Issues with klf 20

[CMG]

I am looking at a set of klf 20s and read that some of them have back delaminating issues. What years had this issue? How can i read the serial number to figure this out? Are there any other known issues i would need to know about before looking at these speakers? I am really excited that i get to finally see one of these speakers in person.

[Brac]

you don't need dates or numbers, just take your hand and strike the box on each side, front, and back if they have delam'd you will hear a difference. If it feels and sounds solid on all sides your good to go.

[Marvel]

I am looking at a set of klf 20s and read that some of them have back delaminating issues.

I think delaminating is the wrong term. The problem is the glue joints between the backs and sides and the front baffle and sides. Even if they are coming loose, it would not be too difficult to repair. However, they won't sound quite right until they are fixed, so you would be buying without knowing for sure how they are supposed to sound. If the price is right and they otherwise look good, i.e., no gouges in the finish, water stains, etc., I would probably pick them up.

Bruce

[moray james]

the problem was one of defective aadhesive used to bond only the front and rear baffles. The baffles are laminated with a nice textured black Melamine finish. The adhesive used is a hot melt adhesive which was designed to bond to the Melamine. The ashesive maker had problems Klipsch had to sue them in the end. The real problem is that just about nothing bonds well to Melamine though some things can stick pretty well like the hotmelt that was custome designed to do so. Please dont think that you can go to the hardware store and buy some hot melt that will stick you can' and it won't. I cannot point you to one single adhesive which has been used by owners or which is on the market which is intended for use on Melamine. So the simple way to deal with this is just remove the baffles clean off all the hot melt (scrape with a sharpe edge) and then uses a Dremel tool (I used the drum sander attachment) and sand off the Melamine wherever there will be a glue joint. The laminate of Melamine is very thin and sands off easily and is fairly short order. Then you can re assemble with carpenters yellow or white glue and be 100% assured that the glue joint will be stronger than the wood. This sounds like a PITA but it is not bad and it is a lot better than using some or any adhesive which is not designed to bond Melamine and then having it fail and having to clean up that mess.

I am sure that you will hear stories of how I did this and I used this and mine are ok. So if you want to believe that then that's up to you but if you want a true 100% fix then you can either do what I have done on two sets of KLF or you can actually try and find an adhesive which is designed as a structural adhesive to be used on Melamine which I can say will be just about impossible for you to find. Please don't tell me about some glue youu found if it is not specified as a structural adhesive on Melamine. White glue and yellow glue will (if you remove the Melamine) provide a fast easy and structural joint that will last longer than you will.

If you think that you have found a suitable adhesive or if someone convinces you that such and such a glue is is fine for the job I would strongly suggest that you test that adhesive on Melamine laminats as close to those used on the KLF baffles. Test them Melamine to Melamine and follow the directions and then see how they hold up. If you by chance happen to find some adhesive that is structural to Melamine and does not cost an arm and a leg and is not highly tocix to use please post about it. As for everything else that I have found on line regarding this issue I have only found patches and what I did is a 100% fix. I have no interests in patches just fixes. I hope this helps and I hope it makes sense. Best regards Moray James.

[superedge88]

the problem was one of defective aadhesive used to bond only the front and rear baffles. The baffles are laminated with a nice textured black Melamine finish. The adhesive used is a hot melt adhesive which was designed to bond to the Melamine. The ashesive maker had problems Klipsch had to sue them in the end. The real problem is that just about nothing bonds well to Melamine though some things can stick pretty well like the hotmelt that was custome designed to do so. Please dont think that you can go to the hardware store and buy some hot melt that will stick you can' and it won't. I cannot point you to one single adhesive which has been used by owners or which is on the market which is intended for use on Melamine. So the simple way to deal with this is just remove the baffles clean off all the hot melt (scrape with a sharpe edge) and then uses a Dremel tool (I used the drum sander attachment) and sand off the Melamine wherever there will be a glue joint. The laminate of Melamine is very thin and sands off easily and is fairly short order. Then you can re assemble with carpenters yellow or white glue and be 100% assured that the glue joint will be stronger than the wood. This sounds like a PITA but it is not bad and it is a lot better than using some or any adhesive which is not designed to bond Melamine and then having it fail and having to clean up that mess.

I am sure that you will hear stories of how I did this and I used this and mine are ok. So if you want to believe that then that's up to you but if you want a true 100% fix then you can either do what I have done on two sets of KLF or you can actually try and find an adhesive which is designed as a structural adhesive to be used on Melamine which I can say will be just about impossible for you to find. Please don't tell me about some glue youu found if it is not specified as a structural adhesive on Melamine. White glue and yellow glue will (if you remove the Melamine) provide a fast easy and structural joint that will last longer than you will.

