Leveling Plywood Butt Joints on Bench Tops

[Capt. Grimek]

I hate to post again so soon and waded through many search posts, but... What's your favorite method to level butt joints in plywood bench tops? Belt sander? Wood putty filler? I have my tops almost completely level and butted up together but there is always one tiny little hump or raised area no matter how careful or how many times I unscrew and realign. Partly due to the crappy plywood out there these days... anyway what do you recommend? Or should I just shim up the cork roadbed after it's laid on top of the cork sheet in the yard? Thanks.

[grizlump9]

 Durham"s rock hard water putty.  work fast, it sets up quick.

grizlump 

[IRONROOSTER]

 Two things I have done are: 1. shim the roadbed, or 2.  use a surform to smooth the cork roadbed over the joint where having a short rise was acceptable.

Enjoy

Paul

[Capt. Grimek]

Thanks. I'll see how things look when the glue and screws dry in the a.m. This is the only part of the benchwork I've glued. It just seemed like it needed that additional strength. I can still remove tops via the L girder screws if necessary.

[dknelson]

I use the David Barrow "domino" method of benchwork, so the ends of my dominos match up with the same width and height -- I bolt them together.  I buy 1/4 inch threaded rod, cut it to length, and then have wing nuts on both ends to bolt the ends together. 

Before drilling the holes for the threaded rod, I clamp the two dominos together so that the plywood tops of the benchwork are as even as I can get them (if that means the legs have to be adjusted later so be it).  I have some large old fashioned hand screw clamps for this purpose.  If you know the Barrow system, I am clamping both the top of the domino and its 1x4 lumber framing -- so you need two large clamps:

If the subroadbed still needs a bit of shimming, I have saved a large supply of those annoying "your name here" plastic credit cards that come in the junk mail.

Dave Nelson

[selector]

If at the boundaries of two modules, use leveling screws under the legs.  If where two sections of ply meet on the same frame, use a sander or a surform file.  Sander is messier, but should do the trick in time.  I would take the time to add a suppor under that butt and screw both ends to it so that one doesn't rise or fall with time...make sure it all moves in concert once you have it groomed to your satisfaction.

A surform will provide a more natural looking contour as it dips a bit in the soil/surface around it.  Mind you, you'd still have roadbed and ballast to elevate it above the slight change in height you have to manage.

[cuyama]

A glued-and-screwed splice plate works very well. Being able to add these splice plates and level adjoining sheets is a good reason to use short risers above the grid or L-girder framework, even for yard areas.

[Capt. Grimek]

Now that the glue and screw job has dried,it's looking 98% good. It's not the complete butt join edge that's off, just a small hump about 2" or so that is caused either by very slightly warped ply or L girder joist ledge. What I've done is to make the joists under the ply butt joints an L girder using 1X4 and 1X2, screwing the edges of the butt joins to the L joist. Everything is level and firm except for the occasional tiny spot where there is a lift/bump, usually towards the center of a panel. I have leg levelers and used them before making things permanent. So, basically I'm trying to decide whether to sand or file down the edge/bump so that it's camphered or sloped at that point, where it meets the adjacent panel and have to deal with a narrow slope by shimming after the trackis laid on top of the cork sheet, or fill the dip and blend the joint with putty and sand. I'd likely need to shim something in the end either way. Luckily, if all else fails,this very slight (really nearly inperceptible) incline (on likely only one track) would head rolling stock back INTO the main yard so that's the good news, if all else fails. If this occurs leading away from a yard on future ply panel joins, I'll need to deal with them in one of the above mentioned ways. I think, considering the poor quality of dimensional lumber and ply readily available these days, that there will always be one little spot that's going to have to be contended with. I guess my BOTTOM LINE QUESTION here, is whether to lay the sheet cork over the 1/32 to 1/16" bump and shim the track later. Or sand/file and fill now even if I can't ever get it completely flush (which is unlikely)? I mis-wrote earlier in that the track will be laid directly on sheet cork NOT cork roadbed over the sheet cork. Thanks guys.

[skagitrailbird]

"BOTTOM LINE QUESTION here, is whether to lay the sheet cork over the 1/32 to 1/16" bump and shim the track later. Or sand/file and fill now even if I can't ever get it completely flush (which is unlikely)?"

  Cap'n,

 Do I understand correctly that the problem is a bump rather than a dip or debression?  If so, It should be relatively easy to remove it with a sander or surform.  Shimming up the track might be required if it is a low spot. 

[Capt. Grimek]

Hi Roger, I just now came from the train room and have fixed the problem after a couple of hours at it. I used a woodcarving gouge to run down the length of the seam, filed and gave it a final sanding. It was a raised hump about 3 inches wide. I think things are close enough to level now, overall that only a tiny bit of business card shimming will be necessary if anything. The cause of the problem, I think, was a small delamination at the edge of one of the sheets of ply where a void hole "let go/expanded at a screw placement/hole". It was flush when I glued and screwed the sheets to the L joist, but separated before the glue dried, from the pressure of the butt edges meeting, I guess. It was a tough call whether to file/sand it down, or try to ramp up the area with putty, but I figured I could always putty as a last resort, so went with the gouge/sanding. Only 3 of these to go. Are we having fun yet? Thanks for the suggestions guys. It's learn as I go 'round here. I'll be gluing the sheet cork right after I glue and screw the next L joist across the aisle. I'll finish up the joins at the R.H. and industries yard/doorway ends later after trying out the #5s ladder in the yard. Thanks for your post.