Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 04-02-08, 10:57 AM   #1
bcoppola
King of the molehills
Thread Starter
 
bcoppola's Avatar
 
Join Date: May 2006
Location: Detroit 'burbs, east side.
Bikes: '04 Giant OCR2, '87 Schwinn World Sport F/G conversion, '85 Schwinn Super Le Tour, '92 Trek 820
Posts: 1,195
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Undoing red Loctite with heat gun?

I have the original 27" wheels on my Schwinn World Sport FG conversion that would be ideal (and cheap!) for a Miyata frame I want to build up as a geared bike for my niece, now that I have a flip-flop rear and front hub + new rims to lace up for the fixed gear. I'm trying to keep the cost down. Otherwise I'd just buy hubs & rims.

I rotafixed the cog with red Loctite. I understand that it takes 500deg F to break the bond. Has anyone tried this with a heat gun rather than a torch? A heat gun would seem to be a bit safer and have less risk of overheating the cog or hub.
bcoppola is offline   Reply With Quote
Old 04-02-08, 11:36 AM   #2
tedshuck
Senior Member
 
Join Date: Aug 2007
Location: Centennial, CO
Bikes: Lynskey 210R, Cannondale CAAD2 MTB
Posts: 128
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
For 500 deg F, I would put it in my oven. This should give you the best assurance that you don't overheat it. You may lose some temper from hardened steel at 500 F though.
tedshuck is offline   Reply With Quote
Old 04-02-08, 11:39 AM   #3
Philatio
we are 138
 
Philatio's Avatar
 
Join Date: Jul 2005
Location: Knoxville, TN
Bikes:
Posts: 678
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
from what I've read, heat makes it easier but it can be broken without it by using enough force (back pressure, reverse rotafix, etc).
Philatio is offline   Reply With Quote
Old 04-02-08, 06:58 PM   #4
tzracer
Senior Member
 
tzracer's Avatar
 
Join Date: Sep 2006
Location: Waterford,WI
Bikes:
Posts: 281
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have loosened bolts held with red loctite without using any heat. Heat does help, but not always necessary. If it seems to be taking too much effort, I will heat it. 200F should be plenty.
tzracer is offline   Reply With Quote
Old 04-02-08, 07:00 PM   #5
Wordbiker
Pwnerer
 
Wordbiker's Avatar
 
Join Date: Jun 2005
Location: Pagosa Springs, CO, USA
Bikes: Road, MTB, Cruiser, Chopper, BMX
Posts: 2,907
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I'd try the heatgun. What can it hurt?
__________________
Quote:
Originally Posted by ahsposo View Post
Ski, bike and wish I was gay.
Wordbiker is offline   Reply With Quote
Old 04-02-08, 07:27 PM   #6
ScrubJ
Senior Member
 
Join Date: Apr 2006
Location: Vero Beach FL
Bikes:
Posts: 1,102
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The only issue with a heat gun (and we run into this at work) is that you might actually heat up other things more than you want to due to how long it actually takes you to heat the piece. If it's a big enough sink, all you'll do is heat up everything.

I'd give it a go without heat first, little chance of damage there.
ScrubJ is offline   Reply With Quote
Old 04-02-08, 08:36 PM   #7
EricJ
Senior Member
 
Join Date: Nov 2007
Location: So Cal
Bikes: Specialized Hardrock Comp w/FreeRadical
Posts: 154
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I agree. Try it without heat. I've used red on lots of motorcycle parts and RARELY had to resort to heat, though I sometimes used an impact driver as a persuader.

http://www.motorcycle-superstore.com...ac=2&zmap=4660

Eric
EricJ is offline   Reply With Quote
Old 04-03-08, 07:36 AM   #8
jgedwa
surly old man
 
jgedwa's Avatar
 
Join Date: Sep 2006
Location: Carlisle, PA
Bikes: IRO Mark V, Karate Monkey half fat, Trek 620 IGH, Cannondale 26/24 MTB, Amp Research B3, and more.
Posts: 3,345
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Go ahead and try without heat. But the red stuff is pretty stout, be careful not to apply more force than the aluminum threads can endure.

Heat is really not a problem. Even using a torch. Be methodical: heat a bit and try to loosen, and again and again until it breaks free.

jim
__________________
Cross Check Nexus7, IRO Mark V, Trek 620 Nexus7, Karate Monkey half fat, IRO Model 19 fixed, Amp Research B3, Surly 1x1 half fat fixed, and more...
--------------------------
SB forever
jgedwa is offline   Reply With Quote
Old 04-03-08, 11:34 AM   #9
BCRider
Senior Member
 
BCRider's Avatar
 
Join Date: Mar 2008
Location: The 'Wack, BC, Canada
Bikes: Norco (2), Miyata, Canondale, Soma, Redline
Posts: 5,456
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Keep in mind that the heat melts the loctite. If you heat it and let it cool again it's still going to be tight. You need to undo it while it's hot from the oven or while it's hot from the heat gun. Stout leather work gloves would be a good idea.

A torch isn't so bad. The flame from a propane torch is quite large. Just keep it moving and don't let the inner cone of flame that is the hottest sit on any plastic parts. It should be hot enough to make water or spit sizzle and a little more. Much more than that and the plastic separators are going to start melting.
BCRider is offline   Reply With Quote
Old 04-03-08, 11:47 AM   #10
markjenn
Senior Member
 
Join Date: Aug 2006
Bikes:
Posts: 882
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
I believe the red locktite spec is more like 240 deg, not 500. Heat gun it and then try to get it off, add more heat if you feel like you're putting too much force on it. It should come off. That's the way you're suppposed to do it.

I never use red unless it is absolutely required by spec.

- Mark
markjenn is offline   Reply With Quote
Old 04-03-08, 02:41 PM   #11
jmichaeldesign
Senior Member
 
Join Date: Sep 2007
Location: Colorado Springs, CO
Bikes:
Posts: 430
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I wouldn't crank on it too hard. The locktite may actually take some of the aluminum threads off the hub if pushed too hard.
jmichaeldesign is offline   Reply With Quote
Old 04-03-08, 03:52 PM   #12
j0e_bik3
"this is not suck"
 
j0e_bik3's Avatar
 
Join Date: Feb 2008
Bikes:
Posts: 387
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I use a tiny micro torch, about 4" away, moving in a circle around the loctite'd cog, and while holding the cog with a chain whip and applying pressure.

the cog will spun free with very little effort in less than a minute.

this is the way I loosen red loctite'd fasteners on motorcycles, except I use a box wrench, instead of a chain whip
j0e_bik3 is offline   Reply With Quote
Old 04-04-08, 07:29 AM   #13
Berre
Senior Member
 
Join Date: Dec 2007
Location: Antwerp, Belgium
Bikes: commuter, racer, ATB,
Posts: 226
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
My B&D heat gun goes up to 500C (about 900F), I guess it would temper martensite (hardened) steel and ruin bearing cups.
Berre is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 06:47 PM.