retrolefty:
As far as heatsink needed, yes you will. The maximum current ratings for SSR only apply if you can also keep the device below it's maximum operating temperature rating. Past experience I've has is that most SSR will 'drop' about 2vac across it's switching device, so at your 8 amp current load, that's 16 watts of heat dissipation that will surely overheat the SSR unless bolted down to a large enough heatsink using proper heatsink paste, etc.
So how big a heatsink? Probably larger then you wish, have room for, or have avalible on hand.
Heh. Well, my motto is, 'Nothing exceeds like excess'. I'll grab a CPU heatsink at MicroCenter. And then maybe I'll lap the back plate of the SSR. And use heatsink compound.
floresta:
I have been using similar units (that I bought used at a hamfest) to control my baseboard heaters for several decades. The only heatsink is the 4" x 4" aluminum plate that I fabricated to mount them on and to cover the standard outlet box that they are mounted in.Don
That's an idea too. But, what would Tim Taylor do? 