Bottlehead Forum
General Category => General Discussion => Topic started by: Dr. Toobz on April 23, 2010, 10:49:44 AM
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My "crack" is waiting on my doorstep for when I come home from work, and I'm eager to start building it. However, it will be used next to an iMac, so I'm debating whether to just go ahead and build it, leaving the plate "silver," or to paint it like my other projects and wait a day to build it. How does the untreated plate actually hold up to fingers and dust and the like? My other BH gear was spray-painted with Krylon gloss black, which doesn't seem all that durable itself (i.e., easily shows dust swirls, etc).
To paint or not to paint? That is the question. Anybody else have "untreated" chassis plates?
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My two cents...
I put a very nice, hard and durable finish on the top plate for my s.e.x. amp, but it was not the kind you can do in a day...
I first cleaned the plate and transformer bell thoroughly and then scuffed them up with some 120 grit sandpaper, and then wiped them down again completely with 100% ethyl alcohol.
I then applied 3 thin coats of SEM self-etching metal primer with about 5 minutes between coats and then let the plate and transformer bell dry for about 2 hours before applying the first coats of finish coat.
For the first round I applied about 6 or 7 coats of Hammerite Rust cap hammered black at 15-20 minute intervals (on a warm, dry day) and then let the plate and transformer bell both "cook" on the radiator in my office for several weeks -- hammerite recommends something like 10 days to 2 weeks between coats if they are allowed to dry more than, I think, 90 minutes.
Then I again cleaned the surfaces with a citrus cleaner followed by 100% ethyl alcohol and applied another 6 or 7 coats to the top plate and another 3 or 4 to the bell, and again let them dry and harden on the radiator.
When all was done the finish was very smooth and even and extremely hard.
Of course the application schedule will vary somewhat according to the manufacturer's recommendations, as well as the final drying time, but typically the longer you can let it sit and harden, the toucher the finish will be.
I will offer that I started just building up the kit on the bare aluminum plate and eventually decided to put the extra effort into putting a nice finish on it, so stripped the whole chassis down to the bare plate and started over. Yes, it was a pain, but worth it, and something that I actually enjoyed doing.
Still not sure what I'm going to do with the Crack as I might decide to eventually build it in another scratch-built chassis as it appears that I may not be able to fit a better tkd volume pot in this one. Then I can also use the stock chassis for experiments with different driver tubes, etc. Worse comes to worse, I can always do what I did with the s.e.x, and strip the whole thing down and finish the top plate and spruce up the base a bit.
HTH,
Jim
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Very impressive! I guess my concern is that if I decide to just build on the bare plate and change my mind later, getting the thing apart without destroying it (or various components) might be difficult. So, it's one of those things I have to try to decide on now, before I get out the soldering station and give in to the urge to build. It's so tempting to just rip open the box and start soldering away, but I may regret it later....
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By far the hardest thing to remove is the IEC inlet/fuse holder. I eventually found that a small, smooth face, clamp mount vise was the best tool. I just clamped the iec inlet about 3/16" below the plate on the spring tabs, and that was enough to be able to push the plate down and get it started, then after taking the whole thing out of the vise, some gentle prying with a pair of flat tip screwdrivers easily freed the piece.
The switch was along the same lines, but the springs could be done (gingerly) with some slip-joint pliers to get it started, and then it was very easy to pull it the rest of the way out by hand.
BTW, the hot sun also works wonders for baking out the paint, but when I do that I cover the plate with an inverted baking pan or put it in a cardboard box so the UV doesn't prematurely fade the paint. It's probably more of a concern here at 5300 feet elevation though.
-- Jim
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I would certainly paint the plate, and especially the transformer cover. I like the textured black paint you can get in a spray can. Two hours in a 160 degree oven and you should be good to go.
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Paul,
Any advise on already assembled end bells?
Thanks,
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Sand or wire brush off any rust you have, then apply bluing solution, then mask off the top of the transformer and spray a clear layer over.
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I'm a little late on this, but I left my sex amp nude, if yoou will, and it looks the same as the day I built it four years ago. maybe a little dusty. I did end up treating the xmer bell, but I did it in place and that was fine.
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Paul,
Thanks. That is easy enough but what is and were do I get bluing solution?
Getting back to the initial question, I have the stock, untouched brushed aluminum top plates on 3 of my pieces. They accumulate dust and fingerprints. No one dusts them by my order. So I clean the tops with Windex about once a year. I dust them more often but the plates stay clean if you are not fingering them all the time.
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I thought the Crack came with an acrylic top of various colors. Am I mistaken? The Crack is what the OP mentioned, and painting this would be different from a metal top plate.
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The only acrylic top is the Quickie.
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Thanks. That is easy enough but what is and were do I get bluing solution?
http://www.pyramydair.com/s/a/Birchwood_Casey_Perma_Blue_Liquid_Gun_Blue_3_oz/2694 (http://www.pyramydair.com/s/a/Birchwood_Casey_Perma_Blue_Liquid_Gun_Blue_3_oz/2694)
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Thanks Paul!
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The only acrylic top is the Quickie.
You are correct. Got the two mixed up.
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Well, I ended up going for the naked look rather than painting. I turned out to like the texture of the bare aluminum, and the color is similar to the iMac it sits next to, giving me the "industrial" look I wanted anyway. With a dark red mahogany-stained base, it looks really sharp! I'll post photos tomorrow, after I complete the poly finish.
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Will you coat the bell too? I electroplated mine several years after building it and I liked the result. Here's a link from the old forum:
http://db.audioasylum.com/cgi/m.mpl?forum=bottlehead&n=136967&highlight=electroplating+tbbenton&r= (http://db.audioasylum.com/cgi/m.mpl?forum=bottlehead&n=136967&highlight=electroplating+tbbenton&r=)
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I polished up the bell a bit with the intention of blueing it and the screws when I have time to visit a gun store or somewhere that carries the solution. I wonder if Wal-Mart or hardware stores might?
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Yeah Wally World, Big5, etc. carry Birchwood Casey bluing. If you find it get the Super Blue version. It's mo' betta than the regular stuff. And shoot a really good coat of clear over it to preserve it, as the blued steel will rust with time.
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I started down that path before I settled on plating. My local hardware store didn't carry it. Then I looked online. There are so many different types of bluing, I finally decided it was impractical to do it "right" (hot process) myself -- thus the plating.
I look forward to photos when you done.