JayWC

Workbench

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I have a Sjoberg work bench. It is an Elite 2000 with the base cabinet. I love the thing because my workbench before that was an old solid core hospital door (3-0x7-0) on two saw horses. However, this winter the back board went for a walk. By that I mean the last board twisted away from the bench and split along the glue line from the rest of the bench. It is now out of plane with the rest of the bench because it is rotated down and away. I can pull it back up into plane if I place pipe clamps about a foot apart along the bench and crank the snot out of them. As soon as I release the clamps, the board twists back out of plane. I am thinking of installing some walnut butterflies all along the point of the break. I think they would need to be fairly deep (at least an inch), be about a foot apart and have a very tight fit to avoid the top moving back downward after I release the clamps. Do any of you have thoughts? Okay, let me re-phrase that. Do any of you have helpful thoughts? LOL. I need them. This was not a cheap bench. I already tried reaching the Sjoberg helpdesk and had no luck.

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How far down and away does it twist? It seems to me that rather than trying to fight mother nature with brute force, you might be better off to remove that board completely, wait for some time (a month? six months?) until it's done twisting, then mill it straight and put it back on the bench in a relaxed state.

Or, if you really want to use brute force, some largish lag screws through the errant board into the main part of the bench might be easier and more effective than the butterflies. You could countebore for the heads and plug the holes if you're worried about the appearance.

In either case, some epoxy wouldn't hurt to help hold the board in place.

-- Russ

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How far down and away does it twist? It seems to me that rather than trying to fight mother nature with brute force, you might be better off to remove that board completely, wait for some time (a month? six months?) until it's done twisting, then mill it straight and put it back on the bench in a relaxed state.

Or, if you really want to use brute force, some largish lag screws through the errant board into the main part of the bench might be easier and more effective than the butterflies. You could countebore for the heads and plug the holes if you're worried about the appearance.

In either case, some epoxy wouldn't hurt to help hold the board in place.

-- Russ

The gap in the bench is a light 1/16". The board is rotated down about 1/16" at the far edge. I thought about lagging it in too, but I'm afraid that lagging across the grain movement will cause problems in the future. I can't easily remove the board because it is still partially glued in at the bottom. I can't figure out why it did it after 6 years in the shop. I've had it since December 2005.

Also, can I get epoxy in a very small crack like that?

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The gap in the bench is a light 1/16". The board is rotated down about 1/16" at the far edge.

Ah. I was imagining a much larger gap and a much newer bench. If it's five years old, the wood is probably not moving around much unless you somehow got it wet or something.

With that small a gap, I would just try to work some epoxy down into the crack and then clamp it back together until the epoxy sets up. Get some epoxy with a long cure time. It will be stronger than the 5-minute stuff, and also give you more time to push it down into the crack.

To help push the glue down into the crack, the material in some candy bar wrappers works really well (plus, you get candy). I don't know exactly what it is, but it looks like aluminum foil on one side and plastic on the other. It's really thin, and strong enough that you can use it to work the glue down into the crack.

post-685-0-45916100-1298997206_thumb.jpg

Two more hints:

One of Marc's videos shows him repairing a cracked cutting board with some epoxy. That video may contain info that may help you.

I've heard that the West Systems epoxies are particularly runny, which may be a good thing in your situation. What I don't know is whether they come in quantities that are reasonably small for what you're doing.

Good luck!

-- Russ

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one thing that you may want to do is wait till summer time to see what happens then. When there is a little more moisture in the air, it may bring it back to where it is supposed to be. Then you can fill it with epoxy and clamp it, maybe with less effort than you would have to do right now. Dont suppose that you could post a pic of it could ya?

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To help push the glue down into the crack, the material in some candy bar wrappers works really well. I don't know exactly what it is, but it looks like aluminum foil on one side and plastic on the other. It's really thin, and strong enough that you can use it to work the glue down into the crack.

post-685-0-45916100-1298997206_thumb.jpg

I always called it aluminized Mylar, but Wikipedia says that Mylar is a trade name and it's aluminized BoPET.

