Here ya go guys and gals as requested. I am going to give my best representation of “MY” way that I do the casting process.
First of all I start with a dry piece of wood (no more than 13% moisture) that I have stabilized in “Cactus Juice” www.turntex.com this hardens and stabilizes the punky or soft parts of the wood that you will mostly find in burls and spalted wood. After I stabilize it i take my ROTOZIP tool and use it to basically clean up the voids and cracks that are in the wood. This is where the resin will go as a filler. I only use “alumilite” www.alumilite.com resin in my cast due to the stability of it. It does not shrink like the Polyester resins such as Silmar 41 away from the wood. Alumilite is a Polyurethane resin which is more of an epoxy style resin so it really grabs the wood. After I get the wood to look like I want it to remove the bark, clear out the voids and shape it a bit I decide what is the best way to cast it. Silicone mold, 1/4” mdf mold if the block of wood is rather large or I also use the white plastic cutting boards found at walmart and make a mold out of those. If I use a mdf for my molds I seal the joints with the real foil type duct tape used on aluminum duct work.
Alumilite is then measured in a 1 to 1 ratio in “GRAMS” very important GRAMS. I use the 16 ounce clear solo cups to pour my resin in and tint it with a NON-WATER BASED DYE (very important) Alumilite does not like water and it will make a chemical experiment in your shop that you do not want to have to clean up. You can also use a powder pigment or mica powder to tint and color the resin to give it the pearl effect. Other glitters and such can be added to the resin as long as they don’t float or are heavier than the resin. If they are they will sink and all the glitter will be at the bottom of your casting. Once you add your pigments and dyes stir the resin and mix thoroughly and try not to make too many air bubbles when you do this. Next add Part “B” in the exact same amount of GRAMS of part “A”. Mix well and make sure you scrape the sides of the cup as you stir. I use Tongue suppressors. Remember you only have about 5 minutes of “Pot Life” this is the amount of time you have once you mix “A” and “B” together before it begins to gel solid. Carefully and slowly pour your resin into the mold or cavity at one end of the opening. This will vacate the air as the resin fills the void. I like to tap the sides or even tap the mold on my bench to make sure most of the bubbles break free from the wood.
Place the mold in a pressure pot at approx 40-60 psi or no more than your pot will allow. Set a timer for no less than 60 minutes and you really dont need to go any longer than 90 minutes unless your shop is colder than 65 degrees.
HINT: if you are pouring in a cold shop you can always heat up your mold or the part “B” of the resin in your microwave for about 20 seconds.
After timer goes off remove the mold and trim it up on the band saw or table saw.
The resin cast in the wood will react just like wood does to cutting, drilling, routing, and sanding.
Finishing the resin: I like to sand it starting at 150 grit and going all the way up to 600 grit. You can apply just about any type of finish over it just as you would wood. I like to spray about 5 coats of poly and micromesh sand up to 12,000 between coats. This will give you a silky smooth glass like finish. Overkill maybe but I am a perfectionist and a little anal.
I hope this helps some of you try new things as casting wood and resin can and will be addicting. Feel free to ask any questions.
-- Wayne Ryan, Texas Blanks, www.facebook.com/Texas Blanks