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Help with wooden rosette please.
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=20526		 Page 1 of 2
Author:  Dave Higham [ Fri Jan 16, 2009 5:58 pm ]
Post subject:  Help with wooden rosette please.
I want to make a wooden rosette with just two or three lines of veneer purfling inside and out. I've looked at the past threads and tutorials and I'm still not sure how to go about it. Just to complicate matters, it's an offset soundhole so none of the rosette is hidden behind the fingerboard. Any words of wisdom?
Author:  Shane Neifer [ Fri Jan 16, 2009 6:53 pm ]
Post subject:  Re: Help with wooden rosette please.
Hey Dave, This is what I would do!

1) Make your first larger ring, the rose ring. 3/8 to 1/2 wide, or whatever suits yer fancy. I would cut this out of my figured wood using a dremel or equivelent so it is a perfect circle.

2) rout out the cavity in the guitar top for this to fit in. Make this cavity very close to perfect, but it does not need to be perfect, just close to it.

3) adding the purfling lines can be done two ways. First would be to rout a channel in the top for the inner and outer purfling lines (this cleans up any less than perfect fit from your rose ring), then you can start to lay in you purfling veneers and trim to length, this is the finicky part. Option two would be to individual circles out of veneer just as you cut the rose ring but at .020 or so that may be hard to do.

At the end, if you are successful you do this.... bliss

Others may have other methods but this the way I will do it!

Good luck!
Author:  jordan aceto [ Fri Jan 16, 2009 10:39 pm ]
Post subject:  Re: Help with wooden rosette please.
Like shane said, first rout and glue just the wood ring, then rout for the purfling lines on either side. If you do a long scarf on the lines, and do it reeeeel well, it is pretty hard to spot the seam.
Author:  Dave Higham [ Sat Jan 17, 2009 3:34 am ]
Post subject:  Re: Help with wooden rosette please.
Thanks guys. I'll give it a go.
Author:  Todd Rose [ Sat Jan 17, 2009 9:50 pm ]
Post subject:  Re: Help with wooden rosette please.
... And your reason for routing for the purflings after the ring is glued in is that it's easier to make a perfect-fitting channel for the purfs that way? Or is there something else or something more behind this method?

I was thinking of trying something a little different from what I've done before on my next one. Here's what I have in mind:

Using a bit that matches the thickness of the purfs I'm going to use, cut out the wood ring, and after each cut (first the inner cut, then the outer), leaving the router base set the way it is, rout the corresponding purf channel in the top. This way, the ring should fit perfectly in between the inner and outer purf channels in the top. Then, rout out the top material in between, for the ring itself. Now, the whole channel, for both the ring and the purfs, is routed out, and, theoretically, it should all fit perfectly. Then, as I've done before, dry fit the ring and the purfs and wick in glue (thin CA glue if it's already a really tight fit, or watered down PVA glue if the fit is acceptibly snug but could use a little help from the water swelling the fibers to make it a really tight fit that will look perfectly clean when it's done).

Any thoughts on that plan, or reasons why you think it would be better to do it the way you described?

Thanks -
Author:  jordan aceto [ Sat Jan 17, 2009 11:27 pm ]
Post subject:  Re: Help with wooden rosette please.
The reason for routing just the wood ring part first is -

---you dont need to rout a perfect slot for the wood ring this way, since when you rout for the purfling lines later the bit will just kiss the edges of the wood. This is just for convenience.

---more important, it is hard to juggle a solid wood ring with inside and outside purfling lines, much easier to do the lines by themselves in a slot that fits them nicely. The lines want to spring out of place and misbehave when you try to do it all at once.

---for me anyways, nothing ever works out the way it should theoretically!

p.s. hey homeboy
Author:  Todd Rose [ Sun Jan 18, 2009 8:38 am ]
Post subject:  Re: Help with wooden rosette please.
Yo, homeboy, one more question for you: What are your favorite skinny little bits for routing slots for purfs? Type of bit - straight, spiral, upcut, downcut? Specific brand and place where you get them?

