Official Luthiers Forum!

Okay, I've always just shaped the pieces by hand, but this forum is full of great ideas. How do you handle your back joint reinforcement strip?

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http://www.presnallguitars.com

Glue on the strip before the braces are installed. Tape a bit of thin AL flashing either side of the strip. A few cut with a small plane and then a formed sanding block to smooth things out.Remove flashing. Cut notches for braces using the braces as a guage.The strip is cut with a safety razor blade and the scrape removed with a chisel. Install the braces.

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A person who has never made a mistake has never made anything!!!

Same here. I use a rabbet plane to shape it, which allows me to plane the round profile almost all the way down to the back plate, so it goes very quickly.

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Rian Gitar og Mandolin

I glue in the back splice before the braces , then I use a rounded sanding block to shape and finish with a 0000 steel wool. Often I will inlay something in or to the side of this for decoration

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I don't use one, and am overly smug about it too

Ok! I've done all of these, (except not using one Lex ). I've thought of jigging or automating to a degree, but then reality sets in and I realize it'd be overkill for a pretty simple task to begin with! Thanks for the replies guys!

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http://www.presnallguitars.com

+1

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I like to brace the back and shape the braces first. Then I install the back strip reinforcement between the braces.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I install the strips, profile with a block plane, sand lightly, then install the braces. Easier for me to mark (with a marking knife) locations on the spruce back strip (offcuts from tops) and clear excess with a sharp chisel than precisely fit the spruce between the braces. Simple, enjoyable task involving nothin' but hand tools.

I do it just like Tome West does. No sense in making an elaborate jig IMHO. Takes ten minutes to get it done.

I did it a bit different on my current build and based on a 60's Manual Contreras guitar I have. I like the unpolished almost random look of the cross grained diamonds.

Mattia, that's how I do it as well.
Fillippo, no sense at all in an elobarate jig, you are right...I was just curious what everyone was doing. Some of the forum folks have a "nuclear solution" for even the simplest things and I thought it'd be fun to see. Too much time on my hands in the hotel, I suppose!

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http://www.presnallguitars.com

I agree with Chris. If you are not using an inlay in the center, you do not need a reinforcement strip. We don't use reinforcement strips on the top, and that works.

Steve

Some of the woods commonly used for backs are more difficult to glue than spruce, and a crossgrain reinforcement adds a lot of gluing surface to the joint, which is a bit of an insurance. If you have ever had to glue them in after the fact, working through the soundhole (yes, it is a royal pain), you may want to do use them even if you don't have a back strip -- it it a lot easier. Just tell everyone that you like the look or whatever...

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Rian Gitar og Mandolin

Exactly! It's good cheap insurance, and besides, it's traditional and I fear change!

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http://www.presnallguitars.com

Agree the back splice adds a big insurance to the back joint. Also I don't see why routing a back strip is any better than butting between if the splice is used. I don't like to add a step in the process that isn't needed. If you have failures in this ,it may be more the technique used. I routed the first few bust stopped within the first few guitars. #151 and still going.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I would argue that it's much better to lay the strip in between the plates as well as put the inside reinforcement in the direction of the long grain.
Jose Romanillos felt that this arrangement (if the guitar is severely dried out) allows the back to separate less obtrusively along the marquetry rather than splitting one of the plates.
In the days before humdity control this was almost a foregone conclusion and is why I think that the center back strip seems fairly ubiquitous on fine older guitars.