Jack 112 - trying to learn as I go

[kekani]

Okay, I gotta be honest - I lurked just for a while before I signed up, and basically got so excited that I just jumped in and hoped whatever research I had done (and questions asked) was good enough to head me in the right direction. Truth be told, the more I read, the more I want to read and learn, but alas, that takes a LOT of time (I'm not too good at searching). But, I still do it and try not to ask too many question that have already been answered. Believe, I could've asked a LOT more than I have.

Anyway, I just got the parts in from Leland today, but I've been busy since I got the plans less than a month ago. Actually, I say busy, but I've really been taking my time. Here's the journey, so far (I think I need to do a couple of posts because of image size):

Layout on a ful 8x4 sheet of 1/2" birch ply. Grabbed if off the blemish pile at Plywood Hawaii (less sanding to do in the long run).


Basic parts cuts from the full sheet. Some angles already done. Random holes in the brace to reduce weight. Also drilled out holes in the phase plug extension.


I had some 3/4 ply lying around, I got lazy and used two of those instead. Homemade clamps out of Poplar came in handy (used for `ukulele building).


Baffle template out of 1/4 mdf I had - guess I plan to build more. Already contacted a friend who will make one for me out of 3/16 plexy (or acrylic, whatever he has), laser cut, then for sure I'll make at least 2 more. Added some rounded corners just to smooth out the look. Unfortunately, I did it on the wrong side of the vents, so I redid this piece again.


I have West Systems epoxy that I use for pore filling instruments, so I just mixed up a batch for the end grain of the ply.


I'll post more later.

-Aaron

[88h88]

What's the epoxy for in the last shot?

[Bill Fitzmaurice]

What's the epoxy for in the last shot?

Good question.

I just mixed up a batch for the end grain of the ply.

Why? It's not in the plans.

[Frederic Gelinas]

Did I read that you want to make more templates? Why? I only need one.

[kekani]

What's the epoxy for in the last shot?

I know most people use Epoxy as a glue, but I learned a trick from Rick Turner in using it as a pore filler for instruments. In this case, it is just used to fill the end grain of the plywood because those surfaces will show. I know I can use bondo, but I already have West Systems in stock, just another path to the same end result.

Did I read that you want to make more templates? Why? I only need one.

Because the one I made out of MDF I did the "old fashioned" way, with my router, saw and guides. The "new" one (it'll either be plexy or acrylic) will be laser cut, no cost to me, and I'll only need one.

When I posted that I'm learning along the way, I am. I've learned a LOT from this forum, and have a LONG way to go, so while I did go through the plans way more then 5 times, I still feel like I'm building on the fly. I just can't read all the posts here fast enough to absorb and get all the tips and tricks, although I've learned more than a few already. In any case, I appreciate any feedback (or tips) to keep me in the right direction.

More pics:
The guide spacer came in handy. I dry fit one side, clamped, then glued the 2nd side first (then back to the 1st side). I was concerned about being square, so this process helped a bit. I wish I had the plate jointer at this time, but this was easy to square up. I'm avoiding drilling holes and using nails since I read that the butt joints are strong enough.


I used the table saw and fence to make sure everything is lined up and square when gluing. This where the plate joiner would've really come in handy, as it would've kept everything square.


-Aaron

[kekani]

Cabinet scraper (well used) to clean up glue squeeze out. I read a post that say's its not necessary, so I did it only on the showing edges, and this one, as the brace will be installed here.


Inner tube from my kids bicycle tires (use this for instruments as well). Another thing I already have, so I used it. Made sure it was square on both planes before I cinched it down. The rubber pads on the clamps allowed me to clamp the angled throat reflectors without a jig (good enough). I'll probably make a jig for future builds to assist in clamping on the angle, but this came out tight enough. So far, everything is still square.


Previewing the fit into the cab. The gap in the top will come down when the finger joints in the sides/top/bottom get glued.


