Instead of riviets----Nylon

[Kevin K]

Looking to replace all my rivets on my Scamp. Has anyone used nylon screws,acorn nuts and nylon cup washers? They would blend in very nice.

Nylon screws




Nylon acorn nuts





Nylon cup washers

[Casita Greg]

They do not posess sufficient tensile strength to hold against the twisting, pulling and other torque forces they would be subjected to. The threads would strip right out after several good bounces. It would be nice if they worked, but they're not strong enough for what you wish to use them for.

[Perry J]

Why? Rivets are the least inexpensive to replace and the easiest.
In your case most of the rivets are 23 years old and still going strong.
Why change?
John

[Kevin K]

All my rivet caps are shot (28 years old) and need to be replaced. I thought this might work. (Nylon screws)

[Perry J]

Originally Posted by Kevin K

All my rivet caps are shot (28 years old) and need to be replaced. I thought this might work. (Nylon screws)

If your rivets are sound and the caps are missing you can just glue new caps on.
I have used Dicor caulking, which is used on Rubber roofs, to replace the caps. Three years and they are still tight.

John

[Andy B]

Originally Posted by Casita Greg

They do not posess sufficient tensile strength to hold against the twisting, pulling and other torque forces they would be subjected to. The threads would strip right out after several good bounces. It would be nice if they worked, but they're not strong enough for what you wish to use them for.

Aluminum rivets may be stronger than nylon bolts but the nylon may be strong enough. If the rivets are installed blind, without a backing plate, the fiberglass around the rivet would fail before the aluminum rivet. The following link shows someone do a pull test with aluminum rivets in a fiberglass panel. It took 134 pounds gently applied to pull each rivet out.
Pop riveting fiberglass - C&L Boatworks Forum

Nylon bolts in the 10-32 size have 166 pounds of tensile strength before breaking. To be fair in the comparison, the 10-32 bolt is a little bigger in diameter than the rivet that was tested.
Plastic Nuts & Bolts.com

[Bruce Thomas]

Nylon will have trouble with shock type loads and moreso when colder. They haven't much shear strength......so lets say you walked up to an installed one with a small hammer and tapped the head on the side........its gone

[Andy B]

Originally Posted by Bruce Thomas

Nylon will have trouble with shock type loads and moreso when colder. They haven't much shear strength......so lets say you walked up to an installed one with a small hammer and tapped the head on the side........its gone

That did not sound right to me, after all why would the make fasteners that the heads would pop off with just a small tap on the side.

I checked in my workshop and I had a few nylon bolts, not sure the size but about the 10-24 size. I drilled a hole in small piece of half inch plywood, inserted the bolt and tightened the nut on the other side. I put the plywood in a vice and tapped on the side of the head with a claw hammer, nothing happened. I hit the nylon head on the side with the hammer even harder several more times and still nothing. I hit it hard enough and long enough that, if I had been driving a nail, it would have been driven through a 2x4. The only damage was dents on the bolt head from the hammer. Based on this I don't think the heads will pop off when hit from the side.

[Casita Greg]

Andy,
Not to be argumentative here, but your "testing" is not based on real world applications, as they would be if installed in a trailer. Yes, they will take, and endure, a certain amount of "abuse" without failure, but I personally don't feel that selecting nylon fasteners would be a good choice in a practical application. If you really feel strongly about these things, then by all means, go for it. I would be very interested in learning how they work out for you after some "field testing" with them installed.
Nylon "nuts and bolts" are not really rated as to their shear strength or tensile strength for very good reasons...they don't really have any. These types of fasteners were never designed to replace "graded bolts" or rivets. They are mainly used where torque and shear strength are not requirements. Such things as such holding your "metal detector" coil on your metal detector (non-metallic application), or in non-pressurized corrosive environments, are just a few examples of what they are more suited for. Any application requiring any modicum of structural strength would not be well suited to nylon fasteners. You are, of course, free to try anything you wish, but please understand that they have serious strength limitations.

[Carol H]

I personally would not want to be the one to try the nylon idea. Would stick with the tried and true rivets. Not sure what you would be saving by going with nylon as the rivets and caps are probable cheaper and I cant see how you would be saving time as it seems to me to be the same amount of work to install. I sure would hate to have to do the job of replacing them a second time if the nylon was to fail faster than the rivets as some have suggested they will.

I base my opinon on the fact that the rivets on my Scamp have for the most part lasted 20 years. I know the trailer had not had any of its original rivets replaced previously. I have slowly been replacing mine one section of the trailer at a time and the main reason for replacing them is a number of the cap holders were broken off at the time I purchased the trailer. Not sure how that happened but in the 4 years I have had the trailer I havent broken any caps holders off. Decided that due to trailer age it was probable not a bad idea to replace not only the rivets with broken cap holders but all the rivets, while I had the the tools out to do it. During the replacement I have so far (only 50% done) only found one rivet that had actually snapped in two. They looked good from the outside and inside but when I pulled the silicon off the broken cap it came totally apart so the only thing holding it in place was the silicon that the previous owner had put over the broken cap holder. After 20 years of use and only one broken rivet (so far) says to me that the rivets really do work well. It may also be that the one rivet that did break was actually broken by the force of what ever broke the cap holder off and not by the stress of the flexing of the trailer while driving over rough roads which the trailer has been over.

As others have said it really is your choose but I personally hate having to do a job twice.

[floyd]

Originally Posted by Kevin K

Looking to replace all my rivets on my Scamp. Has anyone used nylon screws,acorn nuts and nylon cup washers? They would blend in very nice.

Nylon screws
Attachment 36282

Attachment 36283

Nylon acorn nuts

Attachment 36284

Attachment 36285

Nylon cup washers

Attachment 36286

How about stainless steel... then if you want you could use nylon acorn nuts over the stainless regular nuts
I would use stainless machine screws with philips heads, and stainless nylocks.

[Andy B]

Originally Posted by Casita Greg

Andy,
Not to be argumentative here, but your "testing" is not based on real world applications, as they would be if installed in a trailer. ... I would be very interested in learning how they work out for you after some "field testing" with them installed.
Nylon "nuts and bolts" are not really rated as to their shear strength or tensile strength for very good reasons...they don't really have any.

Although I have used nylon bolts in the past, I will not be the one to try them in this application since my Burro does not have any rivets.

My testing was in reaction to the previous statement "lets say you walked up to an installed one with a small hammer and tapped the head on the side........its gone" The testing showed that statement was simply not true and may have mislead someone into thinking that a nylon bolt head would pop off if it was just tapped on the side.

As far as saying that saying "Nylon "nuts and bolts" are not really rated as to their shear strength or tensile strength for very good reasons...they don't really have any."

If you looked at the link I provided in post #6, you would see the the nylon bolt ratings for both shear and tensile strength for both yield and breakage. In that post I compared the tensile strength of a nylon bolt to an aluminum rivet pull out test from fiberglass and the nylon bolt was 24% stronger than the force needed to pull a rivet out of fiberglass.
Here is the link to the nylon bolt ratings again Plastic Nuts & Bolts.com

I will agree that an aluminum rivet has more tensile and shear strength than a similar sized nylon bolt. The weak link is the fiberglass surrounding the rivet if no backing plate is used. If you nail Jello to a tree, it does not matter how strong the nail is because the Jello will fail first.

My goal in this discussion has been only to correct some mis-information.

[Casita Greg]

Well Andy,
You are sure welcome to try whatever you think will work for you. That being said, I wish you luck with your endeavor to use plastic fasteners in your desire to "reinvent the wheel" within the realm of trailer fasteners. Please let us know how this experiment works out for you. We'll all want to know how it pans out.