Filling pinholes and bubbles in resin

John O · Post by **John O** » Fri Dec 10, 2010 6:11 pm

I have several beautifully mastered but not so beautifully cast kits that I have bought over the years. I would like to finally build up one of two over the coming holidays, but with all of the resin kits I've built, I have yet to find a reliable or efficient way to fill bubbles and pinholes. I'd really appreciate some tips.

Thanks for any help.

John O.

Andrew Gorman · Post by **Andrew Gorman** » Fri Dec 10, 2010 8:37 pm

Clean them up, blast on a thick layer of scratch filling primer from the auto parts store, then sand most of that off with 600 grit sandpaper. Repeat as necessary. If the holes are really big, wipe on some Apoxie Sculpt and clean up the resin surface with a rag, or use some glazing putty, also from the auto parts store, but it will shrink more.

Post by **TER-OR** » Fri Dec 10, 2010 11:38 pm

The Gunze Mr. Surfacer is essentially filling primer. You don't want to sand it down to where you see the underlying material, just to smooth the primer. you can also use a cotton swab and alcohol to smooth.

Kylwell · Post by **Kylwell** » Sat Dec 11, 2010 1:01 am

Provided you'd like to keep some of that hard paid for detail, I'd shoot it with Mr. Surfacer 1000 to find the ugly spots then fill with Mr. 500, Aves, or rubberized CA depending on the application.

Then it's sand, prime, repeat. What Ter says is very true, if you can just start to see the resin through the primer you've gone far enough.

John O · Post by **John O** » Sat Dec 11, 2010 10:51 am

I appreciate everyone's replies. I think what I'm dealing with might fall more under Andrew's comment, "wipe on some Apoxie Sculpt and clean up the resin surface with a rag, or use some glazing putty..." than blasting anything with primer.

I'd hoped to avoid posting pictures so as not to have the kits identified, but I don't think there is any way around it to get usefull answers. Here are a couple of pics of the many, many holes I need to fill:
http://picasaweb.google.com/jeovington1 ... 4114282818
http://picasaweb.google.com/jeovington1 ... 8979541090

With other kits having similarly measled out detail, I have tried a mix of glazing putty and zap-a-gap to fill. It's just so damned difficult to get the mixture into the holes. It makes me wish I could miniturize myself just a little, along with a caulking gun and 10 cases of caulk, and I'd be set.

John O.

Kylwell · Post by **Kylwell** » Sat Dec 11, 2010 11:58 am

I hate to say it, but that's "contact the manufacturer for replacement" kind of flaws.

The easiest way to fix a lot of that is carve the detail off and replace with sheet stock and tubing.

Andrew Gorman · Post by **Andrew Gorman** » Sat Dec 11, 2010 4:14 pm

That is nasty! One thing that will work is to fill holes like that with baking soda and then solidify it with crazy glue. You can flatten and do some shaping of the powder as you are packing it in. I've never had problems with this method-I have one model that's 10 or 11 years old and is still solid.

PetarB · Post by **PetarB** » Sun Dec 12, 2010 3:37 pm

I think Kylwell's response is the way to go here. That is nasty!

Post by **TER-OR** » Mon Dec 13, 2010 10:20 am

With some of those you're going to need structural repair, even more than pinholes...epoxy is your first choice, superglue your second. Replacement is a good option, too....

I've used the blac, CA a number of times to fill long holes, but i'm always concerned about curing down inside. It's nice that it can flow, though.

Rocketeer · Post by **Rocketeer** » Mon Dec 13, 2010 3:00 pm

Andrew Gorman wrote:That is nasty! One thing that will work is to fill holes like that with baking soda and then solidify it with crazy glue. You can flatten and do some shaping of the powder as you are packing it in. I've never had problems with this method-I have one model that's 10 or 11 years old and is still solid.

But I've had problems with it. Many years ago, I did extensive bodywork on a 1940 Ford using superglue and baking soda. Several years later, oily-looking stains appeared in the paint where the bodywork was done. I've stopped using superglue/baking soda for bodywork because of that. Other posters on other newsgroups have reported similar problems, so it isn't just my ineptitude.

That rant completed, I have to say, your model looks really rough. If I were in your situation, I'd consider the remove-detail-and-rebuild option someone recommended.

Tankmodeler · Post by **Tankmodeler** » Mon Dec 13, 2010 8:15 pm

Yeah, them's nasty bubbles.

I agree with the others, it's gonna require a combination of epoxy putty, CA and wholesale rescratchbuilding of the details to get that back to a reasonable state where Mr. Surfacer can even start to contribute to the recovery.

I'm not going to suggest getting new parts on the off chance that the manufacturer is out of business (What? A GK maker go out of business! Never!).

Paul

ajmadison · Post by **ajmadison** » Fri Dec 17, 2010 10:50 am

Rocketeer wrote:
Andrew Gorman wrote:That is nasty! One thing that will work is to fill holes like that with baking soda and then solidify it with crazy glue. You can flatten and do some shaping of the powder as you are packing it in. I've never had problems with this method-I have one model that's 10 or 11 years old and is still solid.
But I've had problems with it. Many years ago, I did extensive bodywork on a 1940 Ford using superglue and baking soda. Several years later, oily-looking stains appeared in the paint where the bodywork was done. I've stopped using superglue/baking soda for bodywork because of that. Other posters on other newsgroups have reported similar problems, so it isn't just my ineptitude.

That rant completed, I have to say, your model looks really rough. If I were in your situation, I'd consider the remove-detail-and-rebuild option someone recommended.

I have heard about good results by using similar powders that are not water soluble, which is what is wrong with using baking soda. If you can find pure talcum powder (one that does not have additives in it, like, chuckle, baking soda), try that.

However, from the pics I saw, and this is true of resin or plastic models, try and fill large voids with bits of scrap, and not use pure filler. In some case, it looks like you're better off removing some of the details and replacing them with tubing. Sounds like alot of work, but from past experience, filling bubbles and other defects is a lot of work no matter what.

Lt. Z0mBe · Post by **Lt. Z0mBe** » Sat Dec 18, 2010 10:36 pm

Aves. All things are possible with Aves, Brother:

"And lo, whereupon I beseech the caster to craft the perfect kit, he fooled me. I turned to the false prophet and casting flaws beset me, and my house and my bench. A pox of pinholes soiled the pure resin before mine eyes. In darkness, I turned to Aves. For Aves, you see, cleansed the lepers' sores, restoreth the details, and sculpteth smoothly with the substrate as though glass and amber."

~ Tamiya's Letters to Hobbyland, 16:13

Kenny