Masking off before French Polish?

[kman-oz]

G'day all,

I'm a bit green when it comes to this French Polishing business, so forgive my ignorance here. Can I mask off areas of a piece with Scotch blue low adhesion masking tape before Shellac?

Essentially, I'm French Polishing an infants cot and there are lots of areas where it's impractical to do a continuous coat of shellac (edges and corners for example). I'd like to finish one surface, let it harden for a few days, then mask it off and continue on the adjoining surfaces.

I'm not confident that I can leave the tape on the piece for as long as is takes to apply the full finish, so I'm thinking I should mask it off and do one polishing session, then remove the tape. The next day I should briefly clean up the join with steel wool, then mask and start again.

I realise this isn't ideal, but I don't have a better solution at this stage. So, I have three questions:

1) Does it seem reasonable that I can leave the tape on the piece until the entire finish is applied, or should I remove the tape after each polishing session? The tape is good stuff by all reports, but this will get expensive at $17/roll.
2) If I did leave the tape until the entire finish is applied, could I expect to lift the edges of the finish because it's hardened on the tape? I understand that some paints will give you a nice clean edge under this condition, even after multiple coats, but I don't know how shellac will react.
3) Am I perhaps better off overlapping the new coats onto the already finished surface and wet sanding them back later?

On a test piece I tried overlapping the shellac, but I always ended up softening the already finished surface and making sanding really difficult. This is what prompted the masking tap idea. Not to mention that fact the wet sanding the surface seems to be a little more difficult than I though under the best of circumstances.

Am I on the right track or is there a better way? Thanks in advance for your help.

Dave.

[kman-oz]

Without any responses from this thread I had a go at this anyway, the good news it works well, but the bad news is that even the low adhesive tape will pull stopping and grain fill out of the grain.

Any surface that already had a hardened shellac layer was fine. But, there were a couple of surfaces which had been stopped up and grain filled with a talc/shellac mix which didn't have a hard shellac coating already, these have been damaged by the tape. Fortunately this stage of the finish is a lot easier to repair than the finished shellac.

So for reference the answer is yes, with the condition that you have a day old shellac finish on it already. With a shellac finish that is slightly softened by fresh application the tape leaves a beautiful clean line which is completely invisible on corners and edges.

Dave.

[kiwigeo]

Dave,

On my guitars Im often french polishing into corners and dealing with edges. I get in using a small muneca or if the corner is really tight I build up a tiny muneca over a wedge shaped piece of eraser.

Cheers Martin

[kman-oz]

Thanks Martin,

Neil suggests making three different pads for a full French Polish... I think I made about eight to cover all of the different conditions. My first attempt has been quite the learning experience in fact.

I don't think I'll ever attempt this on anything big and complext ever again. It's taken me over two months to complete the finish, the baby was born three weeks ago!