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Jointing Question - Using Sandpaper?
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=25964		 Page 1 of 1
Author:  Kris [ Tue Feb 09, 2010 2:18 pm ]
Post subject:  Jointing Question - Using Sandpaper?
I was told (by experts, Masters) that jointing should be done using planes, and never by sandpaper. I had also read that using sandpaper makes the jointing not as strong. I would appreciate advices and comments by more experienced luthiers on this subject. I find using planes for jointing very challenging. Also, are there, or do you have favorite ways of testing the soundness of the jointing/jointed tops? Thank you very much.
Author:  Edward Taylor [ Tue Feb 09, 2010 2:33 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
Kris, good topic and thanks for posting it because I have been wondering the same thing. I jointed a sacrificial sitka top (a very poor one) with sandpaper stuck onto a 24" fatmax extreme level that has a machined edge. I did a few other things for practice on it as well but eventually I flexed it to the breaking point... and of course the wood failed long before the glue.
Author:  letseatpaste [ Tue Feb 09, 2010 2:42 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
We used sanded joints in Harry Fleishman's class I took a couple years ago and that seemed to work fine. I think we got it close with 80 or 100, and then finished up with 180. That took some technique in itself to get it done well. The problem is finding something flat enough to make the joint and sturdy enough to put some pressure on without flexing it.

Getting your plane technique down for jointing is absolutely and completely worthwhile for many reasons. That skill will serve you well down the road and is worth spending a little time on now. Do a search for "shooting board" and "tuning handplane" and you'll probably find a wealth of info.
Author:  Corky Long [ Tue Feb 09, 2010 2:56 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
Kris -

I can't comment on the strength of the bond when joining using sandpaper. As a novice, I've also struggled with using a plane in joining top plates and backs, but I'll tell you, I think it's worth the trouble to learn to do it rght. Once you've got a good joint, it's seamless.

You need an extremely sharp plane, which is good practice anyway - we all need sharp chisels, right? And setting up the plane properly is also good practice - there are just too many uses for a good block plane.

There are some very good resources in the archives on setting up planes, sharpening planes (some with sandpaper, that work extremely well) and joining tops. and "candling" - the method to determine if your joint is good enough (or rather, perfect,which it needs to be :cry: )

I've gotten discouraged with it, too, but I'm glad I stuck with it.
Author:  Michael.N. [ Tue Feb 09, 2010 3:39 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I've never done jointing with sandpaper but I would echo the thoughts that using a plane correctly is what you should be aiming for. In the early days it sometimes took me as long as 1 hour (maybe longer) to joint a top or back. Now I can do it in 5 minutes, perhaps 10 minutes if it happens to be a difficult piece. It's simply a case of a well set up plane, a little technique and some practice.
Author:  James A. [ Tue Feb 09, 2010 3:40 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I tried many times with a plane to joint the top. I got so frustrated and scared that I would run out of wood, so I decided to use a sandpaper jig to joint the top. It worked very well and I am very happy with the results. The joint seems very strong and it is nearly impossible to see. Since then, I bought a Veritas Jack plane and have had success is jointing a top. From now on, I will more than likely use the plane to joint, but I wouldn't be afraid to use sandpaper again.
Author:  arie [ Tue Feb 09, 2010 3:42 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I stay away from sandpaper for this work. It's too easy to round off the edges of the joint. Also you'll get a rough, fuzzy, torn edge with abrasive grit embedded in it. I don't know if any of this will help but here's what I do:

