Automatic tapers. Simultaneously apply tape (mesh or paper) and joint compound to any seam and inside corners. Tape is then manually embedded and wiped down on flat seams.
Corner roller. Used right after the taper, it embeds inside corner tape and squeezes out excess compound.
Corner finisher (or angle head). Using the excess joint compound squeezed out by the previous tool, it wipes down the inside corner and coats the tape. It adjusts to compensate for slightly out-of-square corners.
Angle box. Attaches to the corner finisher and holds compound for finish coating inside corners.
Flat boxes. Apply finish coats to seams. Like the corner finisher, they produce uniform results. The adjustable metal blade trowels the compound to the desired crown profile. A typical set of boxes measure 7-, 10-, and 12-inches wide.
Nail spotter. This special flat box fills fastener-headdepressions.
Mud pump. A hand-operated pump that slides into a joint compound bucket and fills the tools.

Drywall covers about 80 percent of a home's interior. Since there's nothing to hide the final coat, it all has to be top-quality work. While many contractors use hand tools to finish drywall, mechanical joint compound application systems can really make it go much faster--especially on competitive, large-scale projects.

I reviewed four mechanical systems: one by Ames that can be rented, and three other systems for sale by Wilco, Apla-Tech, and Renegade. The Ames and Wilco tools require muscle power to feed compound through the tools. The Apla-Tech and Renegade tools move compound with automatic pumps. While these systems differ, they all require some user training and practice to get the best results.

Manually Actuated Tools

Manually actuated tools are muscle-powered. The Ames and Wilco systems require you to manually fill the tools' reservoirs and feed the applicators (see Tool Primer) A hand pump hooked to the side of your compound bucket feeds compound to an attachment (automatic taper, angle box, nail spotter, etc.). You fill the tool, go to the wall, and work until the tool's reservoir is empty, and then fill it again. It takes a little getting used to, but you can customize how rapidly the compound squeezes through each tool and you can also adjust the flat boxes to your desired crown profile.

It takes practice to be able to get the most out of these tools. If you don't get the adjustments just right, you'll move slower than the tool can work. Or you'll have the opposite problem, and won't be able to keep up with the tool. Then you'll put too much mud on the wall.

However, once you get the hang of mechanical joint compound application systems, you'll coat more board than you ever could with trowels and knives.

Ames. Ames, the company that invented this class of tools, rents its system nationwide through franchises at participating drywall supply houses and through its own storefronts. You can't buy these tools, but you can buy virtually the same equipment from Ames' sister company TapeTech Tools through tool distributors nationwide. (Grabber Automatic Taping Tools sells private-labeled TapeTech components as well.) Ames provides excellent support through its training and service departments at more than 150 stores. It backs that up with field specialists and a policy that supplies you with operable tools at a moment's notice.

All the Ames tools I reviewed, the Bazooka automatic taper, corner roller, corner finisher, set of flat boxes, corner applicator (or angle box), pump, nail spotter, and various handles, together rent for $12.50 a day.

I also tried an improved flat box called the Power-Assist Box. Its springs help you push the compound through the tool and onto the seam. It works especially well on tough-to-reach seams where it's awkward to push on the tool. The Power-Assist Box costs a little more to rent than the regular flat boxes, but it's worth it.

After taking Ames' one-day class, I found I could tape and finish much faster than I could with hand tools. And the finish was so good there was less sanding than normal. The work was more physically challenging than I'm used to; although I covered more ground in less time, I was wiped out at the end of a full day.

Luckily, clean-up's a snap; just use a hose, brush, and some empty buckets to wash away excess compound. You can also store the applicators in water for the next day.

It's nice that you can rent these tools inexpensively, since similar systems cost plenty to buy. Ames' system easily and affordably raises the quality of your work, makes taping go faster, and allows you to bid on and take bigger jobs.

Wilco. Wilco Tools currently sells its compound application tools through drywall supply houses. Like Ames, Wilco's are all hand-filled and muscle-powered. A full set of tools like those listed in the sidebar sell for around $3,400.

This fall, Wilco plans to roll out a new design. I tried it and liked it. Many of the new tool's parts are made of molded urethane, not metal, which makes the devices lighter and easier to use. It's also durable. I dropped one from a ladder, and it didn't get scratched. These new tools have significantly fewer parts than their predecessors which, Wilco says, means fewer parts to maintain, clean, and break.

