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-   -   Have a beautiful brazilian cherry bar top that is cracking. (https://www.woodworkingtalk.com/f8/have-beautiful-brazilian-cherry-bar-top-cracking-14929/)

craftsman 20/20 01-30-2010 10:18 AM

Have a beautiful brazilian cherry bar top that is cracking.
 
I have a 16' x 30'' beautiful arch brazilian cherry bar top that I built this summer that is beginning to crack the veneer . The substrate was made from laminating two sheets of 3/4'' birch plywood together and applying a 1/4'' brazilian cherry veneer to it with contact cement. The edge application was three layers of 3/16'' brazilian cherry applied with contact cement.Than stained and finished one coat stain followed by three heavy coats poly the bottom was left raw. What did I do wrong !!! PS do you think that I could apply a thick coat of epoxy to hold it together ?

pabloj13 01-30-2010 10:53 AM

My guess would be that the bottom being left raw is causing the top and bottom to shrink/expand at different rates and that is what is causing the cracking.

Tony B 01-30-2010 11:06 AM

Quote:

Originally Posted by craftsman 20/20 (Post 116368)
The substrate was made from laminating two sheets of 3/4'' birch plywood together and applying a 1/4'' brazilian cherry veneer to it with contact cement. ......

One problem I see is that the plywood substrate will not move to any measurable amount. As for the veneer, it is kinda thick to be called a 'veneer' in the true sense of the word. If that be the arguement, then the 1/4" 'hardwood' surface expanded and contracted with the local climate whereas the substrate did not.
If the bar top is sitting on an open framework, then it is also possible that the top of the bar was more stable than the bottom because the top had 3 heavy coats of poly. If the bar top is sitting on an enclosed cabinet, than this is not likely.
The surprising thing is that the contact cement didnt have enough give to slip and slide with the top, unless the bar was subject to extreme cold.

craftsman 20/20 01-30-2010 10:25 PM

thank you for the response nice to have honest answers.
 
I do believe the hardwood is moving and the substrate is not and causing the cracking should I replace substrate with a hardwood and yellow glue it in place. If yes what is a cost effective comparable hard wood.

Julian the woodnut 01-31-2010 09:25 AM

Your problem is that you built the bar in the humid months of the season and now it is the dead of winter that is the driest season with the heat on. Your 1/4 hardwood surface has shrunk and subsequently cracked. If you had used a true veneer thickness like 1/16" or less, you wouldn't be having this problem because the wood wouldn't have moved as much.

Tony B 01-31-2010 12:02 PM

Quote:

Originally Posted by craftsman 20/20 (Post 116483)
....should I replace substrate with a hardwood and yellow glue it in place. If yes what is a cost effective comparable hard wood.

If you want to replace the substrate with a hardwood, you will have to replace it with a wood that will give you a similar coefficient of expansion or it too will give you problems with differing rates of expansion and contraction.
The best two choices are to make the top of solid Brazilian Cherry from glued up boards or remove the 1/4" thick piece and replace with a veneer of 1/16" or thinner. The thinner veneer will be able to stretch and shrink without cracking. The easiest way to remove it would probably be to plane it off. If you get real lucky and have been living well, you may find that after removing some of the thickness of the existing 1/4" surface, the cracks may not look so bad and can possibly be 'repaired'.

craftsman 20/20 02-01-2010 08:34 AM

Gonna try to thin 1/4'' slab!
 
I will try to thin the 1/4'' slab to minimize movement if this dose not work I will veneer but I am having a hard finding a supplier with a large enough piece have any suggestions?


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