First build T39 16in wide - bp102

[Grant Bunter]

Some chipping out of the plywood around the hole. Hoping the gasket will cover all this and seal well.

What you show in that pic is a classic spot for a leak. Fill it with bondo or similar and sand smooth. Put an appropriate sized bolt in the hurricane nut to protect the threads while doing this.

[Harley]

Some chipping out of the plywood around the hole. Hoping the gasket will cover all this and seal well.

Grant's right, don't take a risk and carefully Bondo the chipped area.

You can avoid chips in baffles by first drilling a tiny pilot hole for each bolt hole and then ( using only sharp drills ) drill from each side with the large drill and DO NOT drill all the way through in either direction. Takes a bit more time, but avoids the chip-out.

[Saddle]

Thanks for the tips Harley and Grant. I'll try the bondo. Couple of those splits were at the edges of a knot. I will NEVER use anything but baltic birch next time. At least for the sides and the baffle.

Live and learn...

I got panels three and four in this evening. Pics in the morning.

[Saddle]

Great job with the t-nuts. That's exactly how you do it. BTW, I like your TS sled and the side runners you made for it. Quite ingenious. I need to get around to making a larger sled. The first (and only one) I built can only handle panels up to 13" wide.

Thanks, that sled has helped a lot so far. I need to firm up the extensions. They allow a little wobble, but all in all...

[Saddle]

Got panel 5, and the 3/5 brace in today. Plywood has some curve to it, but was able to straighten it for now.





Just realized I don't have my wheels for the back. And, have to start breaking in the speaker. Get duratex and bondo... I should have made two of these at once.

[Grant Bunter]

Thanks for the tips Harley and Grant. I'll try the bondo.

No worries. It easier to catch now than when you discover a leak when leak testing

Couple of those splits were at the edges of a knot. I will NEVER use anything but baltic birch next time.

It can happen with any type of ply, or timber for that matter. Though the knot may have played a part...

[byacey]

Fir and spruce plywood is especially bad for tear-out when drilling with a common twist drill. If you use a 1/16" bit for a pilot hole, and then drill from each side with a brad point drill bit, you will have a nice clean hole.

[Saddle]

Fir and spruce plywood is especially bad for tear-out when drilling with a common twist drill. If you use a 1/16" bit for a pilot hole, and then drill from each side with a brad point drill bit, you will have a nice clean hole.

Thanks for that tip. They are on my 'to buy' list now. No more of that stuff...

[Michael Murphy]

I find also if you have sacrificial ply you clamp it behind where your proposed hole is thus eliminating tear out, oh and a good sharp bit. Works great for me with my inferior ply.

[Rickisan]

+100 on the sacrificial ply method.

[Saddle]

+100 on the sacrificial ply method.

I find I'm 'sacrificing' a LOT of plywood!

That's a great idea, and one that I know. Not sure why I didn't think to do it... duh... I have had a lot of 'duhs' on this project.

[miked]

Congrats, Saddle; you're learning via the school of hard knocks. I still have bruises from my OTop builds and they were a year ago. LOL! The messed up thing is that by the time you learn exactly how to do things the best/easiest way, your cabs are built and you "don't need" the knowledge anymore.

I've said in probably 20 diff threads that I could build better looking OTops and T48s than I originally built, in half the time. But all my cabs are built already...maybe someday.

And don't worry about "duhs." As long as you don't injure yourself, nothing else matters. Plywood is replaceable; your fingers aren't. So if you cut on the wrong side of the line and now your panel is 1/8" too short, you've gained experience (for example.) "Experience is what you get when you don't get what you want."

[jimbo7]

Using sacrifical wood is also a must when it comes time to cut out your hand holds. A forstner bit works best. A spade or cup/hole saw bit just tears at the wood.

[Grant Bunter]

Using sacrifical wood is also a must when it comes time to cut out your hand holds. A forstner bit works best. A spade or cup/hole saw bit just tears at the wood.

Same again, if you use a hole saw with a pilot and cut through at least one ply then turn over and cut the remainder there is no tear out...

[Hackomatic]

Same again, if you use a hole saw with a pilot and cut through at least one ply then turn over and cut the remainder there is no tear out...

+1 . . I've also learned to use high speed and very little pressure to initially breach the ply's surface when using a hole saw.