Woodworking Talk banner

1 - 18 of 18 Posts

·
Registered
Joined
·
243 Posts
Discussion Starter #1
Have a piece of African mahagony 48" long 3 1/4" wide and 1 1/2" thick. I bought it about a month ago and cut the board to these sizes and planed it as soon as I bought it from 8/4 to 6/4 but I didn't get around to using it until now. When I grabbed it I noticed it bowed. Next time I know to let it sit for a week or so before planing but now I'm trying to correct it if I can. It's not a huge bow but both ends are raised and as of now I have it clamped to my bench on both ends hoping it will correct itself. Are my efforts going to pay off or am I wasting my time? I do plan to cut it in multiple pieces for candle holders and there's a crack in the middle and appears to be the point of the bowing. The other piece didn't really change a noticeable amount. Here's a pic of what I'm working with
 

Attachments

·
Senior Sawdust Sweeper
Joined
·
1,540 Posts
You are probably right the crack is related but it is a symptom like the bowing. The grain has tensions in it and when you planed it you removed some of the wood that was balancing the stresses. With the balance removed the wood changes shape to adjust. The crack may or may not be part of that adjustment. Best call is to cut out that knot of grain the crack is in and replane the pieces.
 

·
Registered
Joined
·
243 Posts
Discussion Starter #4
Yeah the crack was already there when I bought the piece and I had planned to cut it out.

When I planed it I did plane both sides. I flipped it over with each pass. After I planed it did almost get rid of the crack but now as you can see it is split pretty good and seems to run deeper. When I stored it I stored it standing up leaning against a wall. I will probably cut around it and plane it again. I just can't plane it much more because it's already at the thickness I need it to be.
 

·
Sawdust Creator
Joined
·
8,046 Posts
How big of pieces do you need? You may find that as you cut it down....you get very very close.....
 

·
Registered
Joined
·
1,160 Posts
>>>> Are my efforts going to pay off or am I wasting my time?

Clamping it flat is probably not going to work and may, in fact, further damage the board.

Let me ask, after you machined the wood where did you leave it? Did you lay it down onto another flat surface such that air could not freely circulate to all surfaces? If so, that will cause a board to bow. Boards should be stacked and stickered if you are not going to immediately continue working with them. This is the reason that clamping the board to your bench is likely to further cause bowing.

You can try to now stack and sticker it with a weight on top. Air now flowing around the board may allow the moisture content to even out and allow the board to straighten. Remember to allow air to freely flow to all surfaces.
 

·
Registered
Joined
·
243 Posts
Discussion Starter #7
HowardAcheson said:
>>>> Are my efforts going to pay off or am I wasting my time? Clamping it flat is probably not going to work and may, in fact, further damage the board. Let me ask, after you machined the wood where did you leave it? Did you lay it down onto another flat surface such that air could not freely circulate to all surfaces? If so, that will cause a board to bow. Boards should be stacked and stickered if you are not going to immediately continue working with them. This is the reason that clamping the board to your bench is likely to further cause bowing. You can try to now stack and sticker it with a weight on top. Air now flowing around the board may allow the moisture content to even out and allow the board to straighten. Remember to allow air to freely flow to all surfaces.
I planed it and had it standing up leaning against a wall in my shop. My shop is half of a garage and the doors aren't completely sealed so there is a draft and the weather here in the Dallas area has been kind of crazy the last couple months. One day it is low 20's and very dry and the next it's 50's and raining. I'm kind of thinking the fluctuations in temps and humidity plus the crack was the problem. I have a piece of hard maple and cherry I bought and planed the same day and it hasn't really changed. I'm planning to get the cherry and maple cut tomorrow and plane and cut the mahogany.
 

·
Custom stair builder
Joined
·
241 Posts
I'm a stair builder and glued up about six 42"x42" 4/4 landings out of cumaru. I leaned them against the wall like I've done every other time and came out to the shop a couple days later and the two outer glue ups were cupping more than I had ever seen before. The first thing I did was freak out. Then I was about to start ripping them down and salvaging the pieces that weren't as bad. I had the idea of taking a wet rag and soaking the side that was cupping and after only about 15 mins as it was drying it was considerably better. I did it again the next day and it was to a point where it was acceptable.
 

