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Need help with refinishing table...twisted badly

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Forum topic by phillyB posted 01-30-2015 02:45 PM 1157 views 0 times favorited 25 replies Add to Favorites Watch
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phillyB

9 posts in 685 days


01-30-2015 02:45 PM

Hello! So I’m a long time lurker…First time posting. I’m in Charlotte, NC and have become addicted to woodworking slowly but surely over the last year and a half. Learned a lot and it’s been fun…Have a whole lot more to learn!

TL;DR: My grandparents table which I inherited and was going to refinished is badly twisted and I need to fix it!

So about 6 months ago I was given my grandparents dining room table which they’ve had in use for about 50 years. It’s just pine and was stained and poly’d…nothing terribly expensive it’s a nice table and I would like to keep it in the family for another 50 years. It’s in rough shape and not to my wife’s liking color-wise right now so we were going to fix it up.

The plan was to strip it and refinish it…Simple task! I’ve done a number of finishing projects over the last year and figured it’s as simple as stripping the poly, sanding it down a little, sanding back to smooth, staining, and reapply poly. Well I’d never refinished a table top and I did not do my research…

The table was stored in a warehouse for about a year before I got it, detached from the bottom and legs sitting on a pallet. I don’t know what the humidity was like in the warehouse. When I got it, I began working on it in my garage in the summer heat. I took the top coat of poly off first and began sanding. A few days (or a week, I can’t remember at this point…Worked on it on my days off) later I flipped it and stripped and sanded the bottom. The bottom wasn’t really poly sealed like the top and was very rough, never really finished.

So…I go to start smoothing it out with a higher grit and I notice that it’s all out of whack. At first I thought that I had sanded unevenly, but I knew I was very careful to keep a steady pace and not to linger in one spot. Surely I hadn’t done this much damage to the table! So after reading up on fixing table tops that are warped/cupped/twisted, I come to learn that I shouldn’t have taken one side off at a time and I should have kept airflow moving on both sides. Doh! I also wonder if it became somewhat warped while sitting on the pallet in the warehouse for a year? Not sure if it would do this if it was still sealed with poly but didn’t have airflow on both sides.

Needless to say I’ve tried to even it out with a jack plane and a belt sander but I feel like it’s too much to make any significant progress without taking off a ton of thickness because of the way it is warped on each side. What is the best way to proceed?

I’ve read of techniques such as attaching it to the apron and wetting it? If I do this, how do I know that it won’t warp even worse or become some other crazy shape? I’m in NC and the table is in my garage now, temp stays around 40-50 this time of year in there. Also, how much water do I put on it? Just barely wetting it or coating it with standing water all around?

I’ve also seen that I can make a router sled and level it out that way…I feel like if I do this then I’m going to cut the thickness of the table in half because it is so bad on both sides, not just one.

There’s also a small crack on the top of the table top about 6” in from the edge forming…Some wood filler? Better idea to keep it from getting worse? Should I worry about it at all if I can get it flattened out and sealed up?

What is my best chance at getting this thing straightened out? I’m kind of desperate at this point and I really don’t want to be the one in my family who volunteered to take grandma and grandpa’s table to refinish it and then ruined it!

Thanks in advance!

Philip


25 replies so far

View HornedWoodwork's profile

HornedWoodwork

222 posts in 675 days


#1 posted 01-30-2015 07:13 PM

WOW, that thing is dancing! You could try a press.

Put the whole thing in a large heavy duty plastic bag and pump it full of steam (rent a wallpaper steamer, go crazy for about 8 hours) then place it on a flat surface and use a flat form to clamp or press down against it. you might be able to press it back into shape, and get it sealed before the whole thing snaps back into that bean shape. Not sure that would work and it might reverse over time. I was going to suggest the router sled but I see that it is too warped for that to really be viable.

Maybe you could rip deep relief grooves along the underside and drop in battens to hold the shape? You could clamp the whole thing together as above and hope that when you relieve the pressure the battens reinforce the structure? It looks like the curl is mostly prependicular to the grain, so this may need to be modified.

Pine really can be such a little brat…

-- Talent, brilliance, and humility are my virtues.

