Visit our Popular Forums

shadeemry · 06-03-2014, 01:50 PM

im using a 3x air hammer for buck riveting, and I'm redoing the rivets on some of my skins.. someone used pop rivets and filled the holes in, and never sealed them in the rear. I was having a fun time finding the leak till I used a preassure washer and found it was at the seams.so I went and removed the rear panel rivets, used snips to chop the rivet mandrel off, pulled the rivet out, as I figured it was bad to enlarge the hole anymore then it is. after that, I used a heat gun to pop the sealeant , and what would you know, it was all silicone sealent...very bad, not a hint of vulkem on that seam but the rest had it on that panel. so I ordered some long and short mandrel buck rivets from vintage trailer supply, aluminium of course and proceded to buck rivet.

now im new at this, and any criticisim or pro tips to doing buck rivets is greatly appreciated. im using the dome head bits on the rivet head side and the bucking bar on the mandrel side of the rivet. i was using the long mandrels for this seam. i think im using the wrong air hammer head bit, because the edges are flattining out. any tips?

shadeemry · 06-03-2014, 01:58 PM

you will notice the window frame, im i have 3 spares, which is why i decided i wanted to learn buck riveting, because i was sure i was going to mess something up, but thats a later topic. To get the older rivets out, the dome ones, im using a rivet remover sold by vintage trailer supply, and i tell you what, that tool is AMAZING at removing rivets, and the bit after 600 rivets still hasn't snapped. best 40 dollar investment, no more marred skins and the rivets come out everytime.

Belegedhel · 06-03-2014, 02:29 PM

So...Yes, you have to make sure your rivet set matches the head of the particular rivet you are using. I have been buying my rivets from VTS, and have the buck rivet kit that they sell, and the set that came with that kit, and the rivets they sell are perfectly matched. When you get those"smiley" faces on your rivets, it could also be an indication that your air pressure is too high, and the rivet gun is jumping around on the rivet head. There are some very simple and instructive videos on Youtube that demonstrate buck riveting--you might want to check them out.

I also use the rivet removal took, but find that shearing the rivet with a sharp putty knife by driving it between the panels works really well too.

good luck!

shadeemry · 06-03-2014, 02:53 PM

any good videos that you can link? and whats the desired air preasure on the rivet gun? should i use a regulator and set it to x psi?

shadeemry · 06-03-2014, 02:58 PM

Quote:

Originally Posted by Belegedhel

I also use the rivet removal took, but find that shearing the rivet with a sharp putty knife by driving it between the panels works really well too.

good luck!

im assuming a good way to remove that flattend off kilter rivet is to use a sharp putty knife, awsome ok.

mimiandrews · 06-03-2014, 03:34 PM

Download Advisory Circular 43.13-1B, Chapter 4 here to read the aircraft standards for riveting. They don't all apply to Airstreams, but do give a fairly good overview of how to do riveting correctly.

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/list/AC%2043.13-1B/$FILE/Chapter%2004.pdf

Then drill a few dozen holes in a piece of scrap metal, clamp the metal in a vice to hold it steady, and practice until you can hold the gun steady and centered. That should eliminate the "smiles" you get when the gun bounces. Try different air pressures and find out what works.

There is a different tool (rivet set in aircraft parlance, that you're calling a mandrel) for the gun for each diameter and type of head. Usual for Airstream would be an 1/8" diameter rivet (AN4), so make sure the set you're using matches the rivet head. That should cure the flat spots in the center of the rivet.

The "tail" of the rivet should protrude through the metal 1 1/2 times the diameter of the rivet to produce the correct formed head after the rivet is driven. Too long a rivet, or too large a hole will cause the rivet to bend instead of flattening properly.

Like any skill, it takes practice. Good luck.

Belegedhel · 06-03-2014, 03:39 PM

Yes, definitely you should be using a regulator on you air compressor. Your gun should have the operating pressure range written on it somewhere--seems like it is 75-90 psi on mine. My gun also has a pressure adjustment on the butt of the gun for fine tuning it.

