Butterfly (bow tie) patches

[Michael Furey]

I'm trying to make some butterfly patches to prevent the checking on the end of a board of maple from going any further. I was able to cut out the shape with my router (not pretty but will work). I'm having some trouble making the insert. I was wondering...instead of trying to cut out an insert to match the hole perfectly can I use some type of epoxy or even wood glue? Would this prevent the split from going any further? This is all being done on a piece of 5/4x8 maple.

[Gene Takae]

I think you will find it easier to make the patch piece first, then scribe around it it to prevent splintering, and then remove the waste material.

[Warren Wilson]

A relatively easy way is to use one of these inlay sets -- for about $15. You make your own template.

http://www.leevalley.com/en/wood/page.aspx?p=41779&cat=1,43000,51208,41779

[Michael Furey]

In the future I will try both of these suggestions, however I need this done by today and I don't have a band saw or scroll saw. Trying to do something that is quick and this seemed like something that in theory would work.

[Jebediah Eckert]

How about just making a slightly bigger patch? I take some double sided carpet tape and tape the patch down on slab. Then Trace the edges with a marking knife. I find it easier to just use a chisel but if your router method worked the first time clean it up with that. Putting the patch in with epoxy will be a little more forgiving with a sloppy fit but you will obviously see the epoxy lines where it fills in the gaps. Leave the patch slightly high and don't set any part of the patch lower then the surface of the slap. When everything is dry I clean it up with a block plane, but I'm sure a random orbital sander will do the trick. I just don't have any grit suggestions, I haven't tried that method.

[Jake Elkins]

General question about these bowties: When I've seen them on slabs, they only seem to be placed on one side, and only about an 1/8 of the total thickness. At this point, is this more for decoration? If would seem to me that the ties should be on both sides of the slab, and relatively thick. I also think that filling with epoxy after applying the inlay is a good idea? What is the general consensus?

[Jebediah Eckert]

There shouldn't be anything to fill with epoxy, I'm not sure what you mean.

[Jebediah Eckert]

Here is the first one I ever tried. I had to zoom in so its not the greatest picture. I set it in with epoxy. You can see on the right side it was a bit off and it shows up as a darker line, but I think it's fine, I'm the only one who would notice anyhow.

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[Sam Murdoch]

OP - you describe checks "at the end of a board" is that a check or a bunch of little checks? Is one check a few inches long or just visible as a crack? Do (does) the check(s) go all the way through?

Your answers might decide the solution. Using epoxy as a stop gap can work but I have found that it help to provide a full stop for the crack by boring a hole at the inside end of the crack to physically interrupt the crack. This hole should be as small in dia. as will completely interrupt the crack and as deep as the crack - a bit deeper. Then you can fill with epoxy to stabilize the crack.

However this solution might not be practical or necessary for a series of little checks at the end of a board. In this case you might be able to get away with forcing in some epoxy - forcing either with a syringe or with some pushing with a putty knife. In any case applying epoxy to cracks is usually a 2 or 3 application process. Big cracks will develop bubbles if you go to fast so best to pour slowly and pop any bubbles with a pin.

Hope this is useful info. Photos from you would help us help you. Good luck.

[Jake Elkins]

There shouldn't be anything to fill with epoxy, I'm not sure what you mean.

As shown in the picture below (taken off the web), we see a couple of butterfly splines in large cracks in the slab. The crack itself is not filled with an epoxy, and the splines are typically only a fraction of the thickness of the slab. I guess I am just asking about the mechanics of stabilizing a crack with the method shown below.

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[lowell holmes]

Try this

http://www.highlandwoodworking.com/jasperbutterflytemplate.aspx

[Matt Day]

Jake, what do you mean by "both sides of the slab"? If they are structural, they are only used where there is a crack. Filling with epoxy is up to the builder, but leaving it open is more traditional I think.

As far as how thick they should be, wood is extremely strong with the grain so if you cut the bow tie with the correct grain orientation to doesn't need to be very thick.

[Randy Red Bemont]

A relatively easy way is to use one of these inlay sets -- for about $15. You make your own template.

http://www.leevalley.com/en/wood/page.aspx?p=41779&cat=1,43000,51208,41779

This is what I use and they are very simple to do. I know that doesn't help you today but worth ordering so you have one on hand. Good luck.

Red

[Jake Elkins]

Jake, what do you mean by "both sides of the slab"? If they are structural, they are only used where there is a crack. Filling with epoxy is up to the builder, but leaving it open is more traditional I think.

As far as how thick they should be, wood is extremely strong with the grain so if you cut the bow tie with the correct grain orientation to doesn't need to be very thick.

Thanks for the help.
Lets say I have a 2.5" slab of w. oak with a crack that is 1/4" at the end and travels 10 inches across the slab. The crack is visible on both sides of the slab. What I have seen is one or two thin (1/4" or so) inlay placed on the presentation side of the slab. However, mechanically I think that placing inlays on the bottom of the slab, which would be more-or-less hidden from the viewer after construction would further help to prevent crack propagation. However, I think that mechanically speaking, using a combination of inlay and epoxy would give the best repair.

Hopefully this makes sense.

[Jebediah Eckert]

As shown in the picture below (taken off the web), we see a couple of butterfly splines in large cracks in the slab. The crack itself is not filled with an epoxy, and the splines are typically only a fraction of the thickness of the slab. I guess I am just asking about the mechanics of stabilizing a crack with the method shown below.

330655

i got it. I'm not sure is my answer but I'm sure somebody more knowledgeable would know. I do know I have read a bunch of threads and people tend to argue about wether they do offer much strength or not. I'm sure our thoughts are similar in that the thicker and deeper they go the better makes sense? Even a 1/4" one I would think would do something? I like the "drill" trick to stop the crack. That in combination with a Dutchman can't hurt.

[Michael Furey]

Thanks everyone for all the advice. This is for a table top and the patches are going underneath. On one end the split is pretty long. At least 12". The other end is shorter. Maybe 6". I'm not making the patch so it goes all the way through just about half the thickness. I made one patch which I finally got to fit very sloppily and then I just filled in the gaps with glue. What I was trying to figure out if I could do for the 2nd patch was instead of putting a patch in it, just fill the whole thing with glue or epoxy. This board will be a middle board and edge glued to other boards and will also have a breadboard on both ends. I just want to prevent the splits from going any further and was wondering if this would work.

[Brian Holcombe]

This is a bit curious to use them under the table and especially along with a table that uses breadboard ends..,.not that you can't, but typically you see this sort of patch used with 'live edge' tables.

In your case, if the slab is absolutely wonderfully grained then I might do so, if it's straight grained I would rip it down and glue it. I'd put the butterflies on top regardless.

The butterfly Joints are meant to only to partially through the board, which allows for long grain to long grain contact. If you figure that they are returning some intergity back to the board, then it makes sense to apply them from the top, which will allow them to work in conjunction with the table base which will be supporting the underside.

[Sam Murdoch]

This is a bit curious to use them under the table and especially along with a table that uses breadboard ends..,.not that you can't, but typically you see this sort of patch used with 'live edge' tables.

In your case, if the slab is absolutely wonderfully grained then I might do so, if it's straight grained I would rip it down and glue it. I'd put the butterflies on top regardless.

The butterfly Joints are meant to only to partially through the board, which allows for long grain to long grain contact. If you figure that they are returning some intergity back to the board, then it makes sense to apply them from the top, which will allow them to work in conjunction with the table base which will be supporting the underside.

That's an important point on the subject.