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Panel Repair question

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Forum topic by unclearthur posted 12-27-2017 02:24 AM 611 views 0 times favorited 23 replies Add to Favorites Watch
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unclearthur

193 posts in 1992 days


12-27-2017 02:24 AM

Merry Christmas All,

So I’m making a serving board with some borders and splines which required several panel type (edge to edge) glue-ups. Just as the whole thing was almost finished and ready for final sanding, I noticed that one of the original edge joints, made 3 days ago between two pieces of walnut, has split on one end. The split is about 4” long and maybe 0.005” at the widest. You can see light through it; definitely no good as-is.

I realize the best repair is probably to rip it along that edge joint, re-joint the edges and reglue it …...but
- the sides of the overall piece are now curved, making both the ripping and the re-glueing awkward
- some of the symmetry of the board will be lost

Wondering if there are other options? Would dripping epoxy into the split be viable? (I have the west system epoxy 105/205). Would epoxy fill something so narrow (say 0.001 – 0.005”)? I can live with a bit of discoloration where the split is.

Other ideas? Doesn’t have to be perfect, but I don’t want to scrap the piece especially because I like the grain pattern.

Thanks for any responses ….


23 replies so far

View MrUnix's profile

MrUnix

7053 posts in 2403 days


#1 posted 12-27-2017 02:35 AM

Would dripping epoxy into the split be viable? (I have the west system epoxy 105/205). Would epoxy fill something so narrow (say 0.001 – 0.005”)? I can live with a bit of discoloration where the split is.
- unclearthur

Yes and yes. Although, if you are careful, it could be done almost invisibly, and only really noticeable if you point it out to people. Rather than dripping epoxy into the crack, I’d use something thin to work it in with. If you don’t use too much, there should not be much squeeze out, and what little there is could be removed with a scraper (or a finish sanding) if needed.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Jeff's profile

Jeff

489 posts in 3398 days


#2 posted 12-27-2017 02:50 AM

If it was mine, I’d use some hold downs and a sled and rip it on both sides of that middle piece with figure to retain the symmetry. Re-join, re-glue and you’re back in business.

View TheFridge's profile

TheFridge

10756 posts in 1690 days


#3 posted 12-27-2017 03:28 AM



If it was mine, I d use some hold downs and a sled and rip it on both sides of that middle piece with figure to retain the symmetry. Re-join, re-glue and you re back in business.

- Jeff in Huntersville

Either would work. I’d probably rip it and reglue though

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View unclearthur's profile

unclearthur

193 posts in 1992 days


#4 posted 12-27-2017 04:46 AM

OK thanks ….. trying the epoxy, though it was difficult to work into the crack – don’t have anything that thin with any rigidity …..

If it has to be ripped and reglued, how do you reglue it when the sides are curved? Create matching forms?

And by the way, whats the most common reasons for splitting right on a glue joint like that? Hasn’t happened to me before …...not enough glue? (Used titebond II). I know I only left the clamps on for 2 hours whereas usually I leave them on overnight – is that an issue? I thought an edge glue joint should be stronger than the wood … ie the wood would split before the joint would come apart? Joint seemed OK after the glueup, only noticed the problem today which is 3 days later.

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Loren

10477 posts in 3852 days


#5 posted 12-27-2017 05:11 AM

The slightly distorted tissue in the center board
could be the cause. In the future you might
want to allow sections with distorted tissue
to sit and move longer before jointing the
edges.

I often make glue joints slightly hollow, by
about the thickness of a piece of paper, so
the ends touch but light shows through in
the center. This puts a little pressure on the
ends in the glued up piece and keeps the
joints from separating at the ends where
moisture moves in and out a little more
freely.

I would rip and rejoint and chalk it up to
experience.

View Rich's profile

Rich

3893 posts in 793 days


#6 posted 12-27-2017 05:21 AM

I do repairs like that using various hard fill products from Mohawk. Which one to use depends on the situation, but they have lots of videos on youtube showing how to get started. Done right, no one will be able to tell.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View JBrow's profile

JBrow

1366 posts in 1124 days


#7 posted 12-27-2017 05:05 PM

unclearthur,

If you proceed with the epoxy approach, opening the crack with the utility knife or razor knife could provide enough room for the epoxy. Painters tape could be applied near the opened crack and the epoxy (or other filler) pressed into the crack with a putty knife. Working the filler into the crack from the end of the crack to the table top edge could help force air out of the crack. As soon as the epoxy has filled the crack and before cured, the painters tape would be removed to prevent it from bonding to the top. Sanding flush would be easier.

Another, perhaps less visible repair would start by opening the crack with a utility or razor knife. A thin filler piece of walnut could then glued into the enlarged crack and sanded flush. I all likelihood, the thin filler piece of walnut would have to shaped to create a face-taper from one edge to the other. When the filler piece of walnut dry-fits well into the crack, it could be glued in place.

I see three problems with the rip and re-glue method. These problems are ripping the table top, re-gluing the top, and working the faces and profiled edges flush. Solving these problems would be more work than trying to repair the crack by filling.

The first problem is ripping the top to create a glue-ready joint without a straight edge to register against a fence. A straight edged piece of wood could be affixed to the table top parallel to the glue seam using double-sided tape. The straight edge would register against the fence.

The second problem, re-gluing the top, would require some custom edge cauls. These would be made by cutting the profile of the long edges of the table top onto a piece of wood, leaving the opposite edge straight. The curved edge would rest against the curved edge of the table top and the opposite straight edge of the curved caul would accept the clamps.

