Removing and refinishing bell ends

[crackaddict]

Hi,

I'm working on a Steremour and Crack in parallel (waiting for my Reduction). I decided I like the natural look of the bell ends (after having a not-so-beautifu end result with a black bell end on my first Crack). So I applied Rustoleum satin clearcoat. That was just so matte, that I applied semi-gloss afterwards. All in all I have quite a few thin coats (maybe 6-7). When I tightened things down, the clearcoat crinkled and separated in the area around each screw head. So I need to redo things.

I've started soldering both kits already, so I need to remove the bell ends. Any advice on how to do that?

Then once I get them off, can I just sand or steel wool  the clearcoat off, or do I need to get these things sandblasted? I'm worried the amount of sanding required could scar the surface to such an extent that the gun blueing I'd like to do will still show the scars...

Thanks,
Derek

[Grainger49]

Strip off all the previous paint.  There are strippers that will brush on and crinkle the finish.  Then you can rinse it all off.

Degrease the end bells with something like mineral spirits or alcohol.  Then spray.  I put my Eros end bell and top plate in the oven at 120 degrees for half an hour to bake the carrier out.  But my wife wasn't home and I got the odor out of the house before she came home.

Good luck, post pictures when you are through!

[Paul Birkeland]

Don't remove the covers.

Cut a rectangular hole in a piece of cardboard and slide it over the transformer.  Gently sand away any loose clear coat, then just spray over the cardboard/metal to restore your clear coat.  This will also lock the screws in place.

-PB

[JamieMcC]

I agree with Paul and would be tempted to place the whole amp inside a bin liner, cutting a hole for the transformer to poke through use some masking tape to tape down the cut liner around the transformer onto the top plate or transformer. Then sand away, a dremel with sanding disks followed by a scotch brite pad would make light work of getting back to bare metal and prepping for the next finish. The bin liner would keep the amp safe from any sanding or paint contamination.

[crackaddict]

Grainger49 -- what do you mean "bake the carrier out"?

PB & JamieMcC -- I'm not so far into the projects yet, so maybe I'll just take a chance taking them apart. If that looks no good, I'll try your methods.

I've seen all kinds of threads on the location of lock washers to ground the top plate. The Steremour has four lock washers under the bell end, whereas the Crack has only one, above the bell end. What's the reason for the different approach? I'd like to do all of my amps (Steremour, Crack, Reduction) the same way for consistency.

Thanks!
Derek

[fullheadofnothing]

The Crack has lockwashers under the bell end (third picture, page 14). They are there on all Bottlehead products.

[Grainger49]

Carrier is the part of the paint that evaporates when the paint dries and hardens.

[crackaddict]

Ok. I got some spray-on paint remover. Will try it, and will cure my new finish in the oven before bearing down on it. Who knew...?

Thanks!
Derek

[Grainger49]

Keep the temperature low.  Our oven will set as low as 100 degrees.  I used 120 degrees F.

I'm assuming you have already removed the end bells.  You don't want to bake the Crack or even just the transformer.

[crackaddict]

Hi,

Yes, I got the bell ends off. The stripper worked well, though it seemed to stain a bit, so I sanded with 600 grit wet/dry sandpaper, then hit it with 0000 steel wool. Now I just need to find some gun blue (my local Ace was out of stock) and give it a few coats (will read the instructions to figure out how many), and give it some of the satin acrylic I saw Doc mention (mine is Rustoleum Painter's Touch), then bake it per your instructions.

If any of that sounds off, let me know. Otherwise that's my plan for the weekend!

Thanks,
Derek

[JamieMcC]

If you had a hot torch or gas hob and some engine oil to hand you could try oil bluing looks like fun I doubt the bell ends would take much heating to blue. 

[hardisondan]

I couldn't get any thread to turn the nut on with the lock washer in place because the screw just was a tad too short, so I left it out. I assumed it was just for friction/secure connection.

Now I've read the post: "ground" screw with lock washer?   Another thing to keep me awake at night! 

If it's there for a safety reason I think it would be good to highlight that in the Crack manual. I would have taken it a lot more seriously.

[Doc B.]

There's pretty much a reason for all the parts that are in the kit. There's also an unfortunate minor tolerance variation in a lot of reasonably priced machine screws these days, and that is probably the reason for the thread being tough to engage. Sometimes it takes a little fussing with the stack of parts to get just enough thread visible to grab the nut.

[hardisondan]

Understand every part is important. But maybe a nice warning in red about electrocution risk might be in order. Just a suggestion.

I think I had too many coats of paint on my chassis plate   

Cheers

[Doc B.]

I appreciate the suggestion and we'll certainly take it under consideration. A simple mention that the washer needs to be there for safety is a great idea. There is a fine line here because there are many points in the build where we could write several paragraphs about the design rationale. What we have found over the years is that at some point you can overload the builder with too much info, and that can bring on anxiety about the build that can take some of the fun out.

My humble suggestion to everyone is if you find that a part is giving you some challenges ask us here for advice rather than deleting or changing it. We don't spend the money to put it in the kit if it doesn't need to be there for a good reason.