How to replace snap caps?

[Scott Bacon]

Another newbie question...

The '96 Scamp we just bought hasn't been waxed in years (if ever). And it's been stored outside in the high altitude Colorado sun. When washing down the exterior to prep for waxing, many of the snap caps and their washer rings, which cover the rivets, simply disintegrating.

Since the caps and rings were installed with the rivets and a sealant, what is the procedure for replacing them? I'm assuming the rivets would have to be removed (and replaced) to replace the snap cap ring and sealant? Should I have worries about leaks now that these caps, rings and possibly the sealant has been compromised?

No leaks yet, with a thorough washing. But I'd rather not discover a leak during a major downpour somewhere up in the hills.

Thanks for any suggestions!

[Suz]

When I got my trailer, not only were almost every one of the snap rings and caps gone, each was covered with a gob of dirty goo. Slowly but surely I got them replaced. Some of the rivets were easy to remove and reinstall, but some require two people and I usually work alone. I will say, replacing the rivet when installing a new snap ring is usually easier, but if you want to experiment, I'll see if I can explain it. By the way, I was told this wouldn't work, but long term testing has demonstrated that it not only does work, it is hard to tell which is which. Once they are done, keep a supply of the caps and if you make sure you keep them replaced as needed, then you won't have to worry about the rings for a long time.

First you must remove every last bit of the old snap ring and sealer. You may think they are completely gone, but there will be a small bit hidden between the rivet and the trailer. Gettting this out is the very hardest part of the job. It MUST be all out or you will not get a proper fit or seal. Once that is done, take the snap ring and cut it from the center to the outer edge. Put a little sealant (I use RTV clear) on the rivet. Work the snap ring in behind the rivet. Take a pair of pliers (I use needle nose) and squeeze the snap ring closed. Rotate until the cut is at the bottom. Fill with RTV sealant, then snap the cover into place. If the ring is not properly installed, the snap cap will not fit on the ring properly.

Just to repeat a couple of things:

It is usually is easier (and quicker) just to install a new rivet, but there are times when this was better suited for me as a one person job.

If you do not get out ALL of the old snap ring-- and there is always some left under the rivet -- this will not work. A good strong thread is often required to get it all out.

I was told this wouldn't work, but if it is done properly, it has and does work.

[Suz]

If you don't have a rivet gun, you need to get one. My guess is after fooling with just one of these, you're going to want to replace rather than repair.



Oh, and have plenty of paper towels on hand. It's messy work repairing them.

[Scott Bacon]

Thanks for the detailed reply, Suz!

I'm fairly handy, but I've never worked with a rivet gun - pretty easy?

[Suz]

Thanks for the detailed reply, Suz!

I'm fairly handy, but I've never worked with a rivet gun - pretty easy?

Yes -- just remember, finesse is better than brute strength. I still get a couple that I have to drill out and start over, but it won't take long and that rivet gun will be your best friend.

Practice makes (almost) perfect.

[Suz]

Finesse = small squeezes

Brute strength = squeezing as hard as you can

You will also learn how to take it apart as one of the rivet shafts inevitably gets stuck. No big deal. Just remember to keep something under it so none of the parts get lost. Don't ask me how I know this.

[Suz]

By the way, there are differences of opinions on this, but aluminum rivets are recommend by my trailer mfg and are my preference so that is what I use. The theory is that they will break before the fiberglass does. Easier to replace a rivet than repair fiberglass.

If you prefer something stronger, then use stainless, because the steel ones rust. NOT a good thing.

[Penny Taylor]

BTW. I found a place that sells the snap covers, and washers, cheap.
www.mcfeeleys.com
I am going to get a stock of the gray ones, which are on sale, I can always paint them whatever color I need.

[Jim C.]

Scott, We've have good luck with Pro-Dec for hinge snap-caps. Price was $14.00 for 100 delivered. They have an assortment of colors and will send samples for color match, and they have a color catalog as well. Their website is: www.pro-dec.com phone (281)240-0924. They have other products as well. Also, if you have or can rent an air compressor, an air riveter is inexpensive and worth its weight in gold. You might be better off drilling out the old rivets and replacing with new and using butyl rubber (comes in a tube like caulk) for sealant. Butyl comes in white, black, and grey, and is better than silicone for sealing on fiberglass. Advise against using stainless steel rivets as they are powerful enough to pull through fiberglass on tightning. Aluminum would be your best bet. Also, after putting the snap caps on your rivet smear a little butyl on the rivet to waterproof any space due to overdrilling, or expansion and contraction through the years. Before you snap the cap apply some butyl to the hole in the head of the rivet from which the draw bar has been pulled. That should make everything waterproof. Hope this helps.

