Home made amp case - should I spray or should I no?

[RichardH]

Sorry about the bad Clash pun.
Building an Avondale 260Z, and had some spare bits to make a case from some sheet aluminium. I had a load cut a while ago - enough for 3 half width and one full width case. Basically top, bottom, front and back are in 1.6mm sheet, and they are all attached to side panels which are 10mm thick - this is designed to provide some structural rigidity, plus heatsinking.

Previously I've just used self tappers to fix the panels to the side "bars", but as I have some rather nice socket headed machine screws, I've sunk some colserts into the top of the case to take them.

As this is full width, and there will be a hefty transformer inside, this time I've bonded some aluminium angle to the front and back panels, so that the base and top are attached along this long edge, again adding to the rigidity.

Now, all my other equipment is black (chrome bumper era), and my immediate feeling is to spray this in the same way - but it does look rather nice as it is.....

 

[prowla]

Spray it pink!

 

[LesW]

Mill finish aluminium has little heat dissipation capability so a slight roughing of the surface would be an advantage. If you're going to paint the case which incidentally looks terrific, first apply an etching primer to form a bond between the top coat and the alloy. Failing which, the whole lot comes off after a time. Best of luck with the project.

 

[RichardH]

Prowla - pink - LOL - first Pink Fish branded product?

Thanks for the kind words Les.
"A slight roughing" - would sanding and spraying with a satin finish do the job here then, Les, or do you need more increase in surface area (i.e. rougher surface)?
I was going to butt the module heatsinks hard against the 10mm side bars. Black being a better radiator, it looks like spraying is best (and I know it's the right thing to do). I guess I can always fix some heatsinks along the sides if I find it's getting too hot.

 

[RichardH]

Update - just done some research into self etching primers, and found that Halfords do some, made by U-Pol. However, my local store is discontinuing it (reduced the price from £15 to £10, though), so if anyone's doing anything similar, it might be worth getting some of the primer now.

Richard

 

[RichardH]

Well, I'm afraid that zebra stripes and pink both went by the wayside, and I sprayed it black.



More pics here

Currently unsure about internal layout - I went for one of Les's soft start modules, and wonder if it ought to be sited well away from the amp boards, or whether it could sit between them like the pic on my site. Then I could have power socket in the middle of the rear panel, and nice short power cable runs.

 

[RegH]

The man himself has some pictures of his 260Z layout on his site:-

260Z pics

Look neat don't they. He has mounted the Soft Start on the rear of the front panel close to the on/off button.

I have a 260Z kit (and Grad1) on the way - hope I can make as neat a job of mine.

Good luck

Reg

 

[Rico]

Sure looks good, Richard - and sorry this is late. Did you not consider epoxy powder-coating? Inexpensive, very durable, choice of finishes and colours.

Rico

 

[RichardH]

Reg - yes, I've seen those pics. I think that Les's case is a little deeper than mine (which is modelled on the 250's dimensions, except a little higher), so he has room for that beast of a transformer plus the soft start module. He also has a double skinned front panel, so is able to bolt though the inner panel to hold the module in place - a luxury I don't have.
As the switch is out of the path, and is just a trigger, it occurred to me that it didn't matter how long that cable was, and it would keep the "main" cable run short. I'll hold on until Les is back from his hols, and see what the man says.

Rico - didn't know about that one - sounds like it would have been a good option. Is it something you have to get done, or can it be a DIY job?

 

[Rico]

Is it something you have to get done, or can it be a DIY job?

Richard

specialist equipment. Your kit is suspended and grounded, the spraying equipment poitively charges the epoxy powder... watching a spray tech is pretty interesting - a little different to "wet" painting. The kit is then baked in an oven for long enough for it to go off, and then gently cooled at room temp.

Mattes, crackle finishes, all sorts. Greater thermal mass often sends a matte slightly glossier than expected.

Try a yellow pages search, or local industrial coatings/paint shops - should be able to help.

Not just for hifi - great for automotive wheels, bike frames, speaker stands etc.

HTH

Rico