not completed yet....
What are we trying to achieve?
| The general consensus is that, to
achieve a mirror-like finish you must fill the pores on the wood before
applying the finish. This assumes however that you are concerned to have a
mirror-like finish. The high gloss of sprayed nitro-cellulose and
polyurethane finishes, (both highly carcinogenic), seems to have set
the standard. To be taken seriously by most buyers, instruments today seem
to need to have this quality. It is NOT obligatory to fill the pores of
any wood. To my mind, the more one puts on or into the
wood, the less true its ability to vibrate.
Whether or not you fill the pores is a question of, where the pore filling is to be done, the possible effect on the sound, and what you want the instrument to finally look like. It is thought that a mirror finish lends a more elegant look to an instrument, whilst not filling them, produces a 'closer to nature' look. So, something about pore filling, (sometimes called 'filling the grain'..) and then one has a choice.......
| Naturally all wood is different, and is
used differently, according to these different characteristics. Pores can
be small and hard to see, as for instance on cherry
poplar and maple. (Much used for the backs and sides of
instruments). Equally, they can be large and clearly visible,
as on ash, walnut and mahogany. (Much used as neck blocks).
If the pores of 'open-grained' woods are not filled before the application
of a finish, then they will still be visible afterwards. As with most
areas, there are many ways to fill pores, and no concensus over which is
There are initially 2 basic choices if you wish to fill pores;
The choice is determined by the nature of the finish you wish to use. The method is to apply a number of coats of the finish, and sand back to wood. By doing this the finish will gradually fill the pores. When no more grain pitting can be seen, the pores are filled, and proper finishing can begin;
1. Pore-filling with Finish
| Using a scraper to cut back the
finish during the pore filling procedure is possible, but using sandpaper
2. Pore-filling with Paste
| Paste wood fillers: either
oil or water based, comprising a bulking agent, (often very
finely ground silica) binder and carrier. The
bulk fills the pores, the binder holds the material in the pores, whilst
the carrier allows it to be applied. The can be bought coloured or neutral.
If neutral, they can be coloured to match the wood as below..
to be completed...........