Missing o-ring on M1350?

[scanlin]

I'm building my first M motor, DMS 1350w. The instructions talk about 5 o-rings but I only have 4: one pre-installed on the forward enclosure and 3 thin ones that go between each of the 4 grains.

What I'm missing is the thicker O ring that you place on top of the forward enclosure before putting in the epoxy.

The instructions refer to this thicker O ring and show a photo of it, but it's not in my kit.

Is it optional? I've called Aerotech and left messages for Carl (support) but no response yet. I'm trying to fly Saturday morning so need to epoxy by tomorrow (Friday morning). If I need an O ring (which I think I do) then does Home Depot or some such sell them? Thanks.

 

[rfjustin]

Are you able to post a copy of the instructions please? I tried downloading from RCS website, linky no worky.

 

[Antares JS]

Is it optional?

I guarantee it's not optional. Get the o-ring specs from the instructions and head down to the hardware store and find a match.

I had to do this myself once for a seal disc o-ring.

 

[3stoogesrocketry]

I'm building my first M motor, DMS 1350w. The instructions talk about 5 o-rings but I only have 4: one pre-installed on the forward enclosure and 3 thin ones that go between each of the 4 grains.

What I'm missing is the thicker O ring that you place on top of the forward enclosure before putting in the epoxy.

The instructions refer to this thicker O ring and show a photo of it, but it's not in my kit.

Is it optional? I've called Aerotech and left messages for Carl (support) but no response yet. I'm trying to fly Saturday morning so need to epoxy by tomorrow (Friday morning). If I need an O ring (which I think I do) then does Home Depot or some such sell them? Thanks.

That o-ring is more of a epoxy dam then a sealing o-ring. It prevents epoxy from running down into the motor case onto the grains.

 

[scanlin]

Are you able to post a copy of the instructions please? I tried downloading from RCS website, linky no worky.

Here are 3 pages of instructions and a photo of what I have in my kit. I'm missing the thick o ring mentioned in steps 1.3 and 1.4.

 

[scanlin]

I was able to speak to Aerotech yesterday and they confirmed that the thicker O ring was to stop the [very runny] epoxy from running inside the case before it cured. The O ring was not necessary as long as I could prevent the epoxy from running. Couple of solutions offered to make a dam were to use some 5-min epoxy to tack the forward enclosure into place and seal the tiny gap where the O ring would have gone, or even just use some blue tape to make it a tight fit and close off the place where it might run. Then put in the runny epoxy to secure the forward enclosure.