Cupping issues.

[gregsolano]

Man I miss Norm on saturdays!

[mtylerfl]

Hello,

If I am carving on only one side, that's the side that will tend to cup (upwards). One thing I try to do is pay attention to the direction of the tree rings by looking at the board ends. I'll plan to face the rings so they are curving downwards when placing the board into the machine. That helps compensate for the upward cupping tendency.

Another thing I've noticed for box tops is they are less prone to cupping if kept under about 7"x10" in size. Don't know why, but that's what I have observed on Select Pine as well as Maple (if I use Pine, the Select grade is all I use - none of the "wet"-pitchy stuff, in other words). Red Oak seems the most stable for me, but I don't like to carve it much - the grain is too open and is prone to chip out on very detailed carvings.

I think one "for sure" way to prevent cupping (when carving on just one side) is to cut the board in 3 or more strips and re-glue them together while alternating the grain up/down.

[liquidguitars]

With the moisture constantly at 97% here in Illinois, I have had a ton of carvings cupping before I am able to get any sort of finish on them. I mainly use pine and let each one sit on a vented shelf. Is there any recommendations for 1 preventing it, 2 bringing it back straight once it's set in?

One nice thing about using thick sleds is that you can screw down the board on the ends to remove the twists and cups.. once carved the board will relax a little.

also a good idea if you sand or plane the board make sure to surface each side, this will allow even heat and moisture transfer keeping the board flat.

[RogerB]

you can take the cupping out by using a heater that will dry the board .Heat the wood and after it cools finish all sides and ends.Works most times .Don't burn it bake it. I glue pine at 3 inch strips less stress on the piece.

RogerB

[Ike]

With the moisture constantly at 97% here in Illinois, I have had a ton of carvings cupping before I am able to get any sort of finish on them. I mainly use pine and let each one sit on a vented shelf. Is there any recommendations for 1 preventing it, 2 bringing it back straight once it's set in?

Sorry my PM was a repeat! Using different material helps too! I use redwood and it tends not to warp, the same applies to cedar. Plus the way the board was cut makes a difference vertical and flat cut. Most lumber is flat cut how you know is by the end grain if the lines are curves and vertical run up and down,

Problem with today's lumber is it is cut too soon and the grain is not tight as old growth. Funny guess it just another I have been lucky, but the last 30 years I have been gluing redwood and I glue so the grain matches! I have have little problem with warping!

However I have had warping with second growth con common wet redwood. So I try to get dry heart redwood and better grades of other lumber and try to get vertical grained. Even with the rough cut material I mostly buy I check the moisture content and the grain. Really wet boards the first couple days I set them on end to allow gravity to release the water. Then sticker properly and let it dry for a year. If I can't wait I try to find the driest best lumber for the current project.

But the biggest problem is being harvest too soon and it has little heart wood! So whenever I can I buy old growth redwood, pine, mytlewood or whatever I buy it if I can! These days I have been gluing up strips rather then wasting my OG redwood! With Gorilla glue I just glue the boards without dowels or biscuits. Plus remember with dowels and biscuits if you drill too deep and the carving goes across the area. It will expose the dowel and the void!

Ike

[mtylerfl]

Thanks Ike, for the additional info and the illustration. All the Select Pine I get at Lowes has the "flat grain" as shown in your photo. The Maple I get from a local cabinet shop is also the flat grain (I've still got a couple 7ft 1x12 Maple boards like that to use up). I'm going to see if I can get the cabinet shop to special order some hardwood for me with the vertical grain so I can try some out!