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hogwylde09

CF4 back panel glue issue

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I found out during a living room remodel of sorts so let me explain while keeping it short and to the point.

Moved all the big gear out to paint. 
I had the MC75’s driving Belles up front and Dynaco ST-70 on the rear CF4’S. C20 pre. Since the main sound imaging comes from the front I didn’t notice too much about the rear. 
I threw together a temporary fresh rebuild Fisher 400 and the CF4’S when I noticed the cabinet rattle.

I’m much better with a soldering iron than woodworking. 
How do I approach removing the back from one has about 1/2 side maybe midway loose glue?

I have KLF30’s that get little use, but took a pounding before I got them. No glue problems with them. 
I don’t think I’ve read the CF series have this?

Ver. 3 or 4 

 

 

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11 minutes ago, hogwylde09 said:

How do I approach removing the back from one has about 1/2 side maybe midway loose glue?

why take out the panel , take out the drivers first  -------then you would be able to glue  the panel by using clamps --or  heavy weights

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@RandyH000 so I could remove the drivers, crossover, sound absorption foam then apply the glue around the perimeter of the back. From the inside? If so and the whole panel is still very much intact would I still need clamps or weight?

 

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depends on how loose the back panel is,  i have repaired quite a few speaker & sub boxes that had rattling panels & have had excellent results with gorilla glue. this again depends on the situation but heres the jist of what you should be able to do if you dont want or need to remove the panel. 

 

remove all drivers & lay on its back,  then reach in side & cut away or clean up any residual glue thats around the seams of the back board, then use some coarse 80 grit sand paper to roughen up about 1/2"-1" area on all sides of the back panel.  then simply follow the directions on the bottle & it will seal the back panel almost permanently.  basically you take a spray bottle with water & lightly mist water into the seam all the way around, not soaking or dripping wet. then you apply a consistent bead about 1/4" wide all the way around the seam, the glue will expand & force its way into the seam then dry rock hard. it wont expand the cabinet or anyting but because it expands it gets down in where its needed far better than a normal wood glue & is much stronger than normal glue. 

 

i have done this on forte size speakers that were literally split apart on 3 sides from falling off a stand, also done it to KG5.5 that had the back boards loose, & a few different sub boxes for home & car audio.  gorilla glue is excellent stuff for this type of work & can be bought anywhere including walmart for about $5 that can do 2 or 3 pairs of larger speakers. all the speakers ive done it to are still in use 5-10+ years later & as strong as the day i did it.  this is the easiest & best way to fix this issue without actually removing the board & using clamps.   

 

 

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Thanks @EpicKlipschFan sounds like a plan. 
After digging back into the Epic threads I also found the info. Might as well do some crossover and port extension work at the very least while down. 

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@hogwylde09  Here's some pictures of the repair I did on my CF-3's a few years back.  Also had to do this to the KLF-30's i had for a short time.  You can see how sloppy the glue work was. I had areas that had no glue at all on them and apparently that was ok with QC.  

 

These are from the CF-3's as the front baffles on the CF's come off by removing the female grill plugs on the front baffles and removing the Phillips screws. Makes it simple.  

 

 

IMG_3725_copy_768x1024.jpg

IMG_3727_copy_1024x768.jpg

IMG_3729_copy_768x1024_1.jpg

IMG_3728_copy_768x1024.jpg

IMG_3729_copy_768x1024.jpg

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6 hours ago, hogwylde09 said:

@RandyH000 so I could remove the drivers, crossover, sound absorption foam then apply the glue around the perimeter of the back. From the inside? If so and the whole panel is still very much intact would I still need clamps or weight?

 

you're hearing a rattle , so something is not very tight or a panel is loose ,  I would glue the cab then take the clamps or weights ,  add a few screws , all around , and wait for the glue to dry before unclamping  , look at @avguytx  's pictures , he's one of the best on the klipsch forum for the CF3-CF4 cabinet restorations -

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This is a good reference thread.

 

 

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11 hours ago, RandyH000 said:

you're hearing a rattle , so something is not very tight or a panel is loose ,  I would glue the cab then take the clamps or weights ,  add a few screws , all around , and wait for the glue to dry before unclamping  , look at @avguytx  's pictures , he's one of the best on the klipsch forum for the CF3-CF4 cabinet restorations -

 

where are you suggesting to add screws all around? 

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What I did was cut 1x1" (3/4" square) "glue blocks" out of solid oak pieces from Lowes (or anywhere like that).  I pre-drilled holes in the oak for the screws to go through to keep the glue blocks from splitting then glued and clamped down and nailed in place.  Once dried, I used an adhesive similar to F26 where it was on 2 strips, dropped the panel in and clamped it down, then screwed into place using 1-1/4" coarse wood screws.  Don't use drywall thread screws as they don't grab as well.  I also braced them by adding on to the cross braces to the back walls as they had no bracing at all.  I believe I added some extra 3/4" pieces to the tops and bottoms to give them a little more solidity.