Used a dado blade to make simple joints, just to keep it square. Again, just a different path on my learning curve that I'm comfortable with. There are certain things I need to do for myself to give me the confidence to build this cab, and this is one of them. I'm sure if I thought about it, I could've come up with something else (like just follow the plans?), but I'd probably do this again - helps me keep it square.


-Aaron

[kekani]

I know this is not the process, but is one that I'm comfortable with. Only the mouth panels are being glued. The angle on the panels are cut to size to the sides. Bisquits? My friend offered a plate joiner (now permanently borrowed) for me to use. Not the nicest or newest, but it does the job. I had to attach a 3/4" extension on the tool to get to the angle on the 1/2" ply between the mouth and throat (same with the mouth and sides). I'm not sure I would've done this glueup without the joiner and bisquits to hold it in place. Believe it or not, the tire tube has a fair amount of tension.


I've posted this pic in another thread, asking about the damping material (thanks Leland & rogerc).
Gluing phase plug extension(now) while I can get clamps in, and reach it for sanding flush (painted just to see if the epoxy filled the pores of the end grain ply). Cutting damping material - seems like a lot! Got this free from a friend. My issue will be actually applying glue, then installing through the back. The fit is so tight, I'm thinking of running it without glue on the inside panels (its not like they're going anywhere) and just glue the ones closer to the back. The "fingers" on the foam act to hold the adjacent piece in place, in two directions. They're also a tiny bit oversized so they'll get smashed into place. Suggestions, anyone?


Took the time to lay a coat on the baffle assembly, and just dry fitting. From the weight so far, seems like another 10# from the driver and other hardware that will be added will allow it to still come in around the stated 40#, which is MUCH less than a JBL JRX115 (which I hope to replace subsequent builds with). Its really square (shape), comparatively speaking (to a PA cab).


Dry fitting allows me to test the sequence of assembly when I actually glue it together. Here's a shot of the back with a bisquit. Yup, that's an FF in a "0" hole. That's what HD had, and it fits good enough. Haven't glued anything yet, so I can still pick up the "0" size if needed - so far, I sat on it, and its pretty solid. A back panel will be routed out prior to assembly. In addition to the back, bisquits are now all over the place to keep the baffle assembly aligned to the top, and the mouth plates to the sides. And that is some cheap ply veneer chipping out - one more reason I'll be using my West Systems to "pore fill".


That's it for now. Gotta cut the driver spacer next, and glue the box together - got my straps out already. . .

-Aaron

[Melissa Goudeseune]

Looks good so far!

One question before you, ahem, glue yourself into a corner

Are you planning to apply West epoxy to all the edges, let it cure, and then use PL Premium to glue the whole cab together? If so, may I highly suggest that you try that glue sequence on a couple of scrap pieces, to see how well it holds?

I know in boatbuilding that a secondary bond with epoxy isn't as good as a primary bond. I haven't tried this with epoxy and PL Premium, but it would be an awful shame to scrap the cab at that point if the glue doesn't work well .

[Gregory East]

Very good idea. I was surpirsed to find our Gorilla grip expanding PU doesn't make a good bond with PVC.

[kekani]

Looks good so far!

Thanks for the support. Much needed, sincerly. . .

Are you planning to apply West epoxy to all the edges, let it cure, and then use PL Premium to glue the whole cab together?

For the West Systems, its only going to be used to pore fill edges and surfaces that will be finished, and not glued, basically doing what bondo would do. Once the cab is glued together, and the edges rounded, the end grain of the ply will show on both faces. Since I got the cheap ass ply (mistakenly - I read it the plans more than twice, but I didn't get it, at the time) with veneer, the epoxy will do well to secure whatever chipout I may have on the rounded edges (I'm sure there'll be some). Of course, I'm so anxious to play this thing, the thought of filling pores just means more down time. But, I'll keep on keeping on.
The part of the plan that sticks out for me is the airtight part, so PL is the glue of choice for me, and I'm trying to follow at least that to a "T". Never used PL before until now, and I got the whole tube, so I'm going to (and have been) use it.

