It all depends on what your stripping.Thick aluminum castings, it isn't going to hurt.When your applying a new coat of something especially (paint) you want the surface microscopically rough for the coating to adhere to prevent the paint from peeling or flaking.It will give it a long lasting durable finish.Originally Posted by Audio_by_Goodwill
Yeah paint adhesion is typically the argument I hear for a more aggressive media. However, in many cases adhesion was never an issue, but rather removing glopped on layers of someone else's choice in color. In stripping a soft metal like aluminum, I'd rather use the less aggressive media. The case of a vintage horn, even more so, because I wouldn't want to alter the original surface.
Audio_by_Goodwill
Michigan, USA
I stripped many things from engine manifolds to horns and assure you... It's Not A Problem !
It has more to do with the amount of pressure (psi) you are using with the abrasive (Glass Bead).You only use just enough pressure to remove what you need. My advice to him was for something he is more likely to find...In my area I don't know anyone who uses Walnut Shells.But there are quite a few that use Glass Beads. To each his own...
Perhaps we could do a movie of that horn's life titled "Single white 329"
Your neighbors called. They like your music.
WTF is the deal with log-in timing out before i can finish typing a 500 word post?
Aluminum requires the proper primer, generally "self-etching". If you can find the 2 part stuff, you hit paydirt. But don't breathe the overspray from yellow part as it has a fairly nasty acid in it.
I used to supervise/coordinate a job that involved painting aluminum cast for the military. Abrading anything other than flash lines was strictly forbidden.
Now with that said, whether or not you break the surface "skin" with abrasives is probably a lot less critical with an acoustic waveguide than it is with high performance aircraft parts. Personally, i'd go with walnut shell or plastic media first for blasting old paint off. But, i might still opt for a light blast with a "sharp" abrasive depending on how the surface looks/feels, especially with die cast aluminum that tends to form a very glassy skin.
Not all vegetables make good leaders.
I disagree ... I have come across a lot of old Horns (Especially Multicells) with flaking paint with just the original coat.I'll show you one right here.In fact my Tar-Filled 1005's have their original coat that is flaking badly and is in need of a new finish which I plan on doing this summer. By Glass Bead.
Don't know Bowtie ! There are a lot of things with this software that leave a lot to be desired.
I like glass bead on most kinds of aluminum, i run it in my blast cabinet a lot as it's easy to control and not go deep into the aluminum's grain. I've also found that with fresh bead and lower pressure you can leave a surface that is much akin to a shot peened steel surface........need of a new finish which I plan on doing this summer. By Glass Bead.
Not all vegetables make good leaders.
Thanks for all your input. Still can't believe I won that auction. As for now I think I will be happy just to bolt on a 288c and give a side by side listen with a 311-90. I have one set of A-7' cabs close to being restored. The test A-7's I will use this weekend were used by a band and the port has been modified. I will run the 515's in the cabs. The throat adapter was removed for shipping, I didn't see a gasket, I assume I'll need to make one. This is going to be a fun project.
Those aren't cast horns, Though. They were made with sheet that was probably oiled while in the role. That oil may not have been removed before paint was applied.
Audio_by_Goodwill
Michigan, USA
I beg to differ AbG. See here......http://www.google.com/url?sa=t&rct=j...H7BxUw&cad=rja
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