The International Cessna^® 170 Association

Stop drill the crack and watch to see if it propagates. I have seen spinner domes drilled and then "Welded". It's not acually welding, but sort of low temrerature aluminum "brazing" done at a much lower temperature even using a propane torch. The repair was subsequently dressed down relatively smooth. It was very successful, lasted a long time, and saved a very expensive part.
I think that most of the spinner domes are made of 2024 alloy aluminum and that is not really a weldable alloy.

There are thousands of repaired spinners. That being said you won't likely find a mechanic today that will state there is an approved method to do it and once again there in lies the problem.

As for your larger spinner. There is no specific larger spinner for a 170A because they never came with that spinner. There are several slightly different larger spinners you may have so you need to identify it a little better.

BTW your likely to find a new spinner that matches yours here: http://www.aircraftspruce.com/catalog/appages/bn1.php

Unless you just hate the look you can make a small patch and then make one on the other side. Do stop drill it. I have done that for spinners before for a temporary fix until the owner could get a new one or to finish the season and they seem to last a lot longer then that.

The Wag Aero spinners are less precisely made...and have a rougher finish, as reflects the price.
But time spent polishing can resolve most issues.

Stop drill....then weld the outer edge to prevent regrowth.
I've done that on a baron spinner, and it's lasted 14 years so far.

You would need to weld it. Just a stop drill and it would propagate still. I was flying a Cessna 205 in the arctic once that was just stop drilled as it was one of those quick 135 turn arounds. I noticed a flash on the return trip on the left side in the sun. When I landed most of the spinner was gone. I do not think they are 2024 just based on how I have been able to remove dents so I do think that welding and then smoothing would be an option. Not sure where you are located but any good machine shop should be able to weld it and sand it so you cannot see it. If they have any liability concerns just tell them it is for your off road vehicle

Good luch and I would go spinnerless over the 700.00 dollars...save up for those Aerocets

Arash,

I'm going to assume the obvious that the pictures you posted were of your prop and spinner. That being said, what is the deal with the turbulator tape on the propeller blade? I've been a little out of the loop for a while, but don't recall ever seeing this.

Please elaborate. If this has been discussed previously in another thread, I apologize.

Best regards,

Ryan

Sounds like you already have a plan but another option, I have had a fiberglas spinner (from Wag Aero?) similar in shape to your's on the 170 since it was rebuilt in 1972. It is still in great shape, no cracks ever.

I know you already know this but if not, make sure the edge of the metal in that radius where the crack originated is as smooth as you can possibly get it. File it smooth with a fine half-round file then smooth it more with emery cloth. Do that evenly on both sides of the spinner. Any nick, snag, or dent can be the stress riser for a new crack to form. The weld looks very good.

For $400, the repair station probably puts about $350 in paperwork on the job.

Now you have 655.00 to apply towards the Aerocets

Did you learn what alloy of AL our spinners are made of?

FredMa wrote:Did you learn what alloy of AL our spinners are made of?

Spinners are usually made of 3000 or 5000 series aluminum alloys, which can be spun, machined, drawn or welded.
Since 3003 is cheap, I suspect that's what ours are made of. (2024 is not generally weld-able, although it can be spot-welded.)

I was already aware that 2024 is not weldable except for spot welding. I just wasn't sure what the c-170 spinner was made of. I can't recall reading that anywhere.

Aryana wrote:

Aryana wrote:$45 to weld/repair...this thing can crack every year and its still a better deal than a new one!

Lasted 15 hours before it cracked again

Next time you weld-repair it, Warm the oven first, then immediately bake it at 450-500 for about 2 hours and turn the oven off...letting it return to room temperature slowly. (Anneal it.)

did you buy the spinner from N419a for sale in the trademart? Sorry for all the questions but I am still trying to figure out why your spinner cracked in the first place. Did your old spinner fit excessively tight around the backplate? Perhaps you can compare to the new one. Does your prop have a noticeable vibration? did it crack in exactly the same place?