6 replies to this topic

[AdmiralDonSnider]

I wondered if any second layer is necessary to prime ones AP stars with Shimizu´s Igniter B (NaNO3 based). I assume it is used like plain BP - and a water soluble binder is added for priming purposes?

Any problems known with that prime (extremely hygroscopic etc.)?

How do you prime your AP stars?

[portfire]

I'm sure others here will be more helpful than I

Anyway, as you know AP doesn't like NO3's. My quess is 'Step Priming', using a Potassium Perchlorate based prime (NC based to add water barrier?) over your AP star then maybe BP, Greenmix over that.

Although I have AP I've never worked with it as yet, so can't say for sure......Must get the books out again

[portfire]

From Passfire

Name: AP Prime

Source: David Bleser

Potassium Perchlorate 75%

Red Gum 12%

Charcoal 9%

Dextrin 4%

Notes

Dry core first, then roll about 1/32'' of this prime on all AP stars before more layers or final BP prime. If next comp is nitrate based, then apply this prime with 6% NC lacquer to prevent nitrate leeching into the AP core.

[AdmiralDonSnider]

Well, AP is said to like NaNO3 - at least Shimizu says it. Otherwise he won´t have voted to use his Igniter B for AP based stars. The Igniter B contains 80 parts NaNO3. However he states that no undesired reaction occurs with NH4ClO4.

I know about other AP primes from Hardt: they are KClO4-based and one of them uses lead compounds. I just wanted to save some of of the more expensive chems.
Another thing is I don´t like to work with nitrocellulose lacquer - and as you said if you don´t you can´t use BP as a second stage prime because the star will be rendered useless due to osmosis.

[portfire]

Yup, I stand corrected The double decomposition doesn't occur with NaNO3 and the same go's with BaNO3

[seymour]

As long as your Sodium nitrate is pure!!!

I tried it with agri grade stuff and was disappointed with the results. They did not burn and the sodium had ruined the beautiful AP stars.

[pyrotrev]

Using NaNO3 will prevent the formation of hygroscopic ammonium nitrate. However NaNO3 itself is hygroscopic to an extent, particularly when impure. Shimizu recommends this prime only when the relative humidity is less than 80% (which up this way is virtually never )

Edited by pyrotrev, 24 February 2009 - 01:26 PM.