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07-17-2004, 08:46 AM #1
I have an old aluminum Starcraft runabout and get water in around several of the rivets when the boat is being pushed hard.
Where can I find small quantities of Aluminum rivets and what is the best way to set them?
07-17-2004, 01:47 PM #2
Maybe this may be one of those uses for those zinc based soldering rods. I think the name is like Aluma-Fix or something like that.
If there still decently structurally sound, maybe all they need is a bit of filler to seal them up?
my 2 cents...
07-17-2004, 05:55 PM #3
Starcraft makes some great boats, I've had a couple and they were fine little 12' and 14' fishing boats. Early 80's, I looked into buying a used Starcraft runabout that leaked when I took it out for a trial. I postponed the decision to buy and was later very happy I had. Seems that sometimes the aluminum flexes so much when they are pushed hard (local boat dealer told me that he felt Starcraft was putting way to much engine on them even though they somehow did get BIA certification for the HP)that fatigue cracks propagate from one rivet hole to the next and then the rivets loosen up. Hope that is not the case with your boat because the fix for this is rather radical (read that as expensive) and in extreme cases the boat has only scrap metal value.
On a lighter note, to your question;
"what is the best way to set them?"
Four rules I learned 1. you don't push on ropes, 2. urinate on electric fences, 3. sod goes green side up and 4. in the case of rivets and boats - the smooth side to the water.
07-17-2004, 06:49 PM #4
If the rivits are loose and wallered out sometime you can give them a vigorous licalize wire brushing, goop them with aluminastic, then re-set the existing rivets with a helper bucking from the opposite side. Do not over drive them. You'll cause the metal between the rivits to upset and buckle.
Generally when there is fastener failure in aluminum boat the total failure of the boat can't be far behind.
07-18-2004, 12:55 AM #5
I would imagine that riveted alumninum boats are put together like riveted aluminum airplanes. Aircraft Spruce & Specialty (www.aircraft-spruce.com) should have all the tools and supplies you need. Dont know about small quantities though. Jeff
07-18-2004, 07:37 AM #6
As mendoje1 mentioned aluminium boats are put together in a fashion similar to aluminium aircraft and can be repaired as such. The problem you usually run into with a boat is that they sometimes have a compound (more than one direction) curve and without specialized equipment the repair pieces cannot be formed. Find below a link on installing solid rivets and if you do some internet research usually on homebuilt aircraft sites you will find out more also. Here are a few points. Clean the aluminium well and prime with a zinc chromate or epoxy primer before assembling, use some form of sealant to keep out moisture and debris, holes for rivets round and nice slide fit, stop drill any cracks you have.
07-18-2004, 02:09 PM #7
Rivet failure is caused by electrolytic action between the rivet alloy and the hull alloy in most cases, evidenced by a small spot of fine white powder around the area. That said, I have done a few boats and used braiser head rivets from a company in the Bronx. The name escapes me right now but it was something tricky like Rivet Supply Co. You need rivets that are total thickness + 125% of the rivet diameter long. I use 1100 series alloy since it is preferently corroded before the hull alloy. Hulls are usually 5000 series alloy. Rivets are sold by the pound, about 1200 rivets of the sizes you will need. They are cheap and yopu will need more than you think. About 3500 go below the waterline on a 22 footer and take 10-12 hours to put in.
Get good ear muffs, an L shaped bucking bar, and a straight and an angled rivet set with a .401 shank from an Aircraft Tool Supply Co. The ATS guys can help you get started if you talk nice to them.
For a couple of hundred rivets just use a cheap long barrel air hammer and 'tease' the trigger. This is a two person job, the one on the outside uses cuts the head off the old one, places the new rivet into the hole and places the set against the head. When the inside person hears the hammer press against the skin, he pushes the bucking bar back HARD and the outside guy squeezes off a few licks with the hammer. In seconds the rivet head is caulked and properly formed and the inside is upset properly. A few practice trys and you'll get the hang of it.
Use a VERY sharp chisel to cut the heads off of a few (4 or 5) loose or bad ones in a row then replace them with new ones. You will find many bad ones near the obvious ones. Also you will probably find that there are some 'oversize' rivets to fix factory mistakes. It is easy to want to overdrive the rivets and to try and use ones that are too long; resist the urge.
Most often there is no sealer between the sheets at the seam since the rivets draw the metal up tight and for a good seal. I you feel there must be a sealer, Pliobond is a good one to use.
There are a lot of boats to be had cheap with loose rivets. Stay away from the ones that have repairs with welds, bolts and and silicone putty.
07-18-2004, 03:34 PM #8
Assuming you decide to rerivet, a few more rivet suppliers- US Tool company sells rivets, sets, air riveters, bucking blocks and everything else for aircraft and auto riveting and repair-
and a good mail order general rivet supplier is JayCee- they have brass, bronze, stainless, mild steel, and aluminum rivets in just about every size and shape.
