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Unread 06-02-2014, 13:57
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Tristan Lall Tristan Lall is offline
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Re: solder a bracket to a brass pneumatic fitting?

Quote:
Originally Posted by JamesCH95 View Post
Why would you flunk a fitting that has been glued in place?

Would VHB or a double-stick tape be okay in your opinion?
It's the usual problem of whether adhesive fastening should be considered a violation of the rule that "[a]ll pneumatic COMPONENTS must be used in their original, unaltered condition" (with exceptions).

Given that adhesion is inherently an interaction between surfaces that (on an atomic level) leaves neither unchanged, there's a case to be made that every adhesion is an alteration. On the other hand, plenty of other things (like simple contact) involve changes at that level, and wouldn't conventionally be called alterations.

FIRST would probably be concerned with the use of solvent-based adhesives on polymer substrates (high risk of error leading to failure, e.g. of a crazed pneumatic tank), or of installations that impose unforeseen loads (e.g. using epoxy to mechanically fasten a dynamic component to the side of a pneumatic cylinder). They probably wouldn't be concerned about masking tape holding a pneumatic tube out of the way, or about normal wear and tear incurred during a short working life. But the rules don't offer a specific basis upon which to distinguish these cases, so absent clarification from the usual official sources, it's going to come down to the officials at each event and their interpretation of the rule.

I think it will be hard to set and enforce a consistent standard using the rule as written, because alteration is easy to find if you're looking. If that's true, a rule update (possibly in the form of some more exceptions) would be preferable to a Q&A response (which can't change the fundamental constraint concerning the "original, unaltered condition").