"DIY-esque" question: refinishing cast aluminum horns?

mhardy6647

The hardest thing about this post is figuring out in which forum to put it!

I have found the treble horns of my (affordable) dreams: the 2" throat Emilar EH500-2.
I have managed to acquire a pair of them, but both of the ones that are now mine (bwahahahahah! mine, all mine!! ) are suffereing from pretty serious loss of paint.

The horns are cast aluminum & appear to have been unprimed. The satin black pain that's on them is not well adhered.

DSC_7249 (2) by Mark Hardy, on Flickr

My question: is there a straightforward DIY way to repaint them (or touch them up).
They don't have to be perfect but it would be nice if they were all black.

The "phase 2" question is: is there a reasonably cost-effective but really "proper" way to have them refinished? I am guessing sandblasting or bead blasting or suchlike would be part of the process(?).

Thanks for any and all suggestions.

PS: FWIW, this is what a "picture perfect", pretty EH500-2 looks like

DSC_6840 by Mark Hardy, on Flickr

xschop

You can use methylene chloride to easily remove paint. Wash with water, let thoroughly dry. Auto primer then repaint.

littlewoodboats

I would avoid sandblasting cast aluminum. Not all cast aluminum is created equally so blast with caution. If I did them I would soda blast.

For outboard and outdrive lower units we used a zinc chromate primer on the fully prepped surface followed by a color matching paint.

We can get into the prep work if you are interested

pitdogg2

There is also stuff that folks use on firearms that you spray on and then bake that is tougher than nails.

mhardy6647

all helpful suggestions, thanks.
Keep 'em coming.

BlueMDPicker

My vote: find some good touch-up and leave the original patina in place.

PS - hope you really get them singing the way you desire, Doc.

mhardy6647

BlueMDPicker wrote: »

My vote: find some good touch-up and leave the original patina in place.

PS - hope you really get them singing the way you desire, Doc.

I am tempted to do that -- but that probably goes without saying, as I am one lazy m-o-f-o.

I am -- not displeased -- with the way things are sounding.

mrbiron

Good luck finding black paint to touch them up.
Maybe rub a charcoal briquette on them...?

mhardy6647

Oh, darn -- you're right!
Now I need black paint!!

No worries, I'll start another thread -- I'm sure someone here knows where to get it.

.., and, come to think of it, I did just buy some more charcoal.

mrbiron

You could try this Wiki...
Chemists may understand all the lingo but simple minds, such as myself, struggled to understand the compositions.

http://www.wikihow.com/Make-Black

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mhardy6647

Yep2 wrote: »

If there is a powder coat shop close enough, you might give them a call.
That would be a beautiful, durable finish that will last.
Not sure of costs for that?
I refinish firearms for a living & can
say the Cerakote & Duracoat finishes I apply are not cheap by any stretch.

Media blasting should not be a problem with any aluminum, provided you use higher grit AO.
I use 120 grit or higher on aluminium all the time (AO media is not cheap either).

The closest thing to me are trees, mountains, dairy cattle and bears.
... although "firearms" business are big up this a way (Ruger, e.g., has a big facility not too far from us)... so... maybe.

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westmassguy

As long as the horns can be safely removed from the compression driver, use a quality paint stripper, wash them thoroughly (a fine grade Scotch Brite pad will help), apply Krylon etching primer, followed by Krylon topcoat of your choice.

mhardy6647

Drivers are readily removable (I've been swapping between 1" Altecs with adaptors & 2" JBLs).

Any stripper in particular?
I'm out of my depth here (thus the thread!).

Thanks.

xschop

IF my memory is not on vacation, it was a rattle can of "Aircraft Paint Remover" that I used on some aluminum trailing arms. I picked it up at AutoZone.

mrbiron

mhardy6647 wrote: »

Any stripper in particular?
I'm out of my depth here (thus the thread!).

Seriously! You've hit a pop fly with this comment. Talk about a setup

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mhardy6647

whoa -- vintage strippers!
Too good to be true.

befuddle

I would go with the paint stripper route,being aware to protect against getting it on anything plastic or rubber [if that applies here]2-3 coats may be required removing with the scotch bright pad followed by a good cleaning to remove all residue prior to paint,As for paint P.O.R Chassis black has a black satin look to it that looks similar to your picture and can be brushed or sprayed,However I dont know if its available in anything smaller than quarts.Aside from that perhaps you can bring the horn to a paint supplier and they may be able to mix to match the original finish

tonyp063

mhardy6647 wrote: »

whoa -- vintage strippers!
Too good to be true.

Blaze Starr

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littlewoodboats

mhardy6647 wrote: »

whoa -- vintage strippers!
Too good to be true.

I remember dad using the Red Devil. Shite would put a hole in your ozone if not done in a well ventilated area.

mhardy6647

tonyp063 wrote: »

mhardy6647 wrote: »

whoa -- vintage strippers!
Too good to be true.

Blaze Starr

Baltimore's own.