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Re: 2nd scratch build - Carpathian over EIR

Posted: Sat Dec 12, 2015 5:30 pm
by Diane Kauffmds
I've had to deal with all of the issues you're struggling with. I'll let you know what worked for me, and what didn't. I'm sure other members have more experience and will give you the benefit of their experiences.

Issue #1: I made the mistake the first time by making the rosette, removing it, then thicknessing it. Bad idea. I couldn't get it even. The second time, I thicknessed it before routing it into shape. Bad idea again. It was a lot to sand, because of the length of pieces. It heated up and disassembled. What worked for me, was to rout it out first, then thickness it, before removing it from the work board. It enabled me to evenly thickness it.

Issue #2: I had to find a way to keep the darn thing from spinning while routing, thicknessing. First, I tried spray adhesive, which worked great, until it started heating up, then it spun. Second, I tried a couple of spots of duco cement; it didn't spin, but I couldn't get it off either. LOL. I finally ended up using small pieces of double sided tape. I used about 6 pieces of double sided tape, ~ 1/4" x 1/2", evenly spaced around the rosette pieces. That solved the "spin" problem for me, and allowed me to remove the rosette without damage.

Issue #3: I inlaid my first rosette, which ended up getting ruined, because the dremel jig slipped, allowing the dremmel to go too deep. It cut through the rosette completely, which made gluing the abalone impossible, without gluing it to the backer board.

As a result, I bought a Ridgid compact router and made a jig for it (using pieces from the dremmel circle jig). It works great, but I never got the chance to inlay the new rosette. I think in the future, I'll inlay the wood rosette into the top, then inlay the pearl/abalone, after.

Re: 2nd scratch build - Carpathian over EIR

Posted: Sat Dec 12, 2015 7:56 pm
by nkwak
Thanks Diane,

I already put the rosette through the thickness sander for a few passes. I'm pretty sure that it's still proud of the top so there's room to sand it down more once I inlay the shell.

Meanwhile, I've been tapping the soundboard, measured it and now I'm worried. In the middle it's .011 thick. At the edges it reads .088. My sides were similarly inconsistent which tells me that my friend's thickness sander is in need of an adjustment that neither of us know how to do. I may have to purchase another soundboard too, which has me sad because this one was donated.

Re: 2nd scratch build - Carpathian over EIR

Posted: Mon Dec 14, 2015 1:45 pm
by Diane Kauffmds
I've only made 2 guitars, but I've made several tops now. I know of builders (including myself), who sand the edges a bit thinner than the rest of the top, to loosen it a bit. The edges of my tops are ~.085", while the center is .100". I've had no problems with stability and the sound is rich and full; I'm just careful not to take off too much from the bracing when I voice the top/back. Needless to say, if you encounter problems when you brace the top, then I would invest in another top, but I don't see where you'll have a problem.

Re: 2nd scratch build - Carpathian over EIR

Posted: Mon Dec 14, 2015 7:26 pm
by nkwak
I think you're right, Diane. I just measured inside the sound hole of my Larrivee and my digital caliper read 2.67 mm which is slightly more than what this Carpathean spruce top is. I have the braces cut to 3/4" tall - which is comparable to my Larrivee's braces which are pretty stout - so I think I should be fine as long as I don't get too aggressive when carving the braces.

Re: 2nd scratch build - Carpathian over EIR

Posted: Sun Dec 20, 2015 1:30 am
by nkwak
The rosette is coming along. It's not done by I'm trying my best to work cleanly.

Re: 2nd scratch build - Carpathian over EIR

Posted: Sun Dec 20, 2015 3:50 am
by Diane Kauffmds
You did good. It looks great.

Re: 2nd scratch build - Carpathian over EIR

Posted: Sun Dec 20, 2015 10:18 pm
by nkwak
Thanks! I need to clean up some rough edges before I glue it in. I lost count on how many times it broke, too.

Re: 2nd scratch build - Carpathian over EIR

Posted: Sat Apr 16, 2016 8:58 am
by nkwak
As always, family matters trump this project so I only get to revisit this every so often. I've been attempting to brace the back. Low RH and having no radius jig (the back is supposed to have a 22' radius) have been my biggest obstacles. I brought this very issue up for my first build in another thread and have attempted to do the index card method. Otherwise, I still have the homemade go bar deck.


Meanwhile, I also lack a radius jig for the soundboard - but I am concerned that maybe I sanded it too thin. I also lack a circle cutter for my Dremel that goes small enough to rout out the inner rosette ring and sound hole. I'm tempted to pitch it and start over.

I'm conflicted about this though since this Carpathian was a gift from a friend just getting into luthery too. I feel like I owe him to see it through but the top is a bit on the thin and flexible side. Also, I got the rosewood from RC Tonewoods. They were great to deal with but I wonder: do they offer services like Stew Mac where they join and sand the top to a target stiffness or is that something I'd have to enlist a third party to do? Getting this far was such a drawn out process I'm loathe to repeat it.

Re: 2nd scratch build - Carpathian over EIR

Posted: Thu Jun 23, 2016 6:21 pm
by nkwak
After hemming and hawing in it the bullet and just bought the jig to radius my braces from LMI. I then just glued them on using cam clamps. The jigs are to short to sand the rims to the same radius though. Is it really necessary or can I just eyeball it with a plane?

Re: 2nd scratch build - Carpathian over EIR

Posted: Fri Jun 24, 2016 11:07 am
by johnnparchem
nkwak wrote:After hemming and hawing in it the bullet and just bought the jig to radius my braces from LMI. I then just glued them on using cam clamps. The jigs are to short to sand the rims to the same radius though. Is it really necessary or can I just eyeball it with a plane?
I am not sure how you would eye-ball it, it is the long arc from the the heel to the tail and the arc from one side to the other that you want to sand into your sides. For example as the waist moves in towards the center of the instrument the rims rise relative to the radius that you want.

If you down load stewmac's kit build instructions I believe they show a way to get close to the correct radius using a sanding stick. Or you can use your lmi jig to help you draw out a longer arc, find a way to cut the arc and use it as a sanding stick.