Been a while since I've seen SRB. Are you still lead guitarist? I see the band is opening for Habib Koite at the State in April. Might try to catch that show...
Author:  Mark Swanson [ Sun Jan 18, 2009 9:28 am ]
Post subject:  Re: Help with wooden rosette please.
I've tried all these ways, and a few others that were failures. Nothing works as well as the method that Shane outlined, that is the easiest and the best way in my opinion!
Author:  jordan aceto [ Sun Jan 18, 2009 10:00 am ]
Post subject:  Re: Help with wooden rosette please.
Yeah what those guys said... Todd Stocks source is cheaper than what i am used to.

I still play with that band, it is my "day" job, strangely.
Author:  Chris Paulick [ Sun Jan 18, 2009 10:03 am ]
Post subject:  Re: Help with wooden rosette please.
I'm just wondering if once you cut the outer purf ring if you moved the router and cut another ring completely through a piece of wood if it would help with making the purf ring by using the cutout as a form. And do the same for the inner purf ring. I don't know if it would be worth the time involved or not, just a thought.
Author:  Todd Rose [ Sun Jan 18, 2009 10:20 am ]
Post subject:  Re: Help with wooden rosette please.
Thanks, Mark and Todd. All right, I think I'll abandon my other plan and do it this way.

I appreciate the link, Todd. Happy to see they have a wide selection, including metric bits in .5mm increments.

For purf layups made up of 4 individual purfs of .020" each (which tend to measure a hair shy, at about .077"/1.95mm, total), I'm thinking a 2mm bit ought to do it.

Likewise, for a .030"-.020"-.020"-.030" purf layup, which tends to measure a hair under .100", I'm thinking a 2.5mm bit should work.
Author:  Todd Rose [ Sun Jan 18, 2009 10:22 am ]
Post subject:  Re: Help with wooden rosette please.
And thanks for your reply as well, Jordan -
Author:  Chris Paulick [ Sun Jan 18, 2009 10:31 am ]
Post subject:  Re: Help with wooden rosette please.
Nice link Todd. Here is on that has bit's but at an higher price but if you are in need of something at a certain size this may be of some help.
http://www.endmilldiscount.com/end-mill ... t-tr-2.htm
Author:  Todd Rose [ Tue Jan 20, 2009 5:58 am ]
Post subject:  Re: Help with wooden rosette please.
Thanks for the link, Chris -
Author:  Todd Rose [ Tue Jan 20, 2009 9:48 am ]
Post subject:  Re: Help with wooden rosette please.
Todd Stock wrote:
- Leave at least .004 to .005 for glue and expansion of the purfling line...if you insist on using an exact size bit to get a single pass channel, make sure the bit used will leave enough room for glue.


Thanks for taking the time to share all these thoughts, Todd.

Regarding leaving extra room for glue... are you fitting your purfs in the slot dry and then wicking in glue? That's the only way I've done it, and I fit my purfs in very tight before wicking in the glue (CA). I don't deliberately create any extra width in the slot to make room for glue. If I end up with a fit that I consider acceptable, but not quite as tight as I'd like, then I'll wick in watered down PVA instead of CA, and the water absorption will close it up really tight. I'm not saying my method is better than yours; I'm very interested in how you do it, that's why I'm asking.

Using the method of a very tight dry fit and wicked-in glue, I get perfectly clean lines between the purfs and the spruce - and I inspect very closely. Nothing less than perfection satisfies me with regard to details like this.

Thanks again.
Author:  Chris Paulick [ Tue Jan 20, 2009 9:51 am ]
Post subject:  Re: Help with wooden rosette please.
Edit: Todd R., I see you got in just before me.

