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Discussion Starter #1 (Edited)
I am a DIY newbie... I am finding building subs completely frustratingly fun... Here are some issues I have run into... Maybe it will help you in the future...


  • Make sure you have the proper tools. Circular saw with guide, router, jigsaws at minimum; a table saw would be really nice. Real nice.
  • If you use a circular saw, verify that the saw blade is set at 90 degrees by cutting test pieces. Stand the piece on edge and see if it perpendicular. If it is not, the glue won't have much to hold on too. You don't want to see the sub split along the seams under pressure. It is not nice.
  • Don't let the stores cut the wood for you... Their saws are never accurate. You will cry when you find one piece is 19" on one edge and the other end is 18-7/8" and nothing lines up.
  • This is really important. the largest pieces of the build should be slightly oversized. Maybe 1/4".. It is a LOT eaiser to trim oversized pieces with a router than to build up a piece that is too short.
  • Measure twice, cut once... Repeat. Repeat again.
  • If you use T-Nuts or Hurricane nuts, use Gorilla glue to hold it in place. Otherwise you will need a real gorilla to tear the box apart to remove a driver that is stuck because you have a nut that is free-spinning behind the driver.
  • Don't just arbitrarily drill holes in the cabinet until you know what size bolts the speaker will take. Just because one speaker uses 10/32 bolts does not mean another driver the same size will accept it. I found out Polks will only take 8/32 bolts unlike DA's 10/32.
  • When cutting out driver holes, make it a tad bigger than recommended. After applying paint, you may be surprised the perfect cut is no longer perfect. My DA RSS390HO-4 is now a permanent fixture in my cabinet.
  • When you primer MDF, use a sealing primer, such as Zinnser BIN Shellac primer. Do NOT user odor-free (water-based) primer, painting solvent paints over it will cause really bad wrinkles. You will see your finish age before your eyes. The canned version of the primer is a lot easier than using aerosols. Take my word for it. You apply it with a small 6" roller. It dries after an hour, reapply. After a few coats, sand it down with 220 grit paper using a random orbital sander. The finish is real smooth, plus it is not as messy as sprays. , the box looked better with the primer sanded down than the finished results.
  • Painting is harder than veneering. It leaves a big mess with overspray. Removing overspray from a car is NOT my idea of fun.
  • Finishing to a mirror smooth finish is very time consuming. You have to apply a primer, sand smooth, repeat until no unpainted surfaces appear. After applying a few coats of gloss paint, I chose to sand it down smooth and then polishing it with rubbing compound, polishing compound and then car polish. This will be a looong process.
  • Do not use steel wool if you will be using any water based product to finish the box. Any steel fibers in the finish will start to rust. What may look nice now, will be ugly as the finish starts to look like it's getting chicken pox.
  • If you use lacquer based paint, do not even think of finishing it for a month. Lacquers take a looooonnng time to cure, months even. If you sand too early, the paint will come of in chunks and adhere to the sandpaper, gouging the finish. When you sand lacquer, it should be removing like dust. If not, it ain't ready for sanding
  • If you veneer chamfered boxes, veneer the chamfers first. Then trim with a router with a laminate trimmer. Then cover the flat surfaces with veneer cut to size. It will be difficult to trim otherwise.
  • Do not use PSA (Peel and Stick Adhesive) veneers if possible. I find the quality inconsistent. Sometimes the PSA itself separates from the veneer side because of the way it is rolled up. If this happens, it is almost impossble to avoid getting a bubble. Also, PSA veneer does not allow you to adjust placement or dry fit.
  • Avoid cherry veneers that are sold in a roll. Cherry wood darkens in light. You will find the exposed part of the roll is a LOT darker than the hidden rolled part.
  • If you stain veneer, make sure you test the stain on a scrap that is exactly finished as the final piece. If the final box is sanded, sand the scrap. Otherwise the color will be different.
  • Sand veneers before staining to raise the grain.
  • If you stain with wood stain, always use wood conditioner before staining, otherwise the finish will likely be blotchy and uneven.
  • make a list of what steps need to be done. If will be surprised how often you end up skipping a step (like using wood conditioner) with a lapse in memory, ruining all your careful work.
  • Figured out how to easily veneer chamfered cabinets. Or at least I think it will work as i have not tried it yet. Veneer the entire box BEFORE chamfering. When I chamfer a box, it removes about 7/8" of material from the edge of the box. When veneering, you just need to cover to about 3/4" or closer to the edge since the rest of the material closer to the edge of the box will be removed anyway. You must make sure that the veneer is bonded along the edge of the veneer really well to prevent fraying or chipping while chamfering.

