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I've seen the warnings that redwood is quite fragile and splits easily, but boy this stuff is pretty bad.
Dropped it, not hard, when thicknessing and it split a little, but was under the FB area, only 1-1/2", not too much a problem, glued it.
But this happened while sanding the top. Didn't notice it until I'd flicked the dust off with a brush, and of course the splinter with it.
20 minutes found it in one piece, in an untidy workshop, near a windowsill 4/5 feet away.
Is all redwood quite this fragile?
Well, at least I know there's not much run-out in this top.

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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 built one with a redwood top and I probably won't do another, it's just too much of a PITA to work with.

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Steve Smith
"Music is what feelings sound like"

Trouble is I have plans for another 2 extremely nice boards I bought.
If this guitar survives, I will still probably use them.

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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.

Redwood is really inconsistent in its material properties...total gamble.

My sample size is only two, one sinker redwood and the other non-sinker. Both worked the same as spruce. I'm really happy with how the sinker redwood topped guitar sounds and I plan to build with it again. Of course, there's no guarantee that number three won't behave like the top you're working with.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

Superb for sound - an elixir wood for acoustic instruments. Much like with any wood, it takes some figuring out how to handle it. It definitely has its own peculiarities and takes time to become experienced in dealing with those. Spruce has its own set of things. Sorry to hear about the issues, though. I remember the first time I ever scraped a spruce top along the binding and purfling ...

The boss’s favorite top-wood...I’m not so sure.

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We have become a civilization that elevates idiots, prostitutes, and clowns. Am I still to defend it? Yes, for its principles. Yes, for what it was. Yes, for what it still may be.

-Mark Helprin, The Oceans and the Stars: A Sea Story, A War Story, A Love Story (A Novel)

I build most of my guitars with redwood tops, and worse yet I use curly redwood. Meddlingfool had exactly the right answer. Redwood is very inconsistent in properties, especially in terms of being prone to cracking. If I am working on a top that shows signs of splitting, I don't try to save it, even though that can be painful. I just move on because that top is very likely weak some else too. I buy nice potential redwood when I can find it, but have learned to accept the it may be in fact not useable on down the line. IMO however, it's terrific tone wood, fits the aesthetics of the wood combinations I use, and worth the gamble.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

I got hooked on the sound after hearing a soundclip of one which Lance built and was well impressed, but held off building with it due to its reputation until I had some more experience (fixing mistakes), and got at least a little less clumsy.
The tap tone of this set is great, but the other 2 sets are stellar.

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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.

Redwood is one of my 3 top soundboards for tenor ukuleles (port orford cedar, spruce). Definitely dicey to work with, but worth the trouble...very chippy!!

Yes, definitely an inconsistent wood, but can also make some of the greatest guitars, both steel string and classical. My partner in crime, Gerard, refuses to use the stuff. He tells a story about how, many years ago, he was thicknessing redwood through a wide belt sander with a helper passing the wood back to him from the far side. A minor draught caught a panel and it split down the middle. When it happened a second time he called it a day on redwood for good!

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I've only ever built two with Redwood. One was a classical with highly figured redwood like Bob shows above and the other normal. I had no issues with each but the curly stuff was definitely more brittle. I'd probably not build with that again unless it was a laminate double top.

I've noticed some pieces of WRC and Redwood seem to "delaminate" similar to what you are showing. I don't know if it is from windshake or hitting the ground too hard during felling, or if some trees just do that naturally. I like WRC for dulcimers and usually buy it from the lumberyard and resaw it, so I don't cry too much when I get a bad board.

I got tired of spending money to return wood. I'm pretty accepting of everything that isn't plain bad, redwood is the only wood I've ever returned...

I think it was because I was sanding it quite vigorously with 80 grit and caught the edge of the board, now it's glued back, routing the binding ledges went fine, and I think it will be OK.
Going to have to be real careful preparing to glue the bridge on though, not to cut into the surface when removing finish.

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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.

What thickness are these redwood tops that are giving trouble? I am just starting one with my first redwood top. What should I shoot for?

Ed

2.725mm (0.1073") as braced, based on an SG of 0.425 and a measured MoE(long) of 11.83 MPa. (Stiffness lengthwise)
This is for an OM

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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'm building my first guitar; an arch top with a curly Redwood top. It's pretty light. The belly is 240 grams. It goes from about 3mm to to maybe 4.5 mm thick, I have no idea about stiffness. Crossgrain it isn't stiff at all. The deep curl probably cuts down the lengthwise stiffness. It is stiff enough. It's an instrument, not a coffee table. I did get a tiny split when sawing the f holes, but that was my fault for not holding it more securely.

It looks very cool. So that is a big plus.

The only wood that gave me REAL trouble was Red Spruce. It wanted to split continuously after it was finished and varnished. Even glued up! I threw it away. It looked pretty good too.

How do you measure MoE?

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Why be normal?

From BC, I like WRC , but redwood is IMHO extremely prone to cracking . checking and splitting at the most inappropriate times.

I measure by deflection testing, don't know how you do it for an archtop

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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.

Redwood does split relatively easily, but the type of failure Colin is showing where it "delaminates" is less common. When I encounter it with WRC I usually set that board aside for some other non-lutherie use.

I've have used for years.
NOT my favorite top !

Even if all goes well during construction the tone & volume is not as good
I tried many different thicknesses & bracings.
Spruce & Cedar are the kings of tops.

Mike

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Mike Collins

Despite those that have sworn off redwood after a bad experience during their formative years, it is abundantly clear that hundreds of luthiers have cracked the code on successful use.

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We have become a civilization that elevates idiots, prostitutes, and clowns. Am I still to defend it? Yes, for its principles. Yes, for what it was. Yes, for what it still may be.

-Mark Helprin, The Oceans and the Stars: A Sea Story, A War Story, A Love Story (A Novel)

I've only completed one guitar with sinker redwood, but I found it quite reasonable to work with. I am so pleased with the tone that I can't wait to build again with it.

I will have to make note to keep an eye on future builds, now knowing that it can be temperamental.

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-Marcus
http://www.bailieguitars.com
Instagram | YouTube

I was quite successful, just didn't think it was worth the trouble.

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Steve Smith
"Music is what feelings sound like"