Contact cement

Contact cement has been used as an adhesive for decades. One of the most common is rubber cement. I recall using rubber cement to assemble plastic dinosaur models in the late 1960s. The eight-year-old modeler did not do a neat job at all. Walthers Goo and Ambroid cements are also contact cements. I had poor experiences with those when assembling models in the 1980s. In each case, I don’t think I was using the adhesives properly.

Contact cements can be used to join dissimilar materials. The parts must be clean and attachment works best if a thin coat is applied to each part. Allow the parts about 20 minutes to allow the cement solvent to dissipate. Carefully place the parts together. You can apply gentle pressure to align the parts as there is some time for adjustments before the cement takes hold.

There are several kinds of contact cement that are useful in model building. Pliobond has been mentioned frequently in the hobby press over the years, as has Walthers Goo and Ambroid cement. I use Barge all purpose cement to make important joints on my resin freight car models. I’m accustomed to the Barge contact cement properties and how it handles. I’ve found Barge cement stocked with the leather working materials at Hobby Lobby but I prefer to purchase it from a local shoe repair or leather goods store.

I recently arrived at the point to install the roofs on my HO scale Westerfield Models M-15 boxcars. I didn’t think cyanoacrylate glue (CA) would work well in attaching the roof parts to the internal supports so I used Barge cement.

I traced the support locations on the bottom of the roof castings to I could apply the cement to the correct locations. Note just above my thumb is the letter B to indicate the B end of the car. I don’t want to wrongly install the part, so one end is marked for final placement.

I applied the Barge cement with a toothpick along the roof supports and along the lines on the bottom of the roof casting. A thin coat is all that is needed. I let the parts set for about 20 minutes before attaching them.

The wood roof on the M-15d model needed a slight adjustment as it was attached to the car body but went right into place. Here’s the result.

I didn’t have the same luck with the M-15b roof. After applying the cement and waiting 20 minutes, I placed the roof onto the car and I found the casting wasn’t quite wide enough to cover the edge of the car sides. At this point, I began to panic but took a couple of deep breaths. I sliced down the middle of the roof casting to remove one side, as you can see above. I moved the remaining roof half to slightly overhang the car side then went to my styrene stash.

After scraping off some of the contact cement, I placed a piece of 4×4-inch styrene stock down the center of the roof to use as a spacer. After checking the fit of the other roof half, the styrene was fixed into place with CA.

With the spacer in place, I attached the other half of the roof casting. The contact cement was still tacky on some of the parts, to that held it in place as I applied small amounts of CA where the second roof casting abuts the spacer. Once the roof parts were in place, I added CA along the seam at the fascia all around the car.

After everything was dry, the styrene was trimmed flush with the ends of the roof. The running board supports on both cars were carefully sanded to remove a slight angle. The sanding also leveled the spacer on the M-15b roof.

I’ll admit the 4×4 may be a bit too wide of a spacer as the roof overhang is noticeable. I had to act quickly to make it work. I know what to expect when I tackle the other M-15 boxcar models in my stash.

Many thanks to Dr. Denny Anspach for his frequent Barge cement recommendations on the Steam Era Freight Cars discussion list over the years. I might not have used this without his descriptive posts.


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9 thoughts on “Contact cement”

  1. Thanks for the “step-by-step,” Eric. Explains why I was never particularly successful in using Barge’s to assemble Central Valley turnout kits! It was also recommended by Steven Anderson in his late-90’s MR series on scratch building a brass locomotive. He used it to hold brass components together while soldering.

  2. Great job Eric. I am thinking no one will notice the width issue but you. After your model is detailed and painted it will likely look fantastic as your other models do.

  3. Great work and thanks for the tutorial on using this. The only way I’ve ever been successful with this kind of cement was to “tack” something in place while waiting to glue with something else.

    Warren

  4. Thank you for the kind attribution, and the excellent description of your applications and use.

    Like you, Eric, I use a lot of Barge Cement, and there is a positive learning curve. It is pretty bullet-proof, but can be defeated by high heat (good luck with styrene and resin in this regard). Its almost instant tackiness, resiliency, excellent resistance to shearing pressures, and working time are very attractive features. Its stringiness can be irritating at times, but it is manageable. It is a minority cement in my armamentarium (Krystal Clear, and ACCs predominate, but none (none!) are as central to really holding things together instantly, efficiently and cleanly as Barge.

    In less humid climates, e.g. the far west and southwest states, I find that the full workable tack time is reduced to around 10-12 minutes or even less, rather than the 20 minutes suggested. Also when two larger impermeable surfaces are joined or closed prematurely , e.g. resin/resin, metal/ metal, etc., there is the possibility of the cement solvent being trapped and not allowed to out-gas. This trapped pool can eventually then burn through resin, and is also the reason why -in an abundance of caution- styrene kit manufacturers advise against contact cements. I handle this issue successfully by being careful in the amount of cement I apply and spread out on the surfaces, and only drive the parts home when I judge- by smell and by the glued surfaces losing their glossy appearance that the solvent outgassing has reached a safe point. Even then, I commonly will just close the two parts to be joined in place, leaving just enough space for some solvent evaporation, then just several minutes later, drive the two parts firmly home, never again to be parted.

    If some glue is squeezed out of the joint, or if -heaven forbid….- a string happens to drape over your pristine model, I wait until the glue begins to set up (almost all the solvent has evaporated) and then with very fine forceps simply pick up and peel off these offending pieces. In most instances this comes right off leaving no trail nor track behind. Timing is important in this regard, however.

    1. Thanks for your extra notes, Denny. I appreciate the hobby tips and techniques you have shared over the years. – Eric

  5. Do be careful about skin contact with any contact cement as it is possible to develop a sensitivity. Subsequent contact will result in an itchy rash; further contact can lead to your skin boiling up, turning hard, and falling off in sheets.

    No extra points for guessing I how know this.

  6. Great post as usual, Eric. Good step by step on a classic glue. Question = I have heard some say that contact cements off-gas over time to the point that a closed environment (such as the interior of a box car) is not a great environment for using contact cements — over time the contact cement will emit vapors that deteriorate the material or the glue itself. Any thoughts?

    1. Joe, this is why there are 15-20 minutes of time between applying the cement to both pieces and joining the pieces. A thin application of cement is all that is needed and the solvent wicks away. With many of our models, this new joint is not fully enclosed for awhile so any remaining solvent can evaporate easily. I’ve not had an issue with the resin kits I’ve built.

      I suspect the disasters occur when a modeler applies an ample amount of contact cement to a car weight and immediately sticks it onto the car floor and pops the boxcar body onto the underframe so it’s ready to use. The solvent vapor has nowhere to go and begins reacting to the model material. This happened to me a couple decades ago with a CB&T boxcar kit that I built quickly. It was a lesson learned. – Eric

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