Todd, What type of glue are you using? Is there a glue line with CA? I ask because I read a GAL artical by Eugene Clark where he says CA doesn't swell the veneer lines. He uses white/ titebond because it does and will tighten up the lines in his Spanish Rosettes.
Author:  Chris Paulick [ Tue Jan 20, 2009 10:04 am ]
Post subject:  Re: Help with wooden rosette please.
Todd S., your dummy mold is interesting. That's why I was wondering if one cut the complete ring out for a form if it wouldn't make cutting the purf lines to length easier. I think maybe you could then just overlap the ends of the lines and make the cut. I got the idea from reading this lastest issue of AL where Manuel Velazquez uses PVC pipe as forms for gluing up his rosettes bundles. You have any thoughts on that ? Either Todd.
Author:  Todd Rose [ Tue Jan 20, 2009 2:40 pm ]
Post subject:  Re: Help with wooden rosette please.
Chris Paulick wrote:
Edit: Todd R., I see you got in just before me.

Todd, What type of glue are you using? Is there a glue line with CA? I ask because I read a GAL artical by Eugene Clark where he says CA doesn't swell the veneer lines. He uses white/ titebond because it does and will tighten up the lines in his Spanish Rosettes.


I'll quote two of my posts from above, which address the choice of glue -

"...dry fit the ring and the purfs and wick in glue (thin CA glue if it's already a really tight fit, or watered down PVA glue if the fit is acceptibly snug but could use a little help from the water swelling the fibers to make it a really tight fit that will look perfectly clean when it's done)."

"If I end up with a fit that I consider acceptable, but not quite as tight as I'd like, then I'll wick in watered down PVA instead of CA, and the water absorption will close it up really tight."

If I haven't made myself clear, or if that doesn't answer your question, please let me know.

As to your question, "Is there a glue line with CA?" - do you mean a line from the CA absorbing into and staining the wood/fiber? As far as that goes, anywhere that's a danger, seal first with shellac. Seal the spruce, seal the edges of the wood rosette ring, even seal the ends of light colored purf lines like maple. Other than that issue, depending on the material used for purfs - like, for example, if I make a .040" line of maple by putting in two adjacent .020" maple purfs - then, yes, if you look closely, you will be able to see that the .040" line is actually two .020" lines. I don't consider that a negative thing.

One more thing I do, as I was taught, is drill several small holes through the top in the rosette channel before gluing in the rosette. After wicking in glue from the top side and letting that cure, you flip the top over and wick in glue through these holes. The holes will be covered up by a plate of spruce that will be glued in behind the soundhole area (before the soundhole is cut). This may be overkill, but has always seemed to me to be a good idea, given the method of installing the wood ring and the purfs all at the same time (fitting them in dry, then wicking in glue), which is how I was taught and how I've done it so far. This extra glue from behind ensures that the relatively wide wood ring is well glued down.

However, now that I'm going to try the way described here, routing for the purfs after the wood ring is already installed, I think I'll put PVA on the back of the wood ring to glue it in place. That would make it unnecessary to wick in glue from behind. When I go to install the purfs later, I think I'll fit them in dry and then wick in glue (their small area makes the additional step of wicking in glue from behind clearly unnecessary). As usual, I'll choose CA or PVA depending on how tight the fit is. That's my plan at this moment, anyway.
Author:  Todd Rose [ Tue Jan 20, 2009 2:49 pm ]
Post subject:  Re: Help with wooden rosette please.
Chris Paulick wrote:
Todd S., your dummy mold is interesting. That's why I was wondering if one cut the complete ring out for a form if it wouldn't make cutting the purf lines to length easier. I think maybe you could then just overlap the ends of the lines and make the cut. I got the idea from reading this lastest issue of AL where Manuel Velazquez uses PVC pipe as forms for gluing up his rosettes bundles. You have any thoughts on that ? Either Todd.


