Estes, "Poopy Clay" and CATOs

[DynaSoar]

I just talked with both Christine in customer service and Mary in tech support at Estes. I'd read here about Estes having changed their clay formulation, and wondered if that was the root cause of the funny flights and one CATO I'd suffered yesterday.

The story that Estes had changed their clay formulation to something softer (termed "poopy clay"), found it insufficient, and changed back, is wrong.

Fact is they changed the clay (actually changed to a different supplier with a different clay) around 2000. This clay was actually harder. In fact, they had a problem with recovery failures due to the ejection charge cap being too tough and not blowing off.

They quoted Fred Shecter's fix for this of scoring the ejection cap slightly to provide a fracture line so this wouldn't happen.

As to my problem, Mary (a true model rocket scientist; she's been in the business since 1973) said that the problem with flaky nozzles sounded to her as if the engines had been exposed to humidity. Then she said that this would also result in swelling of the cases, and the motors wouldn't fit in the tubes well.

Only 10 minutes before this I had been commenting to my wife that I'd noticed the nozzles crumbling when trying to remove them from rockets while test fitting them, and they were such a tight fit even without tape. I had *not* said this to Mary.

Bingo. Mary hit it perfectly. I'd actually damaged the Sandman trying to fit it for launch a month ago due to engines not fitting in the tubes, and had had to fix it before testing it. I'd bought these (10 or 12 packs of E's) on ROL auction from someone who'd at the time claimed they'd been stored properly. Maybe they thought so. Maybe they'd been stored badly prior. Either way, the problem with the clay wasn't Estes's.

Christine, of course, had offered to replace the engines. However, since Es would have required a $20 hazmat fee, rather than replacing them, they would have cut me a check. Well, enougn of these flew fine unless I'd weakened the nozzles, and they fit well enough into some other birds, so I decided I'd just burn them up instead. Had I said "and it blew the side off my Falcon" no doubt they'd have offered to replace that, but honestly I only flew it to see how it flew prior to dismantling it and using the nose as a tail cone elsewhere, so no great loss.

Bottom line, soft clay on Estes motors, especially since 2000, is not Estes' fault.

"And dat's da truplthplthplthplthplth." -- Edith Ann

 

[shreadvector]

BZZZT. Not quite.

The problem with ejection charges was as follows: year A and B D12 motors had a variety of problems proven experimentally by me (after talking with Estes and getting the OK to scrape away the clay and check the ejection charge). Some motors had NO ejection charge granules. Some had a little, but not very much. Some had the normal amount. Normal amount was determined from earlier motor production years. The ejection cap clay would remain intact on the D12 motors and some people thought that was because the clay was too thick or strong. It was not. It crumbled away quite easily. When you launched these motors, you sometimes heard the faint "pfft" of the weak ejection charge venting through the nozzle only (followed by crash) or no sound at all (followed by crash).

Removing 1/4 of the cap provided releif so that if you had SOME ejection granules they would eject your recovery system. If you detected NO granules, you relegated that motor to use in clusters with other good motors.

The nozzles would crumble on brand new motors. So Cal has VERY little humidity. They eroded during firing and even could be damaged by inserting and removing the standard plugs.

Gotta run to a meeting or I'd go on some more....

Originally posted by DynaSoar
I just talked with both Christine in customer service and Mary in tech support at Estes. I'd read here about Estes having changed their clay formulation, and wondered if that was the root cause of the funny flights and one CATO I'd suffered yesterday.

The story that Estes had changed their clay formulation to something softer (termed "poopy clay"), found it insufficient, and changed back, is wrong.

Fact is they changed the clay (actually changed to a different supplier with a different clay) around 2000. This clay was actually harder. In fact, they had a problem with recovery failures due to the ejection charge cap being too tough and not blowing off.

They quoted Fred Shecter's fix for this of scoring the ejection cap slightly to provide a fracture line so this wouldn't happen.

As to my problem, Mary (a true model rocket scientist; she's been in the business since 1973) said that the problem with flaky nozzles sounded to her as if the engines had been exposed to humidity. Then she said that this would also result in swelling of the cases, and the motors wouldn't fit in the tubes well.

Only 10 minutes before this I had been commenting to my wife that I'd noticed the nozzles crumbling when trying to remove them from rockets while test fitting them, and they were such a tight fit even without tape. I had *not* said this to Mary.

Bingo. Mary hit it perfectly. I'd actually damaged the Sandman trying to fit it for launch a month ago due to engines not fitting in the tubes, and had had to fix it before testing it. I'd bought these (10 or 12 packs of E's) on ROL auction from someone who'd at the time claimed they'd been stored properly. Maybe they thought so. Maybe they'd been stored badly prior. Either way, the problem with the clay wasn't Estes's.

Christine, of course, had offered to replace the engines. However, since Es would have required a $20 hazmat fee, rather than replacing them, they would have cut me a check. Well, enougn of these flew fine unless I'd weakened the nozzles, and they fit well enough into some other birds, so I decided I'd just burn them up instead. Had I said "and it blew the side off my Falcon" no doubt they'd have offered to replace that, but honestly I only flew it to see how it flew prior to dismantling it and using the nose as a tail cone elsewhere, so no great loss.

Bottom line, soft clay on Estes motors, especially since 2000, is not Estes' fault.

"And dat's da truplthplthplthplthplth." -- Edith Ann

 

[DynaSoar]

Originally posted by shreadvector
BZZZT. Not quite.

The problem with ejection charges was as follows: year A and B D12 motors had a variety of problems proven experimentally by me (after talking with Estes and getting the OK to scrape away the clay and check the ejection charge). Some motors had NO ejection charge granules. Some had a little, but not very much. Some had the normal amount. Normal amount was determined from earlier motor production years. The ejection cap clay would remain intact on the D12 motors and some people thought that was because the clay was too thick or strong. It was not. It crumbled away quite easily. When you launched these motors, you sometimes heard the faint "pfft" of the weak ejection charge venting through the nozzle only (followed by crash) or no sound at all (followed by crash).

Removing 1/4 of the cap provided releif so that if you had SOME ejection granules they would eject your recovery system. If you detected NO granules, you relegated that motor to use in clusters with other good motors.

The nozzles would crumble on brand new motors. So Cal has VERY little humidity. They eroded during firing and even could be damaged by inserting and removing the standard plugs.

Gotta run to a meeting or I'd go on some more....

Amount of ejection charge is a different animal entirely. Yet she told me exactly as I related. But I certainly don't disbelieve you. The correlation of swollen casing and humidity does make sense. She just related a different story. Why would she blame a harder clay and give me your name specifically, when the problem was something entirely different?

The scientist in me gets very frustrated when this happens. Ah well, I'll just burn the motors and look for alternatives.