HauntWorld Home - Forums Home - Live Chat - Find Haunted Houses - Hauntworld Magazine - Haunted House Supplies - America's Best Haunts - Find Vendors
Haunted House News - Haunted Tradeshows - Join Hauntworld Facebook - Hauntworld Twitter - Advertise - Contact Us

Thread: Polyurethane foam troubleshooting help

Page 1 of 2 12 LastLast
Results 1 to 10 of 12
  1. Default Polyurethane foam troubleshooting help 
    #1
    Join Date
    Jul 2010
    Location
    Kansas
    Posts
    426
    So, we've been using two-part, soft and rigid, urethane foams for a few years now- foaming heads and bodies etc.

    I've used foams from Reynolds Advanced (smoothon), Monster Makers, BITY and some off of ebay, but I seem to be getting a recurring problem with collapse after expansion with the flexible type.

    Needless to say- that makes for some funky feeling and expensive foam props.

    Specifically-

    I use 3 or 4 lb flexible foam to fill fairly large cavities (about 2-5 cubic feet).

    I am using proper/clean mold materials- silicone and fiberglass- and I am using the correct release- either liquid or spray form.

    The temperature of the work space and materials is always above the minimum and I use a scale to measure when required.

    I have hand mixed and jiffy mixed- both carefully and thoroughly- with similar results.

    The only time I do not have any issues is when I am mixing smaller amounts- like 2-6 oz.

    I have contacted all of them for help, but none of them have been able to solve the collapse issue- they just repeat the above list.

    What I THINK is happening may be related to the volume and how it reacts to a free-rise situation. I think as the foam expands to fill, it is in a free-rise state and the bubbles created are expanding beyond the materials ability to keep them trapped. The only solution to that- I THINK- would be to use more- a lot more material so that is reaches a back pressure situation before the air bubbles get to big.

    I've even given this idea to the tech support guys and it gets dismissed... Perhaps I AM insane...

    Anybody?
    How can a man die better than facing fearful odds, for the ashes of his fathers and the temple of his gods.

    What you put into your mind- you put into your life.


    www.zombietoxin.com
     

  2. Default  
    #2
    Join Date
    Aug 2006
    Location
    Nashville
    Posts
    333
    I have occasional collapse issues even on big props... i got a few funky looking full size gators. Two counts, and I am guessing the factors were, one was age of chemicals and the other was room temp. I think I also had one where it seemed like a gas pocket trap. But just guessing....
     

  3. Default  
    #3
    Join Date
    Mar 2012
    Posts
    415
    I have found that when it gets to hot, it starts eating itself before it cures. Or it heats the release to much .
    Less hardner and a clear coat over the release and a cooler place seems to be the trick for me so far...

    Stew
     

  4. Default  
    #4
    Join Date
    Nov 2008
    Location
    Mesquite, TX
    Posts
    2,788
    Im gonna be the odd man out and say your issue sounds like humidity. Do you have a hydrometer to measure humidity? Moisture in the air plays havoc with my foam. having a dehumidifyer in the shop helps greatly, I dont even run foam when the humidity is higher than 70% outside.
    Allen H
     

  5. Default  
    #5
    Join Date
    Nov 2008
    Location
    Mesquite, TX
    Posts
    2,788
    Another answer to your back pressure theory is to use sheet plastic and run the foam in layers, pushing down on the sheet plastic to create pressure. I have done that in the past with success.
    Allen H
     

  6. Default  
    #6
    Join Date
    Jul 2010
    Location
    Kansas
    Posts
    426
    Thanks for the help.

    Well, at first I was suspect of the age of the materials, but after having the same problem with numerous different batches I gave up on that theory for the most part. I hope thats not it- how would you be able to tell?!

    Then I was thinking about the release- maybe it was reacting, but I switched from 2831 to PVA and still got collapse. 2831 seems to be the way to go with urethane foam- I can get several pulls between coats.

    I'd love to try the plastic sheet/ back pressure idea, but I can't get my hands inside the mold cavity.

    As for the humidity- well I did ask the smoothon tech about it- but in regards to low not high. The very first pour we did was in the winter- warm but dry and got substantial collapse. Anyway he didn't give much input in regards to humidity, but I can definitely see how it may play a part. Damn... my workspace is NOT air conditioned and has a pretty large volume that is not well sealed. Dehumidifying it is going to be a biotch.

    I guess I could drag it into my office area...

    Thanks again everyone.

    -Rob
    How can a man die better than facing fearful odds, for the ashes of his fathers and the temple of his gods.

    What you put into your mind- you put into your life.


    www.zombietoxin.com
     

  7. Default  
    #7
    Join Date
    Nov 2008
    Location
    Mesquite, TX
    Posts
    2,788
    Be careful working in a smaller space, most foams off gas syanide as they expand, so ventalation and all that. just covering our butts lol. good luck with it and keep us posted.
     

  8. Default  
    #8
    Join Date
    Jul 2010
    Location
    Kansas
    Posts
    426
    Well, thanks to the weather going bonkers and cooling down to the 60's (!) I can't say with 100% certainty that humidity was a factor, BUT I will say since I moved into a climate controlled area I have had zero collapse.

    To further confuse things I was also using a different foam... so... yeah...

    Anyway, my experience has led me to believe that BITY foams are somehow better. They're probably all the same, but somehow I get less collapse (if it happens) and much better expansion.

    So far, for making body forms, their 3lb flexible has worked the best.

    Another thing I think is important in the learning curve is to give up on trying to cut the amounts used to absolute minimums to save a buck or ten. It seems better to overfill slightly- just make sure your molds are strong enough to handle back pressure.

    Thanks everyone.

    Attack mannequins are now part of our doll attic.....

    Here's a few of the dozen we made.
    Attached Images
    How can a man die better than facing fearful odds, for the ashes of his fathers and the temple of his gods.

    What you put into your mind- you put into your life.


    www.zombietoxin.com
     

  9. Default  
    #9
    Join Date
    Feb 2008
    Location
    SANTA MONICA, CA.
    Posts
    560
    Please tell me your wearing a vapor regulator?
     

  10. Default  
    #10
    Join Date
    Jul 2010
    Location
    Kansas
    Posts
    426
    Yup, sure do. I'm curious- since you're here- what your opinion about foaming is. Would appreciate the pro advice!
    How can a man die better than facing fearful odds, for the ashes of his fathers and the temple of his gods.

    What you put into your mind- you put into your life.


    www.zombietoxin.com
     

Thread Information
Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •