Question concerning sanding sealer

[PiperCPO]

I have read in several posts that many have touted the use of sanding sealer to seal the internal walls of their rockets, to keep moisture absorption at bay. I understand the issue with black powder residue causing water absorption as well. Here in Florida, we are famous for our humidity (though many of us true natives don't think so). I am building a Binder Excel DD and am thinking of doing this. I know all exposed areas of the inner body tubes would need to be coated with at least 2 thin coats (after building of course). To what extent do you all that have done this go? Internal Av bay? MMT tube? I am thinking that with no way of sanding the inside of the 54mm MMT that this would cause a motor case fit issue. Or is this technique really worth the weight tradeoff?

Appreciate the input.

 

[tim cubbedge]

I have only used sanding sealer on blue tube as manufacturer recommends it. Humidity really hasn't effected any of my cardboard tube rockets & I live right on the coast.

 

[MikeyDSlagle]

I've been considering using sanding sealer on the inside as well. Glad you brought it up.

I see no reason to seal the MMT. Only the part that is in front of the top CR and is exposed to the gases.

I was warned about some sealers being made with nitrocellulose. The same thing smokeless powder is made of and it is of course flammable. I don't know how flammable, or explosive rather, the sealer will be once dry. May be something to consider. Like I say, don't know. I'm new to sanding sealers. But also, finger nail polish is made from nitrocellulose and ping pong balls. Soooo

The sealer I use doesn't say anything about having nitrocellulose in it so I am moving forward with it.

Mikey D

 

[PiperCPO]

I have only used sanding sealer on blue tube as manufacturer recommends it. Humidity really hasn't effected any of my cardboard tube rockets & I live right on the coast.

Thanks Tim, I was hoping a fellow Floridian would weigh in on this , I have been trying to decide if I wanted to do it or not. Thanks for the input.

Brad

 

[PiperCPO]

I've been considering using sanding sealer on the inside as well. Glad you brought it up.

I see no reason to seal the MMT. Only the part that is in front of the top CR and is exposed to the gases.

I was warned about some sealers being made with nitrocellulose. The same thing smokeless powder is made of and it is of course flammable. I don't know how flammable, or explosive rather, the sealer will be once dry. May be something to consider. Like I say, don't know. I'm new to sanding sealers. But also, finger nail polish is made from nitrocellulose and ping pong balls. Soooo

The sealer I use doesn't say anything about having nitrocellulose in it so I am moving forward with it.

Mikey D

Mikey, from what I have read, they are suggesting a water based Minwax sanding sealer. I don't know if that has the Nitrocellulose in it that you are referring too. Will have to check. I did see in a post from a conversation about this that you want to use the water based as the other will take weeks to out gas completely.

Brad