Topic: Fiberglass fender + metal fork brace

[Scott S]

 I have this 'glass fender  that I'd like to use. I also have the "guts" of a stock front fender to use as a fender brace. The 'glass fender fits over it rather well. I REALLY am not keen on the idea of hose clamps to the fork lowers as a means of attaching the fender.




 I've used some automotive grade double sided tape before to mount tank badges, etc., but I'm afraif of the flexing on the front end and the amount of air that might get under the fender.
 I've heard there are some heavy duty bonding agents and glues in use these days.
 I'm thinking of cutting off the two tabs on the fender that wrap around the fork legs and bonding it to the metal brace.
 Suggestions on something really strong that will stand up to the flex and "lift" from the wind, etc.?

[bwaller]

I had something similar done by a friend who owns a body shop. He had some crazy strong 2-part adhesive that would bond those two parts together for life!

[Scott S]

 That's what I thought. The tank is at the body shop now. Maybe I'll ask about adhesives when I go pick it up.

[Retro Rocket]

Nice fender Scott, just use some sikaflex mate, it will never come off by itself  and if you ever need to remove it in the future all you need to do is slide a knife between the 2 parts and work it off, sikaflex remains rubbery but bonds well...   Clean both surfaces well, if the metal part to be glued is a shiny surface, sand the part to be glued with course sand paper like 80 grit, lightly scuff the glass surface too...

[chewbacca5000]

It looks like it is designed for a custom fit.  You can drill the holes a little large and use fender washers. 

[bjbuchanan]

The stuff is called panel adhesive, can't remember brand names but the stuff is serious and lots of OE's use it

[Retro Rocket]

The stuff is called panel adhesive, can't remember brand names but the stuff is serious and lots of OE's use it

Yes that stuff is great but once its glued, its there forever....

[martin99]

I've just been doing a similar thing. Didn't want to hack up the stock fender to get at the brace, and not sure it would have fitted nicely inside anyway as the fender I used is quite narrow. Ended up making my own brackets from 2.5mm ally plate. I have a Micron brace fitted for strength.

[Scott S]

 One other question: On one of my build threads someone commented that I had the fender on backwards. One side has a lip, and I placed that at the rear. That's the shorter side.
 Now, I can't look at that picture without second guessing myself.

 Which way do you think it should be facing? Lip to the rear? Or shorter section to the front?

[martin99]

Sorry, that was me! On mine, the one in the picture, there is an arrow moulded in the plastic on the underside. With that pointing forward, it puts the longer section at the back. Makes sense to me, most fenders I think are longer at the back. I do see what you mean about the lip though.

I suggest you try it the other way and see what you like best. Perhaps put a picture up? If you are painting it anyway, it wouldn't take much to remove the lip if you prefer it the other way round

[bjbuchanan]

The stuff is called panel adhesive, can't remember brand names but the stuff is serious and lots of OE's use it

Yes that stuff is great but once its glued, its there forever....

Yeah it seriously is. My buddy does high end bodywork and uses this stuff. It is unbelievable. It is really nice for sheetmetal repairs with a backer, especially on aluminum stuff. No warping, stretching, shrinking, screwing around

[78whiteorbs]

What's wrong with pop rivets or bolts??? As smooth as those engines are I would be afraid to use any kind of adhesive as the engine vibrations and wind would eventually weaken the bond. I would use some rubber washers and some small bolts or pop rivets. If it's a cosmetic thing just remember function over fashion or remember how great it looked when you are hunting for it on the side of the road. You could always have the rivets painted as well and they blend right in.

[bjbuchanan]

Real panel adhesive will not loosen, it chemically bonds. This isn't elmers glue we are talking about, think of it as being welded, for good.

That being said, I would use button head bolts and serrated/lock washer setup for simplicity and lowest cost.

[78whiteorbs]

Also even if it was backwards I like the way it looked how you have it pictured mounted with the short side to the back.

[78whiteorbs]

BJ please do explain how metal and a non metal chemically bond . From my knowledge you cannot "fuse" the two. I know there is a ton of science in adhesive technology but nothing is going to rival a mechanical fastner to join two objects on a motorcycle. Think , have you ever seen an original bike design that utilized "gluing" with any adhesive parts together, especially body parts . You never see this for a reason. This " duct tape " ideology will never work if you plan on riding it . Just one man thoughts that has tried a barrage of ignorance with two wheels and learned a few things along the way.

[bjbuchanan]

BJ please do explain how metal and a non metal chemically bond . From my knowledge you cannot "fuse" the two. I know there is a ton of science in adhesive technology but nothing is going to rival a mechanical fastner to join two objects on a motorcycle. Think , have you ever seen an original bike design that utilized "gluing" with any adhesive parts together, especially body parts . You never see this for a reason. This " duct tape " ideology will never work if you plan on riding it . Just one man thoughts that has tried a barrage of ignorance with two wheels and learned a few things along the way.

I will let Eastwood co help

http://www.eastwood.com/no-weld-panel-adhesive-replacement.html

Higher end vehicles that use exotic materials are all essentially glued together. You can't weld carbon fiber. When I say welding it is just to relate it in some way. This isn't a tube of permatex. These panel adhesives bond so strong that there is no servicing it, after they are joined it is scrapped if you screwed it up. It is extremely high strength. You are looking at it like this is goobering something together, it isn't a duct tape wrap.

