Can you help get the bubbles out of my Polyurethane Cast! 1

[maestro0]

Hi,

My company makes tools for Injection Moulding however we have commited to making 36 large prototypes to secure a job.

We have made an acetal mold of the job which is approx 100cm X 35cm X 15cm.

We have been pouring a thick PU resin into the mold base by hand and forcing down the mold top at an angle hoping to push out the bubbles, and popping any visiable bubbles, but this is hugely inefficient as we have a lot of bubbles after curing.

We have also tried creating a vacuum in the mold but this drags the resin in at such a great speed the outcome is just as bad.

Can you offer any advice as to how we can get rid of these air bubbles?

Thanks, Best Regards
M.

 

[SincoTC]

Try de-gassing the mixed resin before pouring it into the mould. I used to do this under a transparent plastic dome with a small vac pump and wait until the resin stopped foaming.