Mandolin Curved Cabinet Tower build (Bagby Design)

[lowpolyjoe]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

Take your time, it's harder to fix mistakes than to do things right the first time.

No doubt. Problem is, while it takes 10 times longer to correct a mistake than it does to prevent it, it's 1000 times harder to force yourself to take your time in the first place instead of rushing :p

[Jeff B.]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

Very Nice! I am glad you like the sound.
Jeff

[WernerM]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

4) You need more straps.

That is just too funny!!! :D

[biff]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

First, nice work!

When I toured the Theil factory we saw they were using jigs as forms for their side panels and it is much easier with a design like this and parallel sides to do it that way, something I realize right after I do something like this. When you do it, just let the sides run long and trim all after the glue dries.

I have done some work and found that instead of straps it worked well for me to make a bending break by using heavy canvas rather than straps. Take a couple 1x2s and trap an edge of the fabric between and screw them together, you can wrap this around whatever needs to be formed and tighten and clamp by rolling the material around the boards, it really seems to even out the force along the surface and eliminated my need for like 7 or 8 hands.

[1100xxben]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

First, thanks for the compliment djkest.

Obviously you have learned some lessons. I was going to make some suggestions to you after your first post, but then I realized that you were putting up several posts and you've already built it! Anyway, I'll still share my clamping jigs that I used for 2 different curved side builds.

The first one is a small 7-liter cabinet for a sealed Tritrix MTM. I used a piece of 1/8" HDF as the sides of the former to help spread the pressure over the entire side. So, the outermost layer of 1/8" HDF in the picture is part of the clamping jig. It worked quite well for a small cabinet, but requires a LOT of clamping pressure (hence the pipe clamps).





This one was a lot larger and I used some hefty strap clamps to get the pressure needed. I used a piece of 1/4" OSB screwed to a series of 2x2's to help spread the pressure of the straps evenly. I also put the straps over the top of each of the internal braces to make sure I didn't crush the HDF in between the braces and create an uneven surface. Other than the same problem that djkest had with cutting a slightly too sharp of an angle on the back piece, this setup worked quite well.

[djkest]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

xxBen, those are some great photos. Had I used that method, it would have been easier for me. Live and learn. Despite the pain, I have the desire to make another curved cab speaker in the future. I just think they are 'neat' I guess. I was always attracted to the design since I first saw one.

Someone asked about finishing plans. Well, first I need to stop using them, lol. I have some Andrew Jones Bookshelfs that can replace them temporarily. I plan on taking my time with Bondo to get all the gaps filled in, then doing my roundovers and chamfers on everything. 3/4" roundover on the front baffle. Possibly 1/2" chamfer all around the top. Small 3/8" roundovers everywhere else. Of course I still have to flatten the back too. There's a bunch of small hurdles I'll need to clear before it's totally done (like remounting the binding posts).

The white oak baffle will get some dark gray Analine Dye that I got from TimK. I am planning on applying it with the grain. I'd like to still see the character of the grain. Then it will get several coats of gloss Laquer. I want it to be glossy so that visually the baffle is the focal point of the speaker. I think Stainless Steel or Chrome bolts would actually accent the baffle appearance, might replace the black ones.

The speaker body, I need to possibly add sand to the bottom chambers, and also make my stand/feet for it. I think I'd like to raise them up 2-3", and I still need to figure out what I'm going to do for that. It's already pretty heavy, but I'd like to add more weight to the bottom to decrease the chance of them tipping over. I am researching the possibility of custom made machined aluminum feet for them. I also am wondering if a contrasting color or wood should be used, or if it would just be distracting. Probably the latter.

Ultimately I plan on shooting the speakers with a satin black or dark grey with my Dad's compressor and HVLP gun. Not sure if I am going to use Latex, Acrylic, or what. Also not sure if I want to use a clear coat on that. I'm undecided. I would like for the temps to get up a little bit before I start shooting paint.

[djkest]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

I am starting to work on these again. I spent about 2 hours rubbing the front baffles with 220 grit sanding sponge, softening a few of the corners, and buffing the wood to a glossy smoothness. I am getting ready to do the dye, but I am going to do some more research on it first so that I can do it right the first time. For example, I use rubbing alcohol, but do I use 70% or 90%? I read that cheap foam brushes are the best for applying it. I will probably use an old T-shirt to wipe it down.
I found this link:

http://www.woodmagazine.com/materials-guide/finishes/aniline-dyes/

Further, I did a Q & A with TimK on finishing them, here's what he said:

Procedure (correct me if I'm wrong).
1) Sand down the surface to be dyed with 220 grit to a fine finish.
Fine

3) Use a rag to apply the dye, applying in the direction of the grain. Let it soak in for 30 seconds, wipe off excess. Repeat multiple times if necessary to achieve desired color.
This is the scary part. Better to spray it if you can. Analine streaks if you don't apply it extremely evenly. It's very hard to do. You won't need to wipe it off I'll bet, it'll all just soak in and be gone. Practice on the back sides first!

