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  1. GrumpyPlasticBastard

    Material Properties

    Edline: Right now my "tool" consists of process changes. Now that I know that variable A leads to condition X so I need to change Z in the process I'm much better off. As it was before we were flying blind. We have a captive product line, we've made the exact same product out of the...
  2. GrumpyPlasticBastard

    Help finding rubber grommet supplier

    How many do you need and what material? ---- BFL Dreamworks "If we don't have an answer we'll get one"
  3. GrumpyPlasticBastard

    Undercure Rubber - Molding Tool

    Has this mold run these parts before without issues? Or is this an ongoing nightmare? If you've run this before without issue, check that you do not have DIRTY MOLD SURFACES. Take your mold out of the press. Clean your platens, clean the top and bottom of the mold where they contact the...
  4. GrumpyPlasticBastard

    Mineral bonding rubber?

    It's not a matter of "which rubber" you want to look at an adhesion promoter or bonding agent. My company uses LORD CHEMLOC, we've used them for years, various types and grades for the various rods we use. For the record we are injection molding EPDM over fiberglass epoxy rods. To get...
  5. GrumpyPlasticBastard

    Material Properties

    What we have is a standard material from a standard supplier, we always order this material from them. For over two decades. Same plant. Same mixer. Not complaining really. I have a tool now to help overcome the swings in material consistency. ---- BFL Dreamworks "If we don't have...
  6. GrumpyPlasticBastard

    Material Properties

    When I did injection molding of thermoplastics, a material variation of this magnitude was UNHEARD OF. I am told batch to batch variations of this magnitude are normal, in fact it is SOMEWHAT UNUSUAL to get batches that were nearly identical. ---- BFL Dreamworks "If we don't have an answer...
  7. GrumpyPlasticBastard

    Material Properties

    We keep track of our machine settings, for a given viscosity of the material. Say our viscosity is 28MU, I have over a dozen sheets showing that we ran at a historical high of 365 for the mold temp and a historical low of 340. No notes from the operator no numbers in regards to scrap. Go...
  8. GrumpyPlasticBastard

    "KAP-0502"

    Apparently I am missing a piece of info. It is listed as "solid 2" wide .258" thick continuous ribbon of material, gray in color" in the MSDS... and our tracking sheets list KAP as a choice for material. Looking at the EPDM sheets I notice they don't list the fact that EPDM Rubber has...
  9. GrumpyPlasticBastard

    "KAP-0502"

    I have been tasked with finding an equivalent to this material. Originally it was supplied to us by PolyOne, then M A Hanna... then we stopped using it. Apparently P1 assimilated MA Hanna and now they call themselves Excel. A quick phone-call netted me "call back after the holiday please."...
  10. GrumpyPlasticBastard

    Rubber injection molding questions

    I know thermoplastic injection molding inside and out. Rubber... is totally different in many respects. In fact I think they gave it certain properties just to piss me off. I mean... making the feed-stock warmer actually DECREASES the flowy-ness (increases viscosity). And don't get me...
  11. GrumpyPlasticBastard

    Rubber injection molding questions

    Btrueblood: Thank you for your help. I suppose if it works it works, eh? :D I tracked down a few good books on the subject, we'll see what they say. ---- BFL Dreamworks "If we don't have an answer we'll get one"
  12. GrumpyPlasticBastard

    Plastic Material for 8-15um IR transmittance

    Bayer Chemical has special infrared-transparent polymers. ---- BFL Dreamworks "If we don't have an answer we'll get one"
  13. GrumpyPlasticBastard

    PTFE to rubber bonding

    Contact Lord Chemical. Odds are they have a bonding system that can help you. We use Lord here where I work and they have a good tech-support team. ---- BFL Dreamworks "If we don't have an answer we'll get one"
  14. GrumpyPlasticBastard

    Rubber injection molding questions

    Currently I run a six hundred ton rubber injection molding press. Mold has six cavities. How do I go about calculating the tonnage required for a given mold with rubber? Is it the same "projected area" calculation that thermoplastic molding uses? Or are there additional factors I need to...
  15. GrumpyPlasticBastard

    Chemloc 8116 Primer (Lord Chemical)

    GrahamBennett: It works, and it works very well. Apparently it was purchased as an evaluation sample... it was evaluated, found to be superior to our other primer, documented and forgot about. So the answer is: CHEMLOC 8116 does work on fiberglass rods for bonding EPDM. ---- BFL...
  16. GrumpyPlasticBastard

    Chemloc 8116 Primer (Lord Chemical)

    Found two jugs of this in our storeroom. We mold an EPDM compound over fiberglass rods. Due to cash flow issues we are looking to use as much of whatever we have on hand, rather than buying new batches of chemicals. Normally we use Chemloc 610, as that is made specifically for EPDM and...
  17. GrumpyPlasticBastard

    Compression moulding NBR - Quality issue

    Elastomatt: It might help. ---- BFL Dreamworks "If we don't have an answer we'll get one"
  18. GrumpyPlasticBastard

    Buna-N Swelling in Oil

    There is either a contamination in the oil causing the attack... an undocumented additive... or substandard rubber. Send the oil to a lab check for contamination, and have another lab verify that you are getting the right kind of seals made of the right kind of rubber. ---- BFL Dreamworks...
  19. GrumpyPlasticBastard

    Material to design a box to work at low temperature with internal pres

    The walls on the acid chambers... 3/4 inch thick. 1" thick on the hot water tank... 180 degrees. My suggestion is to look up a couple of PVC sheet suppliers and start asking specific questions. ---- BFL Dreamworks "If we don't have an answer we'll get one"
  20. GrumpyPlasticBastard

    Material to design a box to work at low temperature with internal pres

    Polycarb will crack and craze if you aren't careful about what you expose it to. PVC is your best bet, I used to run a Brite Dip Line (chromic and nitric acids, cold water rinse, hot water dry. PVC stood up to all of that. ---- BFL Dreamworks "If we don't have an answer we'll get one"
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