JBL Horn Refinishing Advice

[dooey263]

Hi Y'all

I have been searching for info to enable me to strip, and repaint, a pair of 2350's. Tried the search, with various queries and different search titles, without luck. There's probably a megapost on this subject, that I am just not quite bright enough to uncover..... but I digress...

The pair of 2350's I have, have seen better days. A combination of chipped paint, and white overspray, has made them a little ugly. I want to strip them to bare metal, and maybe powdercoat them black, to match the black 4560 cabs they will sit on.

Now, I'm not really sure if they are some sort of white metal, or aluminum, and i don't think regular grit blasting would be too kind to them. I would prefer to blast, because of the relative ease. Chemical stripping would be an alternative, I suppose, but that damping spray on them may be a pain.

I also would like to do the same with a pair of 2440 drivers. They sat in someones garage in flight cases for 20 years, the aluminum(?) slowly oxidizing and flaking away the paint. Same with the 2395 slant fronts they were attached to... Quite a shame. I don't imagine that textured JBL paint job they had originally can be replicated.... Or can it?

Does anyone have any experience with this they could relate, or could you kindly direct me to any threads on this subject that I am unable to find?

Any help with this is mucho appreciated.

Cheers..... Scott

[Mr. Widget]

I have no experience with these horns, but from reading the catalog info, it appears that JBL sprayed a damping compound on these cast aluminum horns. I would assume then that your plan to strip and repaint these horns while likely would result in a better looking horn, they probably wouldn't sound the same.


Widget

[grumpy]

I'd suggest just cleaning up the fronts and boxing them up with top/bottom
panels that come out to meet the horn 'lips'. You'll 'ruin' the horns in taking off
the damping material.

A nice, even, unit-to-unit-consistent 'krinkle' finish is touch to achieve, even
with the normally available black paint, then painting over with a "JBL gray".
I recall someone here giving their advice regarding holding a temperature
range and perhaps undercoat to to a reasonable job with this type of paint...

[loach71]

I had the same problem with six 2350 aluminum horns. I went the sandblast route -- medium sand to take the horns down to white metal, then fine sand to remove the pitting left by the medium sand. Once the aluminum is sand basted, it is quite reactive to moisture in the air, so you must be able to recoat / paint the horns immediately after the sandblasting.

1) Make sure you air supply for painting / coating is filtered and moisture trapped. Any auto painters supply company can provide the necessary filters and traps for your air compressor. Cost is less than $100 for the necessary filters, traps and fittings. This will make your compressor setup friendly for the application of fine finishes to wood projects!

2) Purchase a "schutz gun" used for applying automotive undercoating. Purchase 4 large size cans (not spray cans) of automotive Rock Guard. This will be sprayed on the outside of the horns / throat adapters in THREE COATS. (some of my friends use 5 coats on their 2345 horns)

3) After the Rock Guard is dry, then spray on a good metal primer (2 coats should suffice) and then 2 coats of the color paint. Make sure the primer and paint are dry before applying the next coat. I primed and painted the Rock Guard so that the horns are the same color on all surfaces.

[dooey263]

Fantastic thread of your doin's Tim... and Thanx all for the sound advice. I did plan to put some damping material back on the horns.

I think your instructions are spot on, and may even be simple enough for me to follow. I will give it a try. Since the horns were also covered with many coats of white paint, I wasn't sure if the grey was over the damping or not, but if you say I can paint over it, that would be the way to go.

Cheers.... Scott

[loach71]

:applaud:Make sure the drivers are removed from the horns! :applaud:and safely stored away from the sandblast locale. You can use the coarse / medium sandblasting to remove all the Aquaplas damping material AND to remove the the dings and scuffs on the horn and throat adapter. I chose to remove the Aquaplas and replace it with three coats of ROCK GUARD. This stuff damps the horn more effectively than Aquaplas...

Make sure you sandblast right down the throat -- this will remove most if not all of the casting blibs and blobs, making a much smoother horn. (we are perfectionists here!).

When sandblasting ENSURE you wear a respirator mask under the MANDATORY blaster's hood, along with earplugs! (deaf audiophile -- what a pity!) During the blasting, ABSOLUTELY ENSURE that you constantly keep the blasting wand IN MOTION at all times. Leaving the wand still while sandblasting will ruin your horn.

