Question on a Pine hollowform

[Richard Madden]

I just finished roughing out a pine HF (don't know what kind of pine) about 9" tall and 8-1/2" in diameter. The walls right now are about 3/4" thick. This piece is being turned end grain with the pith centered top and bottom, and naturally there are several knots. All are tight knots. How would you deal with this as far as drying, the knots, and the pith? I know it's risky leaving the pith, but some, like Bill Bolen seem to have luck. My normal drying procedure would be a 2 or 3 day soak in DNA, let sit for an hour, then wrap with 2 or 3 layers of newspaper with the paper cut away at the opening. Is that OK for this piece, or should I be doing something else, or in addition to this because of the knots and pith? I figured after the piece was dry I would soak the pith with CA. Any suggestions? For now, I sprayed it with water and bagged it in plastic. Any help would be appreciated.:confused:

[Jake Helmboldt]

Richard, I have only turned one piece of pine (shortleaf). It was the bowl I submitted for last month's competition. It had a number of knots and I didn't have any drying problems with it (I simply bagged it if I recall).

Conifers don't seem to check as badly as hardwoods so you may not need to do anything special with the knots. I've heard of using thin CA to penetrate the pith and stabilize it, so you may give that a try. If there is a lot of pitch in the wood it may not readily take much CA (I speculate the pitch may have an impact on checking/splitting, but I don't know that for sure.)

[Richard Madden]

Thanks Jake. I hope this piece will survive because I want to give it to our neighbors, who gave me the wood. They had two pines cut down that were 18" to 22" at he base and I thought they would appreciate a turning from them.

[David Reed]

I have not turned a form like you describe but have thought of perhaps turning away the pith in the bottom making it more of a styalized tube form. After a suitable period to dry and stabilize, clean up the hole in the bottom and replace with a new, non-pith bottom. Keeping the replacement bottom small and inside the foot plus a small neck opening should make the mod inconspicuous to most. Anyone tried this technique?
David

[Dennis Ford]

"Keeping the replacement bottom small and inside the foot plus a small neck opening should make the mod inconspicuous to most. Anyone tried this technique?"
I have done that and it worked. It did require some planning and leaving some wood to hold the piece by after it dried.

Richard;
I have had mixed results with end grain pieces including the pith but have friends that do it quite often so it can be done. I would probably turn the thing thin while wet and let it warp.

[Bill Bolen]

Richard on most of my hf's I turn to completion in one session. If I cannot do that I wrap in a plastic bag until I can get back to it. I feel as if getting a consistant wall thickness down to1/4" or so is the reason I loose so few due to cracking (doesn't count bone-head mistakes on my part though). I know many here use only dry wood or carefully dry with their own process and that certainly works well for them. I turn "kinda green" and "kinda dry" just depends what I pick up. The knots gave me a lot of trouble early on especially at the finishing stage. Knots suck in finish like crazy or will open up cracks if not dealt with and darned if they don't just loose their shape and generally mess things up. I put a decent coat of ca on all the knots prior to hollowing out especially with pine and Red Cedar pieces. Seems to seal them to the point that they are fairly safe. After completion of the turning/hollowing portion of the project the outside needs to be lightly sanded again just to get rid of the wheel marks from the steady. I re seal and re sand the knots again. So far so good. Hope this helps just a bit...Bill...

[Curt Fuller]

I haven't turned any Hollowforms from pine but I've been doing quite a few bowls. The Ponderosa pine I've been working with has shown very little movement, shrinkage, or cracking. In fact almost none what so ever. None of the knots are loose so far either. The wood has been cut for about a year now and I've done nothing but chainsaw it into slabs about 4-5" thick. I haven't even sealed the ends of it. And there has been only very slight end checking. But you know how wood is, my experience doesn't always equal a similar experience for you. Also, my wood has not included any pith. I had to quarter the logs just to be able to move them so that eliminated most of the pith.

[Richard Madden]

Richard on most of my hf's I turn to completion in one session. If I cannot do that I wrap in a plastic bag until I can get back to it. I feel as if getting a consistant wall thickness down to1/4" or so is the reason I loose so few due to cracking (doesn't count bone-head mistakes on my part though). I know many here use only dry wood or carefully dry with their own process and that certainly works well for them. I turn "kinda green" and "kinda dry" just depends what I pick up. The knots gave me a lot of trouble early on especially at the finishing stage. Knots suck in finish like crazy or will open up cracks if not dealt with and darned if they don't just loose their shape and generally mess things up. I put a decent coat of ca on all the knots prior to hollowing out especially with pine and Red Cedar pieces. Seems to seal them to the point that they are fairly safe. After completion of the turning/hollowing portion of the project the outside needs to be lightly sanded again just to get rid of the wheel marks from the steady. I re seal and re sand the knots again. So far so good. Hope this helps just a bit...Bill...
Bill, I'm glad you chimed in on this, I know you are one of those with success dealing with knots and pith. I'm going to have to try once turning to final thickness, but one question; if I'm going to add a threaded collar to a piece, I would think the drying/warping would throw the collar out of round, do you agree? In fact, any kind of lid, threaded or not, fitting a HF once turned would probably be a chancey proposition.

[Bill Bolen]

I sure do agree. I use kiln dry wood for collars that require a precise fit (such as threaded would be). Glue on two sides only to reduce the cracking if the wood of the body of the hf moves. Make sense?...Bill...

[Bernie Weishapl]

Richard I have turned a couple with the pith in the bottom. I have soaked (heavily) the pith on the bottom with thin CA and let it dry before soaking in DNA. I have not had any crack on me.

[Wally Dickerman]

By all means, apply some thin CA to the pith area. It will almost surely crack if you don't. Be aware that the the thin CA will stain the light colored pine. I suggest that you also use wood sealer on the end grain. Why not?

Knots in pine are usually tight and don't cause a problem. Ever see knotty pine interior wall covering? If there appears to be a possible problem just add some med. CA.

Wally