Blending new lacquer with old.

[Sperry]

I'm working on a bouzouki. The top is maybe a little bigger than an A-style mandolin, and 2/3rds of it is one big acetate inlay. The inlay starts almost flush with the wood top above the bridge then slopes a bit higher.

When I scuffed my newly lacquered wood top I put some swirls on the highly lacquered and polished acetate inlay. I figured my acetate spray would melt into both my newly sprayed area and the old area. Wrong.

So I sanded the seam with 1,000 paper, 0000 wool, then 2,000 paper. Then buffed with Novus 2 swirl remover. Got the swirl marks off the inlay; it is back to a polished gloss. There are still marks on the edge of the inlay's lacquer, but they are rather insignificant. They almost look like wear marks from the proud edge of the inlay.

My questions:

If you get a highly polished lacquered instrument, how do you know what was used on it?

Might the original lacquer have been brushed on? Do people brush on clear coat then polish?

Would I have a better chance of blending old and new finish if I knew what was used previously?

[B. Howard]

No matter what type of lacquer, blending procedures are the same. Trying to blend after spraying with retarder or other solvents rarely works unless you re-wet the entire film.......

Your problem stems from surfaces not being level which makes them very difficult to level and buff.

[mirwa]

There are lots of tips and techniques involved when blending areas, it's certainly a skill, one can talk about how to do it, but it does not come close to preparing a person on how to do it, it's a skill that needs to be learned from repetition, repetition and repetition.

The most important thing when blending is smooth transitions from one area to another, also as Howard mentions, nice and flat, so no dips or raises are there to catch your eye.

You can paint a guitar today, mix up the same paint tommorrow and spray a small patch area, and you will likely see it, moisture content in the air, drying temperatures, volume of thinners to paint, these all affect the final end result, so it's not just about getting the same paint.

Steve

[Sperry]

Thank you both!

I resprayed once yesterday, heavy at the transition. Carefully scuffed only the wood today and sprayed again. I'm about done with the lacquer. One more day maybe, with two applications. Then work on the frets while it hardens. Then a good buffing should bring it all together.

The acetate inlay looks clean of marks. On the transition I used 1000/2000 around a foam block. Since I'm in with one established bouzouki player, there are bound to be more. And I'll be a whole lot more careful.

Interesting note: There is no truss rod; I've found the high frets between 9 & 13, on this 27" scale instrument, and it appears the neck could have done a little twisting in the middle.

A re-fret looks easy, if need be. Good for me, since it would be my first. The fret slots are cut right through the side binding, the existing work is functional but a little sloppy, so it would not be hard to do better, and the fret wire looks to be the same size as StewMac Medium/Medium.

The Blog got an article out of it, titled Behlen Stringed Instrument Lacquer, which Mohawk liked and retweeted.

[Sperry]

Thanks again. The transition turned out perfect. I sprayed 1-2-3 and 4-5-6 on the wood only, then pulled the tape. Scuffed with overlap onto the acetate inlay, steel-wooled the transition, then buffed the transition. Then sprayed 7-8-9 over the wood top and onto the transition.

Wet sanded yesterday and polished with #7 white compound. In all honesty, I could use more practice with wet sanding and polishing. I do not think I did either for a long enough period. The vs buffer, I kept it on 1. But I did not want to -again- ruin what was good, in pursuit of something perfect.

When you are polishing, do you press hard, or let the machine do the work?