Back braces on #1

What're You Doing?
Kevin Sjostrand
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Joined: Sat Feb 09, 2008 8:06 pm
Location: Visalia, CA

Re: Back braces on #1

Post by Kevin Sjostrand »

Sharp enough to slice tomatoes!
Looks great.

Kevin
deadedith

Re: Back braces on #1

Post by deadedith »

Nice job!
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: Back braces on #1

Post by nkwak »

Thanks, guys. These pics make them look better than they actually are. I guess I'm picking up some photography skills from my "mentor" as well as learning some quick and dirty tricks. OTOH yeah, that mini plane was a great investment!

On to voicing the soundboard...!
~ Neil
Tony_in_NYC
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Joined: Thu Aug 12, 2010 9:11 pm

Re: Back braces on #1

Post by Tony_in_NYC »

The braces look great. I have a crappy, $3.00 mini plane i got from Amazon. I lapped it, sharpened the blade and learned how to get the blade to shave off paper thin slices of wood, and it is one of my favorite tools for carving the braces.
nkwak
Posts: 650
Joined: Sat Nov 13, 2010 9:55 pm
Location: Pittsburgh PA suburbs

Re: Back braces on #1

Post by nkwak »

4-1/2 years later and I'm back at this point on my subsequent build. I admit it, I forgot the lesson learned and have come up against the same problem. I'm glad I stumbled across this via the search function.

Using a radius dish I sanded the contours on the back braces and had the same issue: without unlimited access to that same radius dish I did not have a workable way to glue the braces down. I tried with clamps, a metal rule to make any flex along the width of the plate to be uniform - I even tried putting a weight in the middle of the plate to try and approximate the radius along the lengthwise axis. Even the index cards proved to be problematic though. There's just no substitute for having that radius dish handy.

So I've decided to try and make a caul with an arc that matches the radius along the width of the brace but otherwise flat. I figure that a 1/4" brace has small enough of a footprint that the brace will flex somewhat when the plate is glued to the rims.

Image
~ Neil
johnnparchem
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Re: Back braces on #1

Post by johnnparchem »

You can also put sandpaper on your caul and use it to put the radius on the braces. This thread previously changed the way I radiused braces. I have found through a bunch of guitars since I changed that the flat radiused braces glued down better than poorly sanded braces sanded in a radius dish where it is really easy to over round the edges.
ruby@magpage.com
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Joined: Thu May 24, 2012 8:03 am
Location: Chestertown Maryland

Re: Back braces on #1

Post by ruby@magpage.com »

Neil
I have built 5 guitars, one ukelele, and put a new back on an old Gibson without dishes. A beam with the right curve to it works just fine:

https://www.flickr.com/photos/ruby1638/ ... /lightbox/

And when it come to sanding the shape into the braces and gluing them on, it may take a little longer but no problem:

https://www.flickr.com/photos/ruby1638/ ... 029319394/

I am not at a point where I want to invest in dishes because this is so easy and effective

Ed
Ed M
nkwak
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Location: Pittsburgh PA suburbs

Re: Back braces on #1

Post by nkwak »

That sounds like a great idea. My caul isn't the best though. The curve is close but that's only good enough for horseshoes IMO. I wonder: I have a flexible rule with a cork backing. I could use that pressed up against my caul as a sanding surface. I think that could work. Don't you?
~ Neil
johnnparchem
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Re: Back braces on #1

Post by johnnparchem »

nkwak wrote:That sounds like a great idea. My caul isn't the best though. The curve is close but that's only good enough for horseshoes IMO. I wonder: I have a flexible rule with a cork backing. I could use that pressed up against my caul as a sanding surface. I think that could work. Don't you?
Sure with some double stick tape. It would be worth a try.
ruby@magpage.com
Posts: 1564
Joined: Thu May 24, 2012 8:03 am
Location: Chestertown Maryland

Re: Back braces on #1

Post by ruby@magpage.com »

Remember that every luthier has a different radius he likes - top and back. My opinion is that you have to build 10 to 20 "identical" guitars to learn what differences you are making, and I only want to build one of a type, so for me to refine these things to the nth degree is impossible. Does not make it any less fun:

https://www.flickr.com/photos/ruby1638/ ... 776959267/

Ed
Ed M
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