Uncovered pith Section - How to fix?

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cpowell

Chuck
Senior User
I uncovered a section of pith when I cut the oval into my rectangular table top glueup. :eusa_doh:

Here's a pic.



The pith area is the round one near the center of the pic. The other light colored areas are just the rough edge from the jigsaw, I haven't shaved that area flat yet.

I intend on rounding the edges and am concerned that I'll open up a mess. Any thoughts of fixing this?

I know I can always use a guide and skilsaw and rip the bad area out and glue in another piece. If I do then I think edge jointing will be difficult since the table top is pretty big to run on the jointer and I don't have enough confidence in my No. 7 to joint edges for an 80 inche glueup.

Any ideas? Superglue...epoxy? Large forstner bit then glue in a plug? I'm open to suggestions.


Chuck
 

SubGuy

Administrator
Zach
Don't know much about this, but an idea might be to drill with a smaller bit and see how deep it goes, I know some can go for awhile. If it's not too deep a forstner and plug sounds good, if you gotta cut it out:dontknow:.
 

Bas

Recovering tool addict
Bas
Corporate Member
Superglue (thin) will help stabilize things, so it doesn't blow up when you round the edges over. If it's shallow, you could try excavating it with a chisel, dremel, forstner bit or very small router bit, and filling it with epoxy. To color it, you can mix the epoxy with sawdust, or use coffee grounds/ cocoa. A plug is probably best, but not easy to do on an edge. Still, as you said, worst case you rip it off and glue up another piece, so it's worth experimenting.
 

cpowell

Chuck
Senior User
Superglue (thin) will help stabilize things, so it doesn't blow up when you round the edges over. If it's shallow, you could try excavating it with a chisel, dremel, forstner bit or very small router bit, and filling it with epoxy. To color it, you can mix the epoxy with sawdust, or use coffee grounds/ cocoa. A plug is probably best, but not easy to do on an edge. Still, as you said, worst case you rip it off and glue up another piece, so it's worth experimenting.
I thought the area would absorb a lot of CA glue but it only took a small amount. I'll let it sit a few hours then get back to cleaning the edges.

I've thought about this a little bit more The pith looks very soft. The top edge surface is around 1/8" thick solid wood but on the bottom the pith is exposed on the face. The bottom open area is maybe 1/8 inch wide x 1.5 inch long.

I may be able to chisel out the soft pith then fit a suitable plug from walnut waste from this project. I could hand shape to get it just CLOSE then stabilize the "hole" with CA, insert the plug and run CA to glue it in place at the bottom of the hole. Let CA cure then fill hole with epoxy/walnut sawdust mix for permanent adhesion. If the epoxy cements everything in place I should be able to cut the profile without risk of blowout.

Does that make sense? The plug wouldn't need to be a super snug fit since the epoxy will bond it to the adjacent strong wood, right?


Chuck
 

Ozzie-x

New User
Randy
Chuck,
I think you are on track with the plug idea. I would fashion the plug to maximize the amount of wood and minimize the amount of epoxy. I'm sure with your level of expectations and skill it will turn out fine. Since it's on the end/bottom it won't be noticeable to anybody but you. These small details like this that we toil over, the average person will never even notice.
 

FredP

Fred
Corporate Member
the plug Idea may work but [there's always a but isn't there] it needs to be tight because when you route the edge it will be more visible. I recommend ripping the section out and adding another strip. if this table top is going to warp it will be at the pith and it may crack there too. that's my 2 cents FWIW.
 

Gofor

Mark
Corporate Member
I would route it out from the bottom (saving as much of the top thickness as possible and routing a very light depth with each pass as you near the top.), Then glue in a machined piece to fit. You may want to step the route out to minimize the slot that will be nearest the top. In that case it may be a 2 layered plug.

Good Luck

Go
 

Travis Porter

Travis
Corporate Member
I would route it out from the bottom (saving as much of the top thickness as possible and routing a very light depth with each pass as you near the top.), Then glue in a machined piece to fit. You may want to step the route out to minimize the slot that will be nearest the top. In that case it may be a 2 layered plug.

Good Luck

Go
I'm with Mark. This may sound like a lot of work, but I believe it is easier than it sounds. I did a similar maneuver recently with some walnut and it worked out very well and is almost invisible.

Like Fred said, there is always a but, and I too would worry about warping around the pith and finding more of that nasty stuff.
 

cpowell

Chuck
Senior User
I'm with Mark. This may sound like a lot of work, but I believe it is easier than it sounds. I did a similar maneuver recently with some walnut and it worked out very well and is almost invisible.

