Pin holes in resin

Devin · Post by **Devin** » Mon Mar 26, 2007 11:39 am

I've got a model that has tons of tiny pin holes. Tons of them. Every time I prime and sand an area it doesn't totally fill in everything, and then the sanding reveals more of them.

Any recommendations? This is a long and featureless piece of resin (a 23" long ironclad monitor deck) that I could just sheet over with styrene and be done with it, but I'd like to find a way around these holes.

Thanks,

Devin

suwalski · Post by **suwalski** » Mon Mar 26, 2007 12:28 pm

You might want to Try Mr. Hobby's Mr. Surfacer 500 or 1000. It should fill them in nicely and give you a good finish.

Devin · Post by **Devin** » Mon Mar 26, 2007 1:41 pm

Thanks. That's actually what I've been using. Spot filling big gaps with 500, then brushing and airbrushing the 1000 overall. Some of the holes just defy being filled, though. I'm starting to think they have mold release agent inside of them that the initial cleaning with Bleech White and lacquer thinner did not remove.

-Devin

Wug · Post by **Wug** » Mon Mar 26, 2007 8:01 pm

Hi Devin,

It sounds like you're most of the way to a solution. Apply the Mr. Surfacer and let it dry. If you see any new pinholes, fill them with more Mr. Surfacer. Let it dry.

Sanding opens more pinholes and might leave your part out of shape. Remove the Mr. Surfacer by wiping it with 91 % or 99% isopropyl alcohol. Regular 70% rubbing alcohol isn't strong enough.

For big open areas, pour some alcohol on a coffee filter and wipe. This removes the Mr. Surfacer from surface but leaves it in the pinholes. You'll probably need to repeat the process for bad areas. Q-Tips can wipe around details.

Eventually this should fill most but not all the pinholes. If there's mold release in the holes, you need to get it out. Open up pinholes that are too small. Use your favorite putty on holes that are too large.

Who manufactured that wormy piece of resin?

Let us know if this helps.

Mike

Digger1 · Post by **Digger1** » Mon Mar 26, 2007 8:09 pm

nominate for sticky, please.

All in favor?

Devin · Post by **Devin** » Tue Mar 27, 2007 1:51 pm

Mike,

Thanks for the suggestions. I've been doing a little of what you suggested, and a little of just building up the coats. It's at the point of saturation now so that even if the Mr. Surfacer shows pock marks where the holes are, a little surface sanding smooths it all out.

I didn't know the coffee filter trick. Very cool.

The resin is an OLD kit from Old Steam Navy of the USS Weehawken, a Civil War monitor. I snagged it on eBay last year for less than half price. Since this casting he's upgraded nearly everything in the kit so these airbubbles shouldn't be an issue with current kits. Other than this issue, it's an impressive model and a lot of fun to work on.

-Devin

Post by **TER-OR** » Tue Mar 27, 2007 9:23 pm

It's pretty much covered in the other thread, but Surfacer should not be fully sanded down to the material beneath it. What you want is a smooth surface of surfacer, not using it like a filler you're accustomed to.

Does this make sense? The alcohol trick works great, but for a truly flat surface I rely on a rigid sanding stick. Usually a fairly fine one.

Devin · Post by **Devin** » Thu Mar 29, 2007 9:40 am

That's what I figured out for myself over the weekend: spray it on, sand it smooth as possible with a wet fine grade, repeat MULTIPLE times. I've got it looking pretty good now. Thanks everyone for the ideas.

-Devin