Casting Questions

[Jim McLain]

I have started turning the rough walnut burl I cut up. The first piece I turned I had to reverse because I could not get a stable tenon on the first side. I am considering casting the blanks in Alumilite deep pour with black color to fill the voids. I would pour the material and put in my vacuum chamber for a minute or two to remove as many air pockets as possible then let it start the cure process. Do you think this process will work. Any insights would be greatly appreciated.

 

[Chris Lawrence]

I prefer to use a plastic bag and lots of duct tape for something like that. You wouldn't need the more expensive deep pour that way. I just place my rough turnings in the plastic bag add some resin and start wrapping from the bottom up with duct tape. Add more resin as needed. I normally do this with rough turned hollow forms with lots of voids. If you rough shape and hollow out first just stuff a plastic bag inside and fill it with sand or marbles to keep the hollowed inside clear.

 

[Erik Christensen]

I do a lot of epoxy repair on cracked wood - most often smaller stuff like home dried olive wood with a lot of cracks to make a pepper mill blank but also bigger stuff like your bowl blanks..

if you have a vacuum chamber and pressure pot already, then you are good to go - wrap your blank in a resin barrier - I have had the best luck with clear vinyl they sell as a dining table top protector, resin tape & hot melt glue... make sure you have a couple of inches of barrier above your blank as you need to keep it covered and resin will bubble as you pull air out

use slow set resin - 50-60 min working time/pot life - put blank in vacuum chamber with resin level such that the blank is completely covered, put under vacuum to pull out entrained air, top off as necessary, after cycling vacuum several times over 15-20 minutes cover with resin a final time and put in pressure pot overnight to cure

It will amaze you how well this works - voids in the middle of the blank get filled and there is minimal defects in the finished surface that you have to deal with

 

[DON FRANK]

In addition the wood you are doing needs to be bone dry. Epoxy is more forgiving than urethanes like alumilite. Alumilite does not like moisture and will bubble giving you a poor casting.