·
Old School
Joined
·
24,017 Posts
I'm a stair builder and glued up about six 42"x42" 4/4 landings out of cumaru. I leaned them against the wall like I've done every other time and came out to the shop a couple days later and the two outer glue ups were cupping more than I had ever seen before. The first thing I did was freak out. Then I was about to start ripping them down and salvaging the pieces that weren't as bad. I had the idea of taking a wet rag and soaking the side that was cupping and after only about 15 mins as it was drying it was considerably better. I did it again the next day and it was to a point where it was acceptable.
+1. :yes: I've never had any luck fixing a bow, twist, or cup, by just stickering flat and allowing airflow. Wetting the one side and clamping up to an overbend condition worked in many situations. A storage plan though would be to sticker for wood that is predominately straight.






.
 

·
Registered
Joined
·
1,160 Posts
Yes, leaning up against a wall can cause warp also. There are two issues. The board will naturally want to warp when it is leaning. Second, if you lean it against and outside wall--particularly a concrete wall, the moisture that might migrate through the wall will affect the board surface closest to the wall. And, the likelihood is that the outside and inside surfaces will end up with unequal moisture. Even leaning it against an inside wall may lead to unequal air access to both sides and warping can result.

In my prior shop, we had big enough spaces that we could stand panels and board almost perfectly up . If we knew that it would be a couple of days before we were to use the piece, we would frequently wrap things in plastic sheeting sealing the edges.

The key is even air access.
 

·
Registered
Joined
·
243 Posts
Discussion Starter #12
Good advice guys! Thanks! I did end up planing again and I was able to keep it at the thickness I need with minimum bowing. The pieces that still have a little I should be able to sand. The tops aren't a problem but I'll want to make sure the bottoms sit flat and I think most of the pieces will and the others may need a little sanding to even it a little more.

I think I may go to HD and pick something up to make a rack that I can store material on that I'm not going to use right away. Some of the stuff I make it kind of mass produced so some materials will be bought in bulk and stored until I cut them. I'm definitely not going to ever plane and let the stuff sit again. From now on if I plane it I'm going to work it the same day. Lesson learned lol
 

·
Registered
Joined
·
4,801 Posts
It's a good idea to partially mill your material and let it re-acclimate to your shop then do final milling (should be minimal) when you're ready to use.
 

·
Registered
Joined
·
243 Posts
Discussion Starter #14
sawdustfactory said:
It's a good idea to partially mill your material and let it re-acclimate to your shop then do final milling (should be minimal) when you're ready to use.[/QUOTE
So if I'm going to take a piece of 6/4 or 8/4 down to 3/4 and 6/4 how much do you recommend I plane if I'm going to store it
 

·
Registered
Joined
·
4,801 Posts
First, I wouldn't plane 6/4 down to 3/4, wastes too much wood. If you're going to store the wood for a while I wouldn't mill it at all at first. First, for me, most of my wood has acclimated to my shop in rough form for days to months. When starting a project I rough mill (say I want a final thickness of 3/4") to 7/8" making sure to take passes from alternating sides of the board. I'll let that sit in the shop for a day to a week depending upon how much shop time I actually have. Then when I'm ready to get to final dimensions, I'll plane and cut then.
 

·
Registered
Joined
·
1,494 Posts
sawdustfactory said:
It's a good idea to partially mill your material and let it re-acclimate to your shop then do final milling (should be minimal) when you're ready to use.[/QUOTE
So if I'm going to take a piece of 6/4 or 8/4 down to 3/4 and 6/4 how much do you recommend I plane if I'm going to store it
Why throw away half of the timber ?

Wouldn't it be better to either buy the dimension you need ,
or rip the length down to size , and still have a usable batten leftover over .
 
1 - 18 of 18 Posts
Top