Newborn 250 10 oz Caulk Gun – 18:1 Thrust

The Newborn 250 caulk gun is a manual smooth rod dispenser for 10 oz (1/10 gallon) cartridges with an 18:1 thrust ratio. Installers and fabricators run it with silicone, hybrid and STP sealants, polyurethane, elastomeric sealants, firestop, and construction adhesive. The 360° revolving frame keeps the bead line on track around corners, and the spout cutter, seal poker, and ladder hook are built into the gun. Thrust ratio is the number to match to your material: the higher it is, the more push you get at the plunger for every squeeze of the trigger.

Key Product Details

Performance in Production

• The 18:1 thrust ratio turns each trigger squeeze into more push at the plunger. On polyurethane, hybrids, and construction adhesive, that means steady flow without fighting the trigger through a full cartridge.
• Newborn builds the 250 on a smooth rod drive, which takes less force than a ratchet gun and runs quieter. Over a full day of caulking, that adds up to less hand fatigue.
• The cradle rotates a full 360°. Turn the cartridge instead of your wrist to keep the bead consistent around corners and in tight spots.
• The starburst release plate uses a reverse-punched hole that releases pressure more easily than a flat, straight-hole plate. Hit the thumb release at the end of each pass to take pressure off the plunger.
• Effective Trigger Grip takes up trigger play automatically as the gun wears, so you keep full trigger action on every squeeze years into the tool’s life.
• The friction plate and drive rod are the parts that wear out on any caulk gun. Newborn investment-casts the DuraCore friction plate and heat-treats the drive rod for durability.
• The spout cutter, seal poker, and ladder hook are built in. Cut the spout, break the seal, and hang the gun on a ladder or scaffold without digging for a knife or a nail.

Common Applications

• Glazing and window and door perimeter sealing
• Kitchen and bath silicone and hybrid sealing
• Waterproofing and restoration joints
• Firestop and intumescent sealant application
• Construction adhesive from 10 oz cartridges
• Hybrid, STP, polyurethane, and elastomeric sealants in commercial and industrial work

Related Products

• Chem-Set RTV4500 100% Silicone Sealant, Standard Colors in 10.2 oz cartridges
• ASI 502 100% RTV Silicone, Standard Colors in 10.2 oz cartridges
• Peri-Bond PB-3 Siliconized Acrylic Latex Caulk in 10.3 oz cartridges for paintable joints
• Sealants (MS, Silicone, Poly) for our full line of cartridge sealants
• Dispensers, Mixers and Nozzles for nozzles, tips, and other dispensing tools

How to Match a Caulk Gun Thrust Ratio to Your Sealant

Match a caulk gun’s thrust ratio to the thickness of the material in the cartridge. Thrust ratio is the mechanical advantage between the trigger and the plunger. An 18:1 gun puts roughly 18 times your grip force on the back of the cartridge, so thicker materials push out smoothly without a hard squeeze.

1. Check the package. The Newborn 250 takes 10 oz (1/10 gallon) cartridges. Sausage packs and larger cartridges need a different gun.
2. Identify the material. Newborn rates the 250 for silicone, construction adhesive, firestop and intumescent, elastomeric, hybrid and STP, and polyurethane.
3. Check the thin and heavy ends. Newborn’s thrust ratio chart (PDF) lays out its guns by material type, from acrylic latex at the thin end to butyl and epoxy at the heavy end. For materials outside the 250’s rated list, check the chart or call us.
4. Factor in volume. On all-day work, the smooth rod drive, the self-adjusting trigger, and the wear-resistant friction plate are what keep a gun pushing consistently.

Frequently Asked Questions

What is the Newborn 250 caulk gun used for?

The Newborn 250 is used to dispense silicone, hybrid and STP sealants, polyurethane, elastomeric sealants, firestop, and construction adhesive from 10 oz cartridges. Newborn rates it for glazing, windows and doors, bathrooms and kitchens, and waterproofing and restoration work.

What does an 18:1 thrust ratio mean on a caulk gun?

An 18:1 thrust ratio means the gun multiplies your trigger force about 18 times at the plunger. Higher thrust ratios push thicker materials with less effort per squeeze.

What size cartridge does the Newborn 250 take?

The Newborn 250 takes standard 10 oz (1/10 gallon) cartridges. It isn’t built for sausage packs or larger cartridges.

Is the Newborn 250 a smooth rod or ratchet caulk gun?

The Newborn 250 is a smooth rod caulk gun. Newborn says the smooth rod drive takes less force than a ratchet gun and runs quieter, which cuts hand fatigue on long runs.

What sealants can I use in the Newborn 250?

Newborn rates the 250 for silicone, construction adhesive, firestop and intumescent, elastomeric, hybrid and STP, and polyurethane. For acrylic latex at the thin end or butyl and epoxy at the heavy end, check Newborn’s thrust ratio chart or call us before you order.

How do I stop a caulk gun from pushing out caulk after I let go?

Press the thumb release plate at the end of each pass to take pressure off the plunger. The 250’s starburst release plate uses a reverse-punched hole that makes releasing pressure easier than a flat, straight-hole plate.

Does the Newborn 250 have a spout cutter and seal puncture tool?

Yes. The Newborn 250 has a built-in spout cutter, a seal poker for breaking the cartridge seal, and a ladder hook.

Does the Newborn 250 frame rotate?

Yes. The cradle rotates a full 360°, so you can turn the cartridge to keep the bead consistent around corners and in tight spots.

Questions on matching a gun to your sealant? Call (800) 220-1966 or email [email protected].