OB-5 Construction by Carlos

Voncarlos · « **Reply #20 on:** 19 Sep 2008, 11:17 pm »

Hi Marty,

Before answering your questions I should first tell you my thoughts and understandings about glue and glue bonds with regards to wood built items, sans the home construction industry. Other folks may have different opinions.

First off, one needs to understand that glue bonds on a molecular level, that is to say that the molecules of glue link to the molecules of wood. Thus, anything that gets between the surface molecules to be bonded, like dirt or oils from you fingers will hinder the bond. You often hear, "roughen up the surface first before gluing" with many people thinking that the glue will make little hooks into the roughened surface and bond better. This is false, glue alone has very little strength. What roughening up the surface does is expose a clean surface. So, the best glue bond one can make will be one that is perfectly mated together (I generally test my joints with a 1 to 2/1000th inch feeler gage), is absolutely clean (I wipe with denatured alcohol or acetone depending on the wood species) and is not starved for glue. So with that in mind, a strong build will be one that has proper glue bonds.

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To make assembly and glue up easier, any reason you did not make the braces a 1/2 wider and make a 1/4 rabbit for the braces in the sides?

I don't see how this would have made glue up any easier. And I don't like hiding the glue joint, I want to see it and check gap with a gap gage during a dry test. I had no problem with the braces moving up and down the body(standing upright) since glue up took place with the body lying face down on the front face baffle. So I don't see how rabbits would help me.

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This should make them stronger, larger glue surface.

Should ??? I'm not planning to subject the speakers to any physical trauma. I suppose if I was building something out of wood in the 17th or 18th century with hide glue, then it had to be delivered by horse and cart over poor dirt roads, I would have made rabbits. Modern glues are very strong if the prep is correct. Besides, look at all the braces in this thing, it's pretty strong.

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Did you also make the sides wider so that you could then flush trim them?

Yes I did.
I don't see why you couldn't make them the way you described, it's just not the way I would choose.

Carlos

mmmanich@comcast.net · « **Reply #21 on:** 20 Sep 2008, 02:18 am »

Carlos

Thanks for the reply, I learned something new today. Please keep the pictures coming. Your work is beautiful.

thank you

Marty

Hank · « **Reply #22 on:** 22 Sep 2008, 11:48 am »

Carlos, your post helps my case as I continually tell newbies to NOT use screws to build cabinets. If saw cuts are accurate and wood pieces fit tight/flush, then screws are an absolute waste of money, and, particularly, time.
Waiting to see your finished cabs - should be awesome

tubesguy2 · « **Reply #23 on:** 23 Sep 2008, 04:00 pm »

This kind of project and pics of this kind always just amaze me, especially since I don't even know which end of the router to injure myself with. Very nice!

Voncarlos · « **Reply #24 on:** 26 Sep 2008, 01:49 am »

Well, I'm making slow progress on the speakers. I'm testing different dyes and finishes and as some of you may know, this can take awhile. And then my gaming computer, out of the blue, starts freezing up on me. This can take an exhausting amount of time to troubleshoot. Maybe I should join a ATI forum. Anyways, here's a pic of the finished repair patch.

Voncarlos · « **Reply #25 on:** 9 Oct 2008, 05:28 pm »

My design for the Front Baffle is quite different. It will be a separate piece that is attached to the Woofer box.
I have been experimenting with different dyes for the Cherry veneer. I started off with some dyes I've had laying around for over 30 years. I really wanted the Cherry to "pop" and glow. So I started with a Deep Red Mahogany dye, but this made it to red. I thought if I could apply a yellow dye first, it would tone it down. I have some Gamboge left over from Violin construction times that is just the perfect yellow color to test. Gamboge is a gum resin obtained from a tropical Asian tree, used as a yellow pigment and as a purgative, and is used as an underlay on the raw wood of a violin before varnishing. This really toned down the red but left a rather flat appearance. This was only a test since Gamboge is supposed to be mixed with water and I used alcohol. But I was getting closer to the effect wanted, so I bought some proper woodworkers alcohol based yellow dye and played with different mixtures and coats.
And "BAM" it worked. I got the exact effect I was looking for.

Here are some of the Baffle pieces.

These next 2 pictures are the same spot, just different angles.

klh · « **Reply #26 on:** 10 Oct 2008, 04:29 am »

Wow. The second one really shows off the grain. I like it a lot.

Voncarlos · « **Reply #27 on:** 17 Oct 2008, 02:18 am »

I started to measure and draw out the lines for the various cuts on the baffles and realized that it was getting a little complex, so I thought I'd better do a full sized mock-up. Since the baffles already have a veneer and finish on them, there's no room for mistakes. I've discovered quite a few unknowns making the mock-up.

Bill Baker · « **Reply #28 on:** 17 Oct 2008, 12:05 pm »

Hello Carlos,
First I wanted to state that I am enjoying your progress report on these speakers.

You are 100% correct in your statements about wood bonding (which you already knew). A tight joint, even if only a butt joint, will yield a bond as strong as the wood itself. I see so many people exercising far too many extra steps in gluing woods that does noting for strengthening the bond........just additional labor.

Clean surface, tight joint and proper clamping are all that is required to build a wood product that will last for an eternity.

