Adhesive Question

[2000wreckedwj]

I got a stupid question here. I have been reading through some restoration articles and everyone keeps mentioning PB. What in the world is PB?

 

[GWPSR]

Re: Adhesive Question

PB is short for Peanut Butter, a nickname for thickened (and usually reinforced) resin. You may hear it called 'pooky' depending on whose threads you follow.

You'll see a number of recipes throughout the threads, but they all have the same goal -- to add material to resin allowing it to be used like a putty for bedding structure to hulls like transoms or stringers, to fill holes, or to create fillets between bulkheads or stringers and the hull to allow easier laminating of fiberglass.

The thickening agents tend to be materials such as Cabosil or milled silica, and many add finely chopped fibers to it for strength.

The real experts will be along any moment to each recommend their favorite blends and suggestions for how to mix it.

 

[jbcurt00]

Re: Adhesive Question

oops thread has an index @page 1, PB is listed in that index:
http://forums.iboats.com/boat-restoration-building-hull-repair/hull-extension-progress-pics-234392.html

peanut butter....posts #55, 81

He doesn't give quantities of each, but as you work with it, you'll get the feel for it. Depending on a lot of different environmental variables, and your work pace, you'll need to make slight adjustments to the mixture to suit what you're filling & etc. Just like adjusting your MEKP % to suit your application & needs.

Poly resin & microballons alone make a nice final fairing & filling compound as a last step before paint or gelcoat, and is easy to sand, mixed to a mayo-like consistency.

Using just cabosil makes a good general purpose filler, mixed to a peanut butter consistency.

Adding in milled chopped fibers (which you can cut yourself from scrap/leftover CSM & cloth) makes hairy PB that is for structural filling, where the filler needs to be extremely strong, and is very difficult to sand once cured. Great for application to a vertical or overhead application. The fine little hairs that stick up, may be brushed down w/ a final pass w/ resin soaked paint brush or a metal spoon dipped in acetone, making it less necessary to sand them away......

 

[Woodonglass]

Re: Adhesive Question

A good starting point to make PB is.. 2 cups resin, 3 cups Cabosil and if you want a Tablespoon of Chopped Milled Fibers to make it more structural.

 

[a1964rn]

Re: Adhesive Question

Depends on the resin, too. You don't use any milled fibers if you use epoxy resin.