The new design seems to allow compound to pass more easily through the tool, which means you don't have to push as hard to get the compound to flow. Like the Ames tools, Wilco's new tools provide an excellent finish. The smooth, curved plastic makes clean-up easy because there are no interior corners to collect old compound.

The price is perhaps the best improvement. The urethane model is expected to cost 30 to 40 percent less than the company's metal tools.

Pneumatic and Automated Tools

Apla-Tech. Apla-Tech tools use compressed air instead of muscle power to move compound. Fill a lightweight tube called a Cannon with joint compound, connect an air hose, squeeze a lever, and air pushes the compound to the applicator. I like this system because it's efficient and takes the manual drudgery out of feeding the tools.

Apla-Tech offers 7-, 10-, and 12-inch coaters for flat, taped seams, as well as 3- and 41/2-inch nail spotters. It also has a pretty cool attachment for coating outside cornerbead.

You can fill these tools with a hand pump and work the Cannon straight off an air compressor, but attach your compressor to the Apla-Pump to really make tracks. Apla-Tech has three different pumps; I used one that holds 10 gallons of compound. You mix it right in the reservoir, then directly fill the Cannon using air pressure. The pump lets you run three Cannons simultaneously.

For taping, use Apla-Tech's flat and inside mud head to apply a bedding coat, then embed and wipe down the tape by hand. For inside corners, apply compound with the mud head, set the tape by hand, embed it with a corner roller, then glaze it with a corner finisher (angle head). The roll plow, which embeds and wipes down tape in one pass, seems to be the best tool for doing inside corners, but, I didn't get to test it.

Apla-Tech makes all those different accessories, but it doesn't make an automatic taper. However, it designs its tools to integrate with other manufacturers' auto-taping equipment.

The Apla-Pump makes on-site clean-up quick. Pour water in the reservoir and connect a short garden hose, then spray off the tools with re-circulated water. The pump also doubles as a texture machine.

You can buy the Apla-Pump, 3-inch nail spotter, 7-, 10-, and 12-inch coaters, cornerbead coating attachment, corner roller, corner finisher (angle head), and 3-foot Cannon for about $4,100.

Renegade Tools. Renegade's solid-state Mudbuggy pump is the heart of its excellent taping and finishing tool system. Its automatic lightweight taper called the Terminator, tapes flat seams and inside corners and is available in various lengths for taping in confined spaces or wide-open areas. Renegade's flat knives for finishing seams come in 8-, 10-, and 12-inch widths; its inside corner finishing heads come in two widths.

The company's coup de grace is the Turbo Taper, which applies compound and tape on flat seams and embeds it in a single pass. It's great for flat seams, but you still need the Terminator to put tape and compound in inside corners. Then you use the corner roller and corner finisher to embed the tape and skim the joint.

If you already own another manufacturer's tools you can adapt them to Renegade's system. The Mudbuggy holds and mixes 20 gallons of compound, which it pumps through a 100-foot hose to the tool. This saves walking back to the bucket to re-load, and you can go almost anywhere in the house without moving the pump.

The Mudbuggy runs one tool at a time, which concerned me, but the company does offer a dual pump that powers two workers at the same time. But, if you only set up for one operator, that guy can move way ahead of the rest of the other guys, who'll have their hands full wiping down seams and rolling and finishing inside corners. And, because most the mud stays in the hose, not in the tool, you move less weight as you work.

Clean-up is fast, too. You pump the system empty, fill the reservoir with water, and pump it out. The Mudbuggy also doubles as a mobile spray rig for applying ceiling or wall texture and as a pump for rolling latex paint.

The Renegade system is in the final production stages, so price projections weren't available as of this writing. These won't be the cheapest tools, but I believe they'll be the best.

Last Coat

All these tools require relatively short learning curves. Each one will increase your production and raise the quality of your finished product. Your small crew can tackle big jobs, or your big crew can coat even more rock.

Myron Ferguson is a drywall contractor in Galway, N.Y. He is author of Drywall: Professional Techniques for Walls and Ceilings, published by The Taunton Press.

Sources of Supply

Ames (rental only)


Grabber Automatic Taping Tools

TapeTech Tool Co.

Renegade Tools

Wilco Tools