Crazing and Painting

Model Railroader General Discussion (Model Railroader)
1

I’ve been trying to find out the answer to this with no success, so I am hoping someone here might have had experience and advice.

I have begun scratching building a while ago using styrene and testors glue. I have noticed some crazing from the glue and I am concerned that when I reach the painting stage, this crazing is going to cause me problems.

So the question is, will it? Will this wash away when the model is being prepared for painting? Is there any other way of removing it?

So what am I in for?

Thanks in advance for any helpful advice,

Jim

2

I am afraid you will be in for a surprise, but maybe not a nice one. Depending on the paint you are going to use, those glue stains and blotches will either be much more apparent, or the paint won´t hold on them properly.

A good cleaning may help.

3

try to sand and then use primer

jeff m.

4

If is small spot and the area is unpainted, you can try some acetone. Use a cotton swab dipped in it and see if that helps. I have had decent luck on “glass”

5

Jim,

We could be of more help if you posted photos.

If you are applying glue at the joint only, where is the crazing occuring? Is the glue leaching out of the joint onto the surrounding area and causing the crazing?

In years past, I’ve had glue leach onto and lightly craze areas beyond styrene joints. The easy fix was to wet sand the area to a smooth finish with 400 to 600 3M Wet-Dry sandpaper. After inspection, I finish up with 1200 grit to get rid of the sanding scratches. No problems with primer and paint applications.

Now I apply masking tape next to areas to be joined just in case I apply a tad too much adhesive and glue leaks out. Once the joint is secure, I remove the tape. Good preventive medicine

6

Now that’s a really great idea - tape the joints on the outside and apply glue to the inside only. Applying glue to the inside is standard procedure, but with the thinner glues that get into the joint nicely also can easily come out the other side if the fit isn’t absolutely perfect - and unless you have some serious precision equipment it will NEVER be that perfect. The tape sounds like a great idea to help prevent that. Plus it holds the parts in place while you apply the glue.

–Randy

7

Thanks for the suggestions.

I’m going to try and post some pictures here in hopes that it will make it clearer.

I use Evergreen styrene and Testors Liquid Plastic Cement. I model in n, so I find it very difficult to not have a little extra glue seep out. Multiply that by many more little parts all together. I’m hoping that an honest wash in warm water and dish soap will be enough. Anyway, on to the pictures…

8

Not one of the pictures I attempted to post are here.

You can see the pictures here - http://www.flickr.com/photos/97556791@N00/sets/72157632059912646/

Jim

9

Looks like you will be ok if you plan on painting the building. I have had crazing on a red brick buidling but a little weathering and it looks like it was part of the mortaring.

10

You can get something called the Touch-n-Flow (www.flex-i-file.com) or use several other ways that utilize a small tube or pipette to apply very small quantities of solvent. Highly recommended for N scale work, I would think.

As others noted, clean it up with some superfine sandpaper or you can get sanding sticks that let you work on small spots or tight places.

Don’t worry. Paint hides a multitude of sins.

11

Jim,

The pictures are helpful.

The glue over-run appears smooth. I sill suggest wet sanding with the wet/dry papers starting with 400 grit or, as mentioned, sanding sticks.

Mlehman’s suggestion of using pipette’s is a good one; especially for N-scale. But regardless of the adhesive that you’ll be using in the future, apply masking tape next to the joints that you will glue and most of your leakage should be eliminated, even on porous surfaces. But don’t use the “Dollar Store” brands of tape as they tend to allow leakage (I learned the hard way, lol [:P] ). Use the better quality performance tapes from 3M.

Randy - Thanks for the kind words. But even with masking tape, if one applies superglue too heavily, then the tape becomes part of the problem too! I had to learn to be patient when assembling models.

12

I’ve been using a microbrush for application. Even so, as can be seen in the pictures, there always seems to be just a little too much.

Thanks for all the advice. I will have to post again when I get to the painting stage to let you all know how it went.

Cheers,

Jim

13

Since switching to Faller Xpert or Testor’s Model Master glue, I have never had any issue w/ craizing. The needle applicator allows for rather precise placement and the thicker viscosity allows for longer working time over the liquid. The Faller can actually be wiped away if any oozes from the joint w/o any damage to the finish (paint or raw styrene).

I will still use the Testor’s liquid for laminating large areas or pieces.