Like Fred said, there is always a but, and I too would worry about warping around the pith and finding more of that nasty stuff.
I may have a jig that I used for straight line routing a while back that could be modified to handle that.

I hope I didn't hide it as well as you hid your drill press wrenches!! :rotflm: :rotflm: :rotflm:

Point taken about pith. I guess I could drill some exploration holes along the center of "the board" with a small bit and push with a straight pin to look for hollows. Or maybe borrow an ultrasonic thickness gauge...does anyone here have one I could use? Maybe tap on the surface and listen for a telltale change in pitch. Wonder what a pith-pitch sounds like? :gar-La; :gar-La; OK I'm losing it. Time to head out to the shop.


Chuck
 

Travis Porter

Travis
Corporate Member
I hope I didn't hide it as well as you hid your drill press wrenches!! :rotflm: :rotflm: :rotflm:

Chuck
The drill press wrenches...:roll:...You haven't forgotten about that......:embaresse


Speaking of that drill press, I am having trouble with it. The front pulley is slipping and I can find no allen screws nothing to tighten on it. I will have to dig out the manuals/parts list to see what is causing that.
 

SubGuy

Administrator
Zach
Point taken about pith. I guess I could drill some exploration holes along the center of "the board" with a small bit and push with a straight pin to look for hollows. Or maybe borrow an ultrasonic thickness gauge...does anyone here have one I could use? Maybe tap on the surface and listen for a telltale change in pitch. Wonder what a pith-pitch sounds like? :gar-La; :gar-La; OK I'm losing it. Time to head out to the shop.


Chuck
I've never done this, but just a thought...In your exploration drilling, if you drill right into the pith from the edge, and then work the bottom. One would assume you could "Inject" water while plugging the pilot in the pith itself. One could assume that the pith is MUCH less dense than the walnut and would readily absorb water. Once water will go in no more, drain the pilot in the pith (for awhile) and measure. Depending on absorption of the walnut and pith (5 to 20% guess), you can figure out how much you have in that one spot. If its alot, i.e work out the volume of cylinder and think about possible length, then replace with new piece, if not I like the plug idea. Ok! maybe I need to leave the computer...head is smoking from all those complicated thoughts. I'm probably overthinking and crazy!:banana:
 

cpowell

Chuck
Senior User
The drill press wrenches...:roll:...You haven't forgotten about that......:embaresse


Speaking of that drill press, I am having trouble with it. The front pulley is slipping and I can find no allen screws nothing to tighten on it. I will have to dig out the manuals/parts list to see what is causing that.
Actually, the funny thing is when your first posted about your drill press problem a while back I was just messing around when I asked where your wrenches were...because I had forgotten that they came with wrenches, too. Then later you found yours. I spent an hour digging around until I found mine. Now they're gone again. :rotflm: :rotflm: :rotflm: :rotflm:

My DP is not very accurate. I think we should look for another DP group buy and this time let's get something with .001 runout or less. :icon_thum


Chuck
 

cpowell

Chuck
Senior User
I've never done this, but just a thought...In your exploration drilling, if you drill right into the pith from the edge, and then work the bottom. One would assume you could "Inject" water while plugging the pilot in the pith itself. One could assume that the pith is MUCH less dense than the walnut and would readily absorb water. Once water will go in no more, drain the pilot in the pith (for awhile) and measure. Depending on absorption of the walnut and pith (5 to 20% guess), you can figure out how much you have in that one spot. If its alot, i.e work out the volume of cylinder and think about possible length, then replace with new piece, if not I like the plug idea. Ok! maybe I need to leave the computer...head is smoking from all those complicated thoughts. I'm probably overthinking and crazy!:banana:
Well I went back out and we got the top flipped over. The pith does NOT run the length of the board, in fact, the pith only goes a few inches then exits that board.

I stabilized with CA and will keep shaping the edge. I'm halfway through shaving the edge to the line. Once done I'll start rounding the edges.


Chuck
 

Travis Porter

Travis
Corporate Member
My drillpress is not very accurate. I think we should look for another drillpress group buy and this time let's get something with .001 runout or less. :icon_thum


Chuck
Honestly, I feel very much the same way......And, I could be convinced to do another group buy for a drill press, but a MUCH more accurate drill press and better made. The thing I like about this one is having a light in it. As for what I don't like about it, the list is long.........
 
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