To paint or not to paint ?

[deliverance]

Powder coat the frame and lacquer the mesh me thinks .

[Scimitar]

Etch primers are out of date now. The modern equivalent is epoxy primer which outperforms etch and doesn't have compatibility problems. The painted surface can also be left in primer permanently if required and it can be tinted to any colour preferred.

[avocollector]

Great as it stands IMHO

[Malcolm T]

I would not powder coat, if it chips how do you retouch it ?.
If you anodize and scratch it, its done for !

Damaged paint job ! no problem just touch up or if you go for a change in colour later just paint strip and re-spray !.

Spray is my option . If its good enough for aircraft and Mil stuff externally then that,s my choice Just make sure the ali surface is not damaged , NO scratches etc PREPARATION is the key ( no pun ).

IF it were me
I would wet block sand the surface with 500 - 600 grit with plenty of warm water suds you.ll be surprised at how much debri comes off, let dry and and de-grease with paint thinner then prime then top coats.

OR take it to a pro spray shop and let them do it 100%.
You really want the surface Etch Primed with Zinc Chromate yellow, hence the pro spray shop ! Zinc Chromate etches into the metal and provides a key for the paint. Make sure any earth points to the cover are left bare or use stainless steel tooth washers and fastners if its all painted, for earth bonding. You can buy blackodized stainless steel fastners in the UK.
Find yourself a company like this in your area and talk to them, well worth it because they have all the gear for it . Good luck
http://www.goldburnfinishers.co.uk/pretreatment.php

[ribbonmicsrus]

Originally Posted by g4wim_tim

I'm open to being convinced either way - currently I'm leaning toward leaving the case 'naked'.

What a lovely job you have done Tim. I think it looks great as it is, back in the day I used to leave all my homebrew naked. Look forward to hearing that rig.
73
Andy G3UEQ

[g4wim_tim]

Hi Guys,

thanks for all the comments / suggestions.

Hope I've made the right choice, but have opted to powder coat the frame and lacquer the inserts.

If all goes to plan should have the case back in the next day or two ready to assemble.

I'll post some more pictures later.

As a tx, I'm getting good reports on it but ironically have yet to have a 160M contact - the band I originally built it for as a Codar AT5 on steroids !

Regards Tim

[ribbonmicsrus]

Sounds good Tim, shame we are too far apart for my meager 160m aerial, I have an AT5, KW160, TW Topbander, and one of G3WCE Bruce's impeccably built rigs to call on, oh and a Vanguard!

Perhaps one day when conditions are good.


73
Andy

[boxdoctor]

Here's a link to an article on D.I.Y. anodising.
Looks do-able and cheaper than going to a pro outfit to have the job done. Tony.

https://www.americanradiohistory.com...PW-1962-11.pdf Page 638.

[g4wim_tim]

Hi Guys,

well rightly or wrongly here is it powder coated with lacquered ventilation panels.

In some ways I preferred the 'naked look' but over a period of time I'm sure the scratches and marking out would have gotten to me whereas power coating hides all those sorts of marks.

I've also included a couple of shots of the chassis interior showing RF deck and modulator plus one from on top.

As for performance easy 70 watts carrier with 99% modulation and only 2% distortion at full mod as measured on my HP8901B.

AF response 340Hz to 3kHz -3dB and 220Hz to 4.8kHz -6dB

100Hz carrier ripple is -48dBc at full power on all bands and 50Hz hum is -68dBc - all in all acceptable AF performance and getting good audio reports on air.

RF harmonics are circa -60dBc when turned correctly.

For my next project I may well try some of the alternative finishes suggested, but first of all have to figure what to build next time !

73 Tim

[HamishBoxer]

Totally a pro job.

[Kentode]

That's a fantastic piece of kit, congratulations.

[G4YVM David]

Wow. That's mind bogglingy good. Terrific work and thanks for sharing.

[deliverance]

Excellent looks very professional .