Solving the third problem would begin during the re-gluing operation. Keeping the two sections of the top flat, flush, and the ends aligned would be necessary. If the wood glue is allowed to rest a minute or two until it tacks but before the wood glue begins to skim over the two table top pieces would grab and be less prone to sliding around. Some additional waxed face cauls could also be added to keep the faces flush during glue-up.

The re-glued table top would be narrower than the original top by the kerf of the saw blade. As are result the end profile of the top will not flow smoothly across the glue seam. Once the glue seem is flushed up on the faces, either the end profile would have to be re-cut or the end profile feathered with sanding.

On occasion I have seen a slight gap in the joint at the end of a glued panel. I attributed it a failure to place clamps close enough to the ends and then applying too much clamping pressure elsewhere. I figure the excess clamping pressure compressed the fibers enough to introduce a slight bow in the planks during glue-up resulting in the joint at the clamp-deficient end opening up slightly.

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LesB

1866 posts in 3647 days


#8 posted 12-27-2017 06:50 PM

Lots of great suggestions here.
So, if you decide to “epoxy” the opening I would suggest using medium or thick Super Glue instead. It is easier. First I would clean out the opening then fill it with fine walnut sanding dust…push as much as you can in. Then moving quickly drip in some thin super glue, this soaks the sawdust, immediately followed with the thicker version of glue, continually adding more until it stops sinking in. Let it cure for a while (thick super glue can take up to 15 minutes to set up) then scrape and sand. The crack should almost disappear.

However, if it were mine I would carefully rip the piece apart along the seam using a band saw to reduce the kerf size and also because you don’t have a good straight edge to guide you on a table saw. Then plane the edges true and smooth and glue back together.
I like Loren’s idea of making the edge slightly “hollow” (bowed) in the center there by creating pressure on the ends to keep them closed. I am curious as to how he does this??

-- Les B, Oregon

View Rich's profile

Rich

3893 posts in 793 days


#9 posted 12-27-2017 07:00 PM


I like Loren s idea of making the edge slightly “hollow” (bowed) in the center there by creating pressure on the ends to keep them closed. I am curious as to how he does this??

- LesB

It’s an old school method called a spring joint using a plane to dish out a tiny amount of wood in the center of the joint. The idea is that when you clamp in the center, it pulls the joint together so you have good pressure all along the glue line. It’s similar to the concept of having a slight convex face to cauls used to flatten a panel during glue up to ensure you have even pressure along the entire face.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View Loren's profile

Loren

10477 posts in 3852 days


#10 posted 12-27-2017 07:05 PM


I like Loren s idea of making the edge slightly “hollow” (bowed) in the center there by creating pressure on the ends to keep them closed. I am curious as to how he does this??

I joint both pieces straight then take a pass
or two off the center of one using a hand plane.
I learned it from a James Krenov book.

View CharlesNeil's profile

CharlesNeil

2457 posts in 4074 days


#11 posted 12-27-2017 07:09 PM

if you glue it , and pull it together is going to open again, you have to relieve the internal stress,, here is an old video i did , and it works like a champ
https://www.youtube.com/edit?o=U&video_id=AyoWG49y1eQ

View unclearthur's profile

unclearthur

193 posts in 1992 days


#12 posted 12-27-2017 09:41 PM

Note – I think the proper link for CharlesNeil’s video is:
https://www.youtube.com/watch?v=AyoWG49y1eQ

Its a good video …... not a technique I would ever have thought of for sure.

Thanks for all the suggestions ….. the creativity / knowledge on LJ never fails to amaze me.

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unclearthur

193 posts in 1992 days


#13 posted 12-28-2017 12:53 AM

so mostly for the reasons described by JBrow above, I went the easy route and just tried to fill the split with epoxy, without clamping anything. For now the epoxy seems to have filled the gap, leaving just a black line, which is fine for my purposes:

It was hard to push the epoxy into the split as it was so narrow, and it could be the epoxy has only filled very close to the surface. And I guess the wood could move and the split widen again. We’ll see.

Thanks to all for the suggestions.

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unclearthur

193 posts in 1992 days


#14 posted 12-28-2017 01:00 AM



..... Painters tape could be applied near the opened crack and the epoxy (or other filler) pressed into the crack with a putty knife. Working the filler into the crack from the end of the crack to the table top edge could help force air out of the crack. As soon as the epoxy has filled the crack and before cured, the painters tape would be removed to prevent it from bonding to the top. Sanding flush would be easier.

This is basically what I tried, as I remember seeing it done to stabilize some knots on a wood whisperer episode. However, I found that
- the epoxy soaked right through my painters tape, making it sort of ineffective as a masking material. Is there a better tape to use?
- the epoxy seemed thicker then on the video I saw (though I think it was the same 105/205 epoxy) – closer to honey than CA glue – which made getting the epoxy into the crack more difficult than it seemed for the WW; my shop was around 60 F …... is there a way to thin the epoxy or should it be heated to make it flow better?

View bilyo's profile

bilyo

424 posts in 1306 days


#15 posted 12-30-2017 04:45 AM

You’ve fixed it and it looks good. For the future, if it happens again, you might try holding the end of your shop vac on the underside of the split as you are dripping in the epoxy. I’ve never tried it, but I understand it works. Also, a good tool for working glue into narrow places is feeler gauges that mechanics use. You can get a set at an auto parts store.

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