1. set up a shooting board and take a rough cut just to clean up the outer edges of the plates.
2. now on to the joint side. orient the plates like so -invert one board and mirror it to the other board.
3. sandwich a spacer board between the plates and my shooting board and clamp it down.
4. clamp a steel straight edge under the plates and just shy of the finished cut. I use this as a guide for the plane.
5. clamp something towards the back of the plates to use as a stop.
6. cut away.
7. remove and check with suitable light source for tightness.
8. reclamp to the shooting board.
9. repeat steps 6 through 8 to semi-finish the joint
10. now I use a rectangular sandvik scraper to fine tune the seam to the best possible joint. removing just the high spots. these can be more easily seen by rubbing the plates together. the high spots will appear as shiny spots of wood.
11. repeat steps 8 and 9 until no light comes through the joint.
Author:  bluescreek [ Tue Feb 09, 2010 4:00 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I use a surface plate and sandpaper for jointing and havn't have a plate fail yet. As Todd points out , it is the quality of the mate of the joint that matters more than anything. A forced joint is a joint that is doomed to fail.
Author:  Tom West [ Tue Feb 09, 2010 4:05 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
James Allen's post may speak very loudly to part of the problem.How many folks are out there suffering with tools that are either not set up correctly or are virtually impossible to set up and at the same time think the total problem is their technique...?How can people get by this sticking point......not sure...even as good a resource as this forum is it is hard to get this across in this medium.If they had local folks with good woodworking skills even if they were not interested in guitars I'm sure they could get some help straightening out some of these problems. To the question ...yes it can be done by sanding . I think it can be done better with a plane. Time to stop preaching...! Good luck.
Tom
Author:  truckjohn [ Tue Feb 09, 2010 4:40 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I do the Sandpaper + surface plate method as well. There is still a technique to the sandpaper/surface plate method -- you can't just scrub away and expect perfect joints....

I am getting better and better with the Plane (It seems pretty fast and quite a bit less messy,) but my planed joints still aren't quite good enough to completely pass candling top to bottom... They are close enough that a couple passes on the surface plate flattens them out well enough to easily pass candling.

I do like planing -- and I am still working on my technique to get closer and closer to 100% planed... but I also am not going to waste a couple tops "Chasing the gap" trying to get it from 99.7% to 100%...

Thanks

John
Author:  Hesh [ Tue Feb 09, 2010 5:22 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
Jointing plates with a plane is a learned thing that with some practice, a good plane (very sharp), and proper technique can be quite rewarding and even fast.

I jointed a WRC top this morning with a plane and had a decent joint after I cleaned up the joint in only a minute or two. I have been getting faster since I started practicing on scrap and had some help too. My plane, a Record #5 was set-up perfectly by Todd Stock and my technique comes from Link V. Link taught me to apply pressure to the front of the plane when starting the cut, move to the middle in the middle of the cut and finish with the pressure on the back of the plane. By pressure I mean light pressure shifting through-out the cut from forward aft.

In addition I used to candle using a window to hold the plates against and look for gaps. That kind of sucked at night.... gaah :D Recently Link talked me though how to check a joint for fit without candling instead just closely examining the joint with no forcing anything seeing where there is contact and where there isn't. It works quite well and is IMHO easier than holding the dang things against a window.... or waiting for day break....

I still out of habit check my joints with a bright light after gluing and after I cut my top or back out I still break the ends to be sure that wood breaks anywhere but the glue joint.

I also agree that a well made sanded joint is better than a crappy planed joint and I used sanded joints for the first 10 or so guitar with no failures. If you are sanding your joint be sure to change the sandpaper before jointing a spruce top if you already used the level with sandpaper for the back plates. The darker colored dust in the sandpaper will contaminate your top joint and show as a dark line on the finished guitar.

Arie I used to also use a straight edge at the bottom of my clamped stack as a guide for the plane with the thinking being that the straight edge would force a straight cut. It worked OK but these guys convinced me that the right size plane, very sharp, and proper technique was a better way to go AND you run no risk of ruining the precision straight edge either.

