Suspension Bushing Bonding Methods, Ideas/Oppinions
01-11-2012, 12:54 AM
#1
Racer
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Suspension Bushing Bonding Methods, Ideas/Oppinions
I know the super glue topic has been beaten to death here, so I have a slightly different question.
A bit off topic first.
I have decided to replace my spring plate bushings, I have received my weltmeister netrix ones and plan to put them in. I will be gluing them as that seems to be the consensus. I do have one issue, they did not come with glue. What should I use, Gorilla glue? regular old super glue? and should I put silicone on the outside to minimize squeaks?
Any way the real question is this.
I know the original bushings were bonded to the tube in some fancy way, I forget the name of the process but any how, has any one tried to do this/can it be done with replacement bushings. For that matter how does the process work.
As well, if i heat the tube up and put the bushings on does any one think a bit of the bushings will melt and bond to the tube.
Has any one played with other methods (not glue) to affix the bushing to the tube, if so please share. As an engineer I always question instruction manuals as well as original designs but also respect when some thing is right its right. I will end up gluing them most likely. On that note any tips to gluing them?
Regards
Dave
A bit off topic first.
I have decided to replace my spring plate bushings, I have received my weltmeister netrix ones and plan to put them in. I will be gluing them as that seems to be the consensus. I do have one issue, they did not come with glue. What should I use, Gorilla glue? regular old super glue? and should I put silicone on the outside to minimize squeaks?
Any way the real question is this.
I know the original bushings were bonded to the tube in some fancy way, I forget the name of the process but any how, has any one tried to do this/can it be done with replacement bushings. For that matter how does the process work.
As well, if i heat the tube up and put the bushings on does any one think a bit of the bushings will melt and bond to the tube.
Has any one played with other methods (not glue) to affix the bushing to the tube, if so please share. As an engineer I always question instruction manuals as well as original designs but also respect when some thing is right its right. I will end up gluing them most likely. On that note any tips to gluing them?
Regards
Dave
01-11-2012, 12:11 PM
#2
RL Community Team
Rennlist Member
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I don't think it is possible to "melt" the bushings on to the springplates... You would likely wreck the bushings in the process and I don't think there would be any real fusion anyway.
I would also not put any lubricant on the outer "race" either. The normal operating mode of the bushing is for the inner and outer surfaces to remain static, whilst the movement of the springplate is accomodated by defection (in torsion) of the rubber. By not having the outer race bonded, extreme deformations can be accomodated through slippage at the outer race. I believe that this is what may happen when the spring plate is first installed, and then loaded into its natural resting position. I am not sure though.
Anyway, in my case I went the way of gluing my bushings to the clean (re-plated) spring plates using a cyanoacrylate glue (i.e. "super glue') after cleaning the bushings and using a fine sand paper to prep the rubber where the bond interface would be. Whatever glue you choose, a principle consideration would be whether it is suitable to very low clearance situations. Many glues rely on a minimum bond surface seperation to gain sufficient shear strength. Cyanoacrylate typically needs a very small gap to work.
I didn't just use department store ACC, but rather Loctite "Black Max 380". You can get some info and also link to a data sheet here:
http://www.henkelna.com/cps/rde/xchg...UID=0000000I0R
If price tells the story, then this stuff must be great...
I would also not put any lubricant on the outer "race" either. The normal operating mode of the bushing is for the inner and outer surfaces to remain static, whilst the movement of the springplate is accomodated by defection (in torsion) of the rubber. By not having the outer race bonded, extreme deformations can be accomodated through slippage at the outer race. I believe that this is what may happen when the spring plate is first installed, and then loaded into its natural resting position. I am not sure though.
Anyway, in my case I went the way of gluing my bushings to the clean (re-plated) spring plates using a cyanoacrylate glue (i.e. "super glue') after cleaning the bushings and using a fine sand paper to prep the rubber where the bond interface would be. Whatever glue you choose, a principle consideration would be whether it is suitable to very low clearance situations. Many glues rely on a minimum bond surface seperation to gain sufficient shear strength. Cyanoacrylate typically needs a very small gap to work.
I didn't just use department store ACC, but rather Loctite "Black Max 380". You can get some info and also link to a data sheet here:
http://www.henkelna.com/cps/rde/xchg...UID=0000000I0R
If price tells the story, then this stuff must be great...
01-11-2012, 01:31 PM
#3
I haddah Google dat
Rennlist Member
Rennlist Member
Glue will not hold, just contribute to some funcy stiction related alignment problems until the rubber has some wear and use on it. I might just use soap next time, to aid installation.
01-11-2012, 08:01 PM
#4
RL Community Team
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Rennlist Member
I'm really not so sure...
Chuck Moreland sold his original rubber bushings without glue, but now supplies them with the glue and the sand paper etc. to prep the bushings, as well as detailed instructions. That made me think otherwise.
I then researched a paper made by a couple of Dutch guys that investigated the behavior of exactly this type of bushing, subjected to torsional loading with both the inner and outer faces fixed to the substrate (i.e. in the same way I assume our bushings are designed to work). The bushings they used for their experiments was smaller than our springplate bushings, so I had to estimate the likely outcome by mathematically altering their results using the relative dimensions. I had considered a 15-degree movement of the swingarm and estimated that the shear force on the inner boundary was in the range of 600 to 1100-ish lbs (quite approximate). That Black Max will provide a lap shear strength on rubber of 1400 psi (assuming it is a properly prepared bond). The prepared surface area of the bushing where it was glued was approximately 3 sq.in IIRC so I think there is adequate capacity.
I would not choose rubber if I felt that it would slide in the bushing "race", as it really is not meant for, or suited to, that type of application.
Liquid soap is good for the outer surface during installation as it will dry and not be a lubricant. The signficant pressure that is imparted on the surfaces due to the slightly oversize nature of the bushings plays a big role too.
Chuck Moreland sold his original rubber bushings without glue, but now supplies them with the glue and the sand paper etc. to prep the bushings, as well as detailed instructions. That made me think otherwise.
I then researched a paper made by a couple of Dutch guys that investigated the behavior of exactly this type of bushing, subjected to torsional loading with both the inner and outer faces fixed to the substrate (i.e. in the same way I assume our bushings are designed to work). The bushings they used for their experiments was smaller than our springplate bushings, so I had to estimate the likely outcome by mathematically altering their results using the relative dimensions. I had considered a 15-degree movement of the swingarm and estimated that the shear force on the inner boundary was in the range of 600 to 1100-ish lbs (quite approximate). That Black Max will provide a lap shear strength on rubber of 1400 psi (assuming it is a properly prepared bond). The prepared surface area of the bushing where it was glued was approximately 3 sq.in IIRC so I think there is adequate capacity.
I would not choose rubber if I felt that it would slide in the bushing "race", as it really is not meant for, or suited to, that type of application.
Liquid soap is good for the outer surface during installation as it will dry and not be a lubricant. The signficant pressure that is imparted on the surfaces due to the slightly oversize nature of the bushings plays a big role too.
