Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Blooze on August 07, 2019, 05:29:33 AM

Title: Powder Coated Crack Grounding
Post by: Blooze on August 07, 2019, 05:29:33 AM
I had the top plate and trafo bell powdercoated (they coated all surfaces, was going to cost a fair bit more if they masked anything).  I just want to confirm that I need to scrape the coating off the bottom of the plate at terminal 3,8, and the #8 safety ground bolt? Any other places? The transformer is isolated from the top plate so I don't need to worry about scraping any off the underside of the bell or plate on those 4 holes, correct? Possibly run a 1/4" drill bit by hand through the top plate transformer mounting holes if the fiber washer shoulder doesn't fit?

Thanks for any help!
Title: Re: Powder Coated Crack Grounding
Post by: Paul Birkeland on August 07, 2019, 05:37:49 AM
You don't need to worry about terminal 8, but certainly 3 and the ground screw.  Passing the 1/4" drill bit through those holes is a good idea, as the shoulder washers are a tight fit. I would also scrape off a bit of the coating on the bottom side of the transformer cover around each hole.
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 07, 2019, 03:07:49 PM
You don't need to worry about terminal 8, but certainly 3 and the ground screw.  Passing the 1/4" drill bit through those holes is a good idea, as the shoulder washers are a tight fit. I would also scrape off a bit of the coating on the bottom side of the transformer cover around each hole.


Here's what I have so far. I sure hope the bell doesn't end up rusting in those spots.  It was $30 just to get the bell coated.
Title: Re: Powder Coated Crack Grounding
Post by: Deke609 on August 07, 2019, 03:21:17 PM
Nice color scheme! That is going to look great. Post pics when you're done. What do you have in mind for the base?


cheers, Derek
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 07, 2019, 03:34:26 PM
A dark walnut or coffee with a gloss finish. I’m going to try and cut a 1/8” kerf about 3/16” from the top (or bottom of the supplied boards) and make the rear panel removable using cross dowels and bolts.  Unfortunately my router died on my trial piece so I’ll need to replace it first as I don’t have a table saw to cut the kerf.  That way the top plate is locked in the base. I can then put a clear plexiglass bottom with vent holes on.
Title: Re: Powder Coated Crack Grounding
Post by: Deke609 on August 07, 2019, 03:51:23 PM
Nice. So you can just slide the chassis in/out. Very cool idea.


Word of caution: you should run the idea of plexiglass with holes by PB - I imagine that might seriously cut down on convection cooling even if you made it 50% holes. If it's a no go for cooling reasons, maybe a mesh screen instead?
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 07, 2019, 04:05:58 PM
Very true. I thought about a metal mesh bottom. I’d like to make it non-conductive if possible, just for safety’s sake.
Title: Re: Powder Coated Crack Grounding
Post by: Paul Birkeland on August 07, 2019, 04:14:40 PM
You scraped 8, but not 3.  You need to scrape 3, but not necessarily 8.
Title: Re: Powder Coated Crack Grounding
Post by: oguinn on August 07, 2019, 04:22:16 PM
I had my powder coating done at a motorcycle repair shop. I think he charges me $20 for the plate, bell, and any other shields or clamps I bring in. You might try finding one, too. You can see pics of my stuff (and a couple other people) at my gallery site (http://www.diyaudiogallery.com).
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 07, 2019, 04:38:23 PM
The nearest powder coating to me is almost three hours. These folks were the cheapest. It was $70 for the cream plate and the ruby flake bell.  If they’re in the US I should just mail them my stuff. Probably still be cheaper.
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 07, 2019, 04:39:00 PM
You scraped 8, but not 3.  You need to scrape 3, but not necessarily 8.

And that’s why I don’t even sand paint off when I’m tired. Jeesh 🙄

Title: Re: Powder Coated Crack Grounding
Post by: Paul Birkeland on August 07, 2019, 06:03:43 PM
Yeah, it would have been enough to scrape the bottom side of the transformer cover, not the top side.  I would dab a little bit of clear coat over those spots, as they will probably rust.
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 07, 2019, 06:06:28 PM
Yeah, it would have been enough to scrape the bottom side of the transformer cover, not the top side.  I would dab a little bit of clear coat over those spots, as they will probably rust.

That is the bottom side 😁. Pic makes it hard to see.
Title: Re: Powder Coated Crack Grounding
Post by: oguinn on August 07, 2019, 06:27:24 PM
I’m happy to pass along my guy’s information if you need more stuff powdercoated. My wife would love that color combo, by the way, since she’s an Oklahoma Sooner.
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 08, 2019, 03:11:08 AM
That’d be great if you could share the contact info.

Paul, is there any worry about the bottom part of the bell where I scraped rusting? Maybe a dab of thin primer that the washer can easily bite through?  It definitely wasn’t biting though the powder coat as I cranked down a toothed washer and checked before scraping any off.
Title: Re: Powder Coated Crack Grounding
Post by: oguinn on August 08, 2019, 03:27:07 AM
My guy is Jerry at Cycle House Performance (https://www.cyclehouseperformance.com) in St. Louis. I dealt with him almost exclusively through email to get information on pricing, etc. and then went to see him for color options, so I'm not sure how to handle color picking.
Title: Re: Powder Coated Crack Grounding
Post by: Paul Birkeland on August 08, 2019, 04:46:23 AM
I wouldn't be concerned about the bottom rusting.
Title: Re: Powder Coated Crack Grounding
Post by: Blooze on August 08, 2019, 02:12:54 PM
Thanks Paul for all your help. I got all the hardware mounted this evening and have good continuity between #3 and safety ground. I have good continuity between all the transformer bolts at the bell end and lug #16 so I’m gonna assume the washers bit in well enough on the underside of the bell.