I've learned (quickly) to appreciate the squeeze out, and leave it alone if its not on a shown surface. This was REALLY difficult for me because squeeze out in instruments is quickly taken care of while its wet.

Took care of the spacer today, and routed the back for the access panel (not in the plans, pics to come). Still gotta route for the jack plate, and set up the brackets for the tweets (as well as the assembly jig for the tweets).
I've been wrapping myself around the crossover filters for the past 3 days, searching posts, looking at schematics in the plans, and on the boards, as well as trying to make sense of Leland's circuit board pic off a thread, and his site. Also been trying to absorb the wiring for the DPDT switch for the tweets, which I only saw one schematic for here - I'm going to check the switch just to make sure the schematic matches with the switch positions. Also been contemplating the cutting and assembly of the tweets - finally got it, and plan on doing it reversed every other, as I've seen on a couple of builds.

-Aaron

[LelandCrooks]

It's this board. http://www.speakerhardware.com/2_way_ci ... CB55TB.php

The only modifications are holes for mounting the coils, and new wire holes for the components.

http://www.speakerhardware.com/prebuilt ... mp500w.php
click on enlarge. This is with the 10w resistors. It now comes with 25's, which changes the layout a bit. Moves the .6mh to the outside, laying down, overhanging the board a bit. Turns the .5mh vertical, pretty close to the edge. I keep running Erse out of 10 watters.

[kekani]

Leland to the rescue again. . .

It's this board. http://www.speakerhardware.com/2_way_ci ... CB55TB.php

The only modifications are holes for mounting the coils, and new wire holes for the components.

That's the one. When I placed my order, I didn't know how easy that would've made life, thinking, I'll cross that bridge when I get to it. Guess my confidence in soldering and following a schematic (in the plans) didn't allow enough forward thinking to see what that piece would be in the puzzle. If I were building a quiver of Jacks, that'd probably be the way to go.

http://www.speakerhardware.com/prebuilt ... mp500w.php
click on enlarge.

That is exactly what I was wrapping my head around. Don't ask why but I didn't see the T+, W+ initially, and finally realized what I was looking at, once I saw the pic of the blank board to see where the connectivity runs.

I saw this other schematic for the DPDT from Harley, which is basically ends the same as yours (no?) with both on in the down, and 1 on in the top switched position. Of course, it shows a little different wiring of the piezo's from the plan to accomodate the switch. From connection standpoint, this I understand. Polarity reverse still gotta sink in.
http://billfitzmaurice.info/forum/viewt ... DT#p150624

So, should I solder up all the connections (after I install quick connects to test, especially polarity), or should I keep the quick connects? Dilhemma, and excitement continues. Back to the shop. . .

Aaron

[LelandCrooks]

Same diagram electrically. Rotated.

I solder everything except the connections to the board. Makes troubleshooting easy later on in life.

[kekani]

I like the soldering part - tweets should be fun.

Spent some time in the shop today. I showed my friend a fast way to line up the edges of the fretboard to assure correct bridge placement - used a laser level. I also use it to find center on a square, quickly.


Because I don't have a compass that big, I just centered the driver, and spaced the outer diameter close enough.


I use a center finding ruler for many things in instrument building - this is so I can check the inside diameter.


I was going to build a circle cutting jig because I'm too cheap to buy one. I'm also too lazy to build one. This method is taken from the circle cutting jigs for bandsaws. My router is usually parked in the table.


For the ID, I took it in 3 steps. For the final, my hand is pushing on the outside ring so when it cuts through. . .


. . .there's a little bit to clean up.


Here's the spacer installed.


Another dry fit, with the routed back.


-Aaron

[rogerc]

Looking good!

Re gluing your foam, I just put random stripes/blobs of a (cheap) contact adhesive on the panels and stuck the foam to it. It doesn't need to be adhered all over, just kept in place.

Roger