4) Let dye dry thoroughly (will there be much color shift?)
Gonna take only a few minutes. The appearance wet is how it's going to look with laquer on it. When it's dry it will appear light.

5) Apply Laquer to surface. Use fine steel wool to gently buff between coats. Apply several coats.
Skip steel wool and go buy a 3M sanding sponge. Get the yellow type. Can be had at Wal Mart. 320g.
...
If you end up with some inclusions in the finish that you can't tolerate, just sand and laquer again.

I should have a little time to work on these in the next month, I am taking ~2 weeks off for the newborn that will be arriving.

I know in the previous thread that got deleted (accidentally?) Ben mentioned using kitty litter in speakers. I think I will end up doing that. I can drill a hole in the back of the speakers to pour 10-20 lbs of kitty litter in the base of each. Combined with a wider base (still trying to figure out how that is going to look), it should be relatively stable. I will try and post pics the next time I update this thread.

[woodsart]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

Hey Dan, please do post pics!!

I am starting to work on these again. I spent about 2 hours rubbing the front baffles with 220 grit sanding sponge, softening a few of the corners, and buffing the wood to a glossy smoothness. I am getting ready to do the dye, but I am going to do some more research on it first so that I can do it right the first time. For example, I use rubbing alcohol, but do I use 70% or 90%? I read that cheap foam brushes are the best for applying it. I will probably use an old T-shirt to wipe it down.
I found this link:

http://www.woodmagazine.com/materials-guide/finishes/aniline-dyes/

Further, I did a Q & A with TimK on finishing them, here's what he said:


I should have a little time to work on these in the next month, I am taking ~2 weeks off for the newborn that will be arriving.

I know in the previous thread that got deleted (accidentally?) Ben mentioned using kitty litter in speakers. I think I will end up doing that. I can drill a hole in the back of the speakers to pour 10-20 lbs of kitty litter in the base of each. Combined with a wider base (still trying to figure out how that is going to look), it should be relatively stable. I will try and post pics the next time I update this thread.

[djkest]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)



I think my Aniline Dye is a little weak. I mixed it with about 12 oz of Wood Alcohol (Methyl).

I have applied 9 coats of dye to these baffles (3 coats, 3 different days). I hit it with a yellow sanding sponge to smooth it out. This is what it looks like now. It will change a little bit with the Deft Gloss Lacquer. I think it looks neat, kind of a weathered look to it. It actually looks more brown than I thought, I guess tan + grey = brown. Anyway, I am undecided if I will do more dye, or even combo it with black stain. I will have to use my test piece.

I am getting excited to finish this project, I have a bunch more complicated ideas for the finish so we'll see how that goes. I think the plinths are going to be made of grey dyed white oak as well, with some hard rubber feet. I'm not sure what it says about me when I spend 5 hours sanding and dying some removable baffles.

[Thucker]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

Great job, and thank up you for the detailed pics. They will help me out a lot when I attempt my first curved cabinet build.

Is that your wood glue that's is chalky white on some of the pics? If so, that means you're using the glue in too cold of temperature and the glue didn't bond/cure properly. I learned my lesson the hard way, mine was a little worse, I had to tear my cabinets apart. In the process I was surprised at how easily the glue joints came apart.

[djkest]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

Okay, so I made some progress in the last week.

First, I made a makeshift sanding block out of a piece of 2x6 pressure treated redwood and a full sheet of 60 grit sandpaper. I have spent 3-4 hours sanding the back of Tower 1 to get it pretty smooth. It will be getting a layer of hardboard anyway, but I wanted a flat surface so I wouldn't have bubbles, bulges, or leaks.

I also spent about 15 minutes sanding the top even more, it's nearly "smooth as glass" except for a few glue spots, apparently glue doesn't like to sand as easily as the wood. This will have to be taken care of with Bondo and glaze.

The base- I have made 4 more pieces of 3/4" MDF that are the same size as the internal braces. I think I am going to cut 1/2" off the front and back. These will be affixed to the bottom of the cabinet. I have also made a base of solid White Oak that is 11.25" x 12" wide. I found "dead center" of the piece and then used my circle jig to round the corners. Unfortunately, the radius is so big it barely looks curved at all. These will probably be finished the same as the baffles.

