swollen propellent grains

[Buckeye]

I have some old AT reloads (circa 1997) that I have been using successfully for over a year. Today, I noticed the H180 grains were bulging out the ends in a concave shape. As such, they formed a column too long for the liner. So, I just sanded each end back to square, and assembled the motor. Should I expect any problems?

Thanks!

 

[dixontj93060]

Only one way to know for sure... But I expect you'll be alright.

 

[G_T]

If it were me, I'd just put the grains in a burn pile and fly something else. Rockets and motor hardware are not worth it to me. But I'm cautious. My philosophy on this sort of thing is that if it isn't right, it is wrong.

Gerald

 

[Pat_B]

If it's swollen then just give it few Ibupropulsion tablets.

 

[Rocketjunkie]

It will work, just slightly less propellant, therefore slightly less performance. It will be difficult to ignite.

 

[Zeus-cat]

AP grains are hydrophilic, which means they like to absorb moisture. When they absorb moisture they swell. As Rocketjunlie said they should burn fine. but getting them to light can be difficult.

 

[troj]

AP grains are hydrophilic, which means they like to absorb moisture. When they absorb moisture they swell. As Rocketjunlie said they should burn fine. but getting them to light can be difficult.

In this case, it's an H180, which uses magnesium. My bet is your grains are a bit greenish, with bit white spots -- that's the magnesium oxide that forms.

-Kevin

 

[Buckeye]

In this case, it's an H180, which uses magnesium. My bet is your grains are a bit greenish, with bit white spots -- that's the magnesium oxide that forms.

-Kevin

Yep, that's them.

The reload came with a little segment of thermalite. I will add that to the igniter for a little more oomph for ignition.

 

[tfish]

hopefully the cores have not swollen smaller too.

Tony

 

[tightwad]

I have had one swollen grain and I couldn't get the igniter up into the motor during assembly, being cheap, I carefully used a tap and enlarged the slot big enough to get the igniter into the motor. The motor ignited and burned perfectly.