Filling tube spirals

[Steven88]

I'll repeat my spiral method again.

1) Smear thinned CWF over entire body tube. Smooth it out with your finger(s) to create a fairly even, *thin* layer.
2) Sand. Don't worry about roughing up the glassine.
3) Apply one good heavy coat of filler/primer.
4) Sand.

Done.

If the body tube is on the larger side, and it's just too much area to completely cover with CWF, then just work around the spirals. But don't expend any effort to keep the CWF *confined* to the spirals.

It’s ok to thin the CWF with just plain water isn’t it? And can you thin it too much, unless obliviously if you make it too runny and it runs off?

 

[neil_w]

It’s ok to thin the CWF with just plain water isn’t it? And can you thin it too much, unless obliviously if you make it too runny and it runs off?

Yes, water, and yes you can thin it too much. You don't want it to be watery. I go for thin mustard-like consistency. It takes a relatively small amount of water relative to the amount of CWF to get it there.

 

[SammyD]

Yes, water, and yes you can thin it too much. You don't want it to be watery. I go for thin mustard-like consistency. It takes a relatively small amount of water relative to the amount of CWF to get it there.

What is "CWF"??

 

[smugglervt]

What is "CWF"??

Elmer's Carpenter Wood Filler?

 

[Steve Shannon]

CWF is Elmers Carpenter's Wood Filler (the regular kind). I don't know much about the DAP.

What is "CWF"??

See above

 

[SammyD]

I looked at that and looked at that, and just couldn't figure out what the heck you guys were talking about... LOL! Thank you!

For what it's worth, I use Bondo spot putty after a good coat of primer, then sand to remove high spots - has worked well for years for me...

 

[neil_w]

Bondo spot putty works great but it stinks to high heaven, and that disqualifies it from use in my house.

 

[scadaman29325]

The type of primer matters as well. Using a high build primer will help quite a bit. I use KILZ oil based primer in a rattle can, and usually only takes a couple of coats. If you use KILZ, let it dry for at least 24hrs before you try to sand it and it will sand very easily. After I've sanded both coats almost all the way off I look closely for any low spots and then apply spot putty. (The red stuff you get at the auto parts store, comes in squeeze tube) I usually apply one more coat of primer after I'm satisfied the surface is smooth, and I sand that last coat mostly off. I use KILZ as well on large fiberglassed rockets to fill any of the weave that might show.

Does oil based primer mess with water based paint?

 

[fyrechaser]

Does oil based primer mess with water based paint?

Phil, I have never painted a rocket with water based paint over the primer but I do know that it works fine under or over Latex. ( I believe Latex is water based ) I have used it while painting a room and trying to block a stain which is what it is really designed for. To answer your question, and while I'm certainly no paint expert, I would think it would be fine.

 

[fyrechaser]

And I might add.....test it first to be sure.

 

[scadaman29325]

Latex was the word I was trying to think of when I wrote that. Acrylic is the other I was going to write.

Wow, a lot of info here, just sayin... I've stuck my foot in my mouth so many times, I try to look things up beforehand.

https://www.differencebetween.net/object/difference-between-acrylic-and-latex-paint/

When latex paint is water based, acrylic is chemical based. As the acrylic has chemicals, it is more elastic than latex paint. The acrylic paint contracts and expands better than the latex paint because of this elasticity. The acrylic paint is more durable as it resists flaking, chalking, and peeling.

Unlike latex paints, acrylic is flammable as they have chemical compounds in them. Moreover, the acrylic is also considered to be more toxic than the latex paint.

 

[Angel_of_the_Skies]

I have also struggled with this. The Elmer's woodfiller seems to work great for smoothing fins, but I had mixed results with the tube spirals. I don't know if I inadvertently sanded too much of the dried filler off or what, but once I put on 2 coats, some of those aggravating spirals still showed. It was an improvement over my last few attempts, though. I also wonder just how much trouble it's all worth, especially since any rocket has a chance of getting launched into oblivion.

To me, the trouble is well worth it if I’m not looking to fly the rocket. If I’m flying it, I would only prime, top coat, and gloss the rocket, without much sanding if any. Easy 1 week process.

