Veneering without end grain showing

[Joel Wesseling]

Hello, Im a new member and was directed here by Joe at VeneerSupplies.com
Hoping you can help with a question with some picture to help.

I'm in the process of building loudspeakers with Baltic Birch plywood.
I use dodo joints and the end grain is exposed at cabinet sides and front.
The ply end is 100% flush trimmed a few days after assembly.

The veneer went on nicely and didn't notice any problems but after a few sprayed shellac coats I could see the end grain showing through.
Its clear this is permanent so I need to rethink what happened and how to fix.

Am I going to need a sheet material or dummy veneer to cover the entire surface first or is there another solution?

I do like raw veneers so not crazy about going to a veneer with a backer.

I would appreciate any help..

Joel

[Van Huskey]

I use dodo joints

There is your problem, using an extinct joint will never work correctly...

I can't really help since I haven't had this issue, too late now but count you feel the joint with your fingernail?

As an aside, being a closet audiophile I am curious what transducers you are using and in what type of array. Really nice job on the veneer except for the one issue.

[Clarence Miller]

try investing in a lock mitre bit. They are kind of a PITA to set up but I liked the joint so much I built a dedicated bench top router table with a 20" tall fence.

[Karl Brogger]

.............They are kind of a PITA to set up but ..............

Ladies and Gentleman, understatement of the year.

[johnny means]

No real need for a lock miter. Assuming no one will ever be viewing the inside of the enclosure, you could just use a miter joint and glue a block on the inside corner of each joint. If you really want to get fancy you could veneer you panels first and use a v-fold, for absolutely invisible seams.

[matt tennessen]

for your current set, I guess you can always veneer over what you've got and the end grain shouldn't telegraph through.
Unless you plan on making a ton of cases and have room for a dedicated set-up, I don't know that I'd go with the locking miter bit. Mitering the edges and adding glue blocks, cutting a spline, or using biscuits are all pretty quick and easy.
If you're having trouble mitering the edges, I'd try joining the top and sides with a deep rabbit, that way you're reducing the amount of ply edge as compared to a butt joint. If you're flush trimming the end, make sure you're sanding it smooth too as that router bit is probably not leaving a finished edge due to the make up of plywood.
Finally, have you tried two-ply veneer? I know Rockler sells it, its thicker so less telegraphing and you can sand it a little more. The veneer selection is probably a little more limited but check it out.

[Phil Thien]

Wow, I'm stunned that is happening. How thick is that veneer?

I'd normally miter the corners of a speaker enclosure because that is always how I did it anyhow. Never used a dado there.

Now I'll never try.

[Jeff Bratt]

Are you looking to fix these speaker boxes - or to prevent this problem in future construction? Sure looks like the 100% flush trim isn't completely flush. Is the end grain part proud or recessed? In either case, depending on how thick the veneer is relative to the "step", a couple swipes with a card scraper should smooth out the visible ridge. For future projects, changing to a non-extinct joint may be the best answer...

[Joel Wesseling]

Thanks for the input.

I'm going to try to repair by scraping or edge trimming again.
Worse case I veneer again.

I'm using 1/42" veneer

Flush trimming is done with undersize bearing to slightly cut into side face which requires a bit of sanding

really like raw veneer for selection and price and also less noticable edge overlap

Planning to build more of these for small business so need to get it right.
I believe now what happen was that the glue expanded(thickened) the end of the side panel in the dado joint. I then edge trimmed to soon and went right into the veneering process. Eventualy the ply retracted to its original thickness creating the overhang..

I need to wait longer before trimming but I think the best thing might be to move the end grain to the top and bottom of boxes and use a sacrificial birch veneer applied top to cover end grain . The front has same issue so birch veneer on there as well..
Then veneering all surfaces can be done..
Maybe no Telegraphing with this idea??

Thanks, Joel

[Pat Barry]

Joel, I'm confused why you are using an undersized bearing with the flush trim bit. That defeats the purpose of the bit doesn't it. I think a better solution would be to use the bearing that the bit was designed for and then sand as needed. I think the best solution wold be the miter joint, reinforced with corner blocks. I suspect you will have enough room inside the cabinet for the corner blocks. If you are making a bunch of them, then use biscuits to help make your assembly go quicker and reinforce the corners with the blocks to booot.

[Jim Rimmer]

There is your problem, using an extinct joint will never work correctly...

I can't really help since I haven't had this issue, too late now but count you feel the joint with your fingernail?

After giving him grief about the dodo joint?

[Joel Wesseling]

The plywood is 17ply 24mm BB and cutting a 45 could be difficult with the light duty motor I put in my vintage SCM saw but I realy like the dado for strength and have fixtures and templates to build them with dado. Spent along time building the Templates and dado guide platform etc..

Have several trim bits from whiteside, freud and infinity. They all except one freud leave the edge slightly proud. The one freud cuts into face ever so slightly. When I run it about 1/2inch below the joint I get this perfect smooth flush trim except for a small line on the side face that is easily sanded out. Seems easer then sanding the BB end grain??

The step can be felt with fingernail.

Joel

[Joel Wesseling]

I put some water on the end grain of a scrap piece today the thickness increased about 3mm.

[johnny means]

Joel, if you're going to be doing this type of work with any regularity, you might want to rethink your construction method. Veneering over a joint like that is pretty much always going to be a crap shoot. You could even finish one and have it look amazing, only to have the joint mysteriously appear in a few weeks. Remember, all three components there, the plywood face, the end grain, and the veneer are going to spend there lifetime trying to move around in different ways. Even within the end grain itself you'll have long grain plies trying to grow proud of the end grain plies. Often, if you run your finger across the edge of a piece of uncut BB you'll notice a slightly ridged surface, it wasn't made that way, it was at one point cut perfectly smooth.

[Joel Wesseling]

Johnny, what if I move end grain to top of cabinet then cover with 1/8 mdf. this way no end grain is exposed before veneering? Maybe the grains move independenly from the veneer?

The front shows end grain around perimiter as well but planning to use thick hardwood about 1/8" covering front. I guess the edge could be a problem here as well?

Joel