T48 Build Thread

[biggerrigger]

All is not lost. I am sure with Bruce's resourcefulness you guys can come up with a game plan to get this build back on track.

[Rich4349]

I had this VERY problem with my t-60. I was a little over aggressive when inserting the braces on the large back panel (the last long horn section prior to the mouth section). The top most brace was pushed in farther, therefore more bowing out, but both top and bottom were off. I used my Sonic Crafter to cut a thin line down the length of the brace. I was able to weasel the tool into the tiny space between the braces and do the same to the lower brace. The kerf of the SC blade was nowhere near wide enough to compensate for the amount of bow, so I measured how far off I was, at both ends of that board. I marked that amount down the length of the brace and cut asking it, removing about 1/2" most of the length. The pressure of the board pushing in held that strip in place. After I pulled it out, the board then also closed the newly formed gap. I did the same to the bottom brace. Then I just applied a small bead of PL to the inside of the cut braces and left it to dry. Problem solved! Considering how much time, money, blood, sweat, and tears you have in these, I don't think this problem even comes close to meriting scrapping them and starting over.

[miked]

Rich: Thanks for the description of how you fixed your T60. I may wind up doing something similar. Once Bruce checks them out, we'll know more. Scrapping them will not be an option unless they absolutely can't be fixed. Sorry I haven't gotten pics up of what the problem is. I've had other stuff going on that required my attention. One of the cabs is very bad. The other 3 not too bad. IMO, anyway. I'm hoping just cutting out the 7/8 braces and redoing them will fix it, but I have a gut feeling it's going to be worse than that. More later. Pics too.

[miked]

I'm very happy to say that my gut feeling was wrong. The cabs are saved. Huge thanks to Bruce, who had the problem figured out in about 20 seconds. One cab was fine as-is; didn't need any help. The other 3 cabs all needed some space taken out of the 7/8 braces. One cab needed both sets of braces cut, the other 2 cabs cutting just the top brace was enough.

Basically, I shoved all the braces in too far, especially the 7/8 braces and it bulged the back. I also had some "cumulative braces shoved in too far moved all panels out a little bit" error. Bruce brought along his Sawzall; it's one of the few tools I do not own. We got all four cabs fixed in about 90 minutes.

No pics of the carnage in progress; we needed all four hands for this fix. We cut the braces, then Bruce held the braces spread apart while I poured the PL into the joints. We clamped and moved on to the next cab.

On the worst cab, where we cut both 7/8 braces, as soon as we cut through the last leg of the brace, it snapped closed on the sawzall blade. That's how much pressure it was putting on the back. I swear, I only shoved them in hand-tight. I didn't hit them with a hammer or anything. The fix brought the backs in enough that some careful placement of the 2nd side will get the cabs securely sealed. There will be some additional finish work to trim some overhanging edges, but they'll be airtight and that's all that matters. Once the sanding the Duratexing is done, all the little oopses will be invisible.

The Sawzall blade is roughly 1/8" thick...maybe a little thinner. We just cut through the braces, put a ton of PL in the gap made by the blade and clamped the back panel to panel 5 and panel 3, moving the back inwards and squirting the PL out of the joint. I will let the clamps sit until tomorrow night. When putting on the 2nd side I will still need the clamps to squish the backs in a little, but that's OK.

Some pics. This was the worst cab. Note both 7/8 braces are cut.



Pics of the other repairs. Just the top 7/8 brace needed a chop.





Thanks again, Bruce. And thank all you for your support! The Build Train is BACK ON TRACK.

[Tom Smit]

Yee-haw!

[sine143]

see why I was so adament about my warnings of pushing braces in too far

[miked]

Yee-haw!

Hell yeah!! The repair would've been pefect if not for panel 11. The back couldn't be pushed in any further once it reached panel 11. And I wasn't ripping panel 11 out just to get the back that final 1/16". Some belt sand action and Duratex will fix that.

[miked]

see why I was so adament about my warnings of pushing braces in too far

Absolutely. And until the other night when I realized things were waaaay off, I'd have bet $100 that I did not shove them in too far. Good thing I'm not a gambling man. It's a fine art, putting these braces in. Too far and you bulge the back and throw all the panels out of whack. Not far enough and your braces are loose and you have cab rattle you can't fix. I'm VERY happy right now. Too bad I work tomorrow...I'd love a celebratory beverage or six.

[sine143]

I'm awaiting your reaction post to the build once you crank em up . congrats on getting it fixed

[miked]

Well, they'll get sealed up tomorrow, then the 6/10 braces on Wed and then I'll have to stop there for a few days. Got a lot going on for the next 4-5 days after that. It'll be good to let the PL on that second side cure for a few days anyway, before I start banging them around. But at least the building will be done. I will have a LOT of filling/sanding to do. I have countersunk screw holes on that first side and each cab has 30-35 screws in that first side. I countersunk them b/c that made it much easier to slide the cabs around on my workbench while building. Can't rush the finish work anyway. I want them to look as good as they will sound.

The hard part will be resisting the tempatation to install the driver and fire them up before I get them finished.

[Rich4349]

So all you cut out was the thickness of the kerf? 1/8"? I find it hard to believe that that amount was enough to cause so much distress. 3/8", 1/2", or more, sure.
This is a great reason to use the temp bracing, nailed or screwed, on the open top side. (Once the new panel is in place, and before the PL is dry, measurements are taken, both at the top and bottom. As long as the throat width at that point is the same or close (top and bottom), the temp brace is installed and glue allowed to dry. Combine this technique with a brad/nail gun and we're talking PROGRESS! And about 1/3 the number of clamps needed for any given panel.

[sine143]

its a 24 inch panel. if you move a point on that line halfway up that out 1/8 inch it will move the top out 1/4 inch at least.

[miked]

So all you cut out was the thickness of the kerf? 1/8"? I find it hard to believe that that amount was enough to cause so much distress. 3/8", 1/2", or more, sure.
This is a great reason to use the temp bracing, nailed or screwed, on the open top side. (Once the new panel is in place, and before the PL is dry, measurements are taken, both at the top and bottom. As long as the throat width at that point is the same or close (top and bottom), the temp brace is installed and glue allowed to dry. Combine this technique with a brad/nail gun and we're talking PROGRESS! And about 1/3 the number of clamps needed for any given panel.

I bolded exactly what I DID NOT DO. You are 100% right. Bruce told me the same thing. This was a hard lesson learned. I figured "All my panels are perfectly straight and the edges are a perfect 90. I am using a ton of PL and more screws than needed. Nothing could go wrong." Pfft, yeah, except me being totally wrong.

Yep, all I did was cut out the kerf width. On the one very bad cab I had to cut both 7/8 braces. It fixed all three cabs to the 90-95% perfect point. That is good enough for me. I didn't want to cut out too much, then have to fiddle with gluing in shims to make up for the excess I cut out. I am very happy with the fix.

I didn't think just a kerf width would make a difference, but sine explained the math behind it. I don't get the math...I just know it worked!

[hifibob]

Thank god it was an easy fix.. Now finish these babies and fire em up!

[Grant Bunter]

Mike,
I'm really really pleased that what must have been extraordinarily frustrating getting so near to the end of you build, has been sorted to a satisfactory level.
The world is off your shoulders again, and you can progress.

And good on you as well Bruce, champion effort
It says something about this forum that not just words and encouragment can be found here, but people from the forum going and giving a hand for real is plain and simple, golden...