Technique Question re: Using Resin for Deep Water

[Wren]

When pouring resin, people build containers to hold the product until it sets. I\'ve seen a few examples of this for square bases with containers made from styrene and so on.

I\'m considering something that would be a freestanding non-square shape. Would forming it from a piece of plasticene or Play-Doh work? Would the resin stick? Would it work to put Saran Wrap inside the plasticene mould to keep it from sticking? I\'m not concerned about that adding wrinkles to the surface, it might even enhance what I\'m looking to do. How long does the resin take to set enough to demould it? I\'m on a bit of a deadline so I might have to reconsider the idea if it takes weeks to set or something.

 

[freakinacage]

as i understand it, the trick with deeper water is to build it up in layers. that way it doesn\'t take as long to dry (if at all, i tried with deep water once and it simply formed a skin)

i\'m not sure about the whole cling film idea. i know some resins dissolve it. maybe tape? or if you are using plasticine, you could smear the inside with vaseline? have and experiment before trying it on the real thing though. hope this helps (it probably doesn\'t!)

 

[usurpator]

Never attempt something for yourself for the first time (no matter how much info you\'ve got) when you are on a deadline!
I\'m serious here!

 

[Einion]

Originally posted by Wren
Would it work to put Saran Wrap inside the plasticene mould to keep it from sticking? I\'m not concerned about that adding wrinkles to the surface, it might even enhance what I\'m looking to do.

This is something you\'d have to do a test pour on unless you can find a specific

or

for the brand you\'re using.

Using petroleum jelly as freakinacage suggested would be safer (even brushed thinly over the Saran Wrap maybe) since this is very commonly used in casting as a release agent, both for the silicone rubber and resins.

Originally posted by Wren
How long does the resin take to set enough to demould it? I\'m on a bit of a deadline so I might have to reconsider the idea if it takes weeks to set or something.

Typical casting resins take only a couple of hours to set, not to worry. At most you\'d have to wait a day.

Einion

 

[generulpoleaxe]

liquid vaseline is better (the jelly type stuff leaves subtle ridges etc that are then left on the resin)

takes a good day for roughly 1cm of depth to fully cure wren.

 

[freakinacage]

Originally posted by Einion

Using petroleum jelly as freakinacage suggested would be safer (even brushed thinly over the Saran Wrap maybe) since this is very commonly used in casting as a release agent, both for the silicone rubber and resins.

yay!

 

[airhead]

Wren, I cannot answer your question directly, but try not to pour more than about an inch at a time. Too much means it gets too hot and ends up cracking internally.

There is generally a range to add hardener (read) 6-20 drops per ounce (for example only !) You can pour thicker with the 6 drops, but it may take 24 hours to cure. You must pour thinner lifts with the 20 drops/oz. but it will cure in 30 minutes.

This all also depends on humidty, ambient temperature, initial temperature of the resin, how well the mold holds heat, etc.

When I was trying the gelatinous cubes, I found that mixing a bit of hot (20 drops) resin and painting over the cube with a disposable brush would give me a nice hard \'wet\' finish that helped hide mold lines and scratches where I had filed off seams.

 

[hakoMike]

The water effect I used recently took *weeks* to completely cure to the point where it wasn\'t still tacky, but I was able to brush over it with GW \'ard stuff to get a non-sticky finish in about a day.

I glued scotch tape to the inside of my fixture (sticky side toward the resin) to help me get the fixture loose from the resin. The resin I used is unrelenting when it adheres to anything solid.

 

[Wren]

Thanks for the replies everyone. I did some searches for general information trying to figure out what product to buy, and thought I would pass along some of what I learned in case it helps anyone else.

From what this person says, there are a few basic types of casting resin. What airhead describes sounds like a polyester resin. I ended up buying the Magic Water product, partly because I could get it locally. Between its expense and the fact that it mixes 2 parts to 1 part, I think it sounds like what the FAQ writer describes as an epoxy resin. It\'ll take minimum 24 hours to set, so I figure I\'ll be able to do an experiment or two before deadline looms. I\'m a little concerned as it seems like the manufacturer doesn\'t intend it for moulds at all, so not sure if it\'ll demould at all, but should work great for some bases that have been giving me problems if nothing else. ;-> I\'m a little tempted to order away for this product, as it has such a quick cure time. All of them sound pretty nasty for fumes and toxicity, which should be fun given that I get sick from the fumes of Tamiya clears. ;->

hakoMike - I\'m not sure what category the florist \'water\' falls into. During my searching I saw a link about a similar product that said something interesting. It said the product fully cures where it\'s _not_ exposed to air. If the top of the item stays tacky, they recommended doing exactly what you did - varnishing it to seal it and promote full cure. I\'ve got some \'ard coat ready if I need it. I was also think of using it on the item I want to embed in the resin to make sure it doesn\'t leach into the resin.

usurpator - Normally I would totally agree with you and follow your advice about not experimenting on a deadline. In this case the deadline is for the Iron Painter contest, and the nature of that contest is to push one\'s boundaries and experiment. My opponent seriously outclasses me, so I\'m pretty much out this round. At least this way I get to learn something new and go down fighting. ;->

 

[airhead]

Wren, yes, I was talking about the casting resin you can get at the hobby shops/craft stores to make \'acrylic\' paperweights and such. Polyester resin with dropper bottle of hardner.

I\'ve found most epoxies have a yellowish tint - unless you specifically ask for a casting clear type resin. But they tend to be much more forgiving in the ratios. 1:1 or 2:1 are normal - stay close and it should set.

looking for lots?
try bateau boats - I got a sample/starter box for about $20, microballoons (snow), wood flour, a quart of epoxy, cloth, spreaders, and some other goodies.

http://boatbuildercentral.com/proddetail.php?prod=E_try

 

[generulpoleaxe]

wren, use liquid vaseline on the mould and it will come away from the resin without problems (just did my first deep water base)

you can use gw inks to colour it as well (it only needs a tiny amount)

and make sure the mould is fully sealed as the resin will get through any gaps (had bits of filling and sanding to do afterwards as i hadn\'t double checked for gaps)

 

[Wren]

I don\'t think I\'ve ever heard of liquid Vaseline before, where do you get that?

 

[airhead]

I get my mold release from these guys:
http://www.smooth-on.com/

My local artist supply (Pearls) carries their product.

I tried thinning Vaseline with mineral sprits to make a brush-on release. I don\'t think I got it right.
:no: lol

 

[generulpoleaxe]

i can only find it online here http://www.homecrafts.co.uk/html/product.asp?cat1=1&cat2=1493&cat3=4474

sorry, it\'s uk based.