Paddy
27th March 2005, 09:48 PM
I have just had great results from using an Alcohol soak on wet Cherry blanks. With the first four samples, ready to turn in 14 days and no sign of cracking or distortion after turning down to about 3.5 mm thick and finishing with Tung oil
Previously had little success with...Detergent soak.. Boiling (lost colour as well as cracking)..Slow air dry under wood shavings, three months to stabilise and still a 50% failure rate, also tried ….Micro waving…. Freezing.
After WFG11 gave me the reference , to Dave Smith’s report at http://www.woodcentral.com/cgi-bin/...icles_473.shtml (http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=turning&file=articles_473.shtml). I decided to have a go using Methylated Spirits, as I had some in the workshop.
Cut 80 mm slices off the log and sealed them in plastic bags, until they were mounted in the lathe. Turned the bowl blanks to 15 mm thick,( with sap running off the tool). Noted that all four blanks had a 15 mm long hairline crack in the base across the pith area.
As soon as the blank was turned placed it in a small plastic bucket with a snap on lid and filled the bowl blank to the top with Metho, on checking about an hour later noted that the blank was saturated with fluid and that the outside surfaces were also wet. Inverted the bowl in the bucket and left it to soak overnight in the fluid.
Inverted the bowl over a jam jar inside the bucket and left it to drain for a few hours, to recover as much of the Metho as possible. Started with 1000 ml of Metho and still have 700 ml after four blanks have been soaked.
After the soaking in metho, the cracks in the pith area had closed up on all blanks.
Diameter of blank prior to soak…153mm --- Dry blank..140mm
Diameter of base clamping recess 100mm -- Dry blank..95mm
Height .. did not change
Thickness started at 15mm----------- finished at 13 mm approx.
Weight at start…….500 grams Stabilised at 295 grams...approx 41% loss .
Three blanks ran true within 2mm when re-mounted and one blank one was out by 5mm.
There are no visible cracks or distortion on the finished units 7 days after finishing, with Tung Oil.
I found that painting the ends of the cut logs with sealant did not prevent cracking along the centre of the timber. However covering the ends with plastic bags, taped tightly around the bark did a great job, even after 6 months only about 50mm had to be cut off to get back to clean wood.
Seems great on this Cherry, have another 3 meters to convert into blanks!!
Previously had little success with...Detergent soak.. Boiling (lost colour as well as cracking)..Slow air dry under wood shavings, three months to stabilise and still a 50% failure rate, also tried ….Micro waving…. Freezing.
After WFG11 gave me the reference , to Dave Smith’s report at http://www.woodcentral.com/cgi-bin/...icles_473.shtml (http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=turning&file=articles_473.shtml). I decided to have a go using Methylated Spirits, as I had some in the workshop.
Cut 80 mm slices off the log and sealed them in plastic bags, until they were mounted in the lathe. Turned the bowl blanks to 15 mm thick,( with sap running off the tool). Noted that all four blanks had a 15 mm long hairline crack in the base across the pith area.
As soon as the blank was turned placed it in a small plastic bucket with a snap on lid and filled the bowl blank to the top with Metho, on checking about an hour later noted that the blank was saturated with fluid and that the outside surfaces were also wet. Inverted the bowl in the bucket and left it to soak overnight in the fluid.
Inverted the bowl over a jam jar inside the bucket and left it to drain for a few hours, to recover as much of the Metho as possible. Started with 1000 ml of Metho and still have 700 ml after four blanks have been soaked.
After the soaking in metho, the cracks in the pith area had closed up on all blanks.
Diameter of blank prior to soak…153mm --- Dry blank..140mm
Diameter of base clamping recess 100mm -- Dry blank..95mm
Height .. did not change
Thickness started at 15mm----------- finished at 13 mm approx.
Weight at start…….500 grams Stabilised at 295 grams...approx 41% loss .
Three blanks ran true within 2mm when re-mounted and one blank one was out by 5mm.
There are no visible cracks or distortion on the finished units 7 days after finishing, with Tung Oil.
I found that painting the ends of the cut logs with sealant did not prevent cracking along the centre of the timber. However covering the ends with plastic bags, taped tightly around the bark did a great job, even after 6 months only about 50mm had to be cut off to get back to clean wood.
Seems great on this Cherry, have another 3 meters to convert into blanks!!