how to know how much hardener?

[EyeofSauron]

so, my resin shipment arrived today, and i got enough hardener and stuff

well now, as it is polyester resin, it says: 1,3-2,4 % of hardener versus resin

now how the hell should i know how much 1,3-2,4 % are?

 

[pandatrooper]

Usually, I calculate by weight using a digital scale and mixing cups (subtracting the weight of the cups).

 

[terra1]

my resin came with instructions... 2-3cm per 10ml! centimetres!!!

i mixed 20cm toothpaste style hardener per 100ml.

id go with the middleish suggested amount, if not enough hardener it wont set for days and to much it will be unworkable within 5 mins.

eyeball it on a test mix.

what resin is it??

 

[EyeofSauron]

well it polyester resin PHD-DIEPAL 1981 B/55

if that helps

my digital scale doesnt go that low, so that kinda sucks (because on 100 g thats a max of 2,4 g, which isnt really acurately measurable )

also, i think it is supposed to be in drops, because it comes with that kind of tip on the bottle

how many drops do you think there need to be on a regular plastic cup(.25 liter)

 

[Dougie Fett]

well it polyester resin PHD-DIEPAL 1981 B/55

if that helps

my digital scale doesnt go that low, so that kinda sucks (because on 100 g thats a max of 2,4 g, which isnt really acurately measurable )

also, i think it is supposed to be in drops, because it comes with that kind of tip on the bottle

how many drops do you think there need to be on a regular plastic cup(.25 liter)

The kit I got before had a small syringe for measuring the catalyst!
Maybe try one of those, can get them in a chemist/pharmacy.
And then just weigh the resin with an accurate gram scale.

 

[PepMaster]

With my resin I use the 3M/Bondo Resin, which I use cups so 1/4 a cup of resin is 24-28 drops of hardener. Depending on the tempature outside.

 

[Bowelrock]

Ill be honest.. I eyeball it.. 1 drop of the hardener can kick off a 5 gallon bucket over time i have seen it happen.

 

[clonesix]

Polyester resin to catalyst ratio is 100:1, or 1% catalyst. This should be adjusted up or down with temperature. Its summer, and hot out there, so you can cut that to .5%.

The best way to get this is to use a triple-beam balance scale and weigh everything. If you are going to do a lot of laminating, invest in one, they are worth it.

Without a scale, the next best method is volume (and this IS why metric is better) Most of the plastic mixing cups you get at the hardware/paint store have the measurements printed on the side, in litres. A litre is 1000 g. You will also need a small measuring cup with cc (cubic centimeters) on the side. These are found at your hardware/paint store, or at the pharmacy.

1 cc of catalyst weighs 1 gram


500 g resin, or 1/2 litre, takes 5 g catalyst, or 5 cc. (3 cc in hot weather)


You can be off on the measurement, and It will only effect the cure time.



One last note: Resin cures by volume and heat. So if you are done and have an inch of resin in the bottom of the cup, DO NOT let it sit and walk away! It will generate enough heat to smoke, and create toxic fumes, possibly a fire! At the very least, ment the plastic cup.

After it solidifies, add water to the top until finished curing, and then you can throw solid material away.

 

[Luis Abreu]

Im using this prestolith special Polyester Resin - motip-dupli.de, its my second try and im guessing that this second go isnt going to cure also. My hardener is not liquid. Its kind of a paste, this time iv put 4 "drops" but i guess its still to little cuz i put my build on the sun curing and its still sticky!

 

[ApophisV]

I've used the Prestolith polyester resin as well, though I stopped using it since it always stays sticky which makes it pretty annoying for me! I'm not sure if I made a mistake, but my experience is that Epoxy cures to a great surface while Polyester Resin doesn't.