Lastly I certainly can relate to how frustrating it can be and I have walked away from a jointing operation more than once in the past.... But if you learn the proper technique and have the right plane it's really a no-brainer and kind of fun too.
Author:  Michael Dale Payne [ Tue Feb 09, 2010 5:33 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
“I was told (by experts, Masters) that jointing should be done using planes”

When I read such an opening line I always wonder just who the master is? Most of the top luthiers I know would slap me silly if they caught me referring to them as Masters :D

Some sand papers (mostly cheap stuff) can leave behind striates that will inhibit adhesion. But I have joined about half of all the tops I have ever joined with sand paper The other half with a plane on a shooting board. I have never had one fail that said a well planed edge is probably the best surface to joint. But if you use a quality paper, the odds are you will end up with a life time joint.
Author:  Kris [ Tue Feb 09, 2010 5:38 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
Thank you very much for your helpful advices.
I think I need to work on my 'planing' skills. I use (or rather 'try' or struggle with) Veritas #6 for jointing. I remember Gerhard Oldiges telling me years ago how the natural tendency of the human arms to move in circular pattern makes a straight, flat planing difficult for novices: I have this problem, plus a complete lack of practice.
Author:  old man [ Tue Feb 09, 2010 11:26 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I've used sandpaper for most of mine, a plane on a couple. The three I'm doing currently, I did on my jointer. I taped the two pieces together and made one pass on the jointer and got a perfect fit. Three times. Two sitka bearclaw master grade, and one adi.

Ron
Author:  Ti-Roux [ Wed Feb 10, 2010 12:04 am ]
Post subject:  Re: Jointing Question - Using Sandpaper?
old man wrote:
I've used sandpaper for most of mine, a plane on a couple. The three I'm doing currently, I did on my jointer. I taped the two pieces together and made one pass on the jointer and got a perfect fit. Three times. Two sitka bearclaw master grade, and one adi.

Ron


You probably have a real good jointer... or bad eyes pizza
Author:  MRS [ Wed Feb 10, 2010 12:19 am ]
Post subject:  Re: Jointing Question - Using Sandpaper?
By any chance does the master work at the Home depot? There is plenty of them there giving masterly woodworking advice. :)
Author:  Bob Garrish [ Wed Feb 10, 2010 11:17 am ]
Post subject:  Re: Jointing Question - Using Sandpaper?
MRS wrote:
By any chance does the master work at the Home depot? There is plenty of them there giving masterly woodworking advice. :)


Hey, not just any chump off the street becomes assistant manager!
Author:  Christian Schmid [ Wed Feb 10, 2010 11:46 am ]
Post subject:  Re: Jointing Question - Using Sandpaper?
Quote:
In addition I used to candle using a window to hold the plates against and look for gaps. That kind of sucked at night....


How about turning on the light inside and going outside on the porch/balcony/... with the top? You could then 'candle' using the window and the indoor light... :D

Christian
Author:  Michael Dale Payne [ Wed Feb 10, 2010 12:30 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I made a $15 candling box, 2 pieces of 1/2" x 24" x 12" MDF face plates leaving a 1/4" gap between them over a cheap ply box containing a $6 18" kitchen florescent fixture. It works day or night Eat Drink :D
Author:  SteveSmith [ Wed Feb 10, 2010 1:54 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
Christian Schmid wrote:
Quote:
In addition I used to candle using a window to hold the plates against and look for gaps. That kind of sucked at night....


How about turning on the light inside and going outside on the porch/balcony/... with the top? You could then 'candle' using the window and the indoor light... :D

Christian


I just hold em up and use the shop lights. I like the idea of Michael's candling box but just don't have the room.
Author:  WendyW [ Wed Feb 10, 2010 4:26 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
How about some recommendations for what length and brand of planes you all prefer to use for making the joint. Wendy
Author:  Hesh [ Wed Feb 10, 2010 4:51 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
Wendy I use an old Record #5 and it works great. I know virtually nothing about planes but lots of these guys are pretty knowledgeable about planes, where and how to get old ones and tune them up etc.
Author:  letseatpaste [ Wed Feb 10, 2010 4:54 pm ]
Post subject:  Re: Jointing Question - Using Sandpaper?
I used to use a Lie Nielsen #4 1/2, it was a bit on the short side but it did the trick. I think a #5 would probably be about right.
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