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Segmented Turning Issues

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Forum topic by JComer posted 01-21-2021 02:46 PM 406 views 0 times favorited 4 replies Add to Favorites Watch
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JComer

2 posts in 3044 days


01-21-2021 02:46 PM

Topic tags/keywords: turning segmented

This is my first segmented Turning, so I tried a design that seemed to be straight forward. I took the picture right after I finished sanding. I created several of the turnings as gifts but ran into an issue.

After turning and sanding the barrel was completely smooth. You couldn’t feel the transition between the dark and the light wood. After sitting for a couple of days, the light wood appears to have expanded and there is an obvious ridge between the dark and the light layers.

Is this normal? Should I need to let them sit and do a second round of sanding a few days later? Is there a technique I am unaware of? Any advice or suggestions would be appreciated.


4 replies so far

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Maro2Bear

40 posts in 42 days


#1 posted 01-21-2021 02:59 PM

Greetings. What were the two types of wood and was it all kiln dried? I had a similar issue with Cherry and inlaid milliput bands. The natural cherry shrank, but not the band. The cherry wasn’t KD, so thats what happened.

-- Mark B. Glenn Dale, MD

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TheDane

5939 posts in 4671 days


#2 posted 01-21-2021 05:38 PM

What you experienced is generally referred to as ‘glue creep’. In my experience, the glue was not completely cured before you turned the object. It is possible that the material used to glue up the blanks had some significant or disparate moisture content.

I assume you used a PVA glue or some other glue the uses water as a solvent. Though the glue my appear to be ‘dry enough to turn’, it takes some time for the water in the glue to migrate out and fully cure. The thicker the glue joint, the longer it takes. For example, I let the blanks for my stave peppermills sit for up to four several weeks before I process them. Before they go to the lathe, I bake them at 200 degrees for several hours in a toaster oven to get them as dry as possible.
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IMHO, your only real option is to re-mount the pieces on your lathe, re-sand, and re-finish.

-- Gerry -- "I don't plan to ever really grow up ... I'm just going to learn how to act in public!"

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JComer

2 posts in 3044 days


#3 posted 01-21-2021 07:04 PM

Thank you for the replies and advice. I’ll definitely try the suggestions above. The wood I used was unidentified cutoffs from the local Woodsmith store. For my projects I used Titebond III Ultimate wood glue. I’ve never heard of glue creep until now, but it makes sense. I let these dry for a week after gluing them, but I’ll have to try again and see if I need a longer resting time after gluing and a pass through the oven does the trick!!!

Thank you for the help!!!

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splintergroup

4671 posts in 2231 days


#4 posted 01-23-2021 03:56 PM

Be careful with curing in the oven. I used some stabilizing resin on a few breadboard style coasters which requires a 2-hour cure in an oven at 200. I checked the TB III specs and 200 was borderline, but all went well.

I did place a meat thermometer in the toaster oven to make sure it didn’t get too hot. Sure enough, when set to 200, it’d peak to 220 and average out around 210. Setting it to 180 gave me a stable 200 throughout the drying/curing window.

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