Woodworking questions on stabilizing cracks

Any idea if there are shops in the Bay Area that sell pre-cut butterfly joints? I don’t have a bandsaw and prefer not to try with hand tools.
Nothing on Amazon. Etsy has a bunch but they’ll take a while.

Any cabinet shop should be able to help you as long as they do custom work. Maybe check a high school if they have a woodworking class if those still exist.

      Don't heat the slab after pouring the epoxy.  reverse of that.    You need to warm the wood up first, then mix and apply the epoxy letting it slowly cool back down.     Warm the epoxy during the mix.  The warmer it is the faster it will set up..
 Reason for this to prevent bubbles.     
 That cooling down phase will draw the epoxy into the wood.   Of course not cool down to below the curing temp.   

     To get that fine texture you're looking for, rather than sanding it you may consider using " Peel Ply cloth" .    Once cured the cloth will peel off,, leaving an imprint from the cloth.    ( that cloth is a super fine weave )       

    You could do a light first coat to impregnate the wood,, then the second coat using the  Peel Ply...
  Or even top coat a brush / spray on  a satin finish of  varnish.

    I've had epoxy set under colder temps   ( 60's ),, it just takes much longer to cure. Avoid if possible.  70 should be no problem.

   Also remember you can fill that crack with  sanding dust and epoxy mixed into a paste.   for color match... 

     https://epoxycraft.com/top-tips-best-ways-to-use-epoxy/using-peel-ply-to-best-effect/

 Good luck !   sounds like a fun project

As I posted In the other recent thread, I’m also about to work redwood slabs.  I plan to cure the epoxy at 80° or so using a heater.  Heat is important.

On the checks on my slabs I made pencil marks at the ends of the checks to see if they grew while the slabs dry. None of them did.  Mine are all very minor, there’s six of them. I’m not planning to bow tie them.

Holy slabzilla!!!!! That’s awesome!

Aloha,

Isao