Bondo or filler for spiral grooves

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I've always (which is admittedly not that long) used CWF for my spirals. The part of the process that always annoyed me most was applying it initially. I tried a knife blade, then switched to a chopstick. I would lay on a thick layer, then squeegee it off with a razor blade. Still a pain.

Then recently it occurred to me that the answer was attached to my hand. I dip my index finger in the CWF slurry and just rub it around the spiral, applying enough pressure that not very much is left on the areas outside the spirals. Good gravy that is so much faster and easier. It does the whole thing in one step, and leaves relatively little sanding for later.

The benign nature of CWF also means that I can do stuff like this with my finger and not worry about toxicity.

Win!
 
Pete-down and dirty method for applying the filler. Thin your batch with a touch of water, to reduce the consistency to a little like catsup or mustard. Use a sandwich bag or any other cellophane type bag and put about three teaspoons' worth (more for bigger tubes), remove as much air as possible, seal and then twist to force the filler into a corner. Act like you are making an icing bag for a cake. Snip a (very) small corner off and apply it for about a 1/2 a meter along the spiral gap, then squeegee it with an old credit card or similar. It takes a little practice, but fills the spirals quickly with minimum waste. Note this will thicken up a bit as its moved about and the moisture is absorbed by the tube. Don't try to do this all in one go. You don't cover the entire tube with it this way and saves sanding time. 220 grit seems to work for the most part-you can go back for a final sand with something finer (I use 400) before hitting it with spray primer. I hit it with 400 (you can go nuts and polish it out if you want) and then colour coat(s). Hope this helps. Straight smoke and good chutes, brother!

Never thought to ice it on with a bag, I've always used a foam brush to slather it on. Results in a full spiral, but obviously leaves a lot of excess that then needs to be sanded away. Will be giving this a shot!

TO the OP- I've used bondo spot putty on rockets that I've fiberglassed and on fillets, as well as on my first Midpower rockets- these I built before I cared about appearances, so they were already painted. I felt like the bondo would bond better to the paint, as well as the previously mentioned fiberglass compared to CWF. Works fine, but is trickier to work with- dries out faster it seems.
 
I've always (which is admittedly not that long) used CWF for my spirals. The part of the process that always annoyed me most was applying it initially. I tried a knife blade, then switched to a chopstick. I would lay on a thick layer, then squeegee it off with a razor blade. Still a pain.

Then recently it occurred to me that the answer was attached to my hand. I dip my index finger in the CWF slurry and just rub it around the spiral, applying enough pressure that not very much is left on the areas outside the spirals. Good gravy that is so much faster and easier. It does the whole thing in one step, and leaves relatively little sanding for later.

The benign nature of CWF also means that I can do stuff like this with my finger and not worry about toxicity.

Win!

I once tried to get clever (I have a lot of stories that start this way) and pulled a nitrile glove over a roll of masking tape. Trimmed the tip of a finger off, pushed just a little of my LPR tube through (think it was a BT-50), then poured the slurry around the tube in the finger. My intention was to pull the tube through and sorta laminate the CWF slurry into the groove. IIRC, it worked pretty well, but was a huge mess, and not worth the extra effort. Maybe someone can refine the technique?
 
I've always (which is admittedly not that long) used CWF for my spirals. The part of the process that always annoyed me most was applying it initially. I tried a knife blade, then switched to a chopstick. I would lay on a thick layer, then squeegee it off with a razor blade. Still a pain.

Then recently it occurred to me that the answer was attached to my hand. I dip my index finger in the CWF slurry and just rub it around the spiral, applying enough pressure that not very much is left on the areas outside the spirals. Good gravy that is so much faster and easier. It does the whole thing in one step, and leaves relatively little sanding for later.

The benign nature of CWF also means that I can do stuff like this with my finger and not worry about toxicity.

Win!

Same here. Screw it, it's non-toxic and rinses off easily, a finger works perfectly.
 
CWF works great and inexpensive, but where do you buy it, as far as the old formula. The new stuff they have is garbage or maybe I'm not aware of something?

The new color change stuff is excellent imo. Just dont buy the MAX type it has impossible to sand chunkies.
 
I noticed the link that someone posted here. It's $11 on Ebay for a small 4oz tub. That's crazy!! I've used the color change stuff and I like it. I like it because you know when its dry and ready to sand.

HomeDepot and Lowes carry it in my locality.
 
I use spackle or joint compound. Nothing sands easier.
 
What's the method for using this to fill spirals then?
Among our various characters here that will likely vary by character asked. My own tools are toward the low tech end of the spectrum, as demonstrated here on Sunward's Galactic Wave.
Whatever its value as a method may be, I pour a little distilled water in to corner of filler then stir with a bamboo skewer.
I can give no proportions, just by it looks right when stirred. Poured more than intended while trying to take picture at same time. Which is a reason to transfer an amount of filler to another container and work from it instead of store package. (and I'll probably never do that)
'Finger painting' as in 1st and 2nd grade school days works just fine for me for application method.
--> Note, package seal is sensitive to crust on sealing lip and trench.
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On the Bondo - that gets used too. Usually on plastic parts; and, often on tubes after initial filler, sanding, and priming with Duplicolor spray can filler primer of a grey/gray hue.
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You need to read the label on CWF. The color change as I seen it is interior only.
While the old orange lid is exterior/interior. I would prefer exterior for rockets.

Why? The rocket surface will be sealed with primer and paint, and neither wood nor cardboard is terribly resistant to water, even coated inside and out the airframe is susceptible to moisture, the CWF is probably more water resistant than the airframe and fin materials ( I always use Bondo Spot putty on FG rockets so as such have no comparison to how well BSG works on cardboard, or if CWF works all that well on FG).
 
Well Rich, I guess it's just me.
I over kill everything.
I'm awfully picky, and fuss over the little stuff. Anal to a fault you might say.
I guess that comes from days of doing body work and custom paint jobs. (It sucks to have to do redo's on your own time.)
And being a fine wood worker.
Pay me no mind, it's just me.
 
Well Rich, I guess it's just me.
I over kill everything.
I'm awfully picky, and fuss over the little stuff. Anal to a fault you might say.
I guess that comes from days of doing body work and custom paint jobs. (It sucks to have to do redo's on your own time.)
And being a fine wood worker.
Pay me no mind, it's just me.

Thanks for the answer, I was just curious if there was a reason other than personal preference for choosing one version of CWF over the other (other than the MAX version which is evil). Personally I haven't researched the properties of the interior vs interior/exterior, and as such maybe one is better than the other for bonding to the tube or ease of sanding.
 
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