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SCOTSMAN

5839 posts in 3045 days


#2 posted 01-30-2015 07:58 PM

You can either seperate it into four or more pieces,on the TS and reglue it.Make with slight alterations to the top all the edges can be run through at a slight angle Remember these small angles will soon add up.When it is all glued back together then you can clamp it during this period much straighter with the edges cut at a slight angle,I would try to reglue it two pieces at a time seperately then eventually all together.
The other way which works too is to make a series of blind cuts from below IE do not in this case seperate the wood when cutting.You should run these cuts about three quarters of the way through from bottom to top surface to relieve the overall top so that when you lay it down with a heavy weight on top it rests eventually flat.
Before gluing each of the grooves you have just created along their length do a dry run to make sure all is flat.I would actually leave it dry with heavy weights on the top surface, for a few days and see how it then looks. If all is ok regarding flatness then go back and glue the grooves almost to the edges but not quite and repeat the weights on top and it should be reglued flat.Finish it all up with a sander and fill any gaps especially up to the edges with home made woodfiller made by mixing the sawdust removed to make a paste and fill the edges ,and finish.Make sure the colour of the edge gluepaste is perfect not too difficult with pine.In any case please do not be in a hurry, it did not get in that condition in a hurry, so just take your time deliberately so if needed .Best wishes.Alistair

-- excuse my typing as I have a form of parkinsons disease

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phillyB

9 posts in 685 days


#3 posted 01-30-2015 09:56 PM

So this whole thing makes me very nervous…Definitely going to take my time on it. Couple of questions:

What are the chances of the steam bag working? Any negative side effects if it doesn’t work?

If I were to cut it into separate pieces to work with and then re-glue, wouldn’t this make it not quite a perfect circle? Not sure how noticeable it would be and I could be wrong…But 4 cuts multiplied by the kerf of the saw blade and then re-gluing leaves me with less width. Right now the table is 60” across. Would taking a half inch out of the table make it look funny? Or am I wrong on this?

Scotsman, if I were to make the cuts on the bottom of the table, are we talking just making some cuts lengthwise with a circular saw? It’s a bit large and scary to even think about putting up on my Bosch 4100…You say to go about 3/4 through, my worry would be that when flipping the table back over it might snap or something. It’s quite heavy. Are we talking relief cuts just the width of a single pass? Run them with the grain or across it?

When I do this and have the table sitting with weights on it, should I have it laying flat on the floor? Leave it how I’ve got it now propped up so there is airflow on all sides? It worries me that it’s not evenly supported all the way across…

When you talk about making a wood filler from the saw dust, what exactly do I mix the dust with? Just fill the grooves in with glue that aren’t showing on the edges?

EDIT: Sorry, HornedWoodwork, forgot to put my question in regarding the battens and grooves. I’ve no experience with this, so could you please describe exactly how I would go about doing this and what I would need to clamp it?

Sorry for so many questions…Really want to make sure I understand this and have the best chance at getting it just right. I would hate to lose this table…

If there are any other suggestions that would be more fool proof or easily executed, please let me know! I can’t seem to find any examples searching online of fixing cupping or twisting in a round table like this…

Thanks again!

Philip

View HornedWoodwork's profile

HornedWoodwork

222 posts in 675 days


#4 posted 01-31-2015 10:14 PM

The twist can’t be really be fixed, you have to try and restrain it. The wood wants to be in the twisted position, that’s its current natural state, you need to overcome that. With a slab that beefy that is a major challenge. This is an extreme situation and might need some extreme engineering to get you home. The grooves and battens work on the same principle, remove the connective tissue which is pulling the top out of flat and then force it back into shape. The battens (or ribs) if that helps you visualize it better, then add rigid structure but still allow for the wood to move. Instead of hardwood battens you could use plywood ribs. Either way these straight pieces will resist the wood cupping.

To execute this you could plunge cut your circular saw or plunge a router (protect the edge profile) and then ride a straightedge. Fill the groove with glue, then press in your batten or rib. cut the ribs so they fit proud so you can keep pressure. Press the whole thing under a form against a flat surface and leave it to dry under pressure. Hopefully when you take it out of the press it stays flat and you can then knock the ribs flush and reattach the apron.

Watch for cross grain joints. The more I think about it the more I like the plywood ribs.

-- Talent, brilliance, and humility are my virtues.

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phillyB

9 posts in 685 days


#5 posted 01-31-2015 11:16 PM

Ok, so I just want to make sure we’re on the same page here and I’m understanding this step by step…

I should make some plunge cuts with my router or circular saw across the grain? How thick should I make these cuts and also how close to the edge of the table should I get with them? I’m assuming I don’t want to go through the edge because then the battens will be showing? Also how deep do I make the cuts? 3/4 of the thickness of the table?

