Warning: mixing lightweight compound with regular on a taper's still was a mistake

I had this bright idea last week on a basement job in Naperville to mix some lightweight all purpose with my regular setting compound to get the best of both worlds. Figured it would dry faster but still sand smooth. Man was I wrong. The stuff caked up on my banjo in about 15 minutes and I spent an hour cleaning the mud out of the tape head. Then the tape started bubbling up on the seams because the drying times were all off. The homeowner was watching me the whole time too so I had to pretend it was going fine. My foreman came by and just shook his head. Switched back to using straight Durabond 90 on the next room and everything laid down perfect. Has anyone else tried mixing compounds on a job and had it backfire like this?

3 comments

3 Comments

ray_miller418d ago

Hang on, just a quick correction - you said you mixed lightweight all purpose with regular setting compound. But Durabond 90 isn't really a regular setting compound in the same way, it's a hot mud that sets chemically not by drying. So if you mixed a drying-type lightweight with a chemical-set mud like Durabond, that explains why the drying times got all wonky and your tape bubbled. I've made that mistake before (who hasn't, right?) thinking I could get a longer working time out of hot mud by mixing it with something else. Just adding a little water to thin it out works way better than trying to blend different compound types together.

the_robin8d ago

Yeah that was your first mistake right there bud.

kimr107d ago

Oh COME ON, you guys are WAY too quick to pile on the guy! I actually mix compounds ALL the time and it works FINE if you know what you're doing. The problem wasn't the mixing itself, it was that you didn't account for the humidity in that basement or the fact that the Durabond 90 is a different formula. I've mixed all purpose lightweight with regular plus 3 on a dozen jobs and got a butter smooth finish that dried in half the time. @the_robin is probably the type who follows the bucket instructions to the letter and never experiments. The bubble issue was from rushing the tape or not bedding it right, not the mix.