I'm not so sure about this idea. Maybe Todd S. or Jordan or somebody will have some input on that.
Author:  Chris Paulick [ Tue Jan 20, 2009 4:33 pm ]
Post subject:  Re: Help with wooden rosette please.
Todd Rose, you pretty much do your Rosettes like I do. I dry fit and use CA and shellac the edges also. The holes for back gluing is a new idea to me. I haven't done any large wood rosettes yet just purf rings with a shell ring. While I was typing my question you had posted and I realized that most of my question had been answered.
Todd Stock said allow a couple of thousandths for the glue line so I thought that ment that the PVA would itself take up that space. I'm not sure if that's what is ment or if that is just because the wood swells which doesn't seem to happen with CA.
Author:  Chris Paulick [ Tue Jan 20, 2009 7:27 pm ]
Post subject:  Re: Help with wooden rosette please.
I find CA is alright for filling small gaps but you have to watch out for air bubbles that need to be picked out and refilled. Anything a bit larger like around fretboard inlays I'll pack with the wood dust and even make a bit of a mound and then CA. The mound is nice because I find that when sanded level there won't be any white dots in it that may appear if the dust is just level. I think the white dots are small air bubbles near the surface but not really sure. I also like to mark the edge of the inlay black so if there is a small gap your eye will see the black through the CA and make it less noticeable.
Author:  WaddyThomson [ Tue Jan 20, 2009 7:49 pm ]
Post subject:  Re: Help with wooden rosette please.
OK, I'm going to play stupid here, which comes really easy to me, but I have now chiseled out 3 rosettes due to poorly seated purf lines. I figured, OK, I'll try the CA route. I have everything packed into the channel (classical rosette), tiles, wheat, and a bunch of purf lines. I coated the channel and the top with shellac, and now it's time for glue. I did CA all the purf lines and wheat together, at the center point, for each side of the tiles, trying to keep all that mess together for easier installation. It seems to be a pretty tight fit, and holds itself together in the slot fairly well. CA does not seem to do much to the purflings, in the way of staining, so now, do I just flood the whole thing with thin CA? If I wanted to use PVA, could I do that with a shellac sealed channel, or is it too late for that now. I failed using PVA and Fish glue before, but I tried to glue it together as I installed the parts, thereby having purfling lines that didn't seat. Problem was, because of the glue mess, I couldn't tell, and the purfs just get sloppy after being wet with the thinned pva. Ugh, what a mess.

Anyway, if I use CA, do I just flood the joints and lines, and let it dry? It seems to hold together dry, so I guess I wont have to weight it down.
Author:  jordan aceto [ Tue Jan 20, 2009 7:58 pm ]
Post subject:  Re: Help with wooden rosette please.
Yes, flooding everything while it is in place generally works out well.

I will say that of the few classical rosettes i have done, i have a much better time of it inlaying and glueing just the tiles first, then routing for the wheat/rope/purfling lines, kissing the edges of the tiles with the bit. Pretty much the same method we are talking about for wood ring rosettes.

If you have it looking good all layed up dry, flood away.
Author:  Dave Higham [ Thu Jan 22, 2009 8:15 am ]
Post subject:  Re: Help with wooden rosette please.
Thanks to everyone who contributed to this thread. I wish I'd thought about Todd Stock's suggestion of making a dummy at the same time, but it was half done by then. Next time...

I basically followed Shane's advice of inlaying the ring first, using Titebond and then cutting the grooves for three strips of veneer inside and out and flooding these with CA. I cut these two channels with a 1/16" dia. Stewmac downcut bit. I cut a trial channel in a piece of scrap and adjusted my veneers to fit. The thickness of the black veneers seems to vary in the finished rosette. I think the reason for this is that when I cut the two channels, the Titebond burned onto the bit and the resulting channels were a bit wider than the trial. Because of the added difficulty of inlaying veneers and trying to get a continuous ring without a visible join, I didn't notice that the groove was a bit too wide. The CA filled up the gaps and makes it look as if the black veneer varies in thickness. You can also see the joins if you look for them , even so, I'm fairly satisfied with this one. The next one should be perfect. ;) I'll perhaps make a Wells/Karol jig before then though.

Click on the pics for a better image.
Author:  Chris Paulick [ Thu Jan 22, 2009 8:44 am ]
Post subject:  Re: Help with wooden rosette please.
Looks pretty darn good to me. The joints aren't to visable like you said. I wonder if they were back cut if that would help any? Or if one could match them up with the grain would help hide them. Or maybe with light color wood there is just no getting away with hiding them.
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