Does Additive F weaken epoxy?

I have read countless posts about Additive F but have yet to find one that can explain exactly what it is and how it does what it does. What I really want to know is if it weakens the finished epoxy in any way. It seems to me that one of the primary advantages of using epoxy is the increased strength, so it wouldn’t make much sense to add something that would weaken the finished product. Can anybody out there shed a little light?

a wax suspended in xylene… i would guss the xylene is there to keep the wax in supspension and that the wax simply floats to the top of the spread out resin to effect surface tension and provide a skin against the air… you ad so little that i would guess it doesn’t effect the strength very much… i could be wrong of course…

jjp is correct, solids mixed into a xylene base to keep it in soloution. Makes it easy to sand and does not effect the physical properties

jjp and J.Troy - Thanks very much for your help. Everyone talks about the miracle curative properties of this stuff, but no one says anything about possible downsides, if any. Your information is exactly what I was looking for.

There is wax in there? I thought that when laming w/ the “F”, if you filled or glossed before the lam cured all the way it would bond better without sanding. Does the denatured alcohol take off all the wax with a quick wipe?

If you can’t tell I only have some minor ding repair experience with epoxy. I am just amassing info… That and a HD EPS “blank” and a stack of balsa. Some day I’ll get a vac bagger going. It’s tough in a one bedroom apartment.

Thanks,

Spoons

I mixed 2 batches the other day, 1 with additive F and 1 without. In the small dixie cups I was mixing in I had a thin layer of epoxy in both about the same thickness.

Additive F really softens up the epoxy. It’s very noticable. The RR epoxy is very hard without the additive F.

I always thought that people’s complaints about sanding epoxy had to do with it’s raw hardness. Additive F is supposed to solve that problem.

Whether or not that effects breaking strength, I don’t know, but it does affect the stiffness.

You sure you guys aren’t talking about Polyester and Wax? I thought additive F was something more complicated than simply wax.

Quote:

I mixed 2 batches the other day, 1 with additive F and 1 without. In the small dixie cups I was mixing in I had a thin layer of epoxy in both about the same thickness.

Additive F really softens up the epoxy. It’s very noticable. The RR epoxy is very hard without the additive F.

I always thought that people’s complaints about sanding epoxy had to do with it’s raw hardness. Additive F is supposed to solve that problem.

Whether or not that effects breaking strength, I don’t know, but it does affect the stiffness.

You sure you guys aren’t talking about Polyester and Wax? I thought additive F was something more complicated than simply wax.

It is more than just wax…

additive F makes the resin easier to sand.

Jtroy and the others summed it up best when saying that “F” doesn’t weaken epoxy. It has other major advantages not listed, such as easier wet outs and preventing blush, a big factor with epoxy.

It’s the magic koolaid. Don’t leave home without it!

The magic Kool-Aid: that’s what Jim Jones said.

Thanks for the explaination of additive F being wax solid in xylene solution and how it rises to the surface to affect surface tension. Makes sense. But I still don’t understand ‘how’ it affects viscosity enabling easier saturation the way it does??? Seems that would be something beyond surface tension factors created by waxes rising to the surface. It seem the viscous nature of the resin itself would have to be affected???

no one says anything about possible downsides,

I’ve had problems lately. It has been leaving a chunky surface. I think I have a bad can of the stuff. Look for thread " junk additive F". I had to stop using it on my gloss coats. BTW, I don’t have any problems sanding without it. I like it because it helped me with the wet out, so the chunky finish isn’t a factor there.

This may or may not be relavent. When I coated my lab floor with epoxy (the floor surfacing type), I contacted a tech manager I knew at the manufacturer to see if he had any tips for me. He recommended a dose of xylene to help in application. He said the VOC restrictions have caused them to reduce solvents and this has changed the way the material lays down. By adding xylene it would level out better and it wouldn’t drag so much on my applicator rollers. It’s the only epoxy floor I’ve ever done so I can’t say how it would’ve went down with out it.

Sounds like the material change on my floor epoxy with xylene might be similar to the change it has on wetting and leveling in glass laminations. Sounds like it functions as a viscocity modifier. I’d guess there’s more to it.

The wax thing? I think epoxy surface hardens without surfacing agents. I could be wrong.

As with all epoxy lamination you should post cure your boards in an oven. We haev done about 60 boards this month using the post cure process and have had excellent results. You also want avoid using additive F when the temp is falling. If you laminate with a falling temp the board will soften at a lower temp. 2 rules to follow are, laminate with rising temps and post cure and you will have no weakening problems.

Mike

What is your post cure temp regimen? Temp, duration, etc, thx