Routing a redwood top for purfling and binding

[Kevin Sjostrand]

Gang,
I will be doing this procedure on my redwood top in the near future. I have never had a problem routing spruce; no tearout, splintering, etc., but this is my first time with redwood. When I routed for the rosette, I neglected (forgot) to apply some shellac over the area before hand, and was lucky. I only had a little tiny bit of tearout in a small area on the outside perimeter of the rosette that will sand out, but I still felt like a dummy for not doing it. So I am a bit concerned that I may have a problem when I rout for the bindings. I have already applied shellac around the perimeter of the body (over the whole top for protection). Should this be adequate to achieve a nice cut without tearout or splintering? My router bit is not new...done 4 guitars with it. Should I buy a new bit to help myself out here? It would be worth it for what I'm charging for this guitar. What if I used a hand purfling cutter to score the redwood first, then rout to the line? Is this a good procedure to follow on a softwood top such as redwood?
Any experiences to share that will help my confidence will be appreciated. I would hate to screw this up.
Thanks.

Kevin

[Jim_H]

I'm not the most experienced binding router advice giver and I've never worked with a redwood top, so take this with a gain of salt.

Repeating what I've read here and many other places, the best way to prevent tearout is to use a really sharp router bit, and to route 'downhill' (?) if thats the right term.

Here is an image I stole from stewmacs precision router guide instruction page....



As far as specific precautions for redwood, I'll leave that to the pros. I know Rick has worked with redwood quite a bit, so he may have some good tips.

Jim

[johnnparchem]

I routed my last two parlor quitars without tear out on the top. One was western red cedar and one was sinker redwood. I followed the guidelines of routing as shown in this stewmac picture. I think on my first I did not have shellac on the top. On the second I did.

[kencierp]

"Down spiral bits" BAM Carbide and Drill bit City are good sources.

[darren]

Kevin,
I shellacked the top of my redwood guitar and routed following the stewmac diagram as well. my bit (stewmac, bearing guided) was used on 2 previous guitars. No issues with mine, hope i was smart and not just lucky. let us know how it goes.

[Kevin Sjostrand]

Thanks guys,
I have always routed following in the direction shown on that diagram, my router bit/bearing set up is a Stewmac, and I will have shellac on the top around the edges, so I suppose I am good to go!
I guess I will not worry, and just go for it and It will probably be fine. I might just get a new bit though for a "little piece of mind".

Kevin

[Oval Soundhole]

I used a straight Israeli carbide bit in my KMG binding system to rout the channels on my hot tub guitar. Worked fine with no tear out (I shellaced the edges though.

[sdgeorge2]

made 3 redwood tops. no problems with tear-out during routing but varnished tops prior. Did have problems with pullout from tape used during gluing binding/purfling. Had to add multiple coats of lacquer prior. Also had problems with small breaks along the grain. Madden! RR just doesn’t have the shear strength of WRC or spruce but it is gorgeous.

[Kevin Sjostrand]

I did already discover the fiber tearing with tape...glad I used blue painters tape. Taped the top down to my routing board with I cut in the rosette, pulled off the tape, slowly and at an angle to the grain, and I still got fibers up with the tape. I immediately sprayed some shellac on the top.
I think I will purchase a new router bit for this...I'm using the Stewmac bearing guided set up so that is what I'll get. I can't screw this up....
Thanks for the help and advice.

Kevin

[tippie53]

I cannot agree more with Running Dog, you need a SHARP bit on redwood . If you don't you can expect compression fracture on the climb cuts and tear out with the rout cuts