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soaking resin and styrene parts to clean


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In over 50 years of plastic modeling, I've only ever seen one (styrene) kit that REQUIRED cleaning some kind of "release agent" off of it: an ICM YAK-9 (Russian WWII fighter).

I've never made any special effort to wash a kit body (or other parts) BEFORE working on them. AFTER sanding, removing mold lines, and so forth, I'll usually clean a body with either Windex or rubbing alcohol.

Now, resin, that can be another matter....

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I use dish soap and a stiff tooth brush for resin and plastic. All bodies get sanded before paint so that gets rid of any heavy contamination then they are scrubbed with the brush and dish soap and rinsed in hot water.

Most styrene parts don't get washed at all, I've never had a problem. BUT the AMT 70 1/2 Baldwin Motion kit that I got a few weeks ago has an oily residue on it. All parts to that kit will have to be washed.

All resin parts get washed and scrubbed with the dish soap and tooth brush and hot water before paint.

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In over 50 years of plastic modeling, I've only ever seen one (styrene) kit that REQUIRED cleaning some kind of "release agent" off of it: an ICM YAK-9 (Russian WWII fighter).

I've never made any special effort to wash a kit body (or other parts) BEFORE working on them. AFTER sanding, removing mold lines, and so forth, I'll usually clean a body with either Windex or rubbing alcohol.

Now, resin, that can be another matter....

Yeah, sorry.

I misread the thread heading.

I thought Jeff was asking about resin parts.

There's no need to soak styrene parts.

Just a good cleaning with some warm water & dish detergent is all that's needed before paint.

 

Steve

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In over 50 years of plastic modeling, I've only ever seen one (styrene) kit that REQUIRED cleaning some kind of "release agent" off of it: an ICM YAK-9 (Russian WWII fighter).

That kit.....

I love the kit itself. It builds into a beautiful model of a beautiful and important airplane. I but I don't know WHAT ICM bathed it in. I have built three or four, and the newer boxings didn't have an issue, but all my old ones did. Not only did they positively ooze oil, they stank something fierce. And it wasn't easy to wash that grease off. The first one I built, I washed it then set it out to dry. When I came back a day later, it was greasy again. I ended up soaking it for several days in Windex.

I have seen this in other ICM kits of similar vintage, by the way.

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Like a couple of the guys posted above , there is no need to "soak" the resin in anything. I have never soaked a single resin part. A simple wash with hot water and dawn, scrub with ScotchBrite and keep it clean and oil free and you are good. I usually add a bit if TSP to the hot water as this is an excellant degreaser and works well with the Dawn.

 The mold releases the casters use are no different then what the injection mold guys use. You never hear you have to soak styrene to get it clean. So why do you have to soak resin? There is no basis in fact on this "opinion" and it is just an old wives tale... I wish it would go away...

 if you do a search you will see about a dozen of these threads and I and Art Anderson trying to dispell the myth... :)

Mark

Edited by astroracer
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 if you do a search you will see about a dozen of these threads and I and Art Anderson trying to dispell the myth... :)

Mark

If it's a myth, why do most resin casters recommend soaking in something to remove those agents?

I won't pretend to be an expert on this subject, but it seems to me if Modelhaus recommends it, what is the reasoning behind it.

I started a resin kit many years ago not knowing anything about mold release agents & just prepped as I normally would, with soap & water.

Fish eye city!!

I have no clue if doing something different would have helped or not, but when I realized a release agent was used, it made perfect sense to me.

Not looking to start a war or anything, just curious.

 

Steve

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Hi Steve, no worries on the war thing. :) I don't know how or why this got started, it really doesn'y matter. It's just something that has proliferated and has no basis in fact. Soaking over night does nothing different from a quick wash and scrubbing with hot water and TSP. The key ingredient here is the TSP (Trisodiumphosphate).

The real issue here is, in fact, not the mold releases themselves, but the silicone rubber that the molds are made of. Removing the thin film of silicone that attaches itself to the resin during the molding process is what you need to do. TSP is a degreaser designed to remove this silicone film. House painters use it extensively when prepping vinyl and aluminum siding for paint. I use it everytime I paint a full size car to wash and scrub every surface that is getting painted to remove the road grime AND ArmorAll. Silicone... The TSP does this very well and I have no problems with fisheyes.

 Wesley's used to have TSP in it. The formula has been altered since Black Magic bought out Wesley's. There is no TSP in it now... I don't know how it will work for cleaning the resin. I just use TSP bought at the hardware store and mix it with hot water.

As everyone knows, styrene kits are not produced in "rubber" molds so they don't have the silicone issue.

Mark

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In over 50 years of plastic modeling, I've only ever seen one (styrene) kit that REQUIRED cleaning some kind of "release agent" off of it: an ICM YAK-9 (Russian WWII fighter).

I've never made any special effort to wash a kit body (or other parts) BEFORE working on them. AFTER sanding, removing mold lines, and so forth, I'll usually clean a body with either Windex or rubbing alcohol.

Now, resin, that can be another matter....

What he said

The only time I wash a model is after it has been exposed to a paint remover.  Otherwise I just prime and paint.  Never had one problem with paint of any kind.

 

 

Edited by snacktruck67
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What he said

The only time I wash a model is after it has been exposed to a paint remover.  Otherwise I just prime and paint.  Never had one problem with paint of any kind.

 

 

I guess maybe I've been spending too much time restoring old kits.

Sometimes they need a light rinse! :D

 

Steve

 

 photo DSCN5032_zpsbrnthxc3.jpg

 

 

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Be Careful using alcohol on resin parts especially denatured alcohol.  You might literally rub away a script on a body or part.  That is one reason I don't use the 300 series white resin from Smooth - On,  I use their Task 8.  Once it cures it will withstand being boiled in water and is chemical proof.  If the recommended curing process was followed it would be good for 260 degrees of heat.

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 The mold releases the casters use are no different then what the injection mold guys use. You never hear you have to soak styrene to get it clean.

 if you do a search you will see about a dozen of these threads and I and Art Anderson trying to dispell the myth... :)

Mark

I was told that no mold release agent is used when injection-molding styrene parts.  Go figure. If Art is familiar with injection-molding styrene process I hope he chimes in.

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I was told that no mold release agent is used when injection-molding styrene parts.  Go figure. If Art is familiar with injection-molding styrene process I hope he chimes in.

True, MOST of the time the ejection of the parts is left up to the design of the mold, shrinkage of the parts as they cool and the ejector pins used to push the sprues out. Sometimes you get sticky parts that don't like to pop out easily and this is where a mold release may be used. I worked at a small shop where I designed injection mold dies and one of the dies would get sticky after it ran for a couple of hours. A bit of mold release spray would help the sprue pop out during the ejection cycle.

Mark

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