Faraetaildreams Art

Tutorial #3: How To Repair Broken Pieces of a Model Using Super Glue and Baking Soda 

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Broken Models often pose all sorts of individual issues, depending on where the break is, how bad it is, and the condition of the break. In this tutorial I will be repairing a neck break on a Lady Phase CM. 

The neck cracked during shipping but at first they were just hairline cracks. If you look carefully  below the main break on the picture to the right you'll see a smaller, thinner crack. This is what the main break first looked like. 

I was not able to get to it immediately after I got the box, and so it sat on my shelf for some time. During this period the weight of the head caused the neck break to widen and finally it came completely apart. I figured it was time to pull it down and fix the poor thing.

I first needed to find out how strongly everything was attached. After carefully pulling on the head a little bit, it was quickly apparent that the foil underneath the surface wasn't strong enough to hold everything together.

The next step was to pull the head and neck completely off without destroying anything. Then it was time to see how well that foil was crammed in there.

 All the foil after it was pulled out. I used the pliers to remove the foil. I pulled all of the foil out of the body and the head. 

One of the biggest reasons that this CM broke the way it did is because the foil wasn't strong enough to hold the weight of the head and neck in that position. Other than the foil, there was absolutely no support system in place to support the weight of the head/neck after it has been cut.

You need to create a 'skeleton' for any new pieces you cut off and attach back to the body. This is a must in any large CMs or you will have things break like they did here. 

This is actually a very easy fix - though it looks rather bad.

At some point before you pull the glue out you want to check to see how well the two parts fit together. As you can see in the picture, these two halves fit together pretty well - at least on this side. 

I'm not worried about that crack what so ever... I'll show you how to make that seamless too.

On the other side, this is what it looks like. You'll note that this hole is a bit larger than the way it started. You'll see why in just a second... 

Now its time to check and gather your supplies. 

To complete the repair, you'll need:

 good, strong 12 gauge or lower wire (for this, a wire coat hanger works great) that's at least 6 inches long; 

wire cutters that will cut that thick wire.

A good medium viscosity super glue. Liquid, not gel.

My preferred brand is Zap-A-Gap. I can only find it at two stores here in Phoenix (Michaels and a local store called Hobby Bench). Its a bit expensive, the bottle shown at left cost me about $4.00. 

Viscosity of glue refers to the thickness of the glue.* A very very thick glue will not work for our needs, and a very thin glue won't hold very well. This one says Medium CA+ on the front, they also have a red label version that is one level higher, but I don't like that one as much because its very difficult to squeeze out of the tiny opening at the top of the bottle.

This glue is also designed to find tiny gaps, crevices, and depressions and fill it in. This is a good thing!

One other thing about this type of glue is that if you manage to get glue on your hands, on random parts of your model, on your table, on your tools, you CAN neutralize the stickiness by dabbing a tiny bit of Denatured Alcohol on the sticky area. It doesn't take much and it turns the glue into a taffy-like substance that is quite easy to scrape/peel off the unintended surface.

And baking soda of course! Just plain old Arm & Hammer baking soda. I get the boxes at my local .99 Cents store for about $.50 a box. I dump it into a one gallon ziplock baggie, and leave my stainless steel dish in it for easy scooping. Sometimes I use the little spoon tool shown in the pic, but most of the time its just my fingers.

I leave the dish (its actually a cheap cat water dish) on my table and it makes the powder easy to get to and use. 

For those that haven't ever really used Baking Soda, when mixed with super glue it creates a substance that is, on a molecular level, very similar to resin. This allows us customizers the ability to repair plastic ponies.

Even if you have used this miracle combo, keep reading, as you might still learn a few new tricks and treats.

So we have our supplies, we have our broken horse, what do we do next?

We start to build the structural support for the repair. In model horse terms, that means 'glue wire to plastic/resin'. 

So where do we glue that wire to the plastic? That depends on where the break is. Wire usually is used to represent 'bones' in the horse. We want this wire to represent the spine/neck, so it gets glued to the inside of the smaller broken part. In this case, inside the head/neck, under the mane. 

