I am an experienced in wood working, but I have mostly worked with solid wood. When I have used veneer, it is in the form of veneer plywood... used for table-tops and as the panel in frame-panel cabinet doors. Speaker construction is somewhat different than normal cabinetry (obviously).
I am planning a project using 20mm (3/4 inch) Baltic birch plywood, and there will be many countersunk screws on the outside of the cabinet due to the bracing. Before I veneer the outside of the cabinet, I assume I must fill those screw holes and sand flush so that the veneer has a smooth flat face to bond to. I am using peel-and-stick veneer.
What is the recommended filling material? spackling compound (used in gypsum board / drywall construction)? automotive "bondo" body putty? I can think of several materials which might work, but what is the best practice ?
Jim
I am planning a project using 20mm (3/4 inch) Baltic birch plywood, and there will be many countersunk screws on the outside of the cabinet due to the bracing. Before I veneer the outside of the cabinet, I assume I must fill those screw holes and sand flush so that the veneer has a smooth flat face to bond to. I am using peel-and-stick veneer.
What is the recommended filling material? spackling compound (used in gypsum board / drywall construction)? automotive "bondo" body putty? I can think of several materials which might work, but what is the best practice ?
Jim
Two-component epoxy is good. The problem with most stuff is they shrink over time, and that makes on the surface small dips.
There are several two part polyester wood fillers out there which will work fine, as does auto filler. Epoxy too messy, hard to handle for this situation. Clean and lightly sand (220) your screw heads if the fills are shallow.
Mix sawdust with wood glue to make a thick paste.
Good for all kinds of dents, marks and scratches.
Good for all kinds of dents, marks and scratches.
Automotive body filler is fine. No need to use a specific wood filler as the patch won't show. Before applying the vener and after filling the holes I would seal the wood surface, lightly sand it and seal again. It will reduce moisture show through and give the veneer a better bonding surface.
Another +1 here for automotive body filler.
Epoxy would also work, but is softer so is more difficult to sand (it 'gums up' when sanding due to the heat generated). Auto body filler is usually polyester resin with some filler material to make it thick and so it sands better.
Epoxy would also work, but is softer so is more difficult to sand (it 'gums up' when sanding due to the heat generated). Auto body filler is usually polyester resin with some filler material to make it thick and so it sands better.
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Thanks for all the feedback. I had not thought about wood plugs, though I have used them in other contexts such as boat repair. That is a good idea.
I have used clear polyester for casting badges, and that does shrink. Whether car body filler will shrink enough to cause you problems is possible but not certain.
Better not to use screws
In my Basszillas there is extensive bracing and no metal fasteners. As an experienced woodworker you should be able to cut dadoes and rabbets without problems. Optionally you could use biscuits or dowels, neither of which requires drilling on the exterior surfaces.
Building the BassZilla Platinum Edition - Fall 2012
In my Basszillas there is extensive bracing and no metal fasteners. As an experienced woodworker you should be able to cut dadoes and rabbets without problems. Optionally you could use biscuits or dowels, neither of which requires drilling on the exterior surfaces.
Building the BassZilla Platinum Edition - Fall 2012
I first used wood screws, then biscuits, but for quite a few years now I've used dadoes and rabbets with the added benefit of everything going together squarely.
Paul
Paul
I used veneered chip board for some disco speakers.
Worked great until one night going into a gig they got wet.
The chip board just swelled up and fell apart at the ends.
Lesson learned, plywood from now on.
^ Did you not use the iron-on edging tape to protect the raw chipboard edges, along with a couple of coats of varnish Nigel?
That describes the home made cabs I used for my very first disco - guaranteed to be beer and lager proof!
P.S. I used wood screws, but from the inside.
That describes the home made cabs I used for my very first disco - guaranteed to be beer and lager proof!
P.S. I used wood screws, but from the inside.
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Is any fill necessary (assuming the veneer is real wood and not thin as plastic)?
