DIY QB550 quantum board build

[Failsafehydro]

Hello , I was wanting to build a QB550 style light with 4 x QB288 . I was trying to source a 600x600mm aluminum anodized plate but am having issues finding one.
Horticultural lighting group has the
SLATE 4 QUAD PLATE
horticulturelightinggroup.com/collections/diy/products/slate-4-quad-plate
But it seams to be sold out for a while now .
Could I use a regular aluminum plate or does anyone know where I could buy one.
I am having issues finding this item , I have called a few places but the prices are outrageous .
Thanks

 

[canadian1969]

online metals has 24"x24" 0.25" thick plate for $100 plus shipping. Shipping will probably hurt on that tho
https://www.onlinemetals.com/
0.25 Aluminum Plate 6061-T651
I would think that would be more than enough metal to dissipate 400 watts.
http://celsiainc.com/heat-sink-size-calculator/
I used 250 for the volumetric thermal resistance (which may be low), and your plate will not have fins so perhaps adjust the plate thickness to 1cm and you should definitely have enough metal and would be $150.