This picture is taken looking down into the head, upside down.  

Holding the wire in place while trying to finagle the glue can be rather tricky! It took me about 5 minutes to actually get the wire in the right spot while holding the glue in the same hand before I got that first drop of glue in place. Then I literally dropped the glue and grabbed a large pinch of b.soda and literally dumped it on the glue. From start to finish this took about 15 seconds, once I started the process. 

It takes approximately 1 second for the reaction to take place between the b.soda and glue. **

 Here you can see the wire along the top edge of the neck. This is the reason I cut the larger hole in the side of the neck. You want the wire to be connected in two separate places at MINIMUM. If you can manage more than that, the stronger your CM will be.

I made the opening just large enough to easily get my glue bottle down into where the wire is showing. If you look closely enough, you can see where the original plastic was cut and re-sculpted with gapoxio.

This part is probably the trickiest of any of the steps. Right after I secured the wire to the head, I replaced the head back on the body to check the fit. The wire was at an upward angle preventing the head to even get close to the body. I had to bend the wire 4 or 5 times, playing with the angle, to make sure that it would allow the head to fit snugly to the body and still be in the correct spot to continue mimicking the horses' spine.

This is the most important step, IMO. If you do not get the two pieces lined up correctly no matter how much you sand and cover with clay later on, it will never look right. And you will end up cutting it off on purpose again to start all over again.

Once you have the perfect fit between the two pieces, and your wire is firmly anchored inside the head, run a bead of glue around the edge of the neck piece, and stick the two parts together. Hold for at least 30 seconds. Don't let go! You want to make sure that there is a good bond between the two halves because this makes life so much easier when you go to secure the wire in the second half.

Thankfully here, the two halves fit together like laser cut puzzle pieces. They won't always be this easy! 

If the two halves you are putting back together do not fit together nicely, gently sand the two edges and get them as close to matching each other as you can. Don't worry if the edges don't touch all the way around, just some of it.

Now we can anchor that exposed wire to the inside of the body half. After you have bonded the two halves together, it is much easier to drop some glue on that wire topped with some b.soda. Do this several times over as much of the wire as you can. Do it over where the break on the other side of the horse is, this will help the long term stability of the repair if it is stable on both the inside and outside.

More notes on glues...

*Remember when I said that the thickness of the glue matters? Here's why. 

The glue and b. soda will react instantly and create a hard substance that is extremely difficult to break. There is all sorts of scientific terminology I could get into here, but lets just trust that if mechanics use this combo to repair airplanes then it should be just fine for our plastic herds. 

If your glue is too thick, only the top layer of the glue will experience the chemical reaction, leaving the center part soft, flexible, and uncured. This is bad as you want your repair to be as stable as possible. 

If your glue is too thin, you have the opposite problem... you have glue that just will not stay put where you want it. It will run away from you and create little glue trails alllllll over your model in places you don't want it to play. 

This is why you always want a MEDIUM ca+ viscosity glue. Loctite or Zap-A-Gap are both great types of this glue.

Gorilla Glue and others like it are too thick, they won't completely react to the b. soda, and you will have a weak support system. 

Most of your generic super glues sold at the grocery or drug store are too thin.

The gel type glues won't work either, they are of a different chemical composition, and won't react to the b. soda either.

To create a good, strong, stable bond, you can layer the soda glue and get it pretty thick. You can even add blue painters tape into the layers, with soda glue on top of the paint layer for even more stability. 

** This is why you should never, ever get wet super glue on your fingers and then touch the b. soda. The instant reaction between the two will cause a heat reaction, that literally will burn a hole through your skin! This is NOT a technique to be used by children, ever, because of this generated heat. It is also not a good idea to try to get super glue off of your skin by using the b. soda to peel the glue off of your fingers! You will BURN your fingers. The best way to get wet super glue off of your fingers is to either wash it off with soap and water, or rub a tiny bit of Denatured Alcohol on the glue. The D.A. neutralizes the glue, and allows you to peel it off of your skin with little damage to your skin. 

 Continued on Page 2...

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