Best way to repair veneer splits

[cacophonix]

So i've started on my new pair of speakers, and used some of my left over bubinga veneer over the weekend. I used the hot iron method of gluing, and see a lot of veneer splits. I am unsure as to how best to fill them.

For my previous speakers, i tried plastic wood, and wood fillers with disastrous results (filler shrunk, and cracked and never really blended). I am trying to get a smooth finish (sanding sealer + lacquer brushed on) this time around, and wanted to ping the more experienced members here.

Also i have used poplar as baffle trims (1.5" wide x .75" thick), and am looking to see how best to stain it so that it can look acceptable around the reddish brown bubinga veneer. Any thoughts?

I'll upload some pics so that you can see my efforts.

[Rolex]

Is the veneer backed with wood or paper? If not, I would not iron on unbacked veneer. Splits are inevitable and very difficult if not impossible to get it to look right. Cauls or a vacuum press are more appropriate for that.

If you are using backed material, pictures may help to shed some light on the situation. I would suggest removal and reinstallation as opposed to trying to repair the cracks. Especially if you want a smooth finish.

Regarding staining of the poplar, just pick up some of your favorite stain and start playing with mixtures until you get a color you like. I use minwax becaue it's readily available for me.

[bob barkto]

Slivers of bubinga veneer edge glued into the split.

The thin-ness will follow most splits unless they get into some hair pin tight turns.

Using an exacto blade, held backwards, drag the tip through the split to excavate just enough so the veneer patch fits the split and penetrates just a little into the substrate to get past the glue that is there.

I like to glue multiple layers face to face for wider splits. Depending on the grain pattern of course. Not more than two or three thicknesses or the repair becomes noticeable in most wood.

For very large defects a flat patch will do, just a little harder to get a good flat ground for it to adhere to and a good grain match is more important.
Since you did the veneering it's not normally a problem to find a good match from the scraps.

I like CA adhesive for this task for several reasons. It sets fast and will adhere to almost anything and it can be used as a filler for the tiny imperfections around the repair when mixed with some matching wood dust.

Don't try to fill much more than half a hair width cracks or little spots.
Use thin CA for most repairs, the thicker stuff can be too viscous to work into the cracks.

One other trick I use is to glue in a sliver of veneer then gently hammer/mash it down into the split while the glue is still wet. This can fill imperfections quite well. Just make sure the sliver doesn't sit too proud of the surface or it will just crack off at the first hit (no more than ~1/16 proud, practice a little, every wood behaves differently). Don't use all your might, little taps do the job!

Be aware that glue can seep into adjacent grain and make a barrier for any finish or stain. Lacquer is usually no problem, most varnish too. Stains or dyes should be applied before patching. Small artist brush touchups with stain, color laden finish or paint may be needed.

[cacophonix]

Rolex - I used raw veneer ... cannot afford backed bubinga I used the iron on method, and as you mentioned, it caused splits. I've another project in the pipeline, and i might try the veneer glue/caul (http://www.veneering.net/veneer-caul.php).

Bob - Thanks for the wonderful input. I have tried gluing thin strips to fill the gap with varying degrees of success. I'll post some pics...

[cacophonix]

Profile view of my cabinet.



Closeup of the splits. There are several like this.



Below you can see my attempt at gluing slivers of veneer into the gaps. Again, varying results.



I went to woodcraft recently, and picked up a few supplies. A wood putty made by an Australian company (timbermate), general finishes java gel stain, and general finishes oil and urethane top coat. I used the putty and am extremely pleased with the results. I used mahogany color, and unlike the other putty i have used, this one has not shrunk, and has blend in quite nicely. Now, i need to test the gel stain and see if my poplar needs some sort of a wood conditioner to absorb the stain evenly or not.

[Bill Schneider]

You will probably need some sort of pre-stain treatment on your poplar. I've worked with poplar a number of times, and have worked out a system that works for me to prevent blotching.

Here's a photo showing the look I get using Minwax's Gunstock stain on poplar...



I begin by giving the wood a couple of coats of polyurethane FIRST - before the stain.

Then I use a piece of an old t-shirt to apply stain. It applies oddly over the polyurethane finish, but self-levels to minimize brushing marks within a few minutes.

It is important not to revisit a piece that you have already coated. That's another thing that I learned the hard way -- apply it, and leave it alone. Any attempt to brush-up the finish will remove stain once it's been in place for a few minutes.

The parts get a couple additional coats of polyurethane after the stain dries. If a piece needs more stain, it must be applied after a coat of finish, and not over the original stain.

This produces a tinted, transparent coating that does not penetrate the wood itself. It might make a real woodworker cringe, but it's a "formula" that I worked out for my own use. I like the look of it.

BTW, I used Minwax products for both stain and the Poly finish.

[cacophonix]

Thanks Bill!

I don't have a polyurethane and was thinking of using some wax free shellac. Like poly, this should prevent the stain from penetrating the wood and causing uneven absorption. I'll test this shortly and see how it behaves.

Thanks!

[bob barkto]

Shellec is a very effective pre-stain conditioner. Try ~1/4 - 1/2 lb cut.

