alan tani @ alantani.com fishing reel repair rebuild tutorial Titanium screws
Reel Repair by Alan Tani
October 16, 2017, 08:08:46 PM *
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Author Topic: Titanium screws  (Read 1698 times)
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Tiddlerbasher
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« on: August 22, 2017, 05:06:45 AM »

I did a quick search of the forums for info on titanium screws but didn't find anything.

I was searching for a source of 5/40 stainless oval head screws, for a Penn 349 project, and came across this site:

http://www.titaniumbolt.org/products/ based in the US.

Their minimum order quantity was too high for my needs, but if some enterprising gentleman in the US would buy some, they could be divided up and sold to interested parties Smiley
I was specifically looking for 5/40 1/2" and 5/8"

The advantage with titanium is no salt or galvanic corrosion compared to stainless or plated brass. Let's see what you guys think.
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Keta
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« Reply #1 on: August 22, 2017, 05:10:00 AM »

Titanium is high on the nobility scale and tends to play rough with lesser metals when exposed to saltwater.
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In the morning when I wake up I will see what tomorrow will bring.
Hi, my name is Lee and I have a fishing gear problem.
A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain
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« Reply #2 on: August 22, 2017, 11:19:31 AM »

That raises a more general question Lee.  Is it better to have the part or the fastener more noble?  The fastener is cheaper to replace if it corrodes but could become frozen in place and difficult to remove.  The part is more expensive to replace if it corrodes.

I just buy stainless and brass screws at the hardware store for tinkering.  But they only go down to 4/40 and I'd like one size smaller.
-steve
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Keta
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« Reply #3 on: August 22, 2017, 12:51:44 PM »

Best is all metal parts are the same alloy.  Aluminum and Ti is bad, stainless is better. Part of the problem is fesing of parts too.

If I had to make a choice I would use the more noble metal for the frame.
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In the morning when I wake up I will see what tomorrow will bring.
Hi, my name is Lee and I have a fishing gear problem.
A man who carries a cat by the tail learns something he can learn in no other way.
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« Reply #4 on: August 22, 2017, 02:49:06 PM »

A titanium framed 349 would be sweet Grin I can't see it happening soon Grin Grin Grin
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Keta
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« Reply #5 on: August 22, 2017, 07:01:53 PM »

That would be nice.
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In the morning when I wake up I will see what tomorrow will bring.
Hi, my name is Lee and I have a fishing gear problem.
A man who carries a cat by the tail learns something he can learn in no other way.
Mark Twain
mikeysm
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« Reply #6 on: September 06, 2017, 09:26:21 PM »

Titanium is not going to happen it's hard to machine and not cost effective. Most all titanium comes from Russia and is hard to process. So to make a frame out of it would cost allot of money. No one would buy it. Casting it would be the way to go if you were crazy enough to try.

Mike
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jurelometer
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« Reply #7 on: September 07, 2017, 09:29:55 AM »

That raises a more general question Lee.  Is it better to have the part or the fastener more noble?  The fastener is cheaper to replace if it corrodes but could become frozen in place and difficult to remove.  The part is more expensive to replace if it corrodes.

I just buy stainless and brass screws at the hardware store for tinkering.  But they only go down to 4/40 and I'd like one size smaller.
-steve

Here is a good article on this exact topic: http://www.corrosion-doctors.org/Corrosion-Forms/area-effects.htm

"Another important factor in galvanic corrosion is the area effect or the ratio of cathodic to anodic area. The larger the cathode compared with the anode, the more oxygen reduction, or other cathodic reaction, can occur and, hence, the greater the galvanic current. "


(Cathodes are more noble)

So... 

Since titanium is more noble than stainless it would actually enable more corrosion in the aluminum (which is less noble than both),  and the  greater the ratio of stainless (or titanium) to aluminum,  the greater the potential for galvanic corrosion.   The corrosin will occur mostly in the anode, which in this case is always the aluminum.   I guess you could make an argument that it is better to have the hole  than the fastener corrode,  but either way, you are screwed ( Smiley sorry)

Think about what this  means  in terms of corrosion potential with larger parts that might be more noble, such as bridge plates,  stainless reel posts, etc.

If you have a barrier between the metals, it will prevent the corrosion.   Marine grease is what everybody here uses,  and it works pretty well,  but it does not bond to the surfaces at all, so there is always the possibility of losing part of the barrier  as the grease gets squeezed out or rubs off.  There are special coatings made exactly for the purpose of preventing galvanic corrosion in fasteners.  Maybe useful for aluminum reels with stainless screws that may not get a regular full service?

-Jurelometer
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mikeysm
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« Reply #8 on: September 07, 2017, 10:03:06 PM »

You would have to coat the screws with a grease that would insulate and prevent electrolysis. Like super lube.
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RowdyW
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« Reply #9 on: September 07, 2017, 10:21:10 PM »

How about Anti-Seize compound?
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ReelClean
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« Reply #10 on: September 08, 2017, 12:19:12 AM »

Duralac is used for marine/aviation applications where dissimilar metals are mated.  Good explanation here:
http://www.ybw.com/forums/showthread.php?375481-How-does-Duralac-work&s=9bedbc4ba80bf6498c56d5ddc655ea0c

but it is like (as the name suggests) dries like "laquer" and dries hard, so removing screws can sometimes need some work.
cheers
Steve
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Specialist Daiwa reel service, including Magseal.
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