Very good to have a narrow roller (like 2 inches) to apply good pressure. I also hit the veneer with a heavy rubber mallet. Very good therapy.
B.
Very good to have a narrow roller (like 2 inches) to apply good pressure. I also hit the veneer with a heavy rubber mallet. Very good therapy.
B.
5 minute epoxy with the addition of sawdust or one of the various epoxy fillers. Apply, and when set to a 'rubbery' consistency, shave to level with a chisel. When set, a scraper works better than sandpaper.
So to bring an old thread back to life...
I tried many of these methods, just to see which was easiest. The method I like the best is to counterbore the screw hole at 3/8" diameter, then glue in a small section of 3/8 dowel. I cut the dowel rod into 1/2 inch sections on my band saw, and then after gluing I cut them flush with an oscillating multi tool. Then hit is with 100 grit paper before veneering. This proved faster, easier, and less trouble prone than filling the holes with paste or glue or goop.
I tried many of these methods, just to see which was easiest. The method I like the best is to counterbore the screw hole at 3/8" diameter, then glue in a small section of 3/8 dowel. I cut the dowel rod into 1/2 inch sections on my band saw, and then after gluing I cut them flush with an oscillating multi tool. Then hit is with 100 grit paper before veneering. This proved faster, easier, and less trouble prone than filling the holes with paste or glue or goop.
I want to mention another method.
Keep in mind we are talking about situations where internal bracing needs to be secured with a screw from the outside of a cabinet wall. I am using the "highly braced" cabinet technique which avoids structural damping but instead uses extensive bracing to drive resonant frequencies above the excitation region of music/film soundtracks. Cabinets like mine have a LOT of internal bracing.
Most of the bracing can be clamped in place, or secured with a dado cut. However, there often arises a situation where the most straight forward approach is to use the humble screw.
So this final method I want to mention is to use an exposed temporary screw. This procedure is common in boat building, but I have not seen it used very often in furniture or cabinet construction: A pan-head screw and a fender washer are used as a clamp while the glue dries. After the glue has fully cured, the screw is removed. The small hole that remains can be filled with a drop of glue, lightly sanded, and veneered over. This method can be applied anywhere there is an adequate glue joint, but no good way to achieve clamp-up with typical clamps.
Keep in mind we are talking about situations where internal bracing needs to be secured with a screw from the outside of a cabinet wall. I am using the "highly braced" cabinet technique which avoids structural damping but instead uses extensive bracing to drive resonant frequencies above the excitation region of music/film soundtracks. Cabinets like mine have a LOT of internal bracing.
Most of the bracing can be clamped in place, or secured with a dado cut. However, there often arises a situation where the most straight forward approach is to use the humble screw.
So this final method I want to mention is to use an exposed temporary screw. This procedure is common in boat building, but I have not seen it used very often in furniture or cabinet construction: A pan-head screw and a fender washer are used as a clamp while the glue dries. After the glue has fully cured, the screw is removed. The small hole that remains can be filled with a drop of glue, lightly sanded, and veneered over. This method can be applied anywhere there is an adequate glue joint, but no good way to achieve clamp-up with typical clamps.
A reason you don't see some of these suggestions in furniture/cabinetmaking is the word "telegraphing". You learn to not penetrate any surface if it will be either veneered or paint/lacquered. There is always a good chance that any surface imperfection/repair will eventually show up in the finished surface. Dowels on end don't contract lengthwise at the same rate as the surrounding material. Result is round dots under the veneer which you can then do nothing to correct.
Best to exhaust all other methods before going through the face.You can just as easily add a screw block to the end of an interior brace and fasten that to the interior side of the cab wall(s). No need to create additional, time consuming, finish prep on the exterior.
Best to exhaust all other methods before going through the face.You can just as easily add a screw block to the end of an interior brace and fasten that to the interior side of the cab wall(s). No need to create additional, time consuming, finish prep on the exterior.