Long story short…hotcoated tonight with 2cc of Add F per ounce of resin instead of per ounce hardener. Which means i used more than twice what i should have. What should i expect?
I’ll be searching for “too much add f” posts…
feeling like a dipshit
-Andy
check the tall grass at dawn
maybe the epoxy bunny
will leave some colored hrd boiled eggs.
…ambrose…
just a guess
Ambrose…that would be awesome…you think the eggs would be dyed opaque or tinted?
ive more than doubled the amt. of surfacing agent in the FH epoxy a bunch of times on purpose…but i dont know if the RR ratio is lower than the FH ratio, which was way too low to do anything worthwhile.
We double the amount of Additive F to make epoxy gloss coats.
The person who told me to try it: Greg Loehr.
Works well.
BTW, how warm is your workspace? (I’m the fanatic about temps,
the boards are strongest if the temp is not allowed to drop below
80F any time during the build-to-postcure period)…
I just pulled the tape on a gloss
I put half a cap of additive f
and ooooooooohhhh baaaaaabbbby
it is soo smmooooooothe
and the tape was rubbery
after a sit at the blue campfire
and chinese food dinner
a sleep on the couch
an now its 3/4 o’an hour till mid night
on all hallows eve ,
I even can reuse the full bottom masking paper!..?
definitely not production
see a couple partial ant bodies under glass
no mosquitos in the gloss
no moths in it either.
…ambrose…
yeah ep-gloss w/no rub-out
silky rubberry shiny smooth
is swell I’ll tell ask me.
Well, the room was around 69…not ideal i know, but it had to be done as i’ve waited a few days between the lam and hotcoat cuz i ran out of hardener.
Checked her out this morning and seems, for the most part, ok. I’ll update if i find that somethings off.
Thanks for the help.
Ambrose…good to hear about your gloss…oh, and i didn’t find any hidden eggs…wrong holiday…or i’m just not looking hard enough.
Hey biz,
Even at 2cc per ounce of resin (or 4cc per ounce of hardener), you are only at 4.4% by volume. Here’s a graph about how the epoxy will be affected by solvent % volume.
From Epoxyworks magazine:
- Adding a small amount of one of these solvents has a significant effect on the viscosity of the epoxy. For example, adding 5% lacquer thinner makes about a 60% reduction in viscosity (Figure 4).
- Adding 5% lacquer thinner to epoxy reduces the epoxy’s compressive strength by 35%—a big hit in the mechanical properties of WEST SYSTEM epoxy (Figure 5). The addition of more than 5% solvent results in an excessively flexible cured material. Thinning epoxy with solvent causes enough loss of strength that we (and most other reputable epoxy formulators) cannot recommend using it as a structural adhesive.
- Adding a volatile solvent extends the pot life and cure time of epoxy and jeopardizes the reliability and predictability of cure. Additionally, with slow rate of cure, it takes longer before work can be sanded.
- Adding volatile solvent may cause shrinkage of the cured epoxy. Applying thinned epoxy in large, confined areas (like consolidating a large pocket of rotted wood) is likely to trap some of the solvent. In thick applications, the epoxy cures very quickly and not all of the solvent has time to evaporate before the epoxy hardens. Over time, the solvent works its way out and as this happens, the cured epoxy shrinks and in many instances cracks. Shrinkage also causes print through. You may have a surface sanded smooth only to have the resin shrink. This shrinkage often reveals the texture of the substrate. Shrinkage can continue to be a problem until all the trapped solvent works its way out of the cured epoxy.
- Adding solvents, especially acetone, alters the color of the cured epoxy. While the effects are not immediate, adding acetone to epoxy causes the color to change from slightly amber to very dark amber.
- Adding solvent results in a temporary reduction in viscosity. Volatile solvents evaporate quickly as they are agitated during brushing or rolling, causing the viscosity to continually change as time passes.
So, it looks like your coat will not be as strong, may need a little more time time to cure before sanding, and may have have more shrinkage. I think you’ll be fine…
I bet you never make the same mistake again, though…
JSS
“I bet you never make the same mistake again, though…”
You got that right…you know it’s funny…
After our little math session, i went and popped open excel to make myself a handy dandy conversion chart with corresponding amounts of hardener, add f for lam, and add f for hotcoat/gloss for the given amount of resin. Something i could tack up on the wall and reference at a moments glance. It was perfect…
except when i was setting up my formula to do my calculation, i set it to read the amount of resin column instead of the amount of hardener column. Such a tiny mistake made for a huge headache…well, less of a headache now that i know i’m in the clear. I’m planning on doing pinlines so i’ll sand most of this one off anyway to reduce the weight and make good with the second coat.
Thanks again.