Weights-
I weighed almost everything for grins yesterday.
Empty enclosure- 32 lbs
Base - 5 lbs
Faceplate/baffle - 2 lbs
That doesn't include ports, bolts, drivers, crossover, binding posts, or stuffing. So it's easy to think they will be 45-50 lbs each.

Before I add sand to the base. I will probably be adding 20-30 lbs of sand. The problem will be once this is done, they will be difficult to move, being both heavy and awkward. I might make a small "handle" on the back to help move them. A strip of MDF that blends in with the back.

Another thing- I am contemplating a complex system to relocate the binding posts in the base instead of 1/2 way up the cabinets. I would cut a channel in the back to route the speaker wire, and then cover that up with the 1/8" hardboard. It seems like just the sort of overly complex thing I would do. Maybe I won't. At a certain point you want to be done and listen to them.

The baffles- they have 6 coats of gloss laquer, and then I sat down and wet sanded them with 1000 grit paper last night. Unfortunately, I am not really happy with the way they turned out. They look like red oak with a stain on them. I am tempted to strip them all the way down and start over. While they do look nice, they seem to have lost most of the character of white oak, and are not at all what I had imagined when I thought of them in my mind. I wanted a white/grey/black monochrome look not a brown/black look.

[bobbarkto]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

Do you have a little scrap oak to experiment with?

There are two somewhat involved processes that wil turn it a very black, black. No hint of brown or blue.
Silvery gray is also possible using heavy pigments (diluted paint works).

[djkest]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

Do you have a little scrap oak to experiment with?

There are two somewhat involved processes that wil turn it a very black, black. No hint of brown or blue.
Silvery gray is also possible using heavy pigments (diluted paint works).

I do have some scrap I could use. I have looked into oak carbonizing, I've even done it myself. It was a pain in the but1 and I didn't really like it to be honest. I have some Minwax ebony stain. Maybe I'll try mixing the black stain with silver paint and see how that looks. Since it's scrap, messing up won't kill me, it just wastes time. Glazing might be an option. I could strip the wood, seal it, and then glaze it.

Or I could buy some wood conditioner, and use that + ebony stain and see how that looks.

I have also looked at the black polyshades, but that seems to just turn everything very black. I am having a hard time finding a pic, but I've seen oak a few times where the heartwood turns black and the softwood looks grey, that's close to what I'd like to do.

[bobbarkto]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

To get a very consistent color change to black on most oak requires a very dense almost opaque pigment layer or a chemical change.
Minwax ebony will leave a brownish hue with some brown showing similar to what you have now.
Adding silver will make it a lighter black/gray but with the same underlying problem of the brownish hue being somewhat pronounced.

White oak is high in tannic acid. You can use this to your advantage.
A solution of iron oxide (nails dissolved in white vinegar is common) applied to the oak will turn it silvery black.
If your oak is not high enough in tannin or you want a really dense black with no hint of blue/brown/red then a pre-application of a tannic acid such as Quebracho powder dissolved in hot water will do.
Most people find a second application of the Quebracho after the ferrous solution will give the most consistent results.
The advantage with this is the color of the wood is chemically altered and is very lightfast. All the grain and texture will still show.

Be advised the Quebracho is highly acidic and very irritating to mucous membranes and sensitive skin. Safety precautions are advised. Keep it out of your eyes, too.

An easier option is dilute black or gray paint, depending on the color you want, applied like you would a normal wood stain. This will leave a higher concentration of pigment on the surface and will obscure some of the grain but still leave some semblance of the appearance of wood. You will need to experiment with the dilution and setup time to get the right effect on your wood.
It is often advisable or necessary to pre-stain the wood with a black dye (the minwax ebony would work for this but a water soluble wood dye would be better and more densely black).

To get to the mottled gray you will need to apply some gray pigment over the black base.
You can apply a glaze coat of gray paint to the whole surface and selectively wipe it away.
Make the glaze by thinning paint and adding clear.
Vary the concentration of pigment to thinner/clear carrier in your glaze to change the effect.

->Pigment will build in the pores and is very difficult to remove so start with a light concentration and work up until you get the effect you are after.

I do have some scrap I could use. I have looked into oak carbonizing, I've even done it myself. It was a pain in the but1 and I didn't really like it to be honest. I have some minwax ebony stain. Maybe I'll try mixing the black stain with silver paint and see how that looks. Since it's scrap, messing up won't kill me, it just wastes time.

Or I could buy some wood conditioner, and use that + ebony stain and see how that looks.

[bret191]

Re: Mandolin Curved Cabinet Tower build (Bagby Design)

I like the way you attacked the project and I know you will greatly enjoy the end result! Now I am jealous!