Difficulty leveling Rosette

[Jerry Mercer]

I installed a rosette in a Euro Spruce soundboard, leaving it slightly proud so that it could be scraped level. Well, the rosette seems to be very hard and dense material and I'm having a terrible time getting it level with the top. I've tried bench scrapers, sharpened and leveled on the Burns sharpening system; sandpaper on a very flat, hard sanding block, etc. No matter what I do, the method always seems to remove a tiny bit more of the softwood top than the rosette, therefore leaving it still proud of the surface. I also tried finishing the top wood (french polish) to make it harder, but to no avail.

Any help or advice would be greatly appreciated.

Jerry

[mathieu thomas-guy]

I use a finely set block plane and cut in a circular motion, the plane keep the work level and a fine sanding with a block does the job. The trick is the way to sharpen the blade, razorsharp with a slight camber in it and with a 30-35 bevel. That way tear-out is minimized and you dont dig in the surrounding spruce. You can actually eyeball were the plane is working, take your time and work everything level. Any access to a belt/drum sander?!!

[Jerry Mercer]

matthieu,

Thank you, I hadn't thought of using a block plane here, but I see that that could work. I have a very good sharpening setup (ala Brian Burns, if you're familiar with his system, which is sold by LMI). When you say "a slight camber, what do you mean exactly? Do you mean that the blade should be angled one way or the other so that it cuts deeper on one side? Or are you referring to a back bevel?

Yes, I have a Grizzly Drum Sander, but I think that is what got me into trouble in the first place. Because the spruce is so much softer than the rosette, after thicknessing the top, the rosette stood proud of the top, then I started trying to level it by hand. In the past, I've used the sander to thickness tops without this occurring, but it seems that this rosette is harder than most. Anyway, its too late to do anything on a sander now, as the top is on the guitar.

I do think I will try to use a small block plane that I have and set it to a very fine setting and patiently work the rosette down.

thanks again for the advice

[Ronnie Nichols]

That is one of the great things about luthiery. These little problems always make you remember to make your rosette fit closer the next time before you install it. It is a problem to smooth two surfaces that are so much different. It's like inlaying in a fingerboard. It is so hard to get pearl down to the fingerboard profile without changing the fingerboard shape somewhat. I'm learning to get my pearl inlayed as deep as possible to try to help with this type problem. One suggestion I'd make would be to try some masking tape over the spruce to keep from sanding it. You may have to reapply it a few times before you finish. I've been where you are and it isn't easy to accomplish what you describe.
Ronnie Nichols

[Jerry Mercer]

Ronnie,

Whew! Thank you!! One always thinks that they're the only one dumb enough to get themselves into such a situation. I tried masking tape, but didn't think about perhaps needing to re-tape it a few times to get where I needed to be. I agree that I need to be more accurate in cutting the channel next time. It just seems that this particular rosette was jinxed to be difficult from the start. At one point, I almost decided to abandon this top, except it was one that tested well (I'll explain) and has a good tap tone (to my feeble ear). The wood was tested for stiffness and sound quality by Brian Burns. He may explain this on his website www.lessonsinlutherie.com

Thanks again,

Jerry

[mathieu thomas-guy]

Hello Jerry, hummm I tought the top was not yet installed... Bolck plane might not work easily if its not supported on a flat plate, never done it at that stage (you can support with your free hand by the soundhole I guess). I sharpen on a grinder and check the radius I'm putting in with a small square or ruler, I then go and hone the bevel and the flat area on a flat stone (or 3M sharpening sandpaper on MDF), freehand. I think you can't put any radius with a "rigid" guide, à la Burns, its designed to eliminate any guesswork and assure a square cut, wich might not be the safest way to sharpen a plane for smoothing. Great for jointing for sure. As an organbuilder we used to smooth every joint and casework by plane, solid oak or cherry just shine when properly planed and then oiled/waxed. The slight radius give some texture to the surface but prevent corners to dig in; on your guitar if you sand you will remove the so-small irregularities left by the plane. Sanding machine sometimes fail doing their job perfectly level, thats why I'm a big plane user and fan I confess...! (try Veritas planes, cheap and great! or a Lie-Nielsen for the more prolific builders...!)

