Easy Cast Clear epoxy
- Thread starter TKBIG
- Start date
dropshipbob
Master Member
While I have no experience with this exact epoxy, doesn't heat play a big factor in the speed of curing in most resins and epoxies?
TKBIG
Well-Known Member
Thanks for the reply dropshipbob... :thumbsup
I just got an email response from a TAP plastics representative and thought I'd share the tips.
Easy Cast is temperature sensitive. That means that the higher the
temperature, the quicker the cure. There are a couple of ways to do this.
One is to heat the resin and hardener before mixing. This is best done by
putting the bottles in a pan of hot water until they reach the desired
temperature. Raising the resin and hardener temperature will also help to
reduce the viscosity (make them thinner) so that bubbles will disappear more
easily.
The other method is to mix and pour the resin into the mold, then put the
mold in a warm location. I have one customer that puts it in a big box with
a small hole in the side where he sticks a hair dryer. This turns the box
into a small oven. If you are in a warm climate, I have even put molds in
the back window of my car when it is parked in the sun.
I hope those ideas help. Thank you for considering TAP Plastics and I hope
the product works well for you.
I just got an email response from a TAP plastics representative and thought I'd share the tips.
Easy Cast is temperature sensitive. That means that the higher the
temperature, the quicker the cure. There are a couple of ways to do this.
One is to heat the resin and hardener before mixing. This is best done by
putting the bottles in a pan of hot water until they reach the desired
temperature. Raising the resin and hardener temperature will also help to
reduce the viscosity (make them thinner) so that bubbles will disappear more
easily.
The other method is to mix and pour the resin into the mold, then put the
mold in a warm location. I have one customer that puts it in a big box with
a small hole in the side where he sticks a hair dryer. This turns the box
into a small oven. If you are in a warm climate, I have even put molds in
the back window of my car when it is parked in the sun.
I hope those ideas help. Thank you for considering TAP Plastics and I hope
the product works well for you.
Last edited by a moderator:
exoray
Master Member
First off Polyester casting resins are a pain to work with.
Anyway I picked up a cheap toaster oven for under $20, I set it anywhere from 120º to 150º and drop the whole mold and casting in there and fire it up... Cheap, simple and safe...
You can also build a light box, knock together a wood crate, and mount a 100 watt light bulb in there and close the lid instant low heat oven...
I never had any real luck with any clear resins except urethane, what I do for them is cast under pressure for the recommended time, then I remove the part still in the mold I pop it in the oven @ 150º for 30 minutes remove it keeping it in the mold, let it cool back down to room temperature for about an hour and them pop the part out of the mold... Generally that is all it takes...
Anyway I picked up a cheap toaster oven for under $20, I set it anywhere from 120º to 150º and drop the whole mold and casting in there and fire it up... Cheap, simple and safe...
You can also build a light box, knock together a wood crate, and mount a 100 watt light bulb in there and close the lid instant low heat oven...
I never had any real luck with any clear resins except urethane, what I do for them is cast under pressure for the recommended time, then I remove the part still in the mold I pop it in the oven @ 150º for 30 minutes remove it keeping it in the mold, let it cool back down to room temperature for about an hour and them pop the part out of the mold... Generally that is all it takes...
TKBIG
Well-Known Member
<div class='quotetop'>(exoray @ Oct 13 2006, 06:12 PM) [snapback]1337752[/snapback]</div>
Amen brother.
I've had this stuff around the house now for a few months. Thought I'd attempt to use it again...."waste not want not".
Thanks for the tips..
Since my last post I popped them in the oven at 175 degrees for about 2 hours. That seems to do the trick although instead of crystal clear the parts came out very hazy.
Either way, thanks again.
Amen brother.
I've had this stuff around the house now for a few months. Thought I'd attempt to use it again...."waste not want not".
Thanks for the tips..
Since my last post I popped them in the oven at 175 degrees for about 2 hours. That seems to do the trick although instead of crystal clear the parts came out very hazy.
