Prepping plastics

Hey guys, just wanted to throw something out there after an interesting conversation with the bloke from my paint store. He was saying that when he was on the tools before injuring his back thatthat only heat treated new plastic parts, not older ones. I was a little confused as to why one and not the other. Apparently they reckon that after time all the chemicals/release agents have already gone so for older parts they just do the usual clean, prime and paint etc.

Now mind you where I am it’s typically 30c/86f or hotter for most of the year, the main variant is the humidity. I know I’ve picked up some plastic things around the house that have been sitting in the sun and they are dam hot to to touch so this theory actually makes sense to me.

Like I said earlier, I’m just curious on your thoughts and I’m not trying to reinvent the wheel.


  • smedlinsmedlin Member, Business Ninja Posts: 2,320 ✭✭✭✭✭
    To me, I've thought the same thing.

    Living in South Texas, it's like a natural flame treatment.

    I've done several pieces, some mine, some clients, that I know for a fact spent a few years sitting outside (4-wheelers, etc).

    However.. I still flame treated them. It really does not take very long (I have one of those shrink wrap torches). So. to me, i was like, "Why risk it?"

    How much time are you really saving if you don't do it? But if down the road sometimes, it comes back cause the paint is lifting???
  • MidOhioHydrographicsMidOhioHydrographics Member, Moderator, Business Ninja Posts: 10,544 El Moderator
    Remember... flame treatment is changing the surface tension of the plastic due to a chemical reaction between the flame plasma and the surface of the plastic. It's not only the heat.
  • K2ConceptsK2Concepts Administrator Posts: 14,057 El Jefe
    Test it and see...ultimately that' what we all should be doing anyways...but...
  • WileECoyoteWileECoyote Member, Moderator, Business Ninja Posts: 7,962 El Moderator
    Remember your business' reputation is on the line. You had a part that peeled like a banana, and EVERYONE saw it... because you wanted to save 15 minutes on a job that took 3 hours...
  • NotSoFastNotSoFast Member, Moderator Posts: 3,478 El Moderator
    I've seen painted 3 and 4 wheelers that were old when painted without flame treating that failed badly. Parts were cleaned, scuffed, etc but we didn't know about flame treating back then. Just sayin'.
  • ShannonShannon Member Posts: 221 ✭✭✭
    Thanks for the great responses guys, most of the plastics I’ve dipped have either been new or not needed flame treatment so it hasn’t been an issue as yet. 
    @MidOhioHydrographics thanks for that link
    @NotSoFast that’s interesting, I wouldn’t have expected that.
    At the end of the day if I have any doubts about something I would spend the extra time on it to make sure it’s all good to go, as @WileECoyote said save 15 minutes and then have the part come back and doesn’t do your name any good either. 
    I was wondering how solid the information was, I’m guessing as solid as paint on plastic that wasn’t flame treated
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