fiberglass gobos - plywood backing?

[FALKEN]

nobody can answer this?

 

[RICK FITZPATRICK]

nobody can answer this?

First you asked how WE would do it.
Why I don't know cause as usual, you did it your way so what can we say Falken. You designed it. You were determined to build it your way so why ask us. It would be easy to nail a 1/4 inch ply to the edge of a frame. I even showed you how to do it YOUR WAY, by adding a cleat......but noooooooooooooo, your determined to make it difficult. So be it. Try to glue and HOLD IN PLACE while drying, a material face to a 1/4" edge....hmmm, and you made Tube traps.. go figure. As to this last question, you have already answered it yourself

nah..I don't think it will be loose.

 

[FALKEN]

man I was referring to the fiberglass not being loose. I haven't built them yet... the gobos at least. getting it to stay in place while it dries is easy..just lay it on the floor. I appreciate your design Rick, but like I said I would have to re-buy a lot of materials to do it, so I am trying to avoid dropping even more $$ and throwing away a bunch of wood. I am not claiming to be a know-it-all. to the contrary, I have repeatedly said I "don't have the know-how". Instead of answering my question, you are determined to have me do it YOUR way. what the hell.

 

[RICK FITZPATRICK]

Instead of answering my question, you are determined to have me do it YOUR way. what the hell.

On the contrary? "YOU'RE" the one that asked how WE would do it! So when we tell you how because you say you don't know how, what do you do?
Look, I'm trying to help you, hence the drawings. But if you're going to do it your way in the first place, what the hell do you ask us for? Look, I really try to design for simple assembly. Adhereing the edge of 1/4" ply to another framework with construction adhesive is kind of ...well, lets just say it's out of the ordinary I understand why you chose to use precut plywood, and its the same size as the fiberglass. But you asked about the airgap. I gave you a way of solving BOTH problems by simply adding a cleat to not only space the fiberglass out, but to give you a wider edge to fasten the frame to as well as the ply. So, do it your way. I don't really care how you do it. I ran into this same crap for years at where I worked as a CAD draftsman. I'd go to great lengths to show the shop how to build complex and very large projects. Some took very precise and elaborate jigs to install them, which I also would design for installation precision. But the guys in the mill would invariably do it their way, only to have the installers call me up asking how in the hell they were supposed to install this shit cause the jigs didn't match the drawings. I'd tell em..."how the hell do I know, ask the fucking shop guys. " The point is....figure things out BEFORE you buy materials. I showed you a good way to do this, thats all I know. Remember, these are mobile, which means they are going to be moved around a lot. Hence strong joinery. At least to my way of thinking.
As to holding the fiberglass in, I showed you. A nail or screw through the frame should do it, or velcro on the fabric back and ply, or a front edge wood cleat, or an aluminum angle, or a wood angle moulding, or a washer and fishing line, or a washer and screw through the face.........how many ways can you think of? Theres tons of ways, just think about it. I've got at least 20 drawings of this I have posted many times. It just depends on what you want it to look like, your budget, your skills, your ingenuity...hell, just wrap fabric around the whole thing and staple if on the back, or make a pillow case and wire it to the ply, or ...fuck it. NAIL It for christs sake.
Good luck with the adhesive Falken.
fitZ

 

[FALKEN]

so in not so many words the adhesive thing aint fonna work?

 

[e-man]

read the instructions on the liquid nail tube. iirc you can lay down a bead of adhesive, put the surface to be glued down against it, then pull the pieces apart and allow the glue to cure for a few minutes (about 3 -5 minutes), then put the two pieces back together. make sure you have them where you want them. it will grab pretty good.

i agree that a nail here and there will help things hold even better.

also try to make your gobo airtight. i will help its low absorption.

later...