Either way, thanks again.
Chris Martin
Well-Known Member
Firstly, there is no such thing as polyester epoxy. It's either polyester or epoxy. They are two completely different chemistries. Although heating can speed up the cure time, if you're casting a large volume of either resin, it can get too hot which leads to cracks and bubbles in the resin.
Epoxy has a tendency to stick to some silicon rubber moulds so that when you demould your casting, it brings small pieces of mould with it. Polyester resin can stay tacky after it's cured due either to contamination with moisture in the atmosphere or due to the styrene in it soaking into the silicon rubber. In the worst cases, the silicon rubber mould can expand and distort if the absorption is high. Rinsing the resulting cast in cellulose thinner can remove the sticky surface. The silicon mould will more or less return to normal if you let it breath for a couple of days.
The worst problem about the tackiness is that Polyester resin shrinks quite noticeably. It tends to pull away from the mould and if the resin surface against the mould is not cured properly (which often happens), the surface is spoilt. Heating either resin can encourage shrinkage. If you put your mould somewhere merely warm and dry, I'd stick to the recommended curing times on the pack. There's a reason they're formulated to take a long time to cure. It's to give air bubbles a chance to rise, to keep shrinkage at a minimum and reduce the chance of runaway exothermic reaction occuring which will promote the first two problems. If it's a small piece, you might get away with it but if in doubt, practice that honourable old model making art of patience.
From a domestic point of view, polyesters biggest drawback is it stinks. You need to use it outside or away from the house. It's also very brittle. Epoxy resins have little odour which makes them far better for house projects but they rarely cure crystal clear. More often they have a brownish tint to them.
Epoxy has a tendency to stick to some silicon rubber moulds so that when you demould your casting, it brings small pieces of mould with it. Polyester resin can stay tacky after it's cured due either to contamination with moisture in the atmosphere or due to the styrene in it soaking into the silicon rubber. In the worst cases, the silicon rubber mould can expand and distort if the absorption is high. Rinsing the resulting cast in cellulose thinner can remove the sticky surface. The silicon mould will more or less return to normal if you let it breath for a couple of days.
The worst problem about the tackiness is that Polyester resin shrinks quite noticeably. It tends to pull away from the mould and if the resin surface against the mould is not cured properly (which often happens), the surface is spoilt. Heating either resin can encourage shrinkage. If you put your mould somewhere merely warm and dry, I'd stick to the recommended curing times on the pack. There's a reason they're formulated to take a long time to cure. It's to give air bubbles a chance to rise, to keep shrinkage at a minimum and reduce the chance of runaway exothermic reaction occuring which will promote the first two problems. If it's a small piece, you might get away with it but if in doubt, practice that honourable old model making art of patience.
From a domestic point of view, polyesters biggest drawback is it stinks. You need to use it outside or away from the house. It's also very brittle. Epoxy resins have little odour which makes them far better for house projects but they rarely cure crystal clear. More often they have a brownish tint to them.
Chris Martin
Well-Known Member
You'll be fine as long as you don't try to rush it. Speeding things up can often slows things down.
SG Merc
Well-Known Member
I don't want to pull this thread off topic, but I was hoping someone could answer a quick question about baking cured pieces.
How much fumes or vapors will baking a cured piece of resin create? Would it give off more or less harmful vapors than when the resin is still liquid?
How much fumes or vapors will baking a cured piece of resin create? Would it give off more or less harmful vapors than when the resin is still liquid?
Chris Martin
Well-Known Member
Generally, only epoxy benefits from post curing. Heating polyester can have it distort with no benefit in respect of curing. It will completely chemically cure after three weeks anyway. Epoxy too can soften when heated so take measures to ensure your subject keeps it's shape but heating can assist a full cure. If in the slightest doubt, don't chance it. The epoxy will get there. It'll just take a bit longer.
