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Joining the back http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10101&t=16729	Page 1 of 1

Author:	mburton [ Fri Apr 04, 2008 6:35 pm ]
Post subject:	Joining the back
I know this is an extremely basic question, but here it is. How perfect do the two back pieces need to be in order to join them properly? I am using a Lie Nielson No. 102 plane, which is probably on the small side for this task, but I have also tried putting high grit sand paper on a long board and running the edge of the back on that to get them to match up, but there is still a slight gap (holding up to the light I can see light passing through). My thought is that if I use some perfling in between the two pieces, it should be a little more forgiving, kind of acting as a cushion. Do I just need to suck it up and buy a bench plane to get the job done, or will the perfling work? Thanks, Mark

Author:	jerr6 [ Fri Apr 04, 2008 7:00 pm ]
Post subject:	Re: Joining the back
try putting some sandpaper on a 24'' level and use that to get the jiont right

Author:	Howard Klepper [ Fri Apr 04, 2008 7:06 pm ]
Post subject:	Re: Joining the back
Rather than answer your question, I'd back up a bit and say that you have to be able to face the reality that a lot of tools are needed for guitar making. If you can't afford them, see if there is a community college near you with a woodworking shop. You might enroll in a course and get the use of the shop, and even (perhaps) some help from a good instructor who knows about joinery if not guitars. If that doesn't work for you, try getting a serviced kit that has some of the jobs you are not equipped for already done.

Author:	Hesh [ Fri Apr 04, 2008 7:41 pm ]
Post subject:	Re: Joining the back
The purfling will not solve the gap issue and I agree that you really need to have a gapless joint. If you don't have a #5 type plane the level with 120 grit self stick will work. While candling circle the areas the are in contact and then with the level concentrate on the marked areas only. Even though the 24" level is still touching the entire joint if you just put your pressure on the marked/high areas it will take these areas down more. Repeat the process until you have no gaps. Be advised that a freshly planed joint (with-in 15 minutes) will always make a better glue joint then a sanded joint. Also, if you use the level for the top change the sand paper or you will get a dark line down the center seam of your top. Good luck - jointing can be very frustrating and but you will get better at it I am sure. Check out Luthier's Suppliers (Tracy) (link above) for his new offering to joint plates. I have one and they work great!

Author:	Brock Poling [ Fri Apr 04, 2008 10:00 pm ]
Post subject:	Re: Joining the back
Don't worry... this is just one of those things where you have to pay your dues with patience. Here are a couple things I have found to be helpful. If you have a good table saw, put a piece of sand paper on the table, lock the fence and lightly sand both halves of the back in only one direction until the gaps close up. If you are using the sanding method and the gaps are at the ends, take a sanding block and work the center of the seam until the ends touch and the center is open. (I find it is easier to get it to close up this way... it doesn't want to rock on you as you sand). don't put any downward pressure on the plates as you sand. sand lightly and in only one direction. I find the planing method to require more finesse than the sanding approach. While I don't dispute it will make a better joint I have sanded plenty of joints and never had a problem. Just don't fudge and clamp it shut. That will give you problems in the long run.

Author:	Mattia Valente [ Sat Apr 05, 2008 6:46 am ]
Post subject:	Re: Joining the back
...what are the odds of someone owning a good tablesaw but not having any plane larger than a 102? I mean, really. Like others said, get the right tools for the job, practice some more, and get that joint absolutely perfect.

Author:	Chansen [ Sat Apr 05, 2008 12:23 pm ]
Post subject:	Re: Joining the back
Hey Mark, I got my old Stanley #5 off of ebay for around the $30 that Todd mentioned. I did lots of practice on some scrap mahogany before going at it with the top and back. I tuned up the plane as best as I could and used the Scary Sharp method for sharpening the blade. Google, or search the archives for this method if you haven't heard of it. I didn't use the shooting board method, but instead had the two halves clamped straight up and down. After a few swipes I got extremely close but had a bit of snipe at the ends. I ended up solving that by just extending the length that I was jointing with the long mahogany I used to practice on. The snipe at the ends I couldn't seem to avoid was now well past my back and top. I don't know if anyone else has done it this way, but it worked well for me.

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