Official Luthiers Forum!

Hi All

I am french polishing a guitar at the moment and have given it it's first session, on the tops I normally raise the grain with a damp rag and then sand before starting to apply the finish, on this one though when I hold it up to the light side on there are some small dull patches, the rest of the finish feels silky smooth but these patches feel rough to the touch, so I think for some reason the grain has raised maybe I over sanded these small patches ?


My question is for you guys who are experienced with french polish would you just resand and carry on bodying or strip the finish completely ?

Why do either unless it is really raised grain. Are you sure the grain is raised because the shellac will not normally cause that. Or is it that the shellac is rough. As you first start the boding process you are not build a smooth film. You might try spiriting off to see if it is the shellac for piece of mind.

If you do have raised grain then yes sand back smooth and start over, but one body session will not give any indication of the final film

As far as dull and shinny the shellac will be dull where it went on at the right sovent to shellac and oil ratio. It will be shinny where there was too much oil on the muneca this will dull up when spriting off. it will be the glazing process that brings shine to a French polish aplication, not boding. boding is only laing down the shellac. it is the sririting off and glazing that polishes.

Thanks Michael

You may be right it look fine straight on but streaky when the light hits it from the side, but maybe I just never looked at it like this before at this stage

I will spirit it off and see.

Many Thanks

Russ

I'm a rank amateur when it comes to french polishing but I've noticed that mine looks streaky from the side when my muncea was too wet

It wont but if you start and end with the ideal muneca load during boding and with no spirting off the intire surface would be dull and flat in reflection and as in no shinny spots and somewhat swirled with very small ridges. But in truth the shellac oil and solvent dry out at differnt rates and the futher into a padding session the dryer the muneca gets so there will be some variance. During boding the important thing is to see the solvent haze or cloud appear and disappear behind the path of the muneca. If you are too wet you will not see it, if too dry you stick. every thing else is just inbetween. The best test for a properly loaded muneca during boding is the white paper blot. Lightly blot the muneca on a pice of white paper if it leves a intermitten blot that is consistant all over all is fine. If it leaves a solid blot it is too wet and if it leaves an inconsistant itermitten blot it is too dry. Check the Milburn tutorial under the resource page for a photo example.MichaelP38875.7359606481

You may have rubbed the varnish off those rough spots. You have to let it dry and try to drop fill it. Some people try to drop fill with violin varnish (comes premixed in a bottle) The problem may be that the color won't match (especially if the varnish rubs of on the top)when you get some varnish to stick on that spot. In this case you have to sand down to the wood and re-varnish that part of the guitar.

Sorry I cantoffer you much in the way of solutions to your problem Russ
but you have my full sympathy....Im in the middle of a french polish job
on a classical at the moment and can understand the frustrations youre
going through. Hope you get te problems dealt with and we get to see the
finished product very son.

Cheers Martin

Russell, rough areas of wood will show darker than smooth areas, so I doubt that it's a grain issue, Just carry on bodying and stiffing and it should come right. The same appeared on the top that I sent you the picture, 2 more bodying sessions and you can see the result. Don't overdo the alcohol on the stiffing, just 3 or four drops, and don't use gorilla like pressure. Remember to glide on and off the wood and don't let the pad stop on the wood. You'll be fine. E-mail me.

Colin

_________________
I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Do not drop fill Shellac French polish with varnish.!!! there are other ingedents in violin varnish other than Shellac. there may not be adhersion issues but French polish is too easy to correct properly to ad a varnish in th middle of the French polish application.

I am refering to the problem of matching the color on a top where a spot has been over worked. It is important to vary the pattern you polish in and not spend too much time polishing the same location. If you have polished too much in one location, it is very likely the you have removed polish rather than added. If so, depemding on the wood you use and the color of the shellac it can be difficult to finish over the spot and have it turn out perfectly blended in terms of color. You don't want it to look repaired, right. So if you can't match the color you probably have to sand and start again...

Be aware that if those spots are areas where you've removed shellac, then any use of oil in that area will likely discolour the wood as the oil soaks in. Happened in a small spot on the top of my first.

[QUOTE=PaulB] Be aware that if those spots are areas where you've
removed shellac, then any use of oil in that area will likely discolour the
wood as the oil soaks in. Happened in a small spot on the top of my
first.[/QUOTE]

Paul,

Sounds like you know a bit about French polishing. How about getting
over to Adelaide for a tour of the Barossa and some tips on french
polishing my classical?

Cheers Martin

[QUOTE=kiwigeo]

Paul,

Sounds like you know a bit about French polishing. How about getting
over to Adelaide for a tour of the Barossa and some tips on french
polishing my classical?

Cheers Martin[/QUOTE]

A tour of the Barossa would be great as long as I don't have to do the driving.

As for FP, well, I can tell you how not to do it

Oh, and I'd have to fly down there. We drove last time, across the Hay Plain. Four hours at 120km/hr on a gun barrel straight, flat highway. Man, I got excited when there was a bend in the road. But there was only the one, than another couple hours of the straight flat stuff.

Next time there has to be someone serving drinks and nibblies, and aircon.

[QUOTE=PaulB] Oh, and I'd have to fly down there. We drove last time, across the Hay Plain. Four hours at 120km/hr on a gun barrel straight, flat highway. Man, I got excited when there was a bend in the road. But there was only the one, than another couple hours of the straight flat stuff.

Next time there has to be someone serving drinks and nibblies, and aircon.[/QUOTE]

I crossed the nullabour plains Perth to Adelaide once (8 times total up the east coast of the island and back) on a motorcycle way back in about 1984, all 2800 kilometres of mainly straight road.

I got to Adelaide and turned left up into the Adelaide hills and through some of the best biker roads in Australia. My 79 BMW R100RS just ate it up. But as I crossed over the hills and eventually made my way toward the Hay Plains, my heart sank .

Man that road is long and straight, I was so bored and had already had enough given the run across the bore. After the first 25ks I wound the beamer up to 220kph and sat there for the duration. The most interesting thing to see along the way was the giant overhead irrigation crawlers running up and down the cotton paddocks go zipping by.

It was sole destroying stuff for a young bloke who had women to meet and beer to drink to find himself just sitting there for sooooo long feeling like he had just been shot from a cannon.

I made up my mind mid way across that I would NEVER drive that road again, and I never have. Hells bells, to stay a bit on topic, I think I would rather french polish an elephant than drive that road again

Cheers

Kim

[QUOTE=PaulB]   

A tour of the Barossa would be great as long as I don't have to do the
driving.

As for FP, well, I can tell you how not to do it [/QUOTE]

Myself and the boss can take care of the driving. As for the french
polishing...I imagine in a few weeks time well be able to compare notes
on how not to do it. We can discuss same over a bottle of Rockies Basket
Press Shiraz.