Curved cabinet top
5/24/23
Hi
I am making a built in cabinet with a arched top. It will be going into an alcove so only the face and interior of the cabinet will be visible. It is going to be frameless but will be shimmed and have an applied casing which can help keep the front from flexing and it will have a 1/2" back. Radius for the arch is approx 30". My plan is to cnc the forms for the inside radius. Its too big to go in my vac. bag so my thought is just to use a bunch of ratches straps. I plan on using 2 layers of 3/8" bendy ply and then a veneer layer inside and out. (outside won't be seen). Is this enough layers or should I plan on using 3 layers of the bendy ply? I was just thinking titebond for the layers but could use urea resin to help increase the stiffness. I will be using 20 mil backed veneer for the face. Thanks!
5/24/23 #3: Curved cabinet top ...
Leo. Thanks. Would you suggest 2 layers of kerfkore and then the veneer. I have no framework to attach the kerfkore to so it will need to be self supporting. I think I have seen a video where the kerf sides are laminated together resulting in a rigid curve. Is that what you would suggest?
Thanks
5/24/23 #4: Curved cabinet top ...
It gets pretty rigid if you put a veneer on both sides. On the unseen side you can probably use a polybacker.
I've used it for making curved cabinets. In that case I used a curved rib that I nest into a groove and glue to have it retain it's shape.
5/25/23 #5: Curved cabinet top ...
I think you should use two layers of 3/8" bendable ply with veneer on the exterior surfaces. Make a disposable vacuum bag from heavy vapour barrier and butyl tape. Bag up your layers and clamp the bag to your form. Ratchet straps alone won't give the distributed clamping pressure for a successful glue-up. You can google home made vacuum bags to see the set-up.
5/25/23 #7: Curved cabinet top ...
Leo. Thanks.
Tom. I think I will give that a try. Would titebond be an acceptable glue or would you suggest a Urea resin or epoxy glue?
Thanks
5/26/23 #8: Curved cabinet top ...
You will have less spring back with plastic resin glue
5/26/23 #9: Curved cabinet top ...
I press almost exclusively with PVA. Call me stubborn or cheap but I rarely have a glue problem. Spring back may be more with PVA but it won't be and issue with this application when the top is fixed to the gable and back. Choose your glue based on your experience with veneer. Are you confident that you will get the layup in the bag, clamped to the form and drawn down to vacuum before the glue starts to set. If you are using raw veneer will it buckle too much.
PPR will give you a longer open time, I'm not sure if it has less moisture though.
5/26/23 #10: Curved cabinet top ...
Based on my experience I agree with Tom.