JLab in house CTD101K epoxy and contaminants study
D. Kashy
S. Christo
C. Mealer
10/13/14
DRAFT 1.0
Test Description
Thirty Four samples of various combinations of “ingredients” and cure
processes were completed during the period from 10/9/2014 to 10/13/2014.
Ingredients included:
 One single batch of CTD101K mixed to the manufacturers recommended
quantities.
 Mold release 50/50 mix of RAM 225 and 334 with Pylam Acid Red 52 dye as
per FNAL spec
 Bleeder Lease B
 Cyanoacrylite Loctite 430
 CA accelerator ZAP Zip Kicker PT-15
 Kapton film
 Mylar film
 Teflon sheets
Teflon, Mylar and Kapton surfaces were cleaned with ethanol prior to putting
samples on to them. No bakeouts or degasing was performed.
Cure processes included:
 50C Soak
 80C Gel
 135 Cure
Each batch of samples helped us develop the path to move forward.
Observations:
1) Small dots of order 1/16" diameter never cured no matter the
temperature or time, unless covered with Kapton or Mylar.
2) Single layer of glass with long ~50C exposure then high (~135C) never
fully cured
3) Areas of CA/glass with thin layer epoxy did not cure.
4) Single layer of glass with zip-kicker a(ZK) treatment with long ~50C
cured better than non-zip-kicker sample. (ref 2 above)
5) Edges of all glass samples cured much slower or almost not at all
independent of the cure cycle unless covered with mylar or kapton
6) CA and CA with ACC (ZK) seemed to brown up equally.
7) Well cured CA did not affect the curing
8) Some samples of thin layers of epoxy cured eventually.
9) CA does not change colors during 50C soaking.
10) CA turns light brown during 80C gelling.
11) Samples covered with Kapton or Mylar cured faster and/or more
completely than uncovered samples.
12) Zones of glass soaked with CA or CA/ZK are weaker even after curing
(because there is no epoxy in that zone)
13) Samples with Bleeder Lease B did not show any signs of turning green
and the peel ply did release from the surface
Conclusions
1) Thin layers dots of epoxy do not cure if not surrounded by impermeable
membrane even if not pumped on, likely due to loss of Part C
Accelerator (examples dots, edges, CA inside epoxy and long 50C soaked
sample. Note the dots did cure when put in Kapton bag and rapidly cured
at 135C.
2) ZK helps to cure CA and does not affect epoxy curing.
3) CA turns dark Brown upon high temp cure (loss of strength?)
4) Dark brown (vapor or dust) is transportable by epoxy while epoxy is a
liquid
5) ZK only did not affect the curing and may have enhanced it
Test Summary
Samples with thin layers of epoxy likely loose CTD Part C Accelerator and
thus cure more slowly or not at all.
T2 and CCM003 likely cause for incomplete curing
Insufficient time/temperature due to short time and likely inhomogeneity of
mold temperature
Secondary effect? – Loss of accelerator (Part C) on cold side of coil (not
likely?)
Tertiary effect? Contamination from outgassing (?)
Recommendations
1) Add more thermocouples on outside of mold/case (top and bottom)
2) Wrap mold/coil case with Housing fiberglass (and tape seams?) before
installing in box and be sure the box is stuffed with glass
3) After filling the coil with epoxy, keep pump and backfill routine
4) Keep wicking routine (or shorten or eliminate to reduce time under low
pressure and lessen migration of part C)
5) Keep 10C/hr ramp rates
6) Gel Cycle 24 hrs at 85C (slightly higher than CTD recommends because of
in homogeneity of mold temperature)
7) Cure Cycle 16 hrs at 130C (slightly higher than CTD because the
temperature of our molds on outside are not well known (and for Coil
case the area is big and conductive
8) Outgass at lower temperatures (60C)
9) Fill the mold while controlling the pressure reading between 1.5 and
2.5 torr (again to reduce loss of part C)
10) Fill the mold twice as fast (bigger batches to reduce loss of Part C)