With all the shortages of blanks world wide and the need to experiment in alternate floatational aids, the topic of EPOXY has reared it’s head numerous times.
I propose that we start this thread off with helpful information about EPOXY.
It could be about mixing, pouring, stirring, applying, brushiing, conditioning, setting, drying, sanding, finishing or polishng…
I’d like to kick things off with something I picked up from Roy on another thread.
When you have finished using your brush after using epoxy, put it in the freezer so you can use it again later after it defrosts. I tried this 3 times after reading this and it works.
A word of caution, cover rhe brush with cling wrap before it goes in the freezer, it stops any condensation from freezing on the brush and contaminating the next mix…
Ive been waiting for a thread like this… that sounds good, once my glass arrives ill have to try that on this next board… also any info on coloring and swirling, without wasting to much, would be great too
Okay - while it’s mostly for Real Small batches, it scales up;
The hand pumps they sell in pairs are a Real Good thing if your epoxy resin ( like Resin Research, RAKA, System Three ) are something you mix in 2:1 ratio. If they come with a stop for one of 'em, use it for the hardener and it’s one pump of each. Pouring resin into ‘measured cups’, you never get it right, it’s always just a little under or a little over. The same with doing it by weight, if you can pour a small batch within 10% you’re way ahead of me. And it’s usually over, so you wind up adding more,of this…and get that wrong, then more of that…and get that wrong…and eventually the price of the pumps ( under $10 US per pair) is more than made up for in wasted resin.
Usually said pumps kinda lose their prime if you’re not using 'em a lot and you don’t get a full shot, nothing but air coming out for the first part of the pump stroke - in which case you push the thing down until the first drop of resin comes out, put your thumb over the hole and let it return up. This will get you a full ‘pumpful’ on the next stroke and the right mix every time.
Until you are comfortable with how fast it goes off, time and such, take that last bit on the brush and a piece of scrap cloth and do it to it. Then, if you must touch something to see ‘are we there yet’ you can do it to that scrap piece and not get your grubby thumbprints on your finished work- for some reason epoxy seems to pick up grubby thumbprints more than polyester.
Epoxy doesn’t have that basic organic stink, so you can store it in the house or the cellar without everybody wondering if you are fumigating for moths or something. A cool, dark place is best - 10°-15° C. Though below freezing temps are probably not a good idea… This will prolong its shelf life compared to warmer temps or in direct sunlight. I have epoxy stored this way that I’ve had for …well, damned near ten years, some of it… and it still works fine.
Since it’s maybe kind of early in the day for Hicksy to reply, here’s how I do it: I just bung the brush and container in thr freezer, and that includes any excess epoxy in the container which can be re used when it thaws out. when it starts to thaw I add another pump or so of epoxy just to freshen it up. It’s funny because low temperatures encourage ‘B’ reactions with the atmosphere (which we don’t want) but once it goes below the freezing point of epoxy (same as water ?? )there’s no reaction at all, so no ‘B’ reaction.
also we have found using tomato sauce bottles (ketchup) with the snout great for mixing small amounts for dings and laps etc. as we go by weight i can be difficult pouring correct amounts fom the big containers
Goll-ee, and all this time I was just cleaning the brush with denatured alcohol, and then storing it on the shelf…silly me.
Glassers with polyester soak their tools in acetone after use, that gets all the uncatalyzed polyester resin off and the tools may be used again.
Replace acetone with denatured alcohol, and it works fine with epoxy.
If you think the resin may be thick, warm it in a warm water bath. I fill a 5 gallon bucket with warm tap water, works great. Thick resin is very tough to mix properly, and epoxy not mixed properly will not cure properly and you will have a mess.
Cure the epoxy in a small room with a space heater and a closed door. You can sand RR epoxy in 2-3 hours if the ambient curing temp is 100-105F. Warm it just enough to lam before glassing, and when you are done stick the board in a warm room. Or a hotbox, if you really want to minimize heating costs. The final strength will increase, with the same stiffness, if you cure at warmer temps.