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one thing that you may want to do is wait till summer time to see what happens then. When there is a little more moisture in the air, it may bring it back to where it is supposed to be. Then you can fill it with epoxy and clamp it, maybe with less effort than you would have to do right now. Dont suppose that you could post a pic of it could ya?

Finally posting pics Sac. You can see the back boards twisted down by the difference along the breadboard end. It is like this the entire length of the bench. Pic 02 shows the gap well along a pwd straight edge. I am waiting for summer still, but am skeptical anything is going to move.

post-3726-0-63502700-1301319291_thumb.jp

post-3726-0-93373100-1301319300_thumb.jp

post-3726-0-33075400-1301319304_thumb.jp

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Jay,

I'm not sure why the spit occured now. Maybe it's been under stress the whole time and it finally gave way. I once went to see a Sjoberg bench I found on craig's list. It has a crack very similar to the one you're describing and I passed on buying it.

As for the repair, I'm in the epoxy camp. I suspect that a good epoxy and strong clamps will do the trick. That said, If you epoxy and clamp it, and then put in the butterflies while it's clamped, I can't see it breaking free of that.

Good luck.

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Instead of trying to force it back to where it was, could you re-flatten the benchtop with hand planes and then just fill any remaining crack with epoxy? Unless the board is in danger of actually falling off, this might be better than trying to force it back in place.

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I agree with Jeff. I think of this much the same as a house settling over time. Usually they settle, then you repair any cracks and move on. I'd epoxy the gaps before you plane just to make sure the epoxy really got down in the cracks, then plane it flat again.

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I'm thinking this was likely a case where the top was laminated before the stock had fully dried or acclimated. So that board was likely under stress for a long time, and it just took until recently for the glue joint to finally fail. I suspect you won't see much difference even after the seasons change, and I would also suggest that trying to bend it back in place and securing it will eventually just result in another glue failure. I think flattening it and re-gluing is the only good long-term solution. That would typically be challenging with the bread board ends, but since they clearly didn't do their job the first time around, there is probably no mechanical joinery into the breadboards.

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Okay...so...it's mid to late summer. Humidity is high. The crack has mostly closed up; however, it is still evident. The top is also not completely co-planer. I am considering installing the butterflies now. I figure they need to be a minimum of 1/2" deep with a good angle. I am planning to use a router and template. Am I missing another option?

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Alright...end result...I waited all summer and the crack closed up. As we're moving into winter the crack started opening up again. The bench never really returned to flat. So...rather than trying to force epoxy down into the crack with thin strips of material, I decided to use a router and my spiral cut bit to plow a 1/2" groove the length of the bench and down to the depth of the crack. I purchased some hardwood (QS ash in this case to have hardness, strength and low movement of the grain and milled it to be "slightly" smaller than the crack (.008). I used Titebond 3 glue and pipe clamps every 8" or so to draw the top back up to level and to close the joint on the ash. Before I took the pipe clamps off I installed 1/2"x10" lag bolts along the edge. After the glue up and addition of the bolts, I grabbed my #7 L/N hand plane and flattened the top. I am going to see how it does this winter and into next summer. I will know it is dead flat right now so I'll have a good reference.

post-3726-0-82101500-1321287825_thumb.jp

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I know it's been a while and I've been the one to make the last few posts, but I'm going to update everyone. The repairs to the bench were successful, but this summer the end vise started working hard. I couldn't figure out why. I looked at the construction of the bench and realized they (Sjoberg) have a design flaw. There are four dowels in the spreaders that hold the top from sliding off the base. The dowels in the spreader restrain the top (due to cross grain orientation) from changes in width due to moisture. That caused the original failure to be cupping and a split in the top half only. This summer the vise working hard made me check the flatness too. When four dowels were in place it cupped and made the middle high. I took the back two dowels out, the top flattened out and the vise started working again. Maybe i had a bad top or just a perfect storm to create this condition, but I'd be careful with this design and probably not purchase a Sjoberg bench. I think this post brings it fill circle for me. Please let me know your thoughts.

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Thanks for the update Jay especially with the removal of the rear dowels. I have a Sjobergs bench too and it had a slight cup. I flattened the top with my jack and #7 a few months back. I don't have such wide humidity changes where I live but will have a look at removing those rear dowels.

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