Eucalyptus cupping repair with tung oil?
Hello fellow word workers. I purchased (first mistake) a Eucalyptus outdoor table. The top is 3″ wide 1/2″thick boards with tongue into end caps and screwed from the bottom in two locations with cross bars. They are not tongue and groove to each other, there is a gap between boards. The boards have all cupped badly pulling the screws from the bottom. It has not been oiled yet, I was waiting for it to dry out. If I were to only oil the cupped side (top) might that be enough to relax the wood and be able to clamp it flat again? There is not an easy way to disassemble so running the boards through my planner is not a viable option. I can put boards across the width and clamp to flatten the cupping but I had better not try that until I get some moisture into the wood again and I would like it to “set” and remain flat if there is a technique to achieve that result! It was all flat when it was new and still wet from the factory.
Replies
Wait a few weeks to see what it does. Once it has really settled into its new situation you'll know what you need to do. Don't react until then.
When one side of a board gets wet and the other doesnt, the wet side will always cup. It doesnt matter if it is the heart side or the bark side.
I would wait also. You can always put better screws in, closer to the edges of the board, but that could cause the center to split.
I have flipped it over for now onto a carpet. It should get some moisture over night and then some sun now on the backside during the day. Perhaps it will come back.
I intend to tung oil it, they say that helps eucalyptus and teak woods. Might that oiling help hold consistent moisture and stop or reduce the cupping?
Tung oil isn't going to help at all.
I've tried everything, the only way I know to uncup a board is either by ripping in half and reglueing, or ripping several grooves within 1/16" of top, fold it out flat and glue in some strips.
And its "tongue" not "tung". Learn how to spell, wood you.......LOL
Thanks for the reply. I'll let it wet and bake in the opposite direction and see what happens. Over the winter perhaps I can make some progress with it and oil it to help with the color and the cracking a little. This is one instance where I should have gone with fake wood! I would have thought oil would repel moisture and perhaps "hold" it from warping again but I guess the side to the sky will always bake bone dry more than the bottom.
My spelling has never been the best! IT Guy. Back 40+ years ago in 6th grade we had to write up instructions for a wood working project. In one area I wrote "clamp over knight". The teacher responded simply with "ouch"
I have the same table. It cupped, cracked, grain raising and grew mold that kept coming back. I complained to Wayfair after owning just shy of a year and they sent me another one. I am thinking this time, will do the Wax Free Zinser Seal Coat and a marine grade sealer (Interlux’s Interprime Wood Sealer). It’s just so brittle and dry. I am not a wood worker do you think it’s a good plan?
I used Sikken’s Marine Teak Cetol on the first one but it didn’t adhere and I am assuming it’s bc of how oily the wood is? After researching found out this type of eucalyptus is VERY prone to bug problems so still need to find a solution for that. It’s Eucalyptus Grandis (also called Red Grandis, Rose Gum, Flooded Gum)
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