Experimental & Kit Aircraft
Bucking bars for Vans RV and other kit aircraft builds
For experimental and kit aircraft such as Van's RV, Sonex, and Zenith, a 2 to 4 lb tungsten bucking bar covers most AN470 and AN426 solid-rivet work, with low-profile and angled bars for tight flanges and lightening-hole returns.
Homebuilders drive a lot of rivets by hand, often solo, so a bar that delivers full bucking mass without wearing out your arm makes a real difference over a wing or fuselage kit. A tungsten bar gives you that mass in a compact block you can hold steady against the skin while you run the gun.
Most kit builders do well with one general-purpose straight bar in the 2 to 4 lb range for flat wing skins, ribs in open bays, and fuselage side skins. Add a low-profile or angled bar for spar flanges, rib returns at the root, and the confined corners every kit has. If you are working bottom skins overhead or laying up aft fuselage sections, a slightly heavier bar helps it stay put without a death grip.
AN470-4 and AN470-5 rivets are the workhorses of most RV and Zenith builds. A 2 to 3 lb straight bar handles the open-panel work; an angled or low-profile bar handles the tighter spots where a straight bar rocks on a curve or cannot seat flush. The cross-reference guide maps Van's and Sonex part numbers to bar shapes if you are working from plans.
Not sure where to start? The Bucking Bar Selector has a quick pick for kit aircraft, and the How-to-Choose guide maps work area and rivet size straight to a recommended bar.
Common questions
What is the best bucking bar for an RV or kit aircraft build?
A general-purpose tungsten bar in the 2 to 4 lb range covers most of an RV or kit build with 1/8 in AN470 and AN426 rivets. Add a low-profile or angled bar for flanges, rib returns, and tight corners. The Selector has a kit-aircraft quick pick.
Do I need more than one bucking bar for a kit?
Many builders finish a kit with one versatile mid-weight bar, but a second low-profile or angled bar makes flanges, lightening-hole returns, and confined corners much easier. Two well-chosen bars cover the vast majority of access on a typical airframe kit.
Tungsten or steel bucking bars for homebuilding?
Tungsten packs about 2.5 times the mass of steel into the same size, so a small tungsten bar bucks like a much larger steel one. For solo builders that means less fatigue and better control in tight spots, which is why most kit riveters prefer tungsten.
Which bar shape works for spar flanges and rib returns in an RV kit?
A low-profile bar seats flush where clearance is less than half an inch above the rivet, and an angled bar cants to meet a sloped flange face without rocking. Either shape lets you hold steady on the bar while running the gun solo, which matters on rib-to-spar joints and aft fuselage skin laps.
For tungsten in this sector beyond bucking bars, see tungsten for aerospace and aviation from our sister company.