Contact Cement

[D'Snowth]

Exactly how long does it take this stuff to dry before you can start putting foam pieces together? Seems like everybody always say let it dry for "a few minutes," but how long is "a few minutes"? I imagine results wouldn't be satisfactory if you let it dry too soon or even too long.

 

[muppetperson]

Exactly how long does it take this stuff to dry before you can start putting foam pieces together? Seems like everybody always say let it dry for "a few minutes," but how long is "a few minutes"? I imagine results wouldn't be satisfactory if you let it dry too soon or even too long.

I think it is no longer than 10 minutes. Best is the touch dry method. Touch it, and as soon as it isn't tacky, put the surfaces together.

 

[Mavway02]

Honestly, most people use way too much! You need a lot less contact cement than you think. If you have to wait for more than 3 minutes, then you have too much on your foam. The best method of applying the contact cement is to first apply it on to a piece of scrap foam, then just dob it on the surface of the foam pattern

 

[D'Snowth]

In THE MUPPETS ON PUPPETS, Don Sahlin says if you ever make mistakes with contact cement, you can use a hair dryer to undo your mistake. But, isn't contact cement flammable? Seems to me that would be a fire hazard.

 

[Bear Man]

I think Barge Cement specifically is made flexible/soft again on the introduction of heat. I wouldn't suggest trialling that idea on other content cements for the exact reason you state.

 

[Buck-Beaver]

Generally speaking, hair dryers are usually not hot enough to ignite contact cement, especially on a low setting. Never use a heat gun or open flame (like a lighter) though...the fumes are extremely flammable. I've never ignited them myself, but I've worked with several people who have seen it happen. It's a pretty frightening to see apparently.

For the same reason, you should never use household fans, a stove's fume hood or a bathroom fan to vent contact cement...only a proper spray booth. Sparks from regular fan motors can ignite contact cement fumes. In the shop where I work we actually have to keep the contact cement drum in the spray booth grounded in order to further reduce the risk of fire/explosion.

When in doubt, always read your MSDS sheet (the safety information that comes with all contact cement) and the follow all of the recommendations. Many glue companies have a product safety officer who you can call or email for help too.

 

[D'Snowth]

Oddly enough, apparently contact isn't strong enough for permanent bonds like the bottle says, because I found when I made a mistake, I was easily able to just pull it apart with no effort and without doing any damage.

 

[Buck-Beaver]

Are you sure you're using contact cement, not rubber cement? Rubber cement is a different adhesive that is not as strong and usually sold in bottles. Contact cement usually comes in a paint can. When it is properly applied it should create a permanent bond.

Drying times for contact cement vary a lot depending on factors like humidity and temperature. Also, it often will not dry properly below 10°C (50°F) or in extreme heat. You need to let the contact cement dry until it becomes sticky, but not wet (this usually takes 10-15 minutes at room temperature, but it really can vary a lot). Certain materials can require two coats of contact cement to bond properly.

Make sure the brand of contact cement you're using is intended for foam rubber. There are different kinds of contact cement for different applications.

 

[D'Snowth]

I'm using Dap Weldwood brand contact cement, but it's in a 3 oz bottle with a brush as opposed to a can: I couldn't see myself dishing out $10.00 for a can when I didn't think I'd even need to use that much, seeing as how according to this thread, a little bit of contact goes a long way. . . . though now I'm pretty much out of the stuff after completing one puppet and putting together two other torsos.

 

[Buck-Beaver]

Huh. That is weird. Is it possible that the contact cement was too dry? Did you glue both sides of the foam?