I am getting ready to build another pair myself. Either the OB-5 or OB-7, and a pair of the open baffle subs. This time around, I will probably go with Waterfall Bubinga.

Carlos, I can't wait to see the finished product and hear your thoughts on the speakers themselves.

Voncarlos · « **Reply #29 on:** 17 Oct 2008, 04:03 pm »

Hey Bill,
I think Bubinga would look great. Good choice!. I once started an acoustic guitar with Bubinga for sides and back but ended up making the side pieces too thin and had to scrap the whole thing. Darn #/&@#*!

Quote from: Response Audio on 17 Oct 2008, 12:05 pm

I am getting ready to build another pair myself. Either the OB-5 or OB-7, and a pair of the open baffle subs. This time around, I will probably go with Waterfall Bubinga.

Yes, building these things could get addictive aa

Quote from: Response Audio on 17 Oct 2008, 12:05 pm

First I wanted to state that I am enjoying your progress report on these speakers.

I think it really helps to have more pictures and updates. People can see some of the OB series builds and say "I could build that". They're also a great impetus for coming up with new ideas.
My hats-off to Rocket Ronny for his posts on the OB 5 he built.

Thanks,
Carlos

ebag4 · « **Reply #30 on:** 17 Oct 2008, 04:44 pm »

"People can see some of the OB series builds and say "I could build that". "

I don't think too many people are saying this after seeing your specific build. You have some mad skills. Please keep the pics coming.

Best,
Ed

Voncarlos · « **Reply #31 on:** 23 Oct 2008, 02:47 am »

In the mock-up, I've color coded each layer of OSB so everything could be seen a little clearer. With the Baffle being 1½" thick I was a bit concerned about the amount of air flow around the back side of the speaker frame and magnet, so I added an extra ½" in diameter to the back of the baffle.

Voncarlos · « **Reply #32 on:** 25 Oct 2008, 03:57 am »

Here are the baffles with the front piece of cherry applied.

Now that I have the T-nuts installed in the back half of the baffle I am going to apply the top and bottom pieces of maple. The next few pictures are of the same glue up and are a bit redundant, but I just love the look of organized chaos.

Meataxe · « **Reply #33 on:** 25 Oct 2008, 04:39 am »

Excellent photos!

I have never seen clamps like that (lever clamps?) 'down under' do you have info on design?

Cheers!

Voncarlos · « **Reply #34 on:** 25 Oct 2008, 03:08 pm »

These clamps (cam clamps) are my own self made copies of the German made "Klemmsia Zwinge" that are made out of Hornbeam. You can buy them at most Luthiers (musical instrument maker) supply shops and they come in various sizes. I bought 3 of them in the early '80s and found them to be very versatile for wood clamping but at $20.00 a piece back then they were just too expensive to have a lot. So I ended up making about 30 out of hard maple. They clamp without putting too much pressure on the parts, have cork pads that prevent slipping and marring and are easy to use. Other companies make them nowadays as well. I'm sure there must be some Luthier supply shops in Australia or New Zealand were you can get them. Here are a couple of links to places here in the States that I like to do business with.
http://www.stewmac.com/
http://www.lmii.com/Default.asp
I see that Grizzly Industrial has these too, for a very good price:
http://www.grizzly.com/products/6-F-Clamps-w-Cam-Action/H2843

JoshK · « **Reply #35 on:** 27 Oct 2008, 03:36 pm »

Truly inspiring!

I am amazed at your ingenuity coming up with that 9' radius jig. I would have never thought to use a router that way. Now I am already brainstorming how I could use something like that for my OB project.

Voncarlos · « **Reply #36 on:** 30 Oct 2008, 03:47 pm »

Next task was to dimension up some Maple for the sides of the Baffle. This required milling some fairly thin stock through the table saw. I use to find it utterly nerve-racking to cut small pieces through the table saw until I bought the GRR-Ripper.
I love this tool, it gives you complete control and precision of the cut, but let me also say that I don't take this kind of cut lightly. If you've not seen this tool before and you work around a table saw I can highly recommend it. Check it out at: http://www.microjig.com/
And I don't work for them or profit in any way.

Next, I'll cut the holes and do the final rounding-over and shaping.

Voncarlos · « **Reply #37 on:** 7 Nov 2008, 04:51 pm »

I routed channels for the speaker wires to run through before I glued up the two half's, but ended up forgetting one set of channels and had to do them at an angle with a drill.

I knew that they might be a problem when I went to do the round-overs, and of course, they were. The router bit guide-bearing wanted to drop into them. So my first thought was to plug them and I did do this with the first cutout, but it was too time consuming and not very accurate. So, I next thought to apply a thin band of Maple to the inside of the cutout and this worked perfectly!

Voncarlos · « **Reply #38 on:** 8 Nov 2008, 02:39 pm »

The baffles are now assembled and ready for final shaping.

The long straight edges are rounded-over with a router, but the ends are tapered and this had to be done by hand. I much prefer to work slowly by hand with a good sharp chisel, it's so much more peaceful, almost Zen.

So now we have the final Baffle form.

Danny Richie · « **Reply #39 on:** 8 Nov 2008, 02:58 pm »

Wow! That is incredable.