 

[RICK FITZPATRICK]

Hey falken, I didn't say it wouldn't work. In fact, it may work just fine. I've never glued something to the edge of a 1/4" ply cause it just is too narrow usually, to fasten something to it, and the plys usually split easy. Say, why don't you just make the frames outside dimension 2'x4', nail the ply to the back of it and just cut the fiberglass to fit?? Sure would be easier and stronger. Just a suggestion though. Hell, if you set the frame on the floor, set the plywood inside of it, run a bead of adhesive around the joint and let it set overnight, it probably will be fine. Construction adhesive drys really hard over time and with the frames 90 degree joints being nailed it should work ok as long as the panel has a tight fit inside of it. For that matter, you could run a bead of yellow carpenters glue and it should work even better. Set the stuff on newspapers though. Yellow glue will run down into the joint, which is actually good. Good luck.
fitZ
BTW, when ever I have to do something like this, I usually rabit the frame, or run a dado in it. But your problem is the wood panel being the same size as the fiberglass. Hence my suggestion of cutting the fiberglass down.

 

[RICK FITZPATRICK]

also try to make your gobo airtight. i will help its low absorption.

Now wait a minute here. Can you explain to me just how you plan to make fiberglass "airtight". Besides, ever tried to blow in a bottle Hell, you could lay a plain panel of 703 with no frame or nothing, up against the wall and they'll work fine. These are RESISTANCE absorbers, which will absorb to an extent just sitting in a room. Up against a boundary they'll work better. Give em an airgap and it lowers the bandwidth. It has NOTHING to do with being airtight. If that were the case, then all the people building these with NO FRAME would be wasting their time. But thats simply not the case. I think you have these confused with MEMBRANE absorbers. Besides, these are gobos, which by the way he is building them, are simply portable broadband absorbers. To really act as a gobo, you need panels with mass. 1/4" ply will resonate quite easily, which simply transmits the vibration to the air on the opposite face. Hence mass or stiffness, which is harder to vibrate. However, low frequencies simply diffract around them. Hence LARGE gobos.
fitZ

 

[FALKEN]

I think you are both right. Making them airtight will make them slightly LARGER and more MASSIVE because the sound won't slip through the tiny cracks.

 

[RICK FITZPATRICK]

Good grief, I give up

 

[VSpaceBoy]

Good grief, I give up

lol.......

 

[mixsit]

Wow
It's cool though, I'm smiling.
Wayne

 

[RICK FITZPATRICK]

Hey Falken, just be glad your not spraying lacquer on Oak like I am :eek I live on the coast of Oregon, and with humidity changes and moving clouds(spraying outdoors) its enough to make your hair turn grey...er, mine already is well, lets say fall out.......er....that too...damn....well lets just say its a pain in the ass. Hahahaha!!
fitZ

 

[e-man]

ok, ok i forgot we were talking about using fiberglass on one side of the gobo. i made my gobos like free standing bass traps using 1/4 inch plywood on one side for a membrane.

you cannot create an artight cavity using a porous material.

sorry if i contributed to any confusion.

 

[RICK FITZPATRICK]

sorry if i contributed to any confusion.

No prob. I just wanted people to understand whats going on, thats all. Sorry if my manner was less than cordial.
fitZ
BTW, the bottle thing was a joke.

 

[true-eurt]

A bump and a read.....I am using the search button!!


What do I win?

 

[travelin travis]

hmmm, maybe this?

 

[VSpaceBoy]

hmmm, maybe this?

nicely done


how about this

 

[travelin travis]

nicely done


how about this

much more vivid. daddy likes.

 

[Innovations]

I would make them 5" deep 4' wide x 6' high. 3/4" Birch ply frames, with 3 layers 1/4" ply backs with 1/8" steel plate on the exterior, CURVED with 72" radius. Line with 4" 703 and fabric covered faces. Add casters and edge latches for fastening multiple units together.

Well, you asked.

fitZ

Wow, that is a great gobo design. I had never thought of making the back panel curved to add stability and so it would act as a diffuser. (That also seems to be going past a lot of the folks here.)