HPR spiral fillers...

[Hobie1dog]

This is being discussed in the "what did you do today in rocketry?" Several are proponents of the 3M Patch with primer product.

 

[DRAGON64]

In days gone by, I have been known to use a 2oz veil of fiberglass over the airframe to get rid of spirals. I even tried using a leg from my wifes panty hose to veil the airframe, worked great!

 

[DeltaVee]

I like bondo... I use it as an after dinner liqueur....

 

[Hobie1dog]

I already warned my Vendor to never even think about handing me any tubing with spirals to fill.

 

[Joshua Smith]

I use and Highly recommend GoodFila CWF. Creamy smooth, easy to sand, dries fast. I cover the whole tube. I put on nitrile gloves scoop some up and rub it up and down the BT. Let it dry a couple of hours and sand it off. I start with 120, then 220 then 400. You can thin it easily. You can paint it on small blemishes. I use it on balsa and plywood. I used to use Elmer's CWF. Not anymore. No Bondo either. Too toxic.

Here goes

 

[Hobie1dog]

Here goes

6 fins, my kind of rocket

 

[Joshua Smith]

6 fins, my kind of rocket

You'll probably like this then too

 

[bad_idea]

You'll probably like this then too

I like that a lot.

 

[KenECoyote]

I used the filler below for filling spirals on LPR kits, but would it stand up to HPR?
If not, any suggestions for filling spirals on a 4" Super DX3?

View attachment 541502

I've been using a tub of older Elmer's Carpenter's Wood Filler for years now on everything including L2 HP rockets and never had any issue. You'd have paint issues before filler issues (unless your spirals are more like cracks lol).

I used it just now on LP & HP rockets.




4" Patriot Build from last year with "spiral filled" goodness:

https://www.rocketryforum.com/threads/madcow-4-patriot-finishing-paintriot.173543/

 

[BDB]

Does anyone have any specific advice for filling the spirals in Blue Tube? The spiral grooves are HUGE. I have been honestly considering wrapping these 6" dia tubes with a layer of 2 oz glass instead of dealing with that much filling and sanding.

 

[Hobie1dog]

3M, spreads a lot easier than wood filler, and it's some really tough stuff

 

[conneryc]

For HPR I always put a layer of fiberglass on the tubes. Fills the spirals, makes it stronger and resists zippering. It's just my preference as I find it easy to work with.

 

[FlyBy01]

Or just start with a fiberglass kit Just the route I prefer.

 

[Biodragen]

just glass it

 

[KenECoyote]

3M, spreads a lot easier than wood filler, and it's some really tough stuff

How is it to sand?

 

[cwbullet]

I use and Highly recommend GoodFila CWF. Creamy smooth, easy to sand, dries fast. I cover the whole tube. I put on nitrile gloves scoop some up and rub it up and down the BT. Let it dry a couple of hours and sand it off. I start with 120, then 220 then 400. You can thin it easily. You can paint it on small blemishes. I use it on balsa and plywood. I used to use Elmer's CWF. Not anymore. No Bondo either. Too toxic.

So the clear stuff? I have used the thick stuff but not the clear.

 

[Hobie1dog]

How is it to sand?

With some of the other fillers I have to use 400 Grit as they simply disappear quickly making it necessary to apply a second coat, but this stuff requires either 220 or 320 to knock it down, but it's like cement when you get done.

 

[Rob Campbell]

I used the filler below for filling spirals on LPR kits, but would it stand up to HPR?
If not, any suggestions for filling spirals on a 4" Super DX3?

View attachment 541502

It will easily stand up to high power if you fiberglass over it. You don't need much, one or two layers of 2 oz cloth and a layer of 0.75 oz cloth. This will also give a nice surface to prime and paint.

 

[Donnager]

Does anyone have any specific advice for filling the spirals in Blue Tube? The spiral grooves are HUGE. I have been honestly considering wrapping these 6" dia tubes with a layer of 2 oz glass instead of dealing with that much filling and sanding.

I did that once on a 3" Cherokee upscale. Not planning to do it again. It took a lot longer than a 5.5" LOC tube of similar length.

I used a ton of 3M Glazing/spot putty or the Bondo red equivalent, and if you look hard, you can still see them. Seems that there is a high spot on each side of the grooves that makes it tough.

If you ever figure out why the insides of the tubes are smooth, and the exterior of couplers are smooth, but the exterior of the tubes are not, let me know.

 

[teepot]

So the clear stuff? I have used the thick stuff but not the clear.

The thick stuff. It's an off white color. Water based grain and wood filler. I first bought it in 8 oz jars. Now I buy it by the quart.