3m glass bubble thickness

I use 3m k15 glass bubbles mixed 40/60 with cabosil to create an easy sand mixture. I tried to snap and crush some of my left over mix in west epoxy the other day and it suprised me how strong it was. 3m say it can withstand 300psi, but I have only used them for surface coating and fairing

In a real world example how safe and strong would the same mix be on chine lines and some hull fairing, and what thickness would be maximum the pro would lay it on please?

 

The K15 bubble from 3M is one of their lightest and weakest. It's strictly for fairing and lightweight cosmetic fillers. It's a real 'glass bubble and fairly consistent in size. Used with silica and several other additives, makes a fine, easily sanded filler, though there are some easier to sand materials, as well as slightly lighter too.

As filler materials go, it's not very strong, particularly compared to the highest of their "K series" (K-42HS) , which is over 7,000 PSI. In terms of thickness, generally it's best to use as little as necessary to fill an area. You can slather it on pretty darn thick, but you come to a point where having a 1/2" or more of filler in an area, can be approached in a different way, such as bulking in some additional fabrics or using a structural filler (cotton flock, milled fibers, etc.) material instead.

 

Thank you par. Exactly what I needed to hear. Very greatful