07-18-2004, 11:40 PM #9
Thanks for all of the advice.
Right now only a few of the rivets on the bottom of the boat let in a small amount of water. I'll be saving the replies and this winter will try to repair the leaking rivets.
07-19-2004, 12:58 AM #10
I had a 1982 Starcraft 18' Super Sport. I let someone else drive the boat (big Mistake) and they hit a submerged stump while boating a lake in Wisconsin. The impact took out 10 rivets.
I bought replacement rivets from an aluminum boat dealer nearby. You can buy a tool that will fit the rivet head but I made my own from a piece of A-2.
Identify the leaking rivets by filling the boat with water (while on the trailer). Use a knife to pop the heads off the leaking rivets and punch out the remainder of the rivet. Do not distort the hole. Get someone to help you. Get someone inside the boat with a good size piece of steel. Insert new rivet from outside the boat. Use tool with concave radius that fits the rivet head. Hit the rivet about 3 times while your helper backs up the rivet with the piece of steel.
Keep in mind, the rivet must swell inside the rivet holes in the boat, that is how it is made water tight. Not by the rivet head or the flatened end inside the boat.
Riveting is real easy. Watch what you are doing and knowone will notice your boat has been repaired.
I also recomend you contact Starcraft before you start repairs. They may have some suggestions.
In 1991 I bought a new 19' Sylvan. Another riveted aluminum boat. Had no trouble with the rivets in the Sylvan.
07-19-2004, 12:54 PM #11
You are looking for "closed-end, blind rivets." "Pop-rivets" are a trademark of Emhart Fastening technologies. The other main player is "Cherry-Avdel" owned by Textron.
Use this link to Emhart, and you can search for the appropriate catalog number.
You should be able to get the parts at Fastenal, which has something like 3000 outlets in the U.S.
07-19-2004, 03:41 PM #12
AH! Finally a question I know a good deal about!
I put in a bazillion or two rivets in military aircraft.
If you're talking solid rivs, I don't like the idea of using a chisel to "behead" them. Might stretch the hole. Drill them out. Usually, the rivit is going to be a nominal size (3/32, 1/8, 3/16, 1/4) and the hole is drilled slightly over with a number drill (#40, #30, #20, #10 respectivly). Get a nominal size drill, center up good, DON'T wobble. Drill in about the depth of the factory head, no more. If you did good, tilting your drill will pop the head off. You may need to use a punch, but that's OK, then use your punch to drive the shank&shop head out of the hole.
Now, you should prep the hole with some alodine - it'll slow corrosion. Turns the Al slightly brown. Clean the metal off real good with some scotchbrite, wipe with a solvent rag, apply alodine, wait a few minutes, wipe again.
Install your riv's - use wet paint or sealant. It'll seal better, and again, less corrosion. The shooting/bucking described by Geaorge Coates is on the mark. We had signals for the times we DID wear ear muffs, which wasn't often. ( I still hear pretty good)
Shooter pushes rivit in. Bucker presses it back at him to let shooter know he's on it. Shooter pushes it back in and shoots it.
Bucker signals -
One tap, smack it again.
Two taps, That'll do.
Three taps, mark it for removal.
I don't know what alum. riv's are avail. from Jay-cee
Fairly soft ones - MS20426B for brazier head, MS20470B for countersunk head.
If you want a little harder, replace the "B" with "AD".
C088/089 would prob. be overkill for your boat. All the above are supplied anodized.
And when your'e done, you can go to SWMBO, and sing a few verses of "Shake the rivits from my hair, shake em loose and let em fall.."
07-19-2004, 10:52 PM #13
Rudd is right on about drilling the rivets out so as not to distort the hole. However if they are bad on a boat, they really just scrape off, no force at all, not anything near enough force to distort the hole. Part of the problem is that they LOOK OK until you start messing around then another handful need fixing! I found it easy to tap each rivet with the chisel and the bad one would loose their heads and the good one would be ok.
07-20-2004, 10:31 PM #14
Re-riveting is probably the answer, and others have given what seems the best way. What I would do, and assuming that the boat wasn't 'falling apart', is to just coat the leaking rivets on the inside with shoo goo, or the same stuff by whatever name it's sold where you live. Goop is one name. This stuff is a far cry better than silicone rubber, is quite resistant to abrasion, and sticks tenaciously to most surfaces.
I'm not suggesting to avoid a mechanical repair if that's what's really needed, but just to seal a few slow leaks, and if the boat is otherwise solid- why go overboard?
07-21-2004, 01:00 AM #15J Tiers Guest
I have tried "shoe goo" and found that it rolled right off when applied as directed. I think I could have blown it off sneezing.
There are better gluey-stuff products around, IMAO.
Sealing is always better from the pressure side, BTW.