Forum Title: Interesting expirement- DIY accelerator
So today I stopped by my local supply house and tried to pick up a couple bags of 5 minute as this is all I use for patches and such. Turns out someone came in and bought 50 bags to do a house ..... So I had to settle for a bag of 20 minute which I hate waiting around on to set. On my way to go do some patching I remembered that there are some accelerators out there for plaster that should work for durabond also. I did some research and saw USG lists Alum catalyst as one of their accelerators. From making homemade pickles before I know you can get alum in the spice isle at a grocery store. So I stopped in at my nearest grocery store and picked up some and went on to do my patches. Haphazardly I mixed up some alum in my water before adding my 20 minute in hopes of it setting faster. It turns out the grocery store stuff works great . I noticed that it mixed up way more creamy and almost made it slide around like plaster does but in a good way. Set time was approximately 12 minutes or so. These patches were also done over an eggshell paint which if you have ever done so you know the feathered edge of the mud takes a long time to set up than the main body of the patch. This seemed to have been eliminated with they use of alum which was quite surprising. So now being back at my house I decided to do a quick tests to determine the actual effectiveness of alum in varying degrees. For a control I mixed up standard 20 minute, secondly I used 1-1/2 cups of water and mixed 1 teaspoon of alum in my water before adding my 20 minute powder, and thirdly I mixed approximately 1 ounce of alum into roughly 1 gallon of water and used this to mix up the 20 minute. The regular 20 minute took 29 minutes to start firming up and 33 minutes in total until it was fully hard. The second mix took 9 minutes to start firming and 13 minutes to fully harden. The third mix took 17 minutes to start firming and 21 minutes to fully harden. As you can see the higher ratio of alum to water in my second mix made quite the difference. Actually the difference to the 20 minute mud control was a full 20 minutes! I did all this outside at 62 degrees and cold water on a scrap piece of rock using National Gypsum quick set lite. NG's quick set in my experience only sets at its recommended time when the temps are in the 90's so in cooler weather it is much slower. I know this isn't ground breaking or anything but I did find that the alum may have some use in my tool box... especially the part where the edges set up over paint!
Post By: CHARLES S (Charlotte, NC), 03/03/2018