Possible blow out on riser casting !

Went out to check my cast riser this morning, looked good! Removed my sheet metal form , smoothed the cast nice and firm, rounded off the top nicely ! It was ready for the hottest day so far this year (80) predicted... going to let it cure all day ... maybe by tomorrow morning I will try lighting it off ! WRONG ! I decided I would lift the 55 gal barrel over the top of the riser and start prepping its location to seat it in cob. Imagine my distress when I looked down my sonitube form only to see it trying to buckle inward from the moisture in my mix !!! Oh SxxT ! Decided that the only thing to do was slap cob down around the 55 and light it off and see what the cast looks like afterwards... it was possible that it could have caved in on me while trying burn it ! Well it didn't cave in while burning! I won't be able to remove the lid till later this afternoon to see what happened ... I'm hoping for the best and planning on casting a new riser if needed. I was very impressed at how quick the new core took off, even with a sopping wet riser and cold wet brick core ,I registered 816 F at the barrel top in no time. Its down to coals now, I just have to wait for it to cool off enough to open the lid and look inside.... fingers crossed .

It Worked ! There is a bulging where the form crippled but it's solid , and I don't think it will adversely affect the flow enough for me to bother with. I won't need to cast a new riser after all ! The cone on top had some heat cracks from heating so fast when wet , but an application of fireclay and it looks good as new ! Lesson learned! stay with the brand that works... this method worked flawlessly last time the only difference is the brand of sonitube, this one was slightly thinner but seemed to have a waxed coating. I thought it would be fine... Wrong ! Good news is the new core worked very well considering how cold and wet the riser was.