Re: Sealant For Lead Tubing and Brass
By Dave McNally
Robbie Rhodes asked about a sealant for lead tubing:
> Is there a non-crystalline sealant, such as rubber cement,
> which is suitable (and proven)?
The "proven" part is admittedly subjective, but I've had good results with #320 plastic cement (or whatever they call it now) from PPCo [Player Piano Company, Wichita, KS]. Perflex-E cement is also a possibility, since the two are very similar in behavior. Once cured, it's clear, very elastic, and inert. I know of no reaction between it and any materials I've used it with. It's not toxic, contains no petroleum derivatives (as far as I know) and it smells about as 'dangerous' as Elmer's white glue.
I've used #320 with great success for cementing brass nipples into wood, and large PVC pipe into wooden flanges. It's important to carefully wet -both- the hole and the tube first, and have a reasonably accurate fit. (I would _not_ rely on it for mechanical strength with a sloppy loose fit.)
For brass nipples, I prefer to sand the end to produce scratch marks around the circumference (not lengthwise). This aids in maintaining a better grip once inserted.
I use a suitable wire or nail to coat the inside of the hole with glue. This is a _must_, because otherwise the wood will absorb too much of what's on the nipple, leaving voids. Too much glue, and it may bead ahead of the nipple as it's inserted, possibly blocking it, so common sense is in order.
As the nipple is inserted, the excess will bead around the base of the nipple, making a neat looking job, and in fact virtually disappearing once it cures. If it's a good fit, brass nipples glued this way don't pull out when removing rubber tubing from them later.
I see no reason this wouldn't work well for new lead tubing. I'd suggest chamfering the end slightly so it doesn't tend to dig the sides of the hole on the way in. I've always done that with brass.
This glue will not stick permanently to non-porous surfaces -- it can be peeled off. I would certainly _not_ use it on anything that hot glue is appropriate for, since it will seal the grain, and hot glue will not penetrate it afterward.
Regards, Dave McNally - mac366@ibm.net
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(Message sent Mon 30 Dec 1996, 23:15:35 GMT, from time zone GMT.) |
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