Bowtie or butterfly crack repair...question

[AlanS]

I have a job to do, repairing a very old teak outdoor bench. The seat is comprised of 3- 8" wide x 1/2 boards. Two of the boards have very long cracks in them ...approx 15" long. No way to glue the boards back together, age has caused the cracks to remain open. I could, however, put a bowtie or butterfly inlay to secure the crack and avoid it's further cracking and avoid pinching your bum cheek in the crack when sitting. Question. Since the board is only 1/2 thick, do I do a surface inlay (1/4" thick) or through the entire board, visible on both sides? I fear tear out if I go through, but need it to be secure.
Anyone have experience with this repair?

[Timberwerks]

I like to go 2/3's the thickness of the stock being butterflied.

[Bill Holt]

Timberwerks said:

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I like to go 2/3's the thickness of the stock being butterflied.

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+1

[WoodTinker]

I have only used them in an artistic way. But, Every show I have ever watched have never gone the whole way thru with a "Dutchman" as Norm calls it.

I would use two of them and would think that 1/4" in 1/2" stock would suffice.