On Youtube, search for "buck rivet" and "aircraft solid rivet" and you should see quite a selection of videos. I don't recall what specific ones I've watched, but you can check out a few of them and potentially learn a lot with only a few minutes invested.

good luck!

Mixter · 06-03-2014, 07:40 PM

Took me a long time to dial in solid riveting.... Here's some things I learned:

Practice: on scraps first. You can get used to how the rivets respond with too much air pressure, crooked bucking bar, too long of a rivet, too short of a rivet. You'll be able to eyeball and work the rivets much better once you drill a ton of holes and run the spectrum of how these things mess up.
Smileys: Correct "style" rivet set- I found out through SO much frustration, that the rivet set that came with my 3x riveter was for a "universal" head. However the rivets on Airstream are Brazier head. I had no idea, as they look very similar but EVERY time I set a rivet, it would leave a smiley. I see some on yours that lead me to think this may be what is going on. VTS sells the matching Brazier head rivet set. I bought that and no more smileys. (Except old rivets that have been drilled out, but are still dimpled in, will leave smileys just because they are dimpled in.
Air pressure. This is where the practice on scrap helps. I originally saw something in the riveter directions (or somewhere) that 60-90 psi was the range.... it took alot of trial and error to get to the point of where I realized that is WAAAY to high of psi... I dont know if its just me, but I use around 25-30 psi. These Rivets are soft, and they squish real easy.
Rivet length: Make sure they protrude no more than 1.5x the diameter. Buy the long rivets from VTS, and the rivet cutter tool. You can cut whatever size you need for each spot, such as through 2 skins only, or window frame and skin, or 2 skins and a rib, etc. From my experience it is better to err on the shorter than longer.
Rivet Diameter: It is my understanding that industry standard is to go to the next size up because when drilling out a rivet, more than likely the hole will no longer be round. On ALL of the 1,000's of solid rivets I have drilled to replace, I step up from the original 1/8" to the VTS 5/32". Their 5/32 is a "modified Brazier" head because it still has the same size head as the original 1/8", but allows you to use the larger 5/32 so you can drill out a new round hole. Again, these rivets are soft, and I've been successful in squishing them pretty good into a not-so-round hole where I didnt have any other choice.
Sealant: I have been chasing leaks for 7 months now. Every time I think I found and fixed, new ones come up or old ones reappear. As I drill out a seam of rivets, I clean up both sides and squeeze in vulkem (or whatever your favorite polyurethane sealant is), and then I re-rivet through the wet sealant. I've done several of the windows, and most of the vertical seams. This is slow going, but works well. i can't believe these things weren't riveted up wet to begin with- sure would have solved alot of the leak issues.

shadeemry · 06-03-2014, 10:49 PM

Quote:

Originally Posted by Mixter

Took me a long time to dial in solid riveting.... Here's some things I learned:

Practice: on scraps first. You can get used to how the rivets respond with too much air pressure, crooked bucking bar, too long of a rivet, too short of a rivet. You'll be able to eyeball and work the rivets much better once you drill a ton of holes and run the spectrum of how these things mess up.
Smileys: Correct "style" rivet set- I found out through SO much frustration, that the rivet set that came with my 3x riveter was for a "universal" head. However the rivets on Airstream are Brazier head. I had no idea, as they look very similar but EVERY time I set a rivet, it would leave a smiley. I see some on yours that lead me to think this may be what is going on. VTS sells the matching Brazier head rivet set. I bought that and no more smileys. (Except old rivets that have been drilled out, but are still dimpled in, will leave smileys just because they are dimpled in.
Air pressure. This is where the practice on scrap helps. I originally saw something in the riveter directions (or somewhere) that 60-90 psi was the range.... it took alot of trial and error to get to the point of where I realized that is WAAAY to high of psi... I dont know if its just me, but I use around 25-30 psi. These Rivets are soft, and they squish real easy.
Rivet length: Make sure they protrude no more than 1.5x the diameter. Buy the long rivets from VTS, and the rivet cutter tool. You can cut whatever size you need for each spot, such as through 2 skins only, or window frame and skin, or 2 skins and a rib, etc. From my experience it is better to err on the shorter than longer.
Rivet Diameter: It is my understanding that industry standard is to go to the next size up because when drilling out a rivet, more than likely the hole will no longer be round. On ALL of the 1,000's of solid rivets I have drilled to replace, I step up from the original 1/8" to the VTS 5/32". Their 5/32 is a "modified Brazier" head because it still has the same size head as the original 1/8", but allows you to use the larger 5/32 so you can drill out a new round hole. Again, these rivets are soft, and I've been successful in squishing them pretty good into a not-so-round hole where I didnt have any other choice.
Sealant: I have been chasing leaks for 7 months now. Every time I think I found and fixed, new ones come up or old ones reappear. As I drill out a seam of rivets, I clean up both sides and squeeze in vulkem (or whatever your favorite polyurethane sealant is), and then I re-rivet through the wet sealant. I've done several of the windows, and most of the vertical seams. This is slow going, but works well. i can't believe these things weren't riveted up wet to begin with- sure would have solved alot of the leak issues.

