Green Stuff: Increase Curing Speed

[nat is me]

Hey guys

I really enjoy sculpting, and have been doing so for a while. One thing that is starting to annoy me is waiting...Im not very patient when I really get into something and realise I cant touch it for two hours.

Now I was wondering what methods can be used to speed up the curing process of green stuff.

Ive heard of using different %\'s of the two parts of the expoxy putty, but Ive found a consistency that I find comfortable to work with and dont really want to change it.

Ive also heard that heat speeds up the process. What do you guys suggest I use to heat up the green stuff to make it cure faster?

If possible, it would be nice if I could get back to sculpting on a workable surface after 20-30 minutes. Is this possible?

Ive thought of heat lamps as a possibility. Could anyone suggest appropriate bulb wattage?

If you have any other suggestions it would be greatly appreciated

Cheers

Nat

 

[Jericho]

I haven\'t done a terribly large amount of sculpting in my day (well I\'ve done a lot of small things, not like full scratchbuilds) but heating with a lamp does work.

I remember back in the day people were talking about putting a 40 or 60W bulb in a coffee can with a hole cut in the side to let minis in and out. One thing you have to be really careful of is getting things too hot. Greenstuff goes softer under heat before the reaction starts to happen, so that can be an issue with high temperatures.

There\'s also safety concerns, you don\'t want to burn the house down trying to speed up the GS curing process now do you I put an unsightly ring on some furniture once when the lamp was too close to the table and it started to cook a bit... oops

Finally, mixed materials don\'t all take heat very well. If you have plastic elements to the model, or if it\'s mounted on a plastic base, then this is probably not an option. Heating up the model has a very good chance of warping the plastic to some degree. If there\'s any bubbles in the plastic (which isn\'t uncommon) then it\'s even worse.

So yeah, I don\'t know if you can get anything in 30 mins or less, but you might make it so that you can be more or less ready to work again after an hour. I\'m sure someone with more experience cooking greenstuff will be more help than me.

 

[lahatiel]

Info from pages 15-16 of the 1listsculpting Yahoo! group\'s FAQ, found at: http://www.lyonstudio.biz/Sculpting/1listsculpting_FAQ_v2-4a.pdf

3.5 - How do I get Kneadatite\\epoxy putty to cure faster/slower?

Two-part epoxy putties harden by a chemical reaction of the two components. This means that they do not need heat,
like some other sculpting materials containing solvents that have to be evaporated. Still, heat can help to make curing
accelerate. This is already the case with normal curing. The chemical reaction will generate heat, which has the side
effect that thicker areas will cure before thinner areas. There is more material in the thicker areas, which will generate
more heat that will, in turn, speed up the curing reaction.

There are a number of ways of applying heat externally. The most common is by using a lamp. Either place the mini
close to a lamp bulb or make a \"putty oven\" using something like a metal coffeecan with both sides open and the bulb
sticking through the top. Bulbs from 15-40 Watts have been suggested. Bob Lippman measured the temperature in his
\"oven\" and it was about 105-110 degrees F (40-44 degrees C). Jason Wiebe also noted that it\'s possible to use a toaster
oven, as is sometimes used for polymer clays. And hot water for a final suspended dip.

The putty will first become soft when heated; and will start hardening after that. Don\'t touch the sculpt in that period
and make sure it is not resting on an area of uncured putty! It is also possible to make use of this property, as the putty is
a bit stickier when hot. So for better adherence, you can lightly warm the putty before applying it. Just don’t heat it too
long, as that will harden it again. Overheating can cause problems (like creating a spongelike (weaker) structure in the
figure) and care has to be taken to avoid this.

Some details by Bob Finkenauer:

* Kneadatite has about a 90-minute work-life when tested at 75 degrees F (24 degrees C). As a rule of thumb,
every 20-degree F increase in temperature cuts the work life in half -- and every 20-degree F reduction in
temperature doubles the work life (place some mixed Kneadatite in the freezer and it will freeze, but not cure -
warm it up and it will start to cure again. See 3.4.

* The 15-watt bulb idea is a good one. Have you ever measured the temperature inside the can? I\'d recommend
keeping the temperature under 120 degrees F (49 degrees C) while curing.

* Other variables are the mass and shape of the mixed Kneadatite. A 5-gram piece of mixed epoxy in a thin strip
will cure more slowly than a 100-gram ball of Kneadatite, provided that all other conditions remain constant.

* If you want to get the Brown/Aluminum to cure harder, one idea you might want to try is warming the mixed
putty to about 95 degrees F for a few minutes after it is cured. The cured putty will actually soften a bit while it
is being warmed, but after the heat is removed and the cured putty is allowed to return to room temperature, it
may actually be harder than it was before the warming process. The heat should actually force the molecules of
part A and B to react to a greater extent and thus increase the hardness.

 

[lahatiel]

Ah, and here\'s what I was really looking for: Ming Hua\'s (MiniMaker here and elsewhere) photo with text description of his putty oven:

His PhotoBucket album is great resource for all things sculpting-related:

http://smg.photobucket.com/albums/v490/minimaker/

Note: there are no pictures in the main album; use the links to the sub-folders along the left-hand side to look at particular sections.

 

[nat is me]

Thanks for the great advice and tips guys.

Iahetiel: Thanks for the site, its brilliant. It holds a wealth of knowledge. I\'ll be sure to add this to my favourites list

Much appreciated

Nat

 

[Shawn R. L.]

I just put stuff on the dashboard of my car and that does the trick. Have them in a shallow box, because going around a turn and having all your work go sliding away is a bit distracting.

 

[freakinacage]

i bought a portable fridge for a tenner that has a heat option on it. it\'s great - nice and small, has shelves and only goes to a certain temp so you wont burn your work. highly recommend it