When cutting a separate channel for purflings how deep can I cut? The top will only be about 1/16 thick, should I go half of that, or more? When I have cut binding channels in the past sometimes I expose the linings. Can I do that with purflings on the top? They will be shop made purflings by the way.Thanks.
I am not a builder,,but am taking a Hanalima Build class for fun..
you have to pay attention which way you are going with your router,,bad news if you make a mistake this late in your build..got to take the top off and start over again if you want to do it right..
I have seen some ukes on the UU from supposed great builders with router tearout on them..wow so it can happen I guess to best of them too..if they are in a rush to get done..
My purflings are all 2.0mm deep or just a touch less. I inlay them so that at least 1.0mm will be left after scraping back. Now it depends on how thick your top is and the width and type of linings you've installed as to how deep you might want to go on your instrument.
I keep my purfling router set for a .060" deep cut. Some of my soprano tops are only .060" thick, but if the lining offers enough support it works out OK. I used to get occasional tear out until I changed my routing technique. Start at the widest point of a bout and go all the way around in a counterclockwise direction. The only cure for tear out is wider purfling, a sunburst finish, or a new top. Patching the tear never seems to give a satisfactory result.
I like to go roughly 2/3 the thickness of the top. I do this because I don't like the idea of disturbing the bond between the linings and the top. I make the purflings a little thicker than the channel and then scrap them down to flush.
I keep my purfling router set for a .060" deep cut. Some of my soprano tops are only .060" thick, but if the lining offers enough support it works out OK. I used to get occasional tear out until I changed my routing technique. Start at the widest point of a bout and go all the way around in a counterclockwise direction. The only cure for tear out is wider purfling, a sunburst finish, or a new top. Patching the tear never seems to give a satisfactory result.
I have seen a builder who sends his ukes out with router tearout..if the customer can see it then the builder must of see it too..and like you say..patching a tear never seems to give a satisfactory result..
I am building a uke just for fun/hobby but I am aware how you have to route in different directions to not get any tearout..
A wash coat of shellac on the top/back/sides (but top especially) helps minimise tear out. Don't worry about exposing linings. Basically, you can inlay the purflings (or rosette, or any inlay) to any depth your comfortable with getting away with without sanding through- but like Allen said, 1mm (about half a uke top) is safe