    Once the veneer is bonded to the surface, you can use a chamfer bit and route the edges (remember, when chamfering a box, you must chamfer all the vertical edges first, then the horizontal edges, otherwise the corners will be at different angles, I learned this the hard way).. If all goes well, the router will trim the veneer edges flush as you chamfer the box. This should be easier as you no longer need to trim the flat panels exactly to size. Now you just have to apply the veneer to the chamfered edges. You can overlap the edges a bit as well but not too much as the router will lift a bit on the overlapped edges. Then use a sufficiently long laminate trim bit (in this case, 1" since 7/8" was trimmed) to trim the chamfered veneer. Again, this should give you a clean cut. All you have to do from there is to apply veneer to the corners.

    I do not recommed that you use PSA veneer for chamfered boxes. The PSA is very thick and will leave a noticeable band between the veneer edges. Also, PSA tends to gum up the trim bits on the router because the glue is thick and does not really seem to dry (it actually looks like globs of thick rubber cement). If you stain light colored woods with a darker stain, the edges will become very dark and look like pinstripes on the finish. Its because the paper backing on the veneer absorbs the stain more than the veneer itself, becoming darker. Also, since you trim the veneer at 45 degrees, the area of the backing exposed is larger than veneer trimmed at 90 degrees.
I have learned all the above the HARD way... I had no previous experience and no one watching or guiding me... Good luck.
 

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Yeah, but you got it all out of the way on the first project, so the second one will be perfect. Right? :devil:

Welcome to DIY.
 

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Discussion Starter #5
Yeah, but you got it all out of the way on the first project, so the second one will be perfect. Right? :devil:

Welcome to DIY.
Nope... working on my fifth, yes fifth rebuild.... My last build had the chamfered edges fiasco. the edges were all uneven, I did not use wood conditioner so the maple veneer came out blotchy. It was also my first attempt with PSA veneer and the dang veneer bubbled up all over after applying. The PSA adhesive sheet separated from the veneer itself.

:hissyfit:
 

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One question I get asked a lot, is do I need some sort of gasket or seal on the baffle recess to seal the driver in. I found some people wanted it for peace of mind, and often, a sticky back foam gasket is used. Instead of this, I use silicone. DONT STICK THE DRIVER WITH WET SILICONE. Instead, I apply silicone on the baffle recess, then smooth a liberal layer all around the driver hole, then leave it to dry properly. Once dry, your left with a very very grippy, but reusable and replaceable surface. If you drop the driver onto this, then the rubber gasket of the driver completes a perfect seal, and if you try spin the driver on this surface, its pretty much impossible the contact is so good.
 

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Nope... working on my fifth, yes fifth rebuild.... My last build had the chamfered edges fiasco. the edges were all uneven, I did not use wood conditioner so the maple veneer came out blotchy. It was also my first attempt with PSA veneer and the dang veneer bubbled up all over after applying. The PSA adhesive sheet separated from the veneer itself.

:hissyfit:
That's why I put this little feller in there: :devil:

There are new things to, um, learn every time you do another project. There is a good reason why people can make a good living at occupations like plumbing, electrical and carpentry. :)
 

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One question I get asked a lot, is do I need some sort of gasket or seal on the baffle recess to seal the driver in. I found some people wanted it for peace of mind, and often, a sticky back foam gasket is used. Instead of this, I use silicone. DONT STICK THE DRIVER WITH WET SILICONE. Instead, I apply silicone on the baffle recess, then smooth a liberal layer all around the driver hole, then leave it to dry properly. Once dry, your left with a very very grippy, but reusable and replaceable surface. If you drop the driver onto this, then the rubber gasket of the driver completes a perfect seal, and if you try spin the driver on this surface, its pretty much impossible the contact is so good.
This is a great idea! I already bought the foam stuff from PE for my current build but if I am not happy with the turnout, I'll definitely try your method.:clap:
 

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This is a great idea! I already bought the foam stuff from PE for my current build but if I am not happy with the turnout, I'll definitely try your method.:clap:
Just make sure the silicone is fully dry :T

Let us know how you get on :)
 

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PL Construction Adhesive is the best glue I've found for speaker building because it doesn't run like water based glues, it fills in and seals the gap between boards well, it sands downs and paints well, and it bonds with other materials well.