Then I need to cut some plywood battens to fit snugly in the grooves but still sit proud so that I can apply pressure easily…Got it. I let the glue dry and the battens get settled in and then I put the whole thing in a big plastic bag and pump it full of steam for 8 hours while clamping it flat… with what exactly? Sandwich it with a couple of pieces of plywood? Not really sure what I need to use here…I don’t have anything lying around that is that big and that flat.

I’m beginning to understand this method more…What are the chances it works? Also, if it doesn’t work am I any worse off than I was before? I’ve got a reinforced table that is still twisted… What’s plan B? lol…

Again, thanks a ton for the advice, I really appreciate it!

Thanks,
Philip

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ChefHDAN

805 posts in 2310 days


#6 posted 02-01-2015 02:25 PM

Might be time to turn it into a book case or another project, DAUM, that really twisted.

Seriously I’d examine my options for going to new lumber and making a new top for the base,
Time + Effort + Cursing + $ to “Try” to fix it = go with what I know will work once I’ve expended the effort.

-- I've decided 1 mistake is really 2 opportunities to learn.. learn how to fix it... and learn how to not repeat it

View HornedWoodwork's profile

HornedWoodwork

222 posts in 675 days


#7 posted 02-01-2015 04:50 PM

The bag or the battens, not both. Try the bag first because it is less destructive and quite a bit easier. If you use the plywood splines avoid cross grain joints, they will ruin your table. But the rest of your statement is true.

With the bag just steam the top as it is then remove it from the bag after 8 hours and immediately place between 2 flat forms. You can clamp the forms together. Keep pressing until it lays flat, but make sure your forms don’t twist. Leave it in the forms overnight. From the time it comes out of the bag until the time you have it fully fitted into the form you have about 60 seconds, plan according and beware the wood will be scalding hot.

The ribs/battens are more surefire but far more destructive. You need to excavate deep grooves 3/4 like you said, then press the ribs into the grooves with lots of glue, and then press the whole thing flat. It’s far more intense and will cause you a ton of headaches getting everything to work. You might want to consider cutting new tops after all as Chef suggests.

-- Talent, brilliance, and humility are my virtues.

View phillyB's profile

phillyB

9 posts in 685 days


#8 posted 02-01-2015 10:18 PM

Alright so I’m leaning towards cutting the grooves and trying the battens…While the steam method is less destructive, I don’t think I’ve got the stuff to do it. I need to rent the steamer and then I need to find some sort of bag large enough to put the thing in. Any ideas? It’s 60” across, not a small table top…Also, the “forms” that I need to flatten this thing out with, what should I be thinking of using here? I’m thinking just some long straight boards clamped down? Basically some big old cauls.

So if I were to cut the grooves, I want to cut them with the grain and 3/4 of the way through. How close to the edge do I want to get? How wide do I make each groove and about how many should I make across the table? One per board that makes up the table top? I think there are about 6 total making up the table.

I realize it might be easier just make a new table top, but there is some sentimental value here and I’d really like to keep this thing in the family.

Are there any other methods out there that might allow me to straight it out just a little bit more than it is right now so that I may plane and sand it flat without losing too much thickness?

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HornedWoodwork

222 posts in 675 days


#9 posted 02-02-2015 03:59 PM

Yeah, I get the sentimental value. As for the battens keep them about 1 inch from where the facet starts on the edge. Cut with the grain and whatever you do keep the spacing even across the whole field or you will create new opportunities for cupping. With such a large field you may want to space them 6 inches or so apart. I would create the form out of plywood reinforced with an octagonal apron made of 2×4 or 2×6 to evenly disburse the pressure, no small build with a 60” table. This is an extreme measure but I think it will work best. As for other ways to slightly flatten it, I guess you could use the apron to try and pull the twist out, but I would not be too optimistic about it.

-- Talent, brilliance, and humility are my virtues.

View phillyB's profile

phillyB

9 posts in 685 days


#10 posted 02-03-2015 01:03 PM

Ok, so it’s starting to come together in my head and I think I can pull this off. My only two remaining questions are:

1) How wide should each groove be?

2) What’s the best way to make these? I’m assuming I want them all parallel to each other and spaced evenly like you said. I was thinking of using a router with a straight bit and clamping two straight edges to the the table for the router to ride through. Then I can move one of the straight edges over spaced 6” from top and bottom of the still clamped straight edge to make sure its parallel and then proceed. Is there any easier way? Does it matter at all if they are parallel across the entire table?