[Jerry Mercer]

mathieu,

Thanks, I understand now what you mean by "radius" and I can do that by using a slightly worn surface on the Japanese waterstone. I allow one side to wear away with use just so I can knock the corners off the plane iron so they won't dig in. I keep the other side flat. It is also possible to turn the iron slightly in each direction to take the corners off as well. I don't have a
veritas or Lie-Nielsen, but I do have a 9 1/2 stanley that I think allows pretty fine adjustments. I'll have to check the angle.

What's your opinion on the use of bench scrapers? It seems to me that a good stiff scraper properly sharpened should have done the job, but I seem to have done something wrong, because it still left the rosette proud.

It's terrific to be able to benefit from the experience of woodworkers like you and Ronnie. It sure saves a lot of headaches and spoiled work pieces.

Thanks again.

Jerry

[Bob Webster]

Hi, Jerry. Funny, but I just had the same experience, and it's a pretty rare occurence for me. The way I got there is by making sure that the hide glue had every opportunity to swell the rosette and permeate it prior to clamping. Being the half smart devil that I am, I reasoned that I could swab the glue into the channel, insert the rosette, and then warm the assembly, protected with a sheet of parchment, using a clothes iron set well below the steam setting. Worked like a champ. The rosette that I use is the LMI R21 and it's fairly variable in width and always take some windage in cutting the rosette channel. But this time..., I really thought I had it nailed, and it came out of the clamp-up absolutely perfect. One of those GWBush "Mission Accomplished" moments, unfortunately.

The darned thing was harder than hell (can I say that, Frank?). Bottom line is that the glue permeation made levelling the rosette a giant pain. I proceeded with my usual routine of taking off the bulk of the waste with a block plane. That went okay, if not substantially slower, followed by touchup with a cabinet scraper, and (I thought) finished off with 220 grit in my Performax. That, of course, is where the wheels fell off. Two things happened. First, the sander lowered the soft spruce more than the rosette. Second, the sandpaper loaded up with glue from the rosette and created a messy but not unrecoverably deep, trough down the middle of the top.

Through some rather obtuse reasoning, I ended up in the same situation as you, with an assembled box featuring a proud rosette and a trough down the middle of the top. However, I had left the top ~0.2mm fat at glueup. After removing move of the excess, I finally levelled the rosette starting with a thin cabinet scraper and finishing with a utility blade as scraper, then 320 grit sandpaper over everything. The pivotal trick with the scraping part is to introduce enough flex with your thumbs to focus the scraping action strictly to the rosette. It's a bit tricky so patience and taking it slowly has its rewards. The finished product came out great and after French polishing looked just as flat as one could wish for.

Best regards,
Bob

P.S How are things in Arnold? Lots of fond memories of that place and of the nearby Stanislaus River.c

[Ronnie Nichols]

Jerry:
An old carpenter once told me that the difference between a good carpenter and an average one was knowing how to cover your mistakes. I think this saying could be applied to our craft as well.
Ronnie Nichols

[Bob Webster]

Yeah, Ronnie, one of the ways I gauge my progress as a woodworker is by how much CA gets used in the build for unforseen purposes. At first, my efforts were 75% building and 25% picking up after myself and it was rather nauseating at times.

Bob

[Jerry Mercer]

Ronnie and Bob,

I thought I had responded to this, but it didn't show up. Bob, you asked how Arnold is...we're waiting for winter to show up and cure this drought AND pile up some snow for Xmas and skiing. Weather has been quite mild. If either of you were to get up this way, do look me up. Send me a private email at [e-mail] for directions to my shop.

I finally resorted to filling a few little gaps with CA and then very patiently scraping away with a razor blade.

Thanks for all your advice and help. Now on to learning how to do inlays....!!!!

[Bob Webster]

Thanks so much for the kind invite, Jerry. Sorry about the snow. I remember Bear as one of the ski spots that opened early and always closed with a ton of snow in the spring. Really nice down to earth place to go skiing. Almost did a Bono there in my early days, though.

Cheers,
Bob