DO NOT APPLY the ROCK GUARD on the inside of the horn -- it will change the internal dimensions and could negatively impact the response of the horn!

I hope these hints help!:)

[Earl K]

Hi,


,,,,,,,,snip,,,,,,I chose to remove the Aquaplas and replace it with three coats of ROCK GUARD.,,,,,,,,snip

Do you mean this ?

http://3mcollision.com/media/catalog/product/cache/1/image/300x/9df78eab33525d08d6e5fb8d27136e95/m/m/mmm05911-1.jpg (http://3mcollision.com/3m-rocker-panel-spray-clear-05911.html)

Or some other auto product ?


Here in Canada, ( fyi ) the following is easily obtainable.
- Canadian Tire ; "Rocker Guard" (http://www.canadiantire.ca/AST/browse/4/Auto/AutoBodyRepair1/AutoBodyPaintProtectants/PRD~0477935P/Black%2BRocker%2BGuard.jsp?icid=EnjoyTheDrive_Wint er_Driving_WeatherManagement_Guard_477935_FR)
- ( I use it after first applying a primer coat > ( on cars ) > it's paintable, once applied ).


<> cheers

[loach71]

Hi,



Do you mean this ?

http://3mcollision.com/media/catalog/product/cache/1/image/300x/9df78eab33525d08d6e5fb8d27136e95/m/m/mmm05911-1.jpg (http://3mcollision.com/3m-rocker-panel-spray-clear-05911.html)

Or some other auto product ?


Here in Canada, ( fyi ) the following is easily obtainable.
- Canadian Tire ; "Rocker Guard" (http://www.canadiantire.ca/AST/browse/4/Auto/AutoBodyRepair1/AutoBodyPaintProtectants/PRD%7E0477935P/Black%2BRocker%2BGuard.jsp?icid=EnjoyTheDrive_Wint er_Driving_WeatherManagement_Guard_477935_FR)
- ( I use it after first applying a primer coat > ( on cars ) > it's paintable, once applied ).


<> cheers

NAPA Auto Parts offers Rock Guard. In Canada, you'd be looking for Body Pro Gravel Guard in 850 mL (non-aerosol) cans. These cans screw directly on to a "Schutz Gun". The aerosol can stuff you describe is too thin to offer good dampening. Body Pro Gravel Guard is extremely thick -- it resembles tar, hence the requisite use of a Schutz Gun in its application. The Body Pro Gravel Guard dries well and forms a flexible, paintable surface that damps as well or better than the old Aquaplas. The trick is to apply thin coats, allowing the Body Pro Gravel Guard to dry completely between applications.

[Earl K]

Hi,

Thanks for the info about "BodyPro" Gravel Guard ( that greatly helps narrow down the search ) .

We have NAPA up here in Canada, though I had to give up trying to zero in on the product due to their sites' ( persnickety & feeble ) search engine .

Apparently, "BodyPro" is Napas' in-house brand of generic auto-body products .



http://partimages2.genpt.com/partimages/428336.jpg (http://www.napacanada.com/en/PartsAccessories/PartsSearch/SearchByKeyword.aspx#Detail)

FWIW, Napa also sell a "Gravel Guard" product made by http://www.dominionsureseal.com/images/newt-1.gif (http://www.dominionsureseal.com/default.asp)



http://www.dominionsureseal.com/pictures/picR24.jpg (http://www.dominionsureseal.com/Products.asp?catid=31&page=1)

- Dominion Sure Seal makes their Gravel Guard, in ( types ) 1, 2 & 3 .

- It seems the difference may just be in the color .

http://www.dominionsureseal.com/pictures/bvg1,%20svg124.JPGhttp://www.dominionsureseal.com/pictures/bvg2,%20svg2.JPGhttp://www.dominionsureseal.com/pictures/bvg3,%20svg324.JPGhttp://www.dominionsureseal.com/pictures/Bupa.jpghttp://www.dominionsureseal.com/pictures/prodpicb127.gif

<. cheers

[loach71]

Be sure to get the thick, syrupy stuff that requires a Schutz Gun to apply. Its spray vehicle is lacquer thinner, so be sure to work in a well ventilated area AND wear a chemical respirator. The thin stuff in the aerosol can simply won't do the damping job properly.