View HornedWoodwork's profile

HornedWoodwork

222 posts in 675 days


#11 posted 02-03-2015 08:43 PM

Make the groove as wide as the rib but not wider than 3/8”, flood the groove with glue and then press the rib in. If it were me I’d use a straighted and a router bit, don’t kill yourself with the parralel, just watch for cross grain. Most of all GOOD LUCK I hope it comes together for you. When making your router passes make sure you don’t route through the other side of the piece, watch that facet on the top, it looks deep and you could get caught with a low bit, mark well and you should be fine.

-- Talent, brilliance, and humility are my virtues.

View ChefHDAN's profile

ChefHDAN

805 posts in 2310 days


#12 posted 02-03-2015 09:29 PM

I hear ya HW for the sentimental, I’ve got a table from my grandfather in the shop that’s been waiting two years for me to refinish & my wife keeps threatening to give it to Salvation army next time the truck is in the neighborhood… but,,, a question, how much sentimental value will it have to your kids if they know the base was owned by their great grand parents and their father MADE the table top! Sometime old and new can blend to harmony

-- I've decided 1 mistake is really 2 opportunities to learn.. learn how to fix it... and learn how to not repeat it

View Tennessee's profile

Tennessee

2410 posts in 1975 days


#13 posted 02-03-2015 09:49 PM

When I refinished for that awful twelve years, we saw a few of these. We usually went with the groove and batten methods, but I have to be honest, we were only about 50-60% successful. Getting it totally straight and flat is probably not in the cards.
Never steamed anything, but did heat things once in a while. All of it is a crap shoot and there are no guarantees since the wood usually wins in the end.

There is a cause and effect for everything you do to the top. So if you put in battens, some other warp might appear and you are back to square one, with lots of cuts in the wood.

I actually had a table in my shop about 8 months ago, and told the couple that I had to make a new top, since I didn’t even want to try and straighten out the old maple top. They protested, and I said I would be more than happy to help load it back on their truck and they could go find a person who was willing to take on straightening the warp/cup.
They made a couple calls…I made them a new top.

I keep thinking that you might be better served to make a new top out of the old wood? As ChefHDAN says, and a couple of others, it might be simpler just to rip it into strips and add in some new wood, and glue up a new top that would be made of the old wood. (Mainly)

-- Paul, Tennessee, http://www.tsunamiguitars.com

View Tony_S's profile

Tony_S

605 posts in 2543 days


#14 posted 02-03-2015 11:52 PM

JMO.
I’d just cut the top into as few pieces as possible(along glue joints)to flatten it out, re-mill the pieces, glue it back together, and make the table an inch smaller in diameter(approx), and an 1/8” thinner(approx). done, and no one will ever notice the difference….and it’ll be flat.

-- It is the mark of an educated mind to be able to entertain a thought without accepting it. Aristotle

View Logboy's profile

Logboy

43 posts in 2690 days


#15 posted 02-11-2015 05:09 AM

50 years ago they werent normally putting lumber like that in dry kilns to get it to a low moisture content. Because of this the moisture contents were higher than they would be inside a heated home and the wood didnt get to shrink as much before use. Your table was possibly air dried and had a pretty high moisture content when it was sealed in. When you sanded the finish off and exposed the wood it started shrinking again after you put it inside a dry heated environment. Wood afterall is constantly trying to reach equilibrium with its surroundings. Yours is obviously losing moisture and shrinking. As flat sawn wood shrinks it warps toward the outside of the log. If you look you should notice the growth rings on the end of each board go the opposite direction that they are warping. Long story short, you have a couple options. Put the table in a high humidity environment and hope it regains enough moisture for the cells to swell back up and flatten the table, or cut the top apart at the seams, joint each board, and glue it back together. Do not go hosing that thing down with water. Not only can you stain the wood, but you can dissolve the 50 year old glue and have the whole thing break apart. Do you know anyone with a greenhouse you can put it in for a few days? Its worth a shot. An 80 degree greenhouse over 70% humidity will give you a moisture content in the mid teens which is probably what it was when you sanded the finish off. If you do that, keep it out of direct sunlight or it could warp toward the sun. And have patience. Wood is a slow moving sponge. It takes time to gain and lose moisture in wood.

-- No log is too big to saw! www.logboy.com

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