William, Michael:
I've been doing poly work for many years, and I've buffed in about every way possible, with all kinds of compounds and polishes. I've used swirl buffers and buffing wheels, and sanded with rubber-backed sandpaper. I mostly use the buffing wheels, with a Milwaukee handheld straight grinder, lowering the speed with an auto-transformer.
I have 3 different grits of Menzerna compound sticks, but have found more aggressive compounds that work really well. Using paste compounds with a buffing wheel is not the way I would do it, but if it works for you, what the heck.
I found some products at www.Baylandproducts.com that work very well. They have all the wheels, compounds, cloths, etc. that you need. Some are used for buffing metal, but I have used them for poly and they work great. You can call them and ask what they recommend for a particular purpose. Speeds, wheel diameters, buffing wheel material (flannel works great), all that stuff is all in one place.
I don't go beyond 1200 grit anymore because it isn't necessary when using the compounds I have. Sometimes the Menzerna isn't aggressive enough and takes a long time. You have to be careful too with the Konig poly because it is usually softer than the surrounding finish, and you'll make a dip there using a machine too aggressively. I've found especially on Yamahas, the finish is extremely hard, and requires very aggressive compounds to polish up, which tends to create dips in the Konig material. I'm open to any suggestions on Yamaha repairs.
As far as rehydrating the paste compounds, I have no idea what is in it, so I don't know what to suggest. Keep it in an air tight container? If you use buffing wheels, I highly recommend going with compound sticks. Yeah, they do make dust. But at least they don't throw paste on the wall, on your shirt, furniture, etc.
I try to buff as much as I can with the compounds before I go sanding the entire surface. It depends, of course, how badly the finish is scratched. I was amazed when I found out how much easier the more aggressive compounds were at getting out smaller scratches, after spending years sanding them out and rebuffing again. MUCH easier to do with a proper machine and compound. Only sand when you need to.
FWIW.
Paul McCloud
San Diego
----- Original Message -----
From: William Monroe
To: pianotech at ptg.org
Sent: 03/17/2009 7:38:15 PM
Subject: Re: [pianotech] Polyester Finishing
Hi Michael,
Maybe I'll try and sand more, buff less. I do use a large Milwaukee VS Buffer with 8" or 10" lambswool wheels with the [Menzerna] pastes. I think I said Koenig pastes the first time, but they are Menzerna. I'm after perfection, and do a reasonable amount of poly work; touch-ups mostly, with an occasional polishing of a lid or music desk. My work is mainly for a dealer - we haven't any finishing shops around and typically, if it is better they're happy; they aren't going to send off a music desk for some superficial scratches, know what I mean? I've had reasonable success with the pastes so far, except for them drying in the containers. Are the bar compounds really that different?
WRM
On Tue, Mar 17, 2009 at 7:56 PM, Michael Spreeman <m_spreeman at hotmail.com> wrote:
Hi William,
There's no "easy" when it comes to poly work, it just flat out sucks no matter what.
Yes, I would wet sand the entire lid and then buff it. The Konig pastes you have don't work very well with wheels, in my experience. If you have the equivilant of 600 grit scratches, I would wet sand with 1000 followed by 2000. The 3000 is a major pain to sand with and I don't always use it; depends on the situation. Then buff away.
Michael Spreeman
http://www.spreemanpianoinnovations.com
Date: Tue, 17 Mar 2009 19:13:23 -0500
From: bill at a440piano.net
To: pianotech at ptg.org
Subject: Re: [pianotech] Polyester Finishing
Michael,
Good to see you here. So, you wet sand in any situation? What about surface scratches on a lid? I'm talking about cleaning up the case of a used instrument here, rather than a repair type situation. IOW, if the scratches were all over a lid, at about the level of p600 - p800? It would seem in this case that using a wheel would be much faster and much easier on the body.
William R. Monroe
On Tue, Mar 17, 2009 at 5:54 PM, Michael Spreeman <m_spreeman at hotmail.com> wrote:
I use the Menzerna 2.5 pound polishing compound bar with four 12" buffing wheels stacked on a Hitachi 7" polisher. They make a coarse and fine compound. They say the coarse will take out 600grit scratches. I wet sand down to 3000grit and only use the fine compound; it's faster and gives a much better final buff. Finish with Maquiar's #5 Professional New Car Glaze to remove any remaining compound scratches (available at automotive paint stores).
Michael Spreeman
http://www.spreemanpianoinnovations.com
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--
William R. Monroe, RPT
A440-William R. Monroe Piano Services, Inc.
314 E. Church St.
Belleville, WI 53508
608-215-3250
www.a440piano.net
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