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Sikkens Cetol 1 & 23 Plus / Natural Light
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SDR



Joined: 17 Jun 2006
Posts: 14590
Location: San Francisco

PostPosted: Wed Jan 25, 2012 8:28 pm    Post subject: Reply with quote

Thinking further, the Makita tool is designed to control sanding depth -- the amount of pressure exerted on the material by the tool -- in a way unavailable to the user of other power sanders. This is a considerable advantage, as the consistency of the result would translate, all other things being equal, to a consistent finish -- affecting color, sheen, and value (light and dark) aspects of the wood after new finish has been applied.

British author David Pye wrote, in his "The Nature and Art of Workmanship" (1968), about "the workmanship of risk and the workmanship of certainty." By the former he meant such operations as are performed entirely under the control of the hand and the eye -- carving, hand-sawing, etc -- while by the latter he meant work controlled by machine, or (alternatively) guided handwork. Woodworkers rely on machine tools not only to lighten the physical load of their work but, of equal or greater value, to assure the consistency of result that is essential for acceptably defect-free products. Any experienced finisher will say that an irregular surface is virtually impossible to turn into a consistently-finished article.

In the case of the rotary brush sander made by Makita, I would venture that a bit of customizing for the task of sanding a Usonian board-and-sunk-batten wall could result in a satisfying experience. The sander is equipped with a depth-control idler at the front which, in conjunction with the main guide wheel behind the brush, should provide an even pass across a planar surface. If one or another of the standard brush "wheels" works correctly on the given wood and finish, then the same brush, modified so that only two or so inches of bristles are left on its drum, could be expected to plow the recessed batten and the adjacent edges of the planks -- potentially without having to remove or recess any screws.

The success of the effort might depend on the user devising a way to guide the tool along the correct path without deviation -- perhaps a guide, front and rear, attached to the tool.

SDR
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pharding



Joined: 25 Jun 2005
Posts: 2203
Location: River Forest, Illinois

PostPosted: Wed Jan 25, 2012 10:57 pm    Post subject: Reply with quote

We stripped opaque stain off cypress exterior siding on Davenport plus we stripped all of the interior wood trim which had been painted. IMO it is a major mistake to sand down original material to remove a surface film. Too much original material is lost and the results are prone to be uneven. Chemical strippers now are both green and effective for paint or stain removal.
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Paul Harding FAIA Owner and Restoration Architect for FLW's 1901 E. Arthur Davenport House, the First Prairie School House in Chicago | www.harding.com | LinkedIn
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SDR



Joined: 17 Jun 2006
Posts: 14590
Location: San Francisco

PostPosted: Thu Jan 26, 2012 12:21 am    Post subject: Reply with quote

I'm glad to hear it. I'm pretty sure that would be my choice were I in the saddle on such a job . . . for the reasons you state.

My watchword on the job has always been, "Consistent methods produce consistent results." (It gets the idea across without descending into "silk purses and sows ears," if you know what I mean . . .)


SDR
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Healeyjet



Joined: 29 Sep 2009
Posts: 78

PostPosted: Thu Jan 26, 2012 11:31 am    Post subject: Reply with quote

The Makita Brush Sander is used a fair bit in the timber frame industry which was where I first saw it referenced. Here is a video demonstration I found on the 'tube. It looks as though you had best be fairly strong to hold the machine from bouncing around but maybe a light touch is possible.
Ward

http://www.youtube.com/watch?v=kmoVLMi-RhU
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SDR



Joined: 17 Jun 2006
Posts: 14590
Location: San Francisco

PostPosted: Thu Jan 26, 2012 11:56 am    Post subject: Reply with quote

Thanks, Ward.

So -- a nylon brush with a sanding grit designation -- 80, 100, 220. Curious. Is the brush actually equipped with grit ?

Near the end of the video, when the tool is upside down for wheel changing, the front and rear guide rollers are clearly visible. It is obvious from the video that the demonstrator is not making use of the front (adjustable) index roller, nor indeed either roller -- resulting in the "workmanship of risk," randomized sanding work he's doing.

It would be possible to take a much more refined and controlled (and less muscular) approach to working with this tool -- and potentially get a quite consistent surface . Long, even passes -- as if the wood were passing through a stationary widebelt sander at a steady rate -- would be the desired method. Each moment when the sander pauses in place is where a slight divot will be evident.