If you think that you have found a suitable adhesive or if someone convinces you that such and such a glue is is fine for the job I would strongly suggest that you test that adhesive on Melamine laminats as close to those used on the KLF baffles. Test them Melamine to Melamine and follow the directions and then see how they hold up. If you by chance happen to find some adhesive that is structural to Melamine and does not cost an arm and a leg and is not highly tocix to use please post about it. As for everything else that I have found on line regarding this issue I have only found patches and what I did is a 100% fix. I have no interests in patches just fixes. I hope this helps and I hope it makes sense. Best regards Moray James.

When I owned klf-30's I used pl premium gooped into the interior corners where it was coming undone. It seemed to work great. I just did a Google search for "pl premium melamine" and found many links to wood workers and cabinet makers saying that PL Premium works great for bonding melamine. On an unrelated note, over the last couple of years I have been using pl premium for many odd jobs, even patching a leaking gas tank on my van and it has yet to have a bonding failure. A truly amazing adhesive!

[moray james]

RECOMMENDED FOR:

Bonds
most common construction materials such as wood, hardwood flooring,
concrete, stone, marble, slate, masonry, brick, foam insulation,
carpets, metal, cement-based products, ceramic, fiberglass, drywall and
mirrors

NOT RECOMMENDED FOR:

Polystyrene
Tub Surrounds; Water submersion applications; Polystyrene, polyethylene
or polypropylene; Certain materials such as rubbers and plastics may
have bonding difficulties. Test compatibility before use.

As you can see all the materials for which PL is recommended for are porus and those for which it is not recomended are mostly non porus and and or plastic of one type or another . If you want to obtain a data sheet ftom LePages go ahead. I am not saying that some of the fixes that have been used by members don't workbe cause some of them have worked. I am saying that Melamine is a very difficult material to bond to so difficult that I was not able to find a single adhesive which was designed to bond Melamine surfaces and which is considered structural. What you will find is that with materials such as Melamine that adhesives are custom made in comercial quantities just like Klipsch had a specialty adhesive manufacturer make up a special hot melt adhesive for them. Commercially available products are designed for general wide spectrum applications. Materials like Melamine require specific adhesive designs and those are most often developed by the people who manufacture the Melamine itself.

If you sand off the Melamine and clean off all the old adhesive then your baffles can be installed with a clean wood to wood surface and be structurally bonded with PVA adhesive white or yellow to form a joint stronger than the wood itself. No guessing no wondering non toxic fast and you can clean up with a damp rag. If you use a commercial sticky product will it stick - yes - will it stick well - maybe most won't , will it be structural and can you be 100% sure it will work - no. The first three materials listed in the NOT RECOMMENDED list (provided by the manufacturer) above are Polystyrene, Polyethylene and Polypropylene. These plastics are all very difficult materials to bond to and Melamine is much more difficult to bond to than any of these.You can want the easy way out all you like but if the adhesive that you buy does not work in your applicationn then the clean up job and the second go round make doing it as I have suggested look like a cake walk. Best regards Moray James.

If any of the readers here find an adhesive product which is safe to ues is inexpensive and structural for uses with Melamine and they want to post a data sheet (not a retail recommended uses list) I would be delighted to take a look.

[CMG]

I went and looked at the KLF 20s today. They are black finish with a few dings and dents. The sides have a few marks were the black finish has rubbed off. The grills looked to be in good shape with all posts intact. They are asking $500 but she said that they are motivated to sell. I did knock on the sides and back to see if it was solid and everything seemed ok. The seller gave me a few funny looks while i was rapping on it to see if it was solid or coming apart. I was able to remove or adjust all the rear baffles. $500 seems a little steep for these but maybe they would be worth it if i was able to refinish them. Also she assured me that the drivers worked before they aquired the speakers.

[moray james]

Seems a reasonable price if you can obtain a discount on this amount you should be doing well. The only real waythat you are going to determine the condition of the baffles is to pull the drivers and use a rubber mallet around the inside of both the front and back baffles. If there are loose spots you will hear it when you wrap on them with the mallet. Very good drivers but the stock K79 needs to have the stock poly diaphragms replaced with Bob's Titanium units, and I have changed both of my sets from phenolic mid diaphragms to Titanium as well. Great horns nice size box. I prefer these to either the Forte or the Forte ll. Best regards Moray James.