WTT: Tweaking breakthrough AKA "Bye, bye blue tack"

Daniel_Bingamon · Post by **Daniel_Bingamon** » Tue Dec 23, 2003 7:57 pm

Maybe you could pour in some of that acrylic stuff that air hardens.

And yes, Styrofoam is extremely resonant. In fact, Bart Hopkins book "Music Instrument Design" has something called a styrocello, a string instrument with a styrofoam cooler as the resonator.

Jerry Freeman · Post by **Jerry Freeman** » Tue Dec 23, 2003 8:06 pm

Daniel_Bingamon wrote:Maybe you could pour in some of that acrylic stuff that air hardens.

Hi, Daniel.

Is "that acrylic stuff that air hardens" a foam or other very low density configuration? If so, I would like to know more about it. Can you track down the actual name?

Thanks and best wishes,
Jerry

fancypiper · Post by **fancypiper** » Tue Dec 23, 2003 11:43 pm

Switchfoot wrote:I believe the material itself (generically) goes under the monkier of "joint compound" but I could be completely off base on that one...

When I was in construction, they were two separate compounds. Joint compound is used to fill in the joints between separate sheets of the gypsum wall board.

Spackling compound was used to repair or fill in holes in the wallboard, so the compound is dryer and stickier than joint compound and it drys faster than would the joint compound.

OutOfBreath · Post by **OutOfBreath** » Wed Dec 24, 2003 7:52 am

Jerry Freeman wrote:
Daniel_Bingamon wrote:Maybe you could pour in some of that acrylic stuff that air hardens.
Hi, Daniel.

Is "that acrylic stuff that air hardens" a foam or other very low density configuration? If so, I would like to know more about it. Can you track down the actual name?

Thanks and best wishes,
Jerry

It's sold in aerosol cans with a hollow tube for positioning it. You can get it under various brand names at almost any hardware store. Just ask them for a can of expanding foam insulation. It's intended for sealing cracks around windows, etc.

It can be very messy to work with though and also quite expensive for whistles unless you're tweaking a whole lot of whistles at once. That is because the stuff dries out in the applicator once you start using it. There is no way to really clean the applicator very effectively, so you basically want to use the whole can once you've started.

I think to use it on something as small as a whistle you would have to squirt a small pile out on a paper plate or something and then trowel it in place much like you are doing the spackling material now. And, having used the stuff and ruined a shirt, I think it would be a lot messier and more difficult to control than spackling compound.

Now, if your aim was to fill the bore of a whistle with foam, you couldn't beat this stuff

TonyHiggins · Post by **TonyHiggins** » Wed Dec 24, 2003 2:25 pm

What about...a flat, thin wall glued to that space to close it while leaving the space empty??? I guess if the spackle is really acoustically transparent, it doesn't matter.
Tony
(It's a really slow day at work today.) A good thing.

Switchfoot · Post by **Switchfoot** » Thu Dec 25, 2003 2:24 am

When I was in construction, they were two separate compounds. Joint compound is used to fill in the joints between separate sheets of the gypsum wall board.

Ok, I dont know what I'm talking about then...
I'll just go back to lurking

Marko · Post by **Marko** » Thu Dec 25, 2003 12:26 pm

bjs wrote:What on earth is spackle. Can someone translate for UK residents please? I have used beeswax to good effect. Would be interesting to compare with spackle, blue tac etc. Hot beeswax is fun to work with - smells nice but hard not to get scalded . I used cut down packaging from a pen to make a pouring chanel.

happy Christmas
Brian

well at this stage it's obvious, but in the uk spakle is called polyfiller. i dont know if that is a TM or not.

Marko · Post by **Marko** » Thu Dec 25, 2003 12:27 pm

bjs wrote:What on earth is spackle. Can someone translate for UK residents please? I have used beeswax to good effect. Would be interesting to compare with spackle, blue tac etc. Hot beeswax is fun to work with - smells nice but hard not to get scalded . I used cut down packaging from a pen to make a pouring chanel.

happy Christmas
Brian

well at this stage it's obvious, but in the uk spakle is called polyfiller. i dont know if that is a TM or not.

dDave · Post by **dDave** » Fri Dec 26, 2003 3:08 pm

Howdy,

There is a product similar to spackle that dries either water proof or water resistant called Durham's Rock Hard Putty, possibly saving you the step of applying a waterproofing coat. It's sold as a powder that you mix with water (you could play with density by controlling the water content).

http://www.waterputty.com/

Best,

Dave

Jerry Freeman · Post by **Jerry Freeman** » Fri Dec 26, 2003 3:23 pm

Hi, Dave.

Thanks for the suggestion.

I'm familiar with Durham's Rock Hard Water Putty. It needs to be sealed for uses that will be exposed to water, so there's no advantage there. The real problem with Durham's for this application would be the density. I need a material that's feather light, like Styrofoam, to provide the accoustical transparency needed to preserve the brightness of sound from the resonating thin plastic shell.

Best wishes,
Jerry

Jerry Freeman · Post by **Jerry Freeman** » Fri Dec 26, 2003 3:25 pm

By the way, Dave.

WELCOME to the board!

Best wishes,
Jerry

dDave · Post by **dDave** » Fri Dec 26, 2003 3:42 pm

Howdy,

Uh, shields down, Mr. Sulu. We seem to be in friendly space.

Thanks for the welcome, seems folks are a might more neighborly here than some boards....

Best,

Dave

Rod Sprague · Post by **Rod Sprague** » Sun Dec 28, 2003 9:52 pm

Having too much knowledge of high tech materials, I would take glass or plastic hollow micro-spheres (basically microscopic balloons intended as light weight filler in high tech composite materials, they can be found in hobby shops catering to radio control model builders) and mix them with as little slow drying epoxy as will form a workable paste and place that in the cavity with the same disposable stick I mixed up the two part epoxy and the hollow micro-spheres. That composite material would have the virtue of being mixable in the small amounts that it would take to work on only one whistle at a time.

Rod