Self-clamping straight edges are great for circular saw users. Cutting panels on a table saw by yourself is risky.
 

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If lilmike suggests you do something, do it! He suggested I use speakons in my enclosure. I didn't know much about them so I ordered in some binding posts. Then my new amp came in and was shipped with free speakon cables. After connecting a speakon connector to the amp, and disassembling one to connect to the binding posts, I will never use another binding post again. Speakons rock!
 

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Discussion Starter #13 (Edited)
I made some jigs that will help me in cutting MDF more accurately. I could not justify the cost of buying a Festool TS55REQ track saw ($600) so I decided to build my own. I glued two long MDF planks together, the bottom one is 1/2" and the top is 3/4". Make sure that the guide edge is factory cut, it should be longer than the cutting edge to align the saw before it cuts the board and past the board as well. I then placed the saw against the straight edge and cut the excess off. I use the cut edge as a guide. I just align the guide edge to the cut line and presto, I get a straight cut. Instead of using clamps, I glued a rubber non-skid strip to the bottom of the guide. The guide does not move at all when I place the saw and cut the wood.

Note that the motor housing is faced away from the guide. I found out that the raised guide edge forced me to raise the depth of the cut, which with the 1/2" cutting edge, limited my cutting depth. [EDIT]: well, this did NOT work. The saw cannot be held level to the board when cutting against the guide as there is not enough area for the saw to sit on evenly. You have to have the saw with the motor side resting on the guide. This means that the saw guide itself has to be 1/4" thick to limit interference with the motor housing.

I also made a 45 degree cutting guide to cut braces easily and accurately. I glued two strips of wood angled 45 degrees under a board. I placed another strip of the wood that will be cut at the 45 degree angle in between to so that the two strips held the wood in place at the correct angle. i just then glued another smaller guide on top of the assembly that will guide the saw along the straight edge.


here is a picture of the two planks glued together
The guide with the rubber non-skid pad attached with spray adhesive
This is to show how to use it to cut a board, just align the guide against the cut line
here is the 45 degree angle cut guide
 

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Discussion Starter #14
Just another hint... Buy a good circular saw if you don't have one or access to a table saw. i have a cheap Black and Decker saw. The problems are two-fold. The bezel or base is stamped metal. This metal flexes easily making cuts a bit ragged. Get a saw with a thicker base or better yet, cast metal.

The second issue is it uses a wing nut to tighten the base at different angles, such as a 45 degree cut. When you tighten the wingnut, the torque throws the angle of a bit.

Also, try and find a saw that has a outlet that can fit a vacuum to the exhaust where the sawdust comes out. Makes life a lot less messier.
 

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Also, try and find a saw that has a outlet that can fit a vacuum to the exhaust where the sawdust comes out. Makes life a lot less messier.
Oh man, yeah! I just picked up a Craftsman plunge router that has vacuum ports for dust collection. I was blown away by how well it worked with my plain old $30 ShopVac. Instead of clouds of mdf dust, there was only the slightest trace of dust in the air in my garage once I was done.
 

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Keeping the open nozzle of the PL tube sealed with a "wrap" of 2 inch thin package sealing tape keeps the solvent in and the whole tube readably useable with very little waste.
 

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Discussion Starter #17
When buying MDF, do NOT buy it if it has a finished or polished feel to it... Wood glue will not adhere to it.
 

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[*]Do not use steel wool if you will be using any water based product to finish the box. Any steel fibers in the finish will start to rust. What may look nice now, will be ugly as the finish starts to look like it's getting chicken pox.
Steel wool fibers in the finish is horrible regardless of what the finish is. It will leave behind a very rough finish that reminds you of bubbles stuck in it or something. Need to make sure it is completely cured before using it then try to clean it off the best you can afterwards. I'm not sure what the best way of doing this is but apparently its pretty important. I got some fibers embedded in some oil based stain and polyurethane, turned out pretty horrible, I'm going to have to redo it sometime.
 

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When buying MDF, do NOT buy it if it has a finished or polished feel to it... Wood glue will not adhere to it.
I usually don't use MDF but I recently got a flat pack for an 88 Special speaker from the DIY Sound Group that seemed smooth and polished. I glued it right up, it feels very strong and solid. They ship flat packs of the stuff all over the place with no complaints. Did you clamp it properly?
 
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