and I am looking for comments on a few candidate materials for heat shrink tubing to be applied to a [*]CV axle. The tubing was narrowed down to these candidates using the McMaster Carr website (www.mcmaster.com : search "heat shrink tubing) : the recommended applications below are per McMaster Carr:
polyolefin : heavy-duty moisture seal - extra thick protection from damage
fluorinated ethylene propylene (FEP) : harsh environment - abrasion + chemical resistance
poly vinyl chloride (PVC) : less flexible, highest chemical resistance, UV resistant
I think the FEP looks best for a CV axle. I think adhesive-lined tubing would work best, but won’t be critical. I guess that the shrink ratio should be very low, but on the other hand as tight a seal as possible might be best for the rotational forces it would experience.
[*]CV axle (OD ~ 1-1/4 inch) is rusty, the original coating is chipped off, and needs refurbishment - it would get sandblasted, primed and painted ; or simply coated with rusty metal primer. The tubing would span either side of the CV boot, so it would sit in the grease under the boot and be exposed to the elements on the other.
also I was considering Plasti-Dip, but if the heat-shrink tubing works, I don’t see the point.
The only problem with that thought is that I probably spend as much time (or more) screwing around with useless ideas as Jr Mint does. It’s fun. And educational. I’m just having a hard time understanding what he’s trying to accomplish.
@the_same_mountainbike (how does the @ work when there are spaces I still can’t figure this out):
I want to get as close as possible to the original CV axle configuration.
The original CV axle has some sort of hard, black shiny coating that spans the CV boot at the narrowest end, but also does not have a hose clamp on it… if you can imagine what that looks like, then what I surmise about the axle is that there is a very good seal between the boot and the axle coating. importantly, the axle coating resists grease on the interior of the boot.
so if the axle gets a coat of paint, done by an amateur, I can see how the paint will wear away at that interface. trying to do a little better with a little more work - but more work than plasti-dip…
IMHO epoxy-based spray paint is probably the best option. The original was probably “powder coated”. That’s a coating that’s sprayed and then baked on in ovens.
But if it were me I’d probably just use regular spray paint. You should get a perfectly good boot seal with the clamp, even if you do nothing. If you DO use epoxy based paint, wear breathing protection. Trust me, you do not want to inhale those fumes.
I don’t think that any type of heat shrink tubing is going to do the job. If the new boot doesn’t come with a clamp, I’d use a nylon tie strap to secure it. If the shaft is pitted and you are concerned about leakage between the boot and the shaft, I would recommend using a little “The Right Stuff” from Permatex to seal that joint, then put on the nylon tie strap. I would not paint the shaft, but I would clean off any rust or scale.
It doesn’t matter if the shaft is bare, painted, Nitrided, Parkerized, or plated with Platinum; a good boot with proper clamps should not leak any grease.
My wife thinks I’m a colossal nitpicker but I relinquish that crown to anyone who considers heat shrink on a halfshaft…(Waving white flag vigorously…)
@Tester wrote: “You have to clamp the CV-boot to the axle in some manner or another.” I have a brand-new factory axle in-hand, and if there is a clamp, it is inside the boot rim. Since I took the old axles apart, I can say (but will have to double-check) there are no metal squeezy-crimpy things inside the rubber because I sliced it.
@keith “The Right Stuff”, eh? Thought about it because I have some in-hand per your suggestion a while ago… but the final installation will use either a hose clamp or a pinch clamp.
@"the same mountainbike" (… AH-HA - I have just discovered how to use the @ - let the computer recognize (or not) the name, or use double-apostrophe quotations… but it isn’t blue-linked… ) … yeah, so the epoxy - so I appreciate that warning, never thought of that - sounds like a horror movie. but the powder coater I talked to was, well, confusing - they claimed essentially that a polyester coating is good for use outdoors but not for chemical resistance, and the epoxy coating is good for chemical resistance but not outdoors. Perhaps it is just a small selection that coater has, and another coater would have a larger selection. BTW I know PC is costly for one item, but there’s a progressive charge if you give them a lot of items.
… so PC and plating of the axles ought to be another post… but you have me thinking to call another PC…
I can see heat shrink tubing decomposing real fast under the stress of a cv joint. Let’s assume that we are advising a young teen who is just about ready to venture into the world of auto mechanics and is flexing his inventive wings.
@Whitey it is one thing that it costs a lot, but another that two axles are sitting there in a condition that one could obtain from a rebuild/refurb/re-whatever service. FWIW I have one brand-new original complete axle, and the other one I have new (maybe - see previous posts about reman parts, I think you were there) joints ready to put on.
@dagosa I ought to show a pic, but the original hard coating stops before the bearing assembly. the HST would not be under the bearing assembly, but would stop somewhere mid way under the boot, surrounded by grease.
I do not have an axle from a rebuild service because they are actually not cheap compared to new joints only. I am under the impression that one would look like mine or is sand blasted and painted because it would be cheap for them. If a powder coater could apply a durable finish, I’d throw it in with another batch of stuff for PC.
FWIW my last-minute bail-out plan is to paint the axle (not the splines) with rusty metal primer.
