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Collective Insight Requested... -OR- WTB 12" Spinner

Jvon811

Well Known Member
I've tried and tried and tried and now I'm turning to the internet.

As most of you know, or can figure out, attached is a pic of the 12" spinner on my RV-4, FP prop. Screws attach it to the rear bulkhead, there is a front bulkhead (hidden) with a bead of RTV around it to seal tight but the screws do the the holding power. Looks clean, I like it...

I've had the spinner of several times before. BUT, last time... Last time it appeared as though I needed a bit more Red RTV in there to stop any moving/vibration that was occurring. It was showing very minor wear patterns.

Welllll... Bigger the gob, the better job, right? Wrong... It appears I have used RTV and basically glued my spinner onto the front bulkhead.

I have pulled, prodded, prayed, heated (hair dryer, nothing crazy), and pulled some more. I have had my airplane up to 18k' since the RTV so a thought was maybe the pressure in the cone is pretty low and it suctioned on. I drilled the smallest hole I could (#64) to maybe equalize pressure and have even put 120psi of compressed air to it without success. I have used safety wire woven through the screw holes to make nice handles so I could pull really hard and that didn't work. The safety wire started pulling through the sides of the screw holes I was pulling so hard. I have even used a very thin metal ruler as a splitter. Push the ruler in from the backside (between the rear backplate and spinner so I could hopefully work it through the RTV and separate the two. Still no luck, she's on there good.

My question to the VAF is, does anyone have any better ideas before I cut to later repair or have to destroy my spinner?
 

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Perhaps a combination of pulling, heating and pressurizing for an extended period of time. Instead of having the safety wire pull against edge of screw holes have it pull against edge of spinner.

By extended period, I mean hours.

If you could rig something up pushing on prop and pulling on safety wires, or perhaps steel strapping (broader area against spinner edge).

Like a bridge of three pieces of 2x4's, A bolt hole through the center of the center piece. two or three pieces of 1/2" or 3/4" wide steel strapping with hole for bolt.

Gradually tighten the nut, heat, blow air... come back later and repeat. Also try getting in there with another piece of strapping and try penetrating the RTV.

When taking fiberglass out of molds it seems to gradually let go.

I think the secret is continuous pressure (pulling).

Not sure where to come by steel strapping these days. Lumberyard says their bundles mostly come with plastic straps. But worth a try. I kept mine from when I got my steel roofing sheets.

Just a thought.

Finn
 
Aside from the solvent solutions you were given on FB, you might try drilling a large hole in the backplate on either side of the prop. Through this you might be able to reach with a tool to the inner bulkhead. You'd have to replace the backplate (and be careful not to touch the prop when drilling) but could save the spinner that way. I'd try the gentler solutions first.
 
Can you slide a hack saw blade in from the rear? Grind it into a sharp point, than try to break it through the RTV bead, hopefully weakening the bond.
Good luck!
 
Can you slide a hack saw blade in from the rear? Grind it into a sharp point, than try to break it through the RTV bead, hopefully weakening the bond.
Good luck!

Thant is a good idea, but----you might be even better to grind off the teeth, and form a knife edge ----- less chance of damage IMHO.
 
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