When not to use a cartridge
The number one situation I find when a customer calls with a problem doing crack injection is that he is using a cartridge to seal a hairline crack.
Cartridges are a great tool to have in your arsenal. We at Prime Resins are big fans of cartridges. In fact, 30 years ago we were the first manufacturer to package polyurethane injection resins in a cartridge system. They are perfect for small jobs. They can be the most cost-efficient option when considering the time to set up and clean up compared to pumping. Cartridges are ideal when access with a pump is impossible or impractical. See ours here.
Cartridges do have limitations though and are not right for every job. Do NOT attempt to seal a hairline crack with a cartridge. Period. A crack needs to be at least 1/16” or wider (1.6 mm) for a cartridge resin to be effective. That’s about the thickness of a credit card. For cracks tighter than that, you won’t be able to generate enough pressure with a cartridge gun to force the material deep enough into the crack to ensure a proper bond. A true hairline crack often requires 500 psi or greater, sometimes up to 3000 psi, of pumping pressure.
Imagine trying to force water in a pinhole. It’s hard to do and you can’t be sure any actually got in there. Same with using a cartridge for a hairline crack. It isn’t going to work, so don’t waste your time and money. As with anything: choose the right tool for the job. If you aren’t sure whether a cartridge is right for your job, give me a call at 800-321-7212 or email me at email@example.com.
Adam Goldstone, technical consultant and customer support