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Stripped resin body, now soft.


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True, but when was the last time you've seen a paint stripping recommendation provided in a resin kit?

They will usually recommend a particular product or two for removing mold release agents.

Usually this will be Super Clean or Wesley's Bleche White.

Both work well as paint strippers in most cases.

I've never had problems with resin & Super Clean, but I'm sure it has a lot to do with the composition of the resin.

I've used it on Modelhaus & Flintstone stuff & have never had issues.

 

Steve

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Hi,

The body is mostly rubbery, are there hardeners one can use to stiffen it up?

Will a polyester resin hardener work?

NO.

"Polyester resin hardener" is actually an oxidizer / catalyst, the most common one being MEKP...methyl ethyl ketone peroxide, and it ONLY has any effect on still-liquid ESTER resins. 

Most "resin" parts these days are very likely to be urethane-based anyway, and once cured, aren't going to be affected any further by catalysts or hardeners...especially those used in resin systems based on different chemistry.

MEKP is also highly toxic and can be dangerous if handled improperly, is corrosive to soft tissue and can cause explosions and blindness.

Edited by Ace-Garageguy
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Hi,

The body is mostly rubbery, are there hardeners one can use to stiffen it up?

Will a polyester resin hardener work?

As others have stated, no.  Polyurethane resin,  thus compromised, will harden up over time, but if your parts (body shell?) are warped (and almost assuredly they will be) they likely are beyond saving.  I had, on several occasions, a customer or two who did pretty much what you did, with the same results, even with a warning clearly printed on the cover page of every catalog I sent out, and included with every order.  I even bought back (as in replaced) a couple of such bodies, to show potential buyers what would happen with commercial paint strippers.

Art

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Hi,

Thanks to every one for taking the time to reply.

I've nothing to loose and can be tenacious at times, I am having some success using thin super glue.  I'll update with final results once the day is complete.

The body is the wonderful Fisher 908 so I don't wish to give up so easy.

Edited by aurfalien
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Hi,

I found a solution to save it.

I'm pouring very thin coats of 2 part resin inside the body, small sections at a time.  The set time is quick and I let it sit a few seconds before applying to further avoid running.

This is to give it more structural integrity.  I can deal with the outside using putty etc...

In celebration, I am buying the HRM 917 engine kit from Randy and will build a prototype 908 CanAm sort of thing.

I'm pleased.

Edited by aurfalien
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Brian, I don't want to be a killjoy, but I'd be suspect of painting over a surface that was once stable, is now compromised by the stripper that you used. Seems to me that the stripper leached into the resin (porous) and softened it up as you described. I'd be wary of those same chemical compounds which may still be "buried" in the resin, making their way through to your paint job over time.

I've not built many resin kits, but this is more of a skeptical approach on my part as I've had strange things happen over the years with a paint job on plastic after it was stripped.

It's up to you, but just a word of great caution where you might want to test your paint in a small area-------wait a bit to ensure there won't be any surprises later. 

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I'd try to let it dry out for a few weeks, and see if it comes back to normal. If not, I might try coating it with superglue, as I do with common putty to strengthen and stabilize it.

Common naphtha (lighter fluid) will soak into kit styrene, and not melt it, but will turn it crumbly, like a cookie. But let it dry out thoroughly and it's fine. I wonder if something like that might happen here.

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Hi,

Great idea, I've no issues waiting.

I stopped coating the under body with resin as I did a small area for testing.  I've let it soak in warm water over night hoping to leach out any chemicals.

I noticed the water was a bit different after words so the soak did something.

Will let it dry for a few to see what comes of it.

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