cool_hardware52
Contributor
deepblueh2o:The CL's that I am replacing were welded. The first set gave way on the second dive. The replacement pair have given away twice, the seal just comes apart. I don't have near this kind of trouble with drysuit parts that I do, so the glue I know beats the seam I don't trust anymore.
About those monkey signs, there is a gorilla back east that is writing a book....
deepblueh2o,
RF welding urethane is part art and part science. Joint strenght is dependent on several factors, including the age of the urethane, the welding machine parameters, the temperature of the both the material and welding dies.
If you have cl's that pull apart at the seams, you have defective product. If a seam pulls apart through the seam, i.e. the two material halves are intact, but the seam "unsticks" it's likely that not enough rf power, time or pressure was used, or old material.
If the part fails next to the seam, i.e one piece tears off the other leaving two layers at the seam, it may be too much power, pressure, time.
Destructive testing is key with every part run, i.e. weld a few and then test.
When you consider the range of goods that rely on good rf welds in urethane, like IV bags, scuba BC's, even the gell inserts used in some auto seats, it's pretty clear that the process can be highly reliable, your results with your CL's indicates something is wrong.
Glue would be my last resort. I do know of a case where a "well known" CCRB builder made a glue repair to a unit under test by the US navy. The officer who dived the rig next reported a head ache he attributed to the glue and terminated the test, effectively removing the company from consideration. Point being if a CCRB maker could not furnish a glue that would both seal and not off gas nasties what do you plan to use?
Regards,
Tobin George