Use a postal scale to mix properly. I never went this far, but I always took cups and made measured lines on them for mixing. Or just bought cups with measuring lines on them.
Clean with alcohol before use. I use rubbing alcohol, works fine. Denatured may be very slightly better.
Hotcoat when the lam is half cured. Saves you time, and comes out better.
The reason why I don’t use solvents to clean brushes and mixing bowls etc is that then I have this uncurable solvent/epoxy liquid to dispose of, and the uncured epoxy is a lot more toxic than the cured stuff. . . plus any epoxy which I dissolve is wasted. . .if I freeze it I can re use it, also I can sav money by not buying solvent… . . . apart from coconut oil for removing any on the skin, which almost never happens.
What do you do with your epoxy in alcohol solution ?
I’ve tried Roy’s idea a few times now and it does work, I’ve found that the epoxy “remembers” where it was at in the curing stage and continues once it’s defrosted.
Further to the measuring discussion, I weigh all my epoxy to the gram, if it’s a 2:1 mix, 100g of Part A and 50g of Part B…
Howzit blakestah, I've done the same thing with acetone by first using a fine mesh paint filter then using the coffee filter. Doesn't really bring the acetone back to it's cleanest state but does make it clean enough to use in the # 2 acetone bucket.Aloha,Kokua
Howzit Tom, Three buckets,#1 is cleansest,#2 is not as clean and #3 is dirtiest. I rotate them as they get dirty and #3 goes into an old 5 gal resin can and the liquid evaporates and leaves a solid mass that is hard and inert so it can go to the dump with permission since it’s hard.I know that the evaporation is not good but all acetone evaporates some time or another. It’s a heck of alot better than pouring it on the ground which is a big no.no and just the cars that pass my house every day put out way more emmissions that the acetone. I do my best to recycle the acetone as much as possible. Usually takes about 1 or 2 months for the evaporation to harden the guck left in the can.Aloha,Kokua
In my experience alcohol makes epoxy into a slimy mess thats still pretty hard to clean up. Vinegar really takes care of epoxy, neutralizing the stuff on a molecular level, especially if you’re sloppy like me. After vinegar or orange clean (citric acid?), just rinse in water.
We occasionally use vinegar for cleanup too, that’s what the WEST system guys suggested, I didn’t know that it neutralised the epoxy, which sounds helpful. You can’t use vinegar for brushes to be re used though as it wrecks (‘neutralises’ ? the resin)
Okay - while it’s mostly for Real Small batches, it scales up;
The hand pumps they sell in pairs are a Real Good thing if your epoxy resin ( like Resin Research, RAKA, System Three ) are something you mix in 2:1 ratio. If they come with a stop for one of 'em, use it for the hardener and it’s one pump of each. Pouring resin into ‘measured cups’, you never get it right, it’s always just a little under or a little over. The same with doing it by weight, if you can pour a small batch within 10% you’re way ahead of me. And it’s usually over, so you wind up adding more,of this…and get that wrong, then more of that…and get that wrong…and eventually the price of the pumps ( under $10 US per pair) is more than made up for in wasted resin.
IMHO those pumps are crap (or rather they become crap… Atleast the ones I’ve had). If you use them, make sure you do as doc says to really get the full length of the stroke on them and that there are no air in the pump or you’ll be sorry. I recomend using a digital kitchen weight instead, cover it with a wide see-through plastic bag so spills doesn’t ruin it. They probably cost less then the pumps anyway(take you’re wife’s old one, and buy a new one for her once she finds out). Note that mixing by weight might be a little different than mixing by volume as the hardener and resin may have different spesific weights. Check the spec sheet for the resin your using.
For really small batches (think ding repair) it’s hard to measure accuratly. Buy a couple of medium sized syringes (you don’t need the needles). Write R on one and H on the other and make sure you don’t mix them up when using them. Since they are graded in ml or whatever, you should be able to mix really small amounts with good accuracy. Store them separatly in plastic bags.
