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Resin mold release agent removal help


Khils

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I'm sure this has been covered before, just couldn't find it.   In the past I have used Whestley's bleach white ....but no longer available

in this one horse town.   Other resin safe products you are using? Thank you in advance for your time! Kevin 

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14 hours ago, gotnitro? said:

Dawn dish soap w a shake of comet cleaner also works , scrub with an old toothbrush, rinse, air dry. Been using this on a few resin parts lately. 

Hope it helps 

I'm not sure I'd endorse the use of Comet. It's an abrasive, and if it is not thinned with enough water/Dawn, it becomes a paste that can scratch the part.

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2 hours ago, BigTallDad said:

I'm not sure I'd endorse the use of Comet. It's an abrasive, and if it is not thinned with enough water/Dawn, it becomes a paste that can scratch the part.

Comet might be on the coarse side, but most cleansers (with plenty of water) work pretty well.  I've never mixed cleanser with Dawn dish soap...not saying it doesn't work though. 

Too, do the cleaning BEFORE doing any sanding, filing, or grinding on the parts.

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The use of comet isn't really an issue when using dawn and water imo. The parts I've done still require primer and painting...which fills in the tiny scratches you MIGHT get . I don't scrub the part just a light washing works fine...but it's just an idea .

I use duplicolor primers for everything they bite into resin like a dog on steak.

 

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7 hours ago, BigTallDad said:

I'm not sure I'd endorse the use of Comet. It's an abrasive, and if it is not thinned with enough water/Dawn, it becomes a paste that can scratch the part.

I've been using Comet to surface-scuff styrene parts for years, and there's no issue with "scratching".

Comet and a vigorous scrub with hot water and a toothbrush uniformly scuffs a styrene part for great paint adhesion. It gets in ALL the nooks and corners that sandpaper and Scotch-Brite pads miss, but it doesn't obliterate details like sanding can. If it doesn't trash soft styrene bodies, it's not going to hurt resin.

But don't take my word for it.

 

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For that matter, hot tap water, an old toothbrush, and a used bar of plain old Dial soap works perfectly well--it's been my "go-to" stuff for removing the mold "barrier coating" (like a mold release agent) used by most high-quality resin casters),  as well as the skin oil from fingerprints on even styrene model kit bodies.  Just hot tap water, wet the hand soap, scrub a toothbrush on it, and scrub the model kit body and body panels with it--rinse thoroughly with running water, and either gently "pat" the body shell dry, or blow the remaining droplets of water away with my airbrush hose.  (Been doing this for a good 60 yrs or so)

Art

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I second Art's advice and will add to it. Both Art and I are long time resin casters and builders. I also find that simply wet sanding your resin partsgets rid of the so- called "Release Agent".

Here is another tip. Use an airbrush and spray one or two light coats of paint. Don't lay down wet coats on the resin. It will fisheye. Spray can paints have extra solvents in it to keep it more sprayable for longer shelf life. Those are what cause the fisheyes. I have sprayed dry film mold release on a body and shot paint on it from an airbrush as soon as it flashed off which was about 20 seconds. It was just fine.

 

Basically if you are having problems with paint on resin you are seeing the interaction between the waxy surface of the resin and all the extra solvents in your canned spray paints. That also applies to decanted spray paints that are airbrushed.

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3 hours ago, BigTallDad said:

So much for trying to be helpful. 

Nothing wrong with trying to be helpful.

But it just so happens I HAVE used Comet successfully for years...so why shouldn't I mention it?

Not trying to hurt anyone's feelings or be a know-it-all (of which I'm constantly accused); I just have this (rude, arrogant, big-head) thing about sharing the actual truth that I know from first-hand experience.

The "scratching" associated with Comet creates the dulling effect on countertops, enameled surfaces, etc. It also dulls shiny molded tires nicely. The "scratches" are finer than 600 grit sandpaper.

But hey...if all y'all would just prefer I keep things I actually KNOW to myself, rather than disagreeing with "opinions", I'll be happy to never post real info again. Ever.

MORE than happy. 

Edited by Ace-Garageguy
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  • 2 weeks later...
On 2/20/2018 at 4:57 PM, Ace-Garageguy said:

I've been using Comet to surface-scuff styrene parts for years, and there's no issue with "scratching".

Comet and a vigorous scrub with hot water and a toothbrush uniformly scuffs a styrene part for great paint adhesion. It gets in ALL the nooks and corners that sandpaper and Scotch-Brite pads miss, but it doesn't obliterate details like sanding can. If it doesn't trash soft styrene bodies, it's not going to hurt resin.

But don't take my word for it.

 

Man...I thought I was the only one that did this to my models pre-paint...difference being that I use the cheapo paste style toothpaste...gives the plastic such a nice lovely finish for primers...and like you said...every nook and cranny.

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5 minutes ago, dbiggied said:

Man...I thought I was the only one that did this to my models pre-paint...difference being that I use the cheapo paste style toothpaste...gives the plastic such a nice lovely finish for primers...and like you said...every nook and cranny.

I started doing it when I noticed occasionally primer would "pull away" from corners or details that sandpaper or Scotch-Brite couldn't effectively deal with.

Doing a thorough scrub with a mild abrasive and hot water, and a thorough wipe-down with isopropyl alcohol just prior to spraying, and my contamination and adhesion problems dropped to zero.

There is apparently one potential downside. The abrasive scrub, while "breaking" the gloss on injection molded plastic parts, also makes them just a little more sensitive to "hot" solvents in automotive aerosol primers. 

 

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  • 3 weeks later...

This may seem like a silly question, but would Castrol Super Clean work? I've soaked resin bodies in it to remove the release agent, washed the body with warm water and dish soap and never had any issues.

Edited by impcon
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