Curved Sides Glue-Up *** How-To

[tomzarbo]

I was getting ready to glue up the sides on these boxes and I thought while I'm at it I should make a short video on how I glue curved side panels to a speaker carcass.
Hopefully it may help someone who would like to add some curves to their next speaker project but may be a little apprehensive still.

http://www.youtube.com/watch?v=Yeczz...ature=youtu.be

TomZ

[[email protected]]

Re: Curved Sides Glue-Up *** How-To

I can see where your technique is perfect for a small speaker without aggressive curve. with a large floorstander straps come in real handy. I glued and nailed the first layer. Just glue after that.

[mikejennens]

Re: Curved Sides Glue-Up *** How-To

Thanks for the video Tom and for the pics Lowell. The curved sides certainly add to the classiness of a speaker's appearance. Tom, what glue did you use to glue the sides to the box and did you glue the smooth sides of both pieces of HDF together?
Thanks,
Mike

[PWR RYD]

Re: Curved Sides Glue-Up *** How-To

I used Titebond II. I scuffed up the shiny side of the HDF with 150 grit sand paper. I used a 3/16" triangle notch trowel to evenly spread the glue. Rough side in for every layer.

[tomzarbo]

Re: Curved Sides Glue-Up *** How-To

Thanks for the video Tom and for the pics Lowell. The curved sides certainly add to the classiness of a speaker's appearance. Tom, what glue did you use to glue the sides to the box and did you glue the smooth sides of both pieces of HDF together?
Thanks,
Mike

I used polyurethane glue, or Gorilla glue to get the first layer stuck to the carcass. It works great for this because it fills in gaps, and adheres great to the HDF, plus you don't need to caulk because the foam-out from the joints assures each seam is sealed up.

I used Titebond II to glue the layers of the sides together. For that job, you don't want to use Gorilla glue because besides difficulty in spreading it, it may cause bulges in the layers due to the expanding nature of it's curing process. I have the smooth side always facing out and I scuff it with coarse grit sandpaper to give it some tooth.

Lowell, I've used strap clamps as well before, and it's a better way to do it for the most part. This way is just quicker for small stuff. I like strap clamps because you can use shims to tighten things up even after you can't get any more clicks on the ratchet. I have had some issues with pressure on the excess material "levering" the panel away from the carcass, but using a few well placed blocks on the front baffle area keeps the pressure off of the overhanging material.

TomZ

[50 watt head]

Re: Curved Sides Glue-Up *** How-To

Awesome video, Tom, thanks for sharing.

[[email protected]]

Re: Curved Sides Glue-Up *** How-To

I ended up with waves. one must use cauls as Tom did. One must also cut the pieces very close to size as its difficult to use a trim bit on a surface that is not 90 degrees. I did have to caulk all the ribs as an afterthought, didn't know about the foaming action of poly glue. You do have to wet the mating surface to cause the reaction.
Tom, on that particular build, did you stop there, or add more layers? Your video was very well done but wished you would have undone the other to show the results. Kind of like the cooking shows where they take one out of the oven as they put the one in the oven that they had just made.
Can you show a pic of the project now?
I too used titebond II.

[1100xxben]

Re: Curved Sides Glue-Up *** How-To

I also used straps, and lots of 2x2's to keep even pressure between the straps on my curved cabinet stentorians. The build thread is here, which has lots of pictures of my clamping jig/setup. I used Titebond Extend glue, since I had a decent amount of exposed glue time before I got both sides covered and clamped up.

[tomzarbo]

Re: Curved Sides Glue-Up *** How-To

I ended up with waves. one must use cauls as Tom did. One must also cut the pieces very close to size as its difficult to use a trim bit on a surface that is not 90 degrees. I did have to caulk all the ribs as an afterthought, didn't know about the foaming action of poly glue. You do have to wet the mating surface to cause the reaction.
Tom, on that particular build, did you stop there, or add more layers? Your video was very well done but wished you would have undone the other to show the results. Kind of like the cooking shows where they take one out of the oven as they put the one in the oven that they had just made.
Can you show a pic of the project now?
I too used titebond II.

Arlis, that's a great idea. I just finished gluing up the second two layers of HDF on one pair. It ended up being 5/8" thick each side with four layers. It should be pretty dead by the time it cures.
I will try to get down there with the camcorder to take apart the second set.

