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Re: Sealed or Shielded bearings?
cockney steve wrote:yes! just like a waterpump on a car (that’s another racket! )…they also have a drain hole ,which I’d assumed would be your priority mod when you rework this “disposable “machine.
I was initially talking (previous post) about a hole between the two bearings rather than one between seal and first bearing but that latter might be more practical. Have any of the ‘better’ manufacturers used any of these approaches .. or what do THEY do to be able to put a 10 yr g’tee on a machine?
As regards your bonding…investigate “sikaflex”….if it’s good enough to bond car panels together,and fit windscreens, I’m sure it will bond a tub, PROVIDING the plastic is compatible!
Sikaflex is a i-part air -curing polyurethane sealant, -sticks better than s**t to an army-blanket 😆 I’ve stuck a piece of 22 gauge to an old windscreen, -torn the tin with Mole-grips,reduced the (laminated) glass to fragments,but the bond held firm!
Good stuff!. That sounds similar to the Tigerseal then. I’m going to to some test glueings with some silicone and Tigerseal on the tub. What sort of place would be likely to stock Sikaflex please Steve (I’m not that far from their HQ ar WGC) 😉
shielded bearings (tin) primarily for “large” dirt and grit exclusion…”seals” are “splashproof”a damp enclosure will hold the moisture which WILL permeate past these seals.
So sealed are marginally better than shielded for this role then, initially at least?
No-matter how much grease you TRY to pack in, the shaft is revolving, therefore there’s a shear-line running through the grease (not forgetting centrifugal force (centripetal for the pedantic!)…..so water will ,theoretically be able to go along the shaft…..back to plan A-slinger and drain-hole…..or you COULD connect your drain-hole to an aquarium-pump and use a sealed back-bearing, thus the bearings would enjoy positive pressureand the seal would press more firmly against the shaft….but that would make it wear quicker…the shaft surface HAS to be “rough” enough to hold lubricant for the seal!(and they’re really oil-seals, not water seals, except the flat-faced one on my current hoover which bears against a ceramic washer bonded to the spider/shaft interface.
Understood and thanks Steve (interesting stuff). 😉
All the best ..
T i m
Re: Sealed or Shielded bearings?
Tim, perhaps you could get the mod’s to pull all your saga into one thread.
I posted on another, but anyway,
the u-pol product appears to be similar to sika.-both available at motor-factors/bodyshop suppliers (Brown Bro’s local?)
yes, a “sealed” bearing is better protected than a shielded. IMHO, shielded are a waste of tin in this application.
if you can’t drain from in front of the front bearing, to outside the tub,consider making a “gutter” groove UNDER the front bearing and continue it to where you drill your exit-drain. make sure the drain hole is at least 1/4 ” diameter, otherwise surface-tension will hold a plug of water blocking it until there’s enough weight of water to displace it.Re: Sealed or Shielded bearings?
Unfortunately PHP software does not allow us to merge threads, unlike VBulletin etc. 😉
Also worth mentioning that you have overlooked one or two important ingredients in your seal/bearing/water discussion namely temperatures up to 95° and very strong detergents. 😉
Jim.
Re: Sealed or Shielded bearings?
Jim, have you ever stuck a bare forearm on the windowsill of the car on a HOT day?….Sikaflex is a structural bond,they use it for car glass because it makes the pane part of the stress-bearing structure (it’s very strong in tension or compression,doesn’t like bending or torsion, though. (the glass, that is!) If you have a browse on the net, you’ll see that there are various grades, they even do marine grades,which withstand heat, salt, UV, abrasion etc.
household detergent is a walk in the park for this stuff. (barsteward to remove, though, magnitudes tougher than silicone.
Re: Sealed or Shielded bearings?
In the interests of continuity, please continue this thread HERE.
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Penguin45,
Moderator.
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