that was helpful, very helpful, yes I'm using standard mandrels, so im going to vts now and ordering a brazier head set. is their any bucking tips you have for the bucker? do you push all the way against the skin? or do you leave a space for the rivet to expand? me and my bucker are having big issues with this.

on the note of psi, i will be sure to dial it down to my paint gun settings (36 psi) i have a snap on air compressor that has some really good cfm. figured if i was going to get one, to get the best.

is their any other good tools to get? and any neat little measure trick you guys use that i can use to mark my rivets?

Mixter · 06-04-2014, 06:23 AM

that was helpful, very helpful, yes I'm using standard mandrels, so im going to vts now and ordering a brazier head set. is their any bucking tips you have for the bucker? do you push all the way against the skin? or do you leave a space for the rivet to expand? me and my bucker are having big issues with this.

Push the rivet all the way through so the shaft is protruding the proper distance 1.5x the diameter. Set the riveter on the head, and the bucking bar just needs slight pressure on the back. The bucker doesnt need to press very hard. The inside should smoosh down to achieve a bucked diameter of 1.5x diameter. The pieces being fastened do have to be tight together for solid rivets to work properly. Sometimes the bucker has to help keep the skins tight while this is going on. You might press a little harder on the head for the first pop of the trigger, but then lighten up to have a steady pressure- do NOT press so light that the rivet comes off the head... you have to keep the set firmly planted on the rivet.

Practice on scraps with your bucker. Make sure you experiment with the bucking bar on angle so he/she can see that this will mess up the rivet.

Heres a video that helped me:

Installing Aircraft Solid Rivets - YouTube

I bought the bucking bar from VTS. You dont need a special bucking bar, just a piece of heavy steel. But it has some good angles and shape to it that is helpful in getting in tight spaces. I also cut the end off of a 1" receiver hitch for a "thin" bucking bar to get in tighter paces like between a rib and window, where the VTS bar didnt fit.

on the note of psi, i will be sure to dial it down to my paint gun settings (36 psi) i have a snap on air compressor that has some really good cfm. figured if i was going to get one, to get the best.

36 still seems high to me. Practice and see for yourself what works. cfm is not important with a riveter.

mimiandrews · 06-04-2014, 07:24 AM

Look for members of the Experimental Aircraft Association in your local area. These people build airplanes as a hobby. Many of them are expert riveters, and most of them are happy to teach their skills to anyone who asks. EAA.org is the national website. Local chapters are almost everywhere.

shadeemry · 06-07-2014, 07:42 PM

ok, so here is my practice sheets, on the first set, i didn't ave the mandrel and used 2 points you guys have pointed out. cutting the rivet shorter AND dialing down the pressure.. i found 20 worked for me but I'm thinking higher so i don't hit the rivet as much and keep the rivet heads shinier.

On the second 3, i used the dial pressure, the mandrel from VTS, and the rivet measuring length experimentation.

ANY criticism would be wonderful here, as ya'll have been very helpful and I'm a fast learner.