[shirley munson]

I used ss bolts with chrome acorn nuts inside about 20 years ago. No leaks (had sealent under bolt heads) and only one has viabrated loose. Even used little ones for the curtain rods with regular hex nuts. I only use pop rivets in blind situations. The bolts do require a helper but thats what wives are for.

[Scott Bacon]

Wow, thanks for all the great replies! I do have an air compressor, so I'll take a look at the pneumatic rivet guns.

Hopefully, we'll stay leak free. (ooops, probably shouldn't have said that! ) Then I can make this a winter project. And, instead, get this trailer into the hills for some enjoyment!

[Brian B-P]

The only helpful bit of information related to rivet installation which I didn't see above is to use washers. A washer on the inside, properly fitted to the rivet size, gives the rivet tube something to crush against and spreads the load after installation around the hole.

In some cases in my Boler, what is being installed is a steel bracket on the inside for a cabinet, and in those cases the bracket itself would act like a washer if the hole is well-sized, so a separate washer would not be needed.

This is particularly useful if the item being installed is on the outside of the trailer (such as an entrance fitting for water or power), because in that case the rivet is trying to install against just the fiberglass, which I find isn't stiff enough to work well. "Rivnut"-style fasteners, which install like a rivet but leave a nut installed in the hole, can take a lot of force to install (they're like big rivets) and I found I needed the washers to get them to install properly when I used them for my water fill port fitting - they would just expand in the hole otherwise.

[Suz]

Most of my rivets are blind so a washer doesn't work, however if and when one can use them (and you don't have other rivets available), then its a good idea. My Casita actually uses acorn nuts on the ones that are exposed on the inside of the trailer. Really makes for a snug fit, but it does (usually) require someone to be at the other end. I think some ingenious member(s) came up with a gadget for a one person install, but I haven't seen it.

There are several types of blind rivets, including a couple that don't require washers. We had a lot of good discussions that were lost last year. The first one that comes to mind is a banana peel. It's like the one HERE. There's another one that I don't recall the name of at the moment that spreads out differently than the banana peel that is also quite effective.

[Steve B]

Is drilling out the old rivets difficult? Do I use a drill bit that is the same size of the rivet or a little larger/ smaller? Also, what is the the acutal size of most of the rivets throughout the '13 Scamp? Thanks,
-steve

[BobB]

FWIW, Boss RTV sealant is very effective for sealing around rivets as well.

[Suz]

I use a drill bit that's about the size of the rivet shaft. In other words, you don't want to make the hole in the trailer any larger than it already is.

I use a variable speed drill so that I can take it very slowly until I can get a feel for it. Once the outer ring is broken, you can usually take something and just poke the rivet to the inside to clear the hole.

It may take a bit to get the hang of it, just take it nice and slow, don't get frustrated and remember that the more you do it, the easier it becomes. I learned by trial and error and you can to.

Whether removing or installing, finesse is the key to rivet success! ... well, that and practice.

[Steve L.]

Many/most of the blind rivets I drill out end up spinning in the hole meaning I can't finish drilling them out. In other words, the rivet starts spinning as fast as the drill is turning. Another nice thing about aluminum rivets is that I can take a half inch (sacrificial) chisel, lay it flat against the surface, bevel up, and lightly cut the head of the rivet off.

Casita once told me that the drill should be no more than 1/64 inch over the diameter of the rivet.

In a sort of "belt and suspenders" approach I'd suggest a very small dab of silicone in the hole before inserting the rivet and more over the hole after the mandrel snaps.

Pneumatic riveters can be expensive unless you buy from Harbor Freight or some such place. They would probably be adequate for the relatively few rivets (compared to a production tool) you need to replace. Some rivets can be awkward to access and a pneumatic might be helpful. However, hand held riveters are more than adequate.

There must be some sort of guideline as to length of rivet but I don't know it off the top of my head. Often the rivet is holding something to the outer skin. The body of the rivet has to be perhaps an 1/8" longer than the depth of the hole. (Not counting the little bulbous end to the mandrel.) I'm making this rule up as I speak, hoping someone has a more authoritative guideline.

Intuitively, it's a good idea to press the layers to be riveted together before pulling the rivet. It can be a two person job, one inside pushing things against the wall, the other outside running the riveter. In my case, being single, I use creative bracing to hold things in place.

Backup washers are very helpful as Brian suggests. Use them wherever the inside of the rivet is hidden. Casita puts an acorn nut over the ends of exposed rivets to dress up the appearance. I'm attaching a drawing I've posted a number of times.



You need to experiment with a nut size that just fits over the unexpanded rivet diameter. This might not pertain to your application however.

[Patrick M.]

My Casita actually uses acorn nuts on the ones that are exposed on the inside of the trailer. Really makes for a snug fit, but it does (usually) require someone to be at the other end. I think some ingenious member(s) came up with a gadget for a one person install, but I haven't seen it.

That would be Joy and her PVC gadget.