SDR
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egads



Joined: 13 Apr 2009
Posts: 869
Location: Long Beach CA

PostPosted: Thu Jan 26, 2012 1:15 pm    Post subject: Reply with quote

That video shows how you would never want to use it in our discussion. Too bad there was no demo of the 220 grit.
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Healeyjet



Joined: 29 Sep 2009
Posts: 78

PostPosted: Thu Jan 26, 2012 2:25 pm    Post subject: Reply with quote

Egads, I agree with you 100%. It showed to me what the machine was but not really what it would be capable of in the hands of someone who wanted to remove a thin film of finish or as SDR said with the use of guides and properly set depth gauges. Maybe the wire brush that he used could be used as we had hoped but he didn't show that., Instead he showed that if you pushed hard enough it would score the wood. He did mention that the wire brush could burnish a wood surface and I would be interested in seeing that. There is also now a abrasive embedded flap brush available for this machine but I have no idea on its uses.

Ward
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SDR



Joined: 17 Jun 2006
Posts: 14590
Location: San Francisco

PostPosted: Thu Jan 26, 2012 3:00 pm    Post subject: Reply with quote

I'm guessing just the ends of a nylon brush -- with bristles of different thicknesses ? -- acts as an abrasive. News to me . . .

In any event, the difference between the hardness of a film finish -- varnish, etc -- and the hardness of pine, redwood, cypress -- would come into play when trying to remove remains of that finish. Everywhere the finish is already degraded or gone, the bristles would be attacking the surface of the wood, while the still-coated places would be waiting for that action. Once a surface is subjected randomly to that difference in plane and texture, it would require further work to return it to an even surface. The last thing one would want, supposedly, is the condition -- handsome as it might be -- where the softer parts of the grain are reduced below the surrounding hard grain. (Although we know Mr Wright was very fond of Japanese effects, I'm not aware that he ever specified this textured wood surface in his work.)

In addition, any sanding of this sort would almost certainly attack the crisp edges of each board, rounding them -- in an irregular way, again due to the differences between soft and hard grain in each board. (Those who have worked with Douglas fir will be familiar with its tendency to splinter at such edges; the hard grain separates easily from the soft. Perhaps this is why we don't see this very common and handsome wood used for finished siding -- in this country ? Milled construction lumber of fir is now typically provided with a well-radiused -- rounded-over -- edge.)

SDR
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Roderick Grant



Joined: 29 Mar 2006
Posts: 7605

PostPosted: Thu Jan 26, 2012 3:12 pm    Post subject: Reply with quote

I would agree with Paul that a chemical approach would be the best. The only reason to consider sandpaper or brush would be cost. I doubt a chemical solution could compete either for material or time. Degraded areas would have to require special treatment no matter what method is used.
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Roderick Grant



Joined: 29 Mar 2006
Posts: 7605

PostPosted: Thu Jan 26, 2012 3:45 pm    Post subject: Reply with quote

One of the previous owners of Stewart (I think his name was Anderson) had the hefty task of removing 80 years worth of creosote which had turned the redwood structure completely black. He found a chemical that is not on the market; it's used by the military. He got his hands on some and it did such a great job that the house looks almost new ... not a grain of sand or a bristle in sight. Probably wouldn't be too difficult tracing this man by way of T. C. Boyle back to the 90s, finding out the name of the substance and how to obtain it.
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pharding



Joined: 25 Jun 2005
Posts: 2203
Location: River Forest, Illinois

PostPosted: Sat Jan 28, 2012 10:32 am    Post subject: Reply with quote

We like these products a lot. http://www.dumondchemicals.com/
Their products were used on the the Guggenheim and Davenport with great success. They are environmentally responsible, user friendly, and effective. It is important to do tests to identify the right product. One of their products literally disolved the cypress siding in a small test. In general you leave their products on overnight. They are very fine products for restoration.
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Paul Harding FAIA Owner and Restoration Architect for FLW's 1901 E. Arthur Davenport House, the First Prairie School House in Chicago | www.harding.com | LinkedIn
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DavidC



Joined: 02 Sep 2006
Posts: 5983
Location: Oak Ridge, TN

PostPosted: Fri Dec 01, 2017 2:39 pm    Post subject: Reply with quote

Bringing the Sikkens Cetol thread back post-outage.


David
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