Now on the other hand, if I want to achieve a smooth and very aesthetic finish for a shelf rocket, I would go through all the steps you could imagine to get the finish smooth.

I have trouble with CWF too, it seems that if you sand too much, loads of it falls out the spirals. I had some wood glue run down along my BT, where I had to sand down a lot.

As of now, I am currently on my 12th coat of filler primer with spirals still visible.

My only solution would be to redo the spiral fillets, sand, and re prime with filler.

I am planning on my next build to build the rocket, CWF the lug / fin fillets for a smoother transition to the body tube, and perhaps filling in spirals lastly, after my rocket has already been constructed

Quick question, are there build threads on TRF ? I would like to document my builds to help others out !

 

[David Schwantz]

No matter what is used, IMO it is how it is applied. You must feather the edges in so there is less sanding. If filler is starting to dry out as you apply, rewet it or get a fresh dab. I like to use cut up thin card board as a squeegee to apply, they are throw away after. I will sand both with a sanding block by hand, I have a semi hard foam block so it will conform to the tube roundness. I also employ my mouse sander LOTS. Anywhere from 120 to 220 grit. If you sand into the glassine it will cause bumps. Spray with filler primer, let dry well, resand. If the paper is getting clogged, or you are rolling up little balls of primer as you sand, it is still not dry enough to sand. Sometimes I will let tube sit for a couple weeks while I am gone for work.
But again, IMO, it is well worth the effort to make a cardboard tube look like glass.

 

[ewomack]

To me, the trouble is well worth it if I’m not looking to fly the rocket. If I’m flying it, I would only prime, top coat, and gloss the rocket, without much sanding if any. Easy 1 week process.

Now on the other hand, if I want to achieve a smooth and very aesthetic finish for a shelf rocket, I would go through all the steps you could imagine to get the finish smooth.

I have trouble with CWF too, it seems that if you sand too much, loads of it falls out the spirals. I had some wood glue run down along my BT, where I had to sand down a lot.

As of now, I am currently on my 12th coat of filler primer with spirals still visible.

My only solution would be to redo the spiral fillets, sand, and re prime with filler.

I am planning on my next build to build the rocket, CWF the lug / fin fillets for a smoother transition to the body tube, and perhaps filling in spirals lastly, after my rocket has already been constructed

Quick question, are there build threads on TRF ? I would like to document my builds to help others out !

Yes, it depends on what one wants to do. If you're looking to make a model rocket look fantastic, whether you fly it or not, then the effort is definitely worth it. My original message, back from 2019, dates from when I "rediscovered" LPR and I just wanted to build and fly, build and fly, build and fly, to get more experience. I wanted the rockets to look decent, but I was balancing the effort versus the impact of the work needed. I don't remember exactly why I posted that message, but I think I was trying to answer the question "what is the tipping point for doing too much work for a $20.00 - $40.00 LPR kit that might just end up in a tree, or as a CATO, or as a lawn dart?" Looking back now, I think the answer is that the tipping point will vary from person to person and situation to situation. I wouldn't apply multiple surfaces of filler to an Estes Mosquito, for example (unless I just wanted to make a fantastic looking Mosquito), but I definitely would for a $150.00 HPR kit (but again, I would only do that up to a point). Ultimately, the answer will vary by person. My interests have since moved to LPR, so the question has shifted yet again for me.

 

[neil_w]

As of now, I am currently on my 12th coat of filler primer with spirals still visible.

Quick question, are there build threads on TRF ?

 

[hcmbanjo]

Twelve coats of filler/primer?
Here's a two-step method from a recent blog build:
STEP 1
https://modelrocketbuilding.blogspot.com/2023/03/estes-eac-viper-0820-bt-55-upscale-part_98.htmlSTEP 2
https://modelrocketbuilding.blogspot.com/2023/03/estes-eac-viper-0820-bt-55-upscale-part_23.html

 

[Angel_of_the_Skies]

Twelve coats of filler/primer?

I follow almost the same steps you do, however I had wood glue run down my body tube which required a lot more sanding than usual, which knocked out the CWF.

 

[Angel_of_the_Skies]

Sooo, build threads on here ?

 

[neil_w]

Sooo, build threads on here ?

You might find a few.