Motorcycles are so far behind in tech compared to most cars it is a useless comparison. Additionally, there is no such thing as bodywork that is structural or structural to cosmetic. Bikes are hardware wrapped in plastic. Last I checked no bike had a monocoque tub that every other panel and structural member was glued to.

[bjbuchanan]

There is also specialty adhesives for steel to fiberglass and stuff like that. 3m makes them. Auto manufacturers use them all the time, go work on a volkswagen and take a peek at the fenders.

[78whiteorbs]

Right but they are used in combo with mechanical fastners and are "stress fitted" like puzzle pieces. If you are bonding mechanical fastners to fiberglass by glassing them in then then you would be using a combo of fiberglass and bolts and not strictly an adhesive process. Also the fiber glass or carbon fiber is in essence a mechanical bonding agent. Maybe this is coming across I'll mannered (which I totally do not mean to) but attaching a fiber glass fender to a steel fork brace using mere she's I've alone would never be seen on any bike nor should it. If it were a cast abs part or the like that has a self locking design then ok but we are talking about a fiberglass fender and a metal fork brace and attaching the two permanently with some sort of epoxy "super adhesive".

[78whiteorbs]

That slow cure epoxy I see joins metal to metal...which is then bondoed over and protected by paint and would be win stream protected by the rest of the structurally integrated body work. Interesting stuff
Can't be cheaper than four rivets though;-)

[Retro Rocket]

BJ please do explain how metal and a non metal chemically bond . From my knowledge you cannot "fuse" the two. I know there is a ton of science in adhesive technology but nothing is going to rival a mechanical fastner to join two objects on a motorcycle. Think , have you ever seen an original bike design that utilized "gluing" with any adhesive parts together, especially body parts . You never see this for a reason. This " duct tape " ideology will never work if you plan on riding it . Just one man thoughts that has tried a barrage of ignorance with two wheels and learned a few things along the way.

Sorry Orbs, you are wrong, they have been using these types of glue for years and it WORKS, one of my friends builds high end hot rods, the industry standard in Australia and they use a similar glue to bond steel and glass together, it does NOT come off, they have a video showing them driving a 4WD over a bonded panel and not a thing  moved, no damage apart from a few scratches. Just because you haven't heard of it before doesn't mean it doesn't work, they've been using similar glues on Corvettes for a very long time...

[754]

I think the reason we don't see it on bikes, is the type of structure.. No longer seams on panels..like say..a car door skin or metal to composite structure such as honeycomb panels in aircraft.
 That said, though, the probably are using it on some motorcycles, perhaps not noticeable as a bonded part

[bjbuchanan]

You don't see it on a motorcycle bc there is no application. No large panels attached to a sub structure, they are just too simple.

Like I said, there is other products out there.3m makes it all, they can bond anything to anything, just get the right product for the application.

I also said I would just use button heads and a lock washer bc it isn't worth the expense in my opinion

[78whiteorbs]

BJ please do explain how metal and a non metal chemically bond . From my knowledge you cannot "fuse" the two. I know there is a ton of science in adhesive technology but nothing is going to rival a mechanical fastner to join two objects on a motorcycle. Think , have you ever seen an original bike design that utilized "gluing" with any adhesive parts together, especially body parts . You never see this for a reason. This " duct tape " ideology will never work if you plan on riding it . Just one man thoughts that has tried a barrage of ignorance with two wheels and learned a few things along the way.

Sorry Orbs, you are wrong, they have been using these types of glue for years and it WORKS, one of my friends builds high end hot rods, the industry standard in Australia and they use a similar glue to bond steel and glass together, it does NOT come off, they have a video showing them driving a 4WD over a bonded panel and not a thing  moved, no damage apart from a few scratches. Just because you haven't heard of it before doesn't mean it doesn't work, they've been using similar glues on Corvettes for a very long time...

Hey not like I haven't been wrong before, I love to learn.
Like 754 stated though " it's the type of structure."  How practical is it to use a purely contact adhesive (and I am defining this by two vector contact points) on the front end of a 40 year old motorcycle where the most wind drag occurs. I have built boats before and am well aware of the adhesive strengths available for gluing/joining/bonding materials today. I don't think I could be convinced this would be either economical or practical in this particular application but hey everyone has an opinion and you guys are entitled to yours . No sweat :-)

[78whiteorbs]

You don't see it on a motorcycle bc there is no application. No large panels attached to a sub structure, they are just too simple.

Like I said, there is other products out there.3m makes it all, they can bond anything to anything, just get the right product for the application.

I also said I would just use button heads and a lock washer bc it isn't worth the expense in my opinion

BJ I totally agree with everything you just said :-) !

[Retro Rocket]

I also said I would just use button heads and a lock washer bc it isn't worth the expense in my opinion

Thats why i suggested sikaflex, maybe 4 rivets as well. I trailered a boat with an outboard pod about 700 miles before i realized i had not bolted the pod on {15 foot boat, pod was very heavy fibreglass around 50 pound}, the only thing that was holding the pod on was sikaflex, it didn't move at all, it would work well on that fender...