Soft spots in Resin

Tools, Techniques, and Reference Materials Techniques
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Hey guys - I need a meeting of the minds here. I’ve tried and tried to fix this but have failed miserably. My model horse friends have tried…didn’t work either… So, I’m hoping you guys might have some ideas.

I have a resin horse I’m trying to complete but just as I had him prepped, primed, and ready to apply color, I notice these tiny bumps on him that weren’t there before.

Well, it turned out that under those tiny bumps, the resin had gone soft. These types of horses are released by individuals and cast by mom and pop shops for the most part. No corporation, quality control doesn’t always happen, and when things go south with the resin, they go in a hurry.

I’m working on a horse I have named Hellboy (he’s red - or will be - and has a bad attitude). Trust me, you don’t want to know the details. The epic saga this resin model has put me through is worthy of it’s own blog. I don’t know which of the model horse painting gods I pissed off or why they hate me, but they are determined to put me through the Labors of Hercules before this stupid thing gets paint on it.

Fortunately, I don’t think it’s going to be a “leaking” resin. The soft spots were just on the outer layer and only in small patches. I dug them all out with my carbide scraper and sanded them. Then I let it sit overnight to see if the next layer did anything weird. The lower layer has been just fine.

But Hellboy isn’t done jacking with me. Are you kidding? Why quit now? He started months ago and has been on a serious roll! For him, it only gets better…for me, it only gets worse.

Now he has potholes all over his back and butt and I have to fill them. Actually they are a small, roughly oval shape about the size of my pinkie finger. There’s a ridge where the top layer of good resin stops and a very slight dip to the second layer of resin. Like I said, I sanded these like crazy but I can’t get them completely flush with just sanding. There are about six spots and some of them are a bit tricky to get at.

Apoxie Sculpt and the various epoxy putties I have such as Green Stuff are too thick and unmanageable. I tried Bondo Spot Putty but that was too thick as well and plus it sets too quickly for me to get it smooth over the area. I tried thinning it a touch with acetone but it still wasn’t cutting it.

I wanted to try stuff like Squadron or Vallejo putties but no one has it locally, so it’s on order and will get here…eventually…but it will be too late.

A model horse artist friend suggested Windsor & Newton Heavy Modelling Paste. It’s carvable and sandable and she uses it to fill pinholes. I was able to find that at a local craft store. The town I live in isn’t huge, so finding hobby supplies is a real challenge. I have to order everything online unless I can find it at a hardware store, an auto parts store, or (geez this is embarrassing) Hobby Lobby or Michaels. [:$]

The Modelling Paste is a touch thicker than Elmers White Glue. I tried applying it with a brush, then a craft stick acting as a putty knife, and then my fingers. I can get it where I want it but when it dries it has ridges and lines which are absolute murder to sand. When I do get it smooth, it’s so thin that when I apply the primer it’s like it’s not there. And yes, I built it up in gradual layers.

It thins with water so I tried that as well, again built layers, tried brush and fingers…there are still sanding issues with the ridges and lines.

In desperation, I mixed it with some white gesso and thinned again. This application went on better and it’s drying. I’m going to hit it with the sanding sponge shortly and see how it goes.

But honestly, I’m at my wits end trying to fill this stuff and not leave ridges and lines - or at least leave something I can sand that doesn’t take forever…or I sand so much to get rid of the lines that it also loses the fill properties. Ultimately, there is a slight outline around these areas that remains no matter how much I sand. I need to fill and feather those outer ridges somehow.

It’s not for lack of trying, that’s for sure!

And now for the really bad news? I have to finish it before next weekend. I’m leaving for a show on Friday. The last one of the year in this area. After that no more until next year.

Does anyone have any ideas? Please? Help?

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Lady maybe you wanna bin that thing and start a new one?[;)]

I know,I know…sure you’ve thought about it…

Im still not sure why some of the above didnt work for you? Are you expecting a fill that wont need sanding into shape? Or just a fill thats easy to shape? Well…here’s some more alternatives–toothpaste–spakle—wood filler/putty—melted sprue----C/A and kicker / baking soda—or jsut get a good quality putty like 3M Green Spot Putty

Good luck

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[t$t] Thanks Indy…haha, yes, I’ve thought about it. I’ve plotted, planned and schemed this little [cnsod]'s demise. It’s almost learned to fly…across the room…on several occasions. It came very close an adventure filled journey to a far away landfill. And my personal favorite, tying it to the biggest piece of fireworks I can find and lighting the fuse. [8o|]

Unfortunately, it’s not mine, so I can’t shoot it and put it out of my misery. It’s a commission piece and I’m sure you can imagine my reluctance to write an email to this really nice lady and say, I’m sorry but that chunk of change you spent on this resin, well, next time it will probably be more satisfying to walk to the toilet and flush it. That way you actually get to watch it go down the drain.

