We had a good turnout, but not nearly what we should have had for such an excellent opportunity. I don't know why it is that our club members don't want to pay a small fee for an internationally known turner, but that seems to be the way it is for every major tuner we bring in for a visit. $25 for an all-day demo and lunch is a bargain!
One of the things Paul is known for his thin-walled hollow forms, and he spent most of the morning demonstrating his techniques for this project.
The walls are uniformly thin throughout the vessel. Paul passed around a couple of hollow forms he had cut apart.
He also demonstrated his texturing technique that produced these uniform lines. See part II of this topic when I post it.
Here's the interior of this one.
The hollowform was turned end grain with the pith in the center. Paul uses green wood. He was turning a piece of ash for the demo.
The hollowform shape was done between centers.
The headstock end of the form will be where the tenon is formed for the chuck. The top of the form is toward the tailstock.
Nice shavings coming off the tool.
Once the general shape is made, refinements are done to fine tune the form.
Sheer scraping with the gouge. I think this was a Glaser gouge, but I could be wrong.
The inside edge of the flute is used for a fine sheer scrape.
Part of the base was removed to allow shaping of the foot of the vessel.
The parting tool was also used to form the tenon for the chuck.
That nub had to be removed before the vessel could be chucked.
Paul had a nifty folding saw to take off the nub.
The tailstock was brought up to help center and seat the vessel into the chuck.
A slight depression was put into the top to guide the tailstock live center.
Fine tuning the centering and adjusting the chuck was next.
Paul then opened a bit of the neck.
He reverse turns for hollowing. This technique makes a lot of sense - you can see what you're doing, and the tool handle can be placed next to your body rather than out in thin air.
The tailstock was brought back up so the foot area could be shaped a little more. This is needed to assist with a uniform wall thickness down the length of the vessel.
Paul had a gun borer to drill the center hole. This was a cool technique to see. The handle attaches to an air compressor and there is a hole bored through the shaft.
The tape is the depth gauge. A little parafin wax on the tool shaft makes this step go pretty quickly. Paul coated the tool shaft with wax as soon as he finished drilling the hole.
Here's a look at the business end of the borer.
The adapter end for the air compressor fitting.
Once the central shaft is drilled, the hollowing commences. The first thing to do is to remove the bulk of the interior.
Before too much material is removed, the surface is scraped in preparation for sanding. This scraper has a bit of a negative rake to it.
Very fine curls are coming off that surface. The negative rake is pretty obvious in this image.
Another scraper, modified from several others out there on the market, including one by Mark St. Leger and a similar one by Nikos Sirigas. If I recall correctly, I introduced Paul to this kind of scraper when I did a demo for the Arizona Woodturners a few years ago.
This scraper is one of my favorite tools, and it did a great job on this vessel.
Refining the shape of the neck.
A final bit of sheer scraping.
Sanding with Portugese sand paper.
Paul invited everyone up to feel the surface before he started the hollowing.
This was a pretty cool tip - Paul uses CA glue to seal the exterior surface. He said it prevents water loss from cracking the surface. He used a small plastic bag to spread the glue around.
A bit of accelerator finishes the job.
Now the bulk of the interior is removed.
Paul uses homemade tools for hollowing. This one gets in to the tight area between the opening and shoulder of the vessel.
Everyone was pretty focused on watching those shavings come out of the vessel. We have a big screen and an LCD projector hooked up to the digital video camera. All the details are easily seen from throughout the room.
Caliper check for the wall thickness. Paul took the thickness down to a point where his next step could be done - using a fiber optic light to refine the wall thickness.
This technique is more easily done in a darkened room. However, there is one light fixture that never turns off in this demo room. Don helped out by shading the turning with an umbrella.
The fiber optic light goes into the vessel along side the tool. When the wall is sufficiently thin, the light glows from the interior and you can see any thickenings in the wall. The idea is to have the light pretty much uniform, which should give a consistent wall thickness.
After the hollowing is finished, the opening is refined.
The CA glue is sanded off with the lathe turned off.
Barbara started the hot dogs as Paul was in the final stages of making this vessel.
The tail stock is brought up to stabilize the vessel while the foot is refined.
Details, details, details - it helps to see what you're doing.
After the foot is shaped, the wood is removed to a small spindle that can be cut off after the piece is removed from the lathe.
Almost there.
The top is jam chucked so that the bottom can be finished. The live center is placed on the end of the nub and the vessel is centered before turning resumes.
The foot should have a slightly concave surface.
The vessel is secured into the jam chuck with tape. The tailstock is removed so that the finishing touches can be done to the foot.
A bit of fine tuning the concave shape.
A few concentric circles, strategically placed, and then final sanding.
All done except for taking it off the lathe.
Yes, that jam chuck was a roll of duct tape placed on a four-jaw chuck.
Perfect timing - lunch is served. Part II of this day will cover the afternoon session.
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2 comments:
wow -- 25 bucks for all that PLUS hotdogs! i'd LOVE to have j paul demo here.
we pay $40 for 2.5hrs, no lunch and have to clean up!
great write up. make me want to turn more hollow forms.
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