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13 hours ago, avguytx said:

@hogwylde09  Here's some pictures of the repair I did on my CF-3's a few years back.  Also had to do this to the KLF-30's i had for a short time.  You can see how sloppy the glue work was. I had areas that had no glue at all on them and apparently that was ok with QC.  

 

These are from the CF-3's as the front baffles on the CF's come off by removing the female grill plugs on the front baffles and removing the Phillips screws. Makes it simple.  

 

 

 

 

 

IMG_3728_copy_768x1024.jpg

 

I like the added corners ---and screws

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3 minutes ago, RandyH000 said:

I like the added corners ---and screws

 

Yeah, all they originally have is just a small channel they sit into which might have been 3/8" or so.  I miss those speakers.

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      I've fixed dozens of Klipsch speakers with glue issues from KLFs & Epics to KG 3.5 & 4.5s. Each and every time all I did was remove all the drivers, crossovers & wiring, dampening material and binding post plate. Then used a rubber mallet on the inside of the enclosure to loosen and remove the rattling culprit.

       Once the rattling board is removed you take a 1/2" wood chisel or similar and proceed to remove all the old glue from the board you removed and from the enclosure. It comes out fairly easy and shouldn't take more than an hour to do both speakers.

      After the glue has been removed is a perfect time to add any internal bracing for your cabinets to stiffen up any unwanted resonance or dampening material like Dynamat for your horns and woofer baskets to combat the same unwanted resonance if your so inclined.

        Next step is to reglue the rattling piece that was removed. I always used liquid nail and never had any issues. I tend to use a bit more than less when applying my bead of liquid nail around the perimeter of the enclosure. Around the size of a #2 pencil will suffice but lean towards using more rather than less. The fit of the removed board was always snug and didn't leave more than a 16th of an inch on any side which didn't allow any of the liquid nail to squeeze out and mess up the outside look of the cabinet. Any excess of glue will squeeze out inside the box, you can either leave it the way it is and let it dry or you can put on some disposable gloves or whatever you choose to use and wipe down the bead of adhesive that was squeezed out of the channel after attaching the removed piece. I personally let the adhesive dry wherever it ended up.

       After letting the adhesive set for the recommended time, 60 min if you decide to use the proper liquid nail variety, finish reassembling your speakers. Don't forget your dampening material and speaker polarities when hooking things back up.

 

      All in all it really is quite simple to do with about 25 dollars worth of tools from harbor freight and some liquid nail from your favorite hardware store.

   Phillips screwdriver ( to remove drivers ect.)

   Rubber mallet 

   Wood chisel

   Caulking gun

   Tube of liquid nail 

 

I hope this helps someone in the future fix some great sounding Klipsch  speakers.

 

 

 

 

 

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Thanks to all for suggestions and photos. 
At the moment I’m in no rush to repair these.

 I still have @avguytx 3’s. 
My main concern either leaving all intact, just adding glue than knocking the panel out. 
With examining pics of just how little glue these left the factory, not too worried now. Didn’t know what can of worms I’d open. Bits and pieces of back and sides stuck together here and there.
I think I will add the extra Oak reinforcement and screws. 
Excellent to know the front baffles are removable as well. 
 

BE017075-8F56-4970-BF10-6DE31519AAAE.jpeg

153A370A-624F-4BE6-ADF9-9C291FB399F5.jpeg

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Ok, so finally got a little spare time. Someone has been in these before. Wires are labeled. And some type of dampening material throughout the box. What is this stuff? And the glue there now look redone at some point?
I put blue painters tape around the back, pushed into the seam a bit, just in case the Gorilla Wood Glue tries to seep through. 
One top, from a corner, to maybe half way down same side all that was loose. That’s the area I focused on now. Will see how it holds.
Found the 12” driver mounting screws loose as well.

 I don’t like skimping, but I’ve too many irons in the fire atm.


 

F7AE9E36-1D48-4AB6-A576-66C86B8E3066.jpeg

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1 hour ago, hogwylde09 said:

Ok, so finally got a little spare time. Someone has been in these before. Wires are labeled. And some type of dampening material throughout the box. What is this stuff? And the glue there now look redone at some point?
I put blue painters tape around the back, pushed into the seam a bit, just in case the Gorilla Wood Glue tries to seep through. 
One top, from a corner, to maybe half way down same side all that was loose. That’s the area I focused on now. Will see how it holds.
Found the 12” driver mounting screws loose as well.

 I don’t like skimping, but I’ve too many irons in the fire atm.


 

F7AE9E36-1D48-4AB6-A576-66C86B8E3066.jpeg

That is a sound dampening material similar to Dynamat. 

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