I’m going to do everything I can to save this sucker for her and get it looking nice. I hate admitting defeat, especially when an inanimate object is involved.

As to what I’m expecting…I don’t mind sanding, I don’t mind sanding for a couple of hours, but I would like to at least start getting something smoothed out and not have those bloody divots. I have tried wood filler and putty, I even have regular auto body filler, not just the Spot Putty. The CA and baking soda I use a lot but that’s mostly repairing broken stuff - ears, legs, tails, whatever. So that could be a possibility. I don’t have 3M Spot Putty on hand but I’ve got this stuff called Quik Steel I might try.

Toothpaste? Seriously? I’ve gotta admit, that’s a new one on me. [:D] I’ve used it for polishing and cleaning stuff but never as a filler. It doesn’t break down over time?

Melted sprue - I’ve got a ton of sprue…I never throw that stuff away. That sounds intriguing…do you melt it to shape, let cool then apply? Or do you melt it and let it drip on the spot? I would definitely have to run a test horse first - don’t want to screw up the resin any more than it already is.

Thanks again for the help on this - oh the combination gesso and modelling paste actually took a step toward improvement. It wasn’t all fired up great, but there might be some potential if I get the mix right. At least it was an improvement rather than going backwards. haha! But ti’s going to be a long night.

Gotta brew more [C]

It’s 106 miles to Chicago, we’ve got a full tank of gas, a half a pack of cigarettes, it’s dark and we’re wearing sunglasses.

Hit it!

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Crazy Lady~

You’re quite the talker/writer aren’t you[:P][[whstl]

Anyways—you won’t give up—I get that–& I admire a work ethic–it’s a job!

So that was a number of things there-----

  1. Yes Bondo always leaves divets—thats where the 'Spot Putty" is needed—its only for small pin holes and scratches (like those in a bondo’d surface)

  2. Meted sprue–I guess you could melt and drip it in (we used to P-tex skis like that back when I was a ski tech–but-no–the accepted tecnique is to melt the sprue with solvent glue or laquer thinner or acetone (stay ventelated!) and brush the paste into the holes–this is really easy putty/filler recipe

3.Toothpaste I’ve never used on a model–but I’ve read otheres do it–I know if you leave the stuff on the sink bowl it get pretty hard

  1. Did you try using C/A?

bye

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I have used “melted” sprue, but you do not melt it with heath. Sprue is melted by soaking it in MEK of laquer thinner. It then becomes a goo which you can put on the model.

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[:P] Sorry! Yes, I do have a tendency to really get going on stuff like this, especially when I’m stressed - and this crazy thing is stressing me out big time. A lot of times writing stuff down in a post helps me sort it out a bit better.

Thanks again for the info Indy and Borg! I didn’t try the melted sprue but I did use the CA/baking soda on some deeper holes that I found. It turned into a combination of solutions one thing would work on one spot and so on - plus the Gesso and Modeling Paste mix also worked, so with everything late last night, I finally got a solid primer coat on him and the first layer of color! [<:o)]

Hey lookie! I made a post with only three paragraphs! [t$t] hehehe!

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Congrads!

{Look, I made a post with only 1 word!..ok 11)[:#]

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To help prevent the divots, you may want to try outlining the dug out area with some masking tape. That will raise the surface a bit around the divot you are working, so when it does set up and shrink some, you may still have some putty standing proud of the surface you are trying to get up to. Encircle the area with short pieces of masking tape, apply your putty, and when you get to the point it looks as good as it’s going to get, remove the tape. Let it set a while before sanding down. I’ve started doing this and it seems to really help with seams between parts. It gives you a little more stuff to work with vertically, and limits the amount of stuff you have to sand off horizontally.

You can also watch the putty to dry just to a consistent color across the patch and start sanding then. The longer you wait, the harder it gets, so the earlier you can get to it, the easier it will be, a bit. Too early, though, and everything’s balling up on your sandpaper. You have to be careful, and may want to experiment on another resin piece first.

Good luck!

Gene Beaird,
Pearland, Texas