Making ribbons for 1st time caster

[splinterinfinger]

Hi how much hardener would I have to use if I were to mix 5 fl oz of pr, the reason I now ask is I have had now two failures, I thought I put enough hardener in as per instruction from grub32’s video 15 drops per oz of pr.

Is it 5 fl oz to 1 fl oz hardener?

Is it 5 fl oz to 2 fl oz hardener?

Please help be great if you any other guidelines

By the way grub32.s videos are really helpful
Kind regards Mervyn

 

[stevers]

The problem I had is the changing temp and humidity in my shop. It's almost impossible to predict how long it'll take to flash over and be workable. I tried it once and it didn't flash by 11:00 or so so I tried it anyway and ruined the pour. They were still sticky and wouldn't stand up. I haven't tried it since.

 

[Glass Scratcher]

Grub32 says in his video that he used 15 drops per ounce of resin.

He also added external heat to the casting as it was taking to long to cure.

One of the problems faced with this is one induces cure inhibition by increasing the surface area which causes a reduction in the heat generated by catalyzing with the MEKp. You have to add external heat back to the resin to help it cure. You can use a hair dryer on low or a heat gun held off the resin by a few feet.

You could even pre-catalyze your resin with less MEKp, and let it sit, add your colorants, then as it is starting to gel in the cup, pour it out onto a preheated glass, or whatever you are using to make your ribbons on.

 

[splinterinfinger]

Hi all many thanks for the postings, thanks for the detailed info Glass scratcher, the 1st one I cast on to a large picture frame is just tacky after 24 hours the 3rd one I put more hardener ino the casting thinking that I had not put enough hardener in but now your posting explains why.
I will now rush down to the workshop and try the hair dryer.

Thanks guys.
Mervyn

 

[grub32]

Sorry...

I have to apologize for not being around to talk to everyone...Life is crazy...I certain that my pours drying slow were related to high relative humidity. I now know that they will dry much faster with a dehumdifier than with a circulating fan, thats what I used previously.

I have tried up to 25 drops and that seems to work too fast and makes it brittle quickly.

Let me know how it works out with the hair dryer...I am now leaving the dehumdifier on in the basement to bring it down to about 35% in temps of 68 degrees F.

Grub32

 

[bitshird]

I have to apologize for not being around to talk to everyone...Life is crazy...I certain that my pours drying slow were related to high relative humidity. I now know that they will dry much faster with a dehumdifier than with a circulating fan, thats what I used previously.

I have tried up to 25 drops and that seems to work too fast and makes it brittle quickly.

Let me know how it works out with the hair dryer...I am now leaving the dehumdifier on in the basement to bring it down to about 35% in temps of 68 degrees F.

Grub32

what a scoundrel, 68 degrees, you should be ashamed of your self why don't you work in the heat like us poor folk do, well since i can't work any way i guess that makes you the lucky guy doesn't it

 

[grub32]

I know...I am a bad person...I use the basement and sometimes the LOML doesnt like the smell much, but she sure loves the outcome...I am looking into an outside air exchange system to help out and also bring fresh air into the house. But 68...Its a good temp!!

Grub32

 

[jason_r]

Must be nice. Last pour I did was large (over 25oz of resin in 1 block) and it was ~95 degrees.
I poured it as 2 swirls- dual colored green for the bottom half, added dual shades of purple for the top
after the green had gotten good and firm but not yet cured.

I cut the MEKP to 2 drops/oz and it still gelled in 20-25min.

Of course, the flip side is that post-curing is easy. Just set things on the black trashcan with
a clear cover.