[bob barkto]

Shouldn't make a "real" woodworker cringe.
It's another tool in the arsenal to get a result.
Much the same technique is used by anyone who has to make in quantity over time with consistent appearance.

I've always like that piece, Bill. The contrasts are very harmonious to my eye.

...
This produces a tinted, transparent coating that does not penetrate the wood itself. It might make a real woodworker cringe, but it's a "formula" that I worked out for my own use. I like the look of it.
...

[Rolex]

Just a heads up that more splits can develop after the finish is dry. One pair I built a number of years ago before I understood unbacked veneering had cracks as I applied and then continued to crack for about 4 more months.

So don't be surprised if you find more later on, unfortunately.

[CADman_ks]

....

So don't be surprised if you find more later on, unfortunately.

Man, that would be discouraging. I'm glad now that I used paper backed for my first veneer rodeo. While it has it issues as well, at least it's on there, and I don't have any splits.

I'm sorry to hear about the OP's cracks. That would definitely suck.

[cacophonix]

Well ... since i only have raw veneer ... lets see how long the cabinets last. If it becomes too much of an eyesore, i'll just build another.

I tried applying the stain with and without conditioner, and to my eyes, i thought the one without conditioner seemed richer. I rubbed the gel in and after 5 mins, wiped off the excess. The sample with conditioner didn't seem to take much stain, and just rubbing my finger over the stain seemed to take some color off. But with the one without conditioner, the stain seem to penetrate a bit deeper, and i could get a nice rich dark brown color. Like bill mentioned, i'll try to add a top coat and then reapply the stain and see how that looks.

Again, thanks a lot to all the responses.

[Bill Schneider]

Sounds like the experiments are going well.

FWIW, I didn't use a gel stain on my project. I'm sure that gels behave differently, so I'm glad you are experimenting.

When you are satisfied, mind posting some photos? I'd always curious to see the outcomes when using different methods.

[Hank]

My 1 1/2 cents: I've done such repair by sanding a scrap piece of veneer, taking the resulting sanding dust and mixing in some wood glue to form paste, then force it into the cracks/splits, etc with a putty knife. Let dry and sand blends in quite well in most cases. My bud refinishes rifle and shotgun stocks for customers of a local gun shop and he does the same process for nicks in stocks, except he uses epoxy rather than wood glue. You might want to try this on a veneer scrap that has a split.

[cacophonix]

Thanks Hank ... i'll give this a try again. I did try this earlier, but wasn't too happy with the look when the glue dried. Maybe i did not experiment enough. But i'm quite happy with the wood putty though. It hasn't shrunk, and has blended in quite well.

Bill, i'll surely post some pics. I plan on buying a different stain though. This java stain is way too dark. I want to dark the poplar to the extent where it can blend with the bubinga. I'll buy some walnut and mahogany wood finish and experiment.

[cacophonix]

Ok ... so finally i'm done with the cabinets. I'll be putting the drivers and crossovers in tonite. Lot of boo-boos on the way, but many lessons were learnt.

I applied 1:1 shellac/alcohol mix as wood conditioner. And after that i made the huge mistake of lightly sanding to make the surface smooth. What this did was tear into the shellac coating, and when i applied stain ( minwax special walnut finish) , it got absorbed unevenly with some getting in deep and the rest barely making it past the surface. Result - extreme blotching like I've never seen before. To cover this, i tried to apply the java gel stain which is quite dark. But because of the shellac, it did not bond with the wood. I had to then sand off the finish fully, and try again without the shellac this time. I then applied 3 coats of semi-gloss oil/urethane mix. Here is the end result.


Images not available






Images not available

[Carl V]

interesting combination of veneers
nice work...is this a sealed SSR type
design?

[cacophonix]

Yes, this is sealed. I bought a ported version ... but the speaker was too big on my 24" stands. So i decided to build a sealed cabinet. I didn't want to spend too much money on it, so used the extra veneer that i had lying around. Also I've also wanted to try to build a cabinet with hardwood edges ... and bought some poplar as it was inexpensive.

I had applied dark walnut stain to the veneer to tone down the red, but after a couple of disasters, i had to sand it all off, and start again.

[dar47]

Vary nice effort! I like the veneer.

I've found over the years and from necessity that I need to buy dimensioned wood not having the machines to work with rough lumber. Most big box stores where I am only have reasonably priced wood that just cater to the mill work needs hence poplar, aspen, oak, maple and mahogany. The poplar and aspen are usually painted as they don't take stain well. The others are usually stained dark or natural.
I have also found when I bought the cheaper wood I've had to spend more on treatment to get it to look the way I wanted. One of my resent cheap outs was on my Modula's, I thought I had a great deal when I found 1.5" Maple end cut cutting boards at Wall Mart for $25 each to make the front baffles. After milling the waveguide and finishing the speaks one of the boards failed alone a glue joint which should not have happened. I new I should have glued my own fronts.
One trick I discovered when trying to get stain out of some Aspen was to use wood bleach, it opened the pores and broke down the wood fibers. After neutralizing the bleach the Aspen took the stain much better almost like a Oak.

I'm grateful for all the tips I get here, it's saving me from blundering along and spending all my money unnecessarily. ;x(