I actually went down there again today with the camcorder to document how I cut the top/bottom curved panels by using a template/router... but explaining that was a bit harder than I thought it would be. I tried three times at about 8-9 minutes each and wasn't happy with any of them. I may try that again as well since it's fresh in my mind.

Thanks for the input on this, it's a good idea.

As far as keeping the panels close to the needed size, that's a good idea as well; but I handle this in two steps, which I neglected to mention in the video. First thing is I trim close to the cabinet with a jig saw, then finish up with the router. I can cut within a 1/16th to 1/8th with the jig saw and get almost perfect with a flush cut router bit except for the back. That's where the angle is awkward. I just set an angle on the jig saw and again trim close as I can, then stick it in the jawhorse and belt sand until I'm almost there, then finish with a piece of oak flooring with a strip of coarse belt sander sandpaper glued to it. I can get it almost perfect that way.

Also, I trimmed up the two panels on each side of the cabinet before gluing the other two on. Cutting 5/8" thick of that stuff is very difficult and easy to goof up. It's more work trimming twice, but doing it all at once is unpleasant for me I've found, and hard on tools.

By the way, I hope I don't come off sounding like I know all about this stuff, I realize there are lots of ways to do this, and my methods are not perfect, but I just thought that others may benefit from seeing how easy this can be to do with a few tools and some planning.

More to come...

TomZ

[tomzarbo]

Re: Curved Sides Glue-Up *** How-To

I also used straps, and lots of 2x2's to keep even pressure between the straps on my curved cabinet stentorians. The build thread is here, which has lots of pictures of my clamping jig/setup. I used Titebond Extend glue, since I had a decent amount of exposed glue time before I got both sides covered and clamped up.

I remember looking at the pics of your stentorians build and just marveling at how well you planned that whole shebang up. Your crossovers are super-nice as well. I'd be taking the covers off and showing everyone that came in my house if I made crossovers that nice!

I like how you used lots of boards to help pull the sides in with the straps. That's the way to do it with larger sized stuff for shore. It's more critical apply pressure over the entire panel if you are just using one thickness of hardboard as opposed to two or more layers... it's pretty tricky to do with larger sized stuff. You almost have to choreograph the entire thing start to finish or else you run out of time. I've bashed things with a mallet more than once because the glue was starting to 'bite' and I wasn't ready for it.

Thanks, 50 Watt Head.

TomZ

[donradick]

Re: Curved Sides Glue-Up *** How-To

Thanks Tom - very nice video of the glue up.
Maybe one of these days I'll challenge myself with a curved sides build

[cwad8505]

Re: Curved Sides Glue-Up *** How-To

Awesome vid and pics! Thought I'd share a pic of how I did my Poor man's Strads..
Chris

[ErinH]

Re: Curved Sides Glue-Up *** How-To

Thanks for this discussion, guys.

When you lay down the sides, do you worry about excess? Since
I am horrible at cutting the right lengths perfectly, and if there's a significant curve I can imagine not getting the length just right and in that case
I would probably shoot to have extra and just flush trim it out. Is that a viable option?

[VegaMan]

Re: Curved Sides Glue-Up *** How-To

Thanks for this discussion, guys.

When you lay down the sides, do you worry about excess? Since
I am horrible at cutting the right lengths perfectly, and if there's a significant curve I can imagine not getting the length just right and in that case
I would probably shoot to have extra and just flush trim it out. Is that a viable option?

it's how i do it, if the curve is aggressive might have a little trouble with the router wanting to sit evenly.

enjoyed the video tom, always marvel at clean workshops.

[tomzarbo]

Re: Curved Sides Glue-Up *** How-To

Thanks, Vega man.

I did something curved a bunch of years ago and one of the panels ended up being short, that was a mess. So now I just make sure I have about a good 1/2" or so of extra on each side, and then I trim close with a jig saw and get it almost there with a flush cut router bit. It requires a bit of careful handling with the router, but it's at least as precise as using a belt sander on the thing -- which I also do!

I'm really kind of a butcher of a woodworker, but with enough sanding and filling, it all looks pretty enough in the end.
I have to piece the video together I made of doing the last pair of speakers and taking off the clamps, just need some time.

TomZ