.
Your client would be smiling now.
Thanks for sharing this information.