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Forum topic by Manitario posted 10-27-2012 05:49 PM 5942 views 0 times favorited 18 replies Add to Favorites Watch
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Manitario

2377 posts in 1608 days


10-27-2012 05:49 PM

I’m building a dining room table using several 2.5” thick slabs of elm. On one of the ends there are a couple of long cracks through the slabs. I’ve seen many tables like this with “butterflies” over the cracks; my questions for those of you that have done this:
-is this necessary to stop the cracks from progressing?
-do the “butterflies need to be the full thickness of the slab?
Thanks!

-- Sometimes the creative process requires foul language. -- Charles Neil


18 replies so far

View Gerald Thompson's profile

Gerald Thompson

411 posts in 959 days


#1 posted 10-27-2012 06:29 PM

The butterflys should be about half the slab thickness. The cracks will probably progress. The butterflys will enhance the appearance. I was told by a man with lots of experience that a blemish can be enhanced by calling attention to it.

-- Jerry

View Don W's profile

Don W

15434 posts in 1292 days


#2 posted 10-27-2012 08:55 PM

I don’t usually make my butterflys that think. I think 1/2” to 5/8” is enough. If the wood isn’t completely dry the crack may continue. If its done moving it may not. Sometime you can glue the crack and clamp it shut before you add the butterfly, depending how far and how bad its cracked.

Click for details

-- Master hand plane hoarder. - http://timetestedtools.com

View gfadvm's profile

gfadvm

11381 posts in 1415 days


#3 posted 10-28-2012 02:39 AM

I have filled cracks with epoxy and then inlayed 1/4-3/8” thick butterflies. So far, so good. Elm can be more difficult than the walnut I have done so your milage may vary.

-- " I'll try to be nicer, if you'll try to be smarter" gfadvm

View Timberwerks's profile

Timberwerks

304 posts in 1886 days


#4 posted 10-28-2012 02:59 AM

I like to go 2/3 the thickness. I’ve used this method for many years and have never had issues with the cracks opening further.

-- http://djofurnituremaker.wordpress.com/ & https://www.facebook.com/pages/Timberwerks-Studio/126415221682

View 404 - Not Found's profile

404 - Not Found

2544 posts in 1694 days


#5 posted 10-28-2012 02:21 PM

Just a thought, but if you want to stop those splits getting bigger, could you drive a couple of long screws discretely at the end of the split to pin it together. You can still add glue and as many butterflies as you like.

View Dennisgrosen's profile

Dennisgrosen

10850 posts in 1840 days


#6 posted 10-28-2012 02:32 PM

if you want the table build without the cracks
and want to avoid butterflyes
then Charles Neil have a very interressting video on you-tube
about using a bandsaw to ripsaw thrugh the cracks and glue the board together again
several times until the crack is gone …. its a nearly invisble fix
take a look at the video-clip before you deside what to do

good luck
Dennis

View Manitario's profile

Manitario

2377 posts in 1608 days


#7 posted 10-28-2012 08:19 PM

Thanks for the replies guys. I like the cracks in the slabs; the table will have live edges so the cracks add character; I just don’t want them to eventually destroy the table!

-- Sometimes the creative process requires foul language. -- Charles Neil

View MNgary's profile

MNgary

235 posts in 1142 days


#8 posted 11-01-2012 04:37 PM

My understanding is that butterflies are used to strengthen a cracked panel. For example, if a tabletop has cracked, you need to strengthen the top so that if someone sits on it, for example, the panel doesn’t flex to the extant that the crack extends further across the panel. In short, the butterfly prevents a downward force (90 degrees to the panel) from flexing a panel weakened by having a crack through it.

I suspect your cracks are the result of tensions from within the slab and, unless the wood is done moving (tensions are stabilized), I doubt butterflies will help. However, to prevent the cracks from extending as a result of heavy downward pressure, butterflies can be your solution. But make sure they are thick enough to add strength and not just decoration.

-- I dream of the world where a duck can cross the road and no one asks why.

View CharlesNeil's profile

CharlesNeil

1158 posts in 2595 days


#9 posted 11-01-2012 04:47 PM

done numerous of these, what I do is to use some of the pour on stuff either the epoxy or the polyester stuff
( enviorlite , Lowes , craft stores), anyway, put tape on the bottom of the crack and pour the stuff into it, what I have found is that often the crack can be more severe inside the slab, the epoxy will dry slow and flow into it, its more expensive than regular epoxy, but because of the slow dry it fills well and throughly, just make sure the tape is well stuck to the underside, a quick spray with some spray shellac or lacquer will make sure the tape holds well, other wise, it takes alot of material to fill the crack, he he he, trust me I know,
the Enviorlite is cheaper and does a good job, its polyester, then I have also done the butterflies, just for looks mostly, does nice

View Jonathan's profile

Jonathan

2605 posts in 1775 days


#10 posted 11-01-2012 05:16 PM

Great advice on the slower curing epoxy to really fill the internal cracks and really stabilize and strengthen things, Charles. Also good advice on the quick coat of shellac to help the tape fully seal!

-- Jonathan, Denver, CO "Constructive criticism is welcome and valued as it gives me new perspectives and helps me to advance as a woodworker."

View Manitario's profile

Manitario

2377 posts in 1608 days


#11 posted 11-02-2012 03:20 AM

Thanks for the advice guys! I picked up some Envirolite tonight Charles; I’ll give it a try, it certainly is a lot easier to use than chiseling out butterflies on areas people will never see.

-- Sometimes the creative process requires foul language. -- Charles Neil

View CharlesNeil's profile

CharlesNeil

1158 posts in 2595 days


#12 posted 11-02-2012 12:03 PM

here is a little more on using the epoxy/enviorlite, it really does well on slabs, that could be prone to having issues, not to say this is the cheapest way or the only way, but it has never failed me, http://intheworkshop.wordpress.com/2010/10/19/clario-slab-finishing-and-stuff/

View Manitario's profile

Manitario

2377 posts in 1608 days


#13 posted 12-19-2012 06:20 PM

An update; I used the Envirolite; it was easy to use and has a long open time which was helpful because many of the cracks were quite deep and took a lot of epoxy to fill. Its other advantage is that it is relatively thin, so again, easy to pour into cracks. It also drys clear, compared to some 5 min epoxies that have a yellowish tinge. I also ended up using butterflies that were 2/3 the thickness of the top; not easy to do considering the top is 2 1/4” thick, but I hope this will prevent any further cracking in the long run.

-- Sometimes the creative process requires foul language. -- Charles Neil

View Don W's profile

Don W

15434 posts in 1292 days


#14 posted 12-19-2012 06:22 PM

will we see pic’s ? A link to a project ?

-- Master hand plane hoarder. - http://timetestedtools.com

View Manitario's profile

Manitario

2377 posts in 1608 days


#15 posted 12-19-2012 06:44 PM

Hey Don, I’m just putting the final coats of finish on it…I’m hoping after Christmas I’ll be able to recruit a couple of guys to help me wrestle it from the shop into the house (the top weighs in excess of 150lbs) and then post some pics.

-- Sometimes the creative process requires foul language. -- Charles Neil

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