Finishing Help

[bavspaceprogram]

I am almost finished with my scratch built rocket. It is looking really good so far, but since I am a very bad painter in all aspects of it, I have no idea how to finish it. I know that Elmer's Carpenter's Wood Filler is good for getting the grooves out of the BT and making the fins smooth, but how do I apply it (I left the fins off, in case that makes a difference)? And after I finish that, what do I do with primer? I hate painting.

 

[NAR29996]

Your filler needs to be thinned with water to about 50% (or less) of its original consistency. I usually use a second resealable container to mix and hold the thinned version.

You fill the grooves in the body tube by pressing your thinned filler into it. Use the smallest spatula you can find. When it dries, sand off the excess and your grooves should be filled. BEWARE: The filler will shrink as it dries and it may take 2 applications to get the desired results (depending on how anal you are). For this reason, I have just made the switch to Bondo spot putty. It will take building 2-3 models before I'll really know the difference.

For the fins, IMO it is better to put the filler on after the fins are mounted and the fillets done. Otherwise, the balsa may warp. Use a 1/2" spatula to press the thinned filler into the pores. I work from the body tube out. Try not to put it on too thick. When dry sand it smooth. Don't go down to the bare wood. You'll probably find holes that will need to be filled, this is common. You're looking for an even, flat finish.

When you're satisfied, go ahead and prime your model. What brand primer are you using?

 

[bavspaceprogram]

What brand primer are you using?

Rust-Oleum

 

[Handeman]

I gave up on using fillers to fill groove a while back. It just adds extra sanding. I use the Rustoleum Filler Primer I get from the Automotive section at Walmart. It's a heavy, high solids primer that build up fast.

The thing about using the primer to fill grooves is, you have to put the first coat on pretty thick and when it dries, sand down to the tube or fin. Only the stuff filling the low spots should be left on the rocket. That means you will sand off about 80% -90% of what you put on for the first coat. What you end up with is the low spots are filled pretty well. Then repeat this process with the second coat. I've never needed to repeat the sanding down to the BT or Wood on the third coat.

For the third coat, sand it smooth but don't take it down so the BT or wood shows through. This is the base coat that you actually paint on.

Just remember, I'm usually satisfied with a 5 - 10 foot paint job (if it looks good at 5 - 10 feet away, its good enough)

 

[NAR29996]

Rust-Oleum

Good choice!

 

[ThirstyBarbarian]

I gave up on using fillers to fill groove a while back. It just adds extra sanding. I use the Rustoleum Filler Primer I get from the Automotive section at Walmart. It's a heavy, high solids primer that build up fast.

The thing about using the primer to fill grooves is, you have to put the first coat on pretty thick and when it dries, sand down to the tube or fin. Only the stuff filling the low spots should be left on the rocket. That means you will sand off about 80% -90% of what you put on for the first coat. What you end up with is the low spots are filled pretty well. Then repeat this process with the second coat. I've never needed to repeat the sanding down to the BT or Wood on the third coat.

For the third coat, sand it smooth but don't take it down so the BT or wood shows through. This is the base coat that you actually paint on.

Just remember, I'm usually satisfied with a 5 - 10 foot paint job (if it looks good at 5 - 10 feet away, its good enough)

This is what I use too --- the Rustoleum Filler Primer (high build formula). I get it at Home Depot. It does a good job of filling spirals and will fill wood grain pretty well, as long as you've given it a nice initial sanding. I usually end up using 3 coats and sanding in between with progressively finer grit. I use wood filler to fill larger imperfections in fins and joints where body tubes meet. I also sometimes use wood filler to build up fillets if I want a bigger radius. But for most of the small things like spirals and wood grain, I rely on the filler primer. I like a nice finish on my rockets but am not as much a perfectionist as some --- maybe a 4 - 7 foot paint job!

For the color coat, I have been using Rustoleum Painters Touch 2x with results I am happy with.

Try to enjoy painting! It's not that bad! And you can always sand and repaint...

Good luck!

 

[Handeman]

That is definitely a method I would adapt to. I like using the primer to fill most things, but sometimes that does reveal larger issues and the wood filler can take care of that.

What make my painting less of an issue is I was given an explosion proof exhaust fan I hooked up and built a spray booth in my basement. I can paint anytime of the year and conditions are very stable all year long. That makes it much simpler.

 

[samb]

All good tips from the above posters. One thing I'll add is that besides the filler and primer you've got to spend some quality time with the sandpaper, especially on the balsa surfaces. I use 220 grit on the raw balsa before any filler. Then 320 after the filler and primer. You decide how many iterations of fill, prime,sand you want for a particular model.

 

[AfterBurners]

Another options is to paper the fins. There are several threads on this forum that covers the procedures. Some use white glue and others like myself use a spray adhesive to adhere the paper to the fins. The edges can be CA'ed with thin formula CA. Less sanding and less mess. You can also use Aero Gloss balsa filler primer and sanding sealer. It's pretty strong so use it with plenty of ventilation. Over time you will probably try a lot of different procedures. Find one that works best for you and stay with it.

Good luck!

 

[bavspaceprogram]

What would be a good strategy for the nosecone?

 

[AfterBurners]

What would be a good strategy for the nosecone?

Plastic or balsa??

 

[bavspaceprogram]

Balsa.

 

[AfterBurners]

Balsa.

You can soak it with thin CA and allow it some time to dry. Not long actually. After it dries sand it with 220 and then use can use some FnF or Aero gloss sanding sealer. Come back and hit it with some high build primer. Couple coats and sand in between then paint.

 

[samb]

I've done the CA and wood filler like AB described. I like to use those sanding sponges for nose cones. I've also done some with finishing epoxy. Here is a thread w/pictures:

https://www.rocketryforum.com/showthread.php?49317-Balsa-nose-cone-treatment&highlight=deimos

 

[eedetail]

One thing I really like to do with primers is changing the color from coat to coat. It really lets you know when you are
through the last coat. After final sanding, spray with primer *Sealer* instead of filler. It will really lay down flat and smooth,
and just a light sanding to get it ready for a color coat.

 

[gpoehlein]

For most "regular" rockets (3 or 4FN), there are two other options for most of the model (yer still gonna have to paint the nose). One method that I like is the one I'm getting ready to use on my upcoming Level 1 rocket - I'm going to cover the whole rocket with paper. I picked up several colors of light card for scrapbooking (12" x 12" size) at Hobby Lobby, and I plan to glue those panels to the fins and body tube. It is actually a tube fin rocket, so that's why I plan to do this. This has two advantages - you don't have to fill and prime anything but the nose, and you don't have to paint and mask for colors - just give it a couple coats of clear gloss after it is papered. Quick and effective, and there are a lot of colors available to choose from.

The second alternative is what I plan to do for my Estes Leviathan - Monocote. (I would have used it on my L1 cert model, but I didn't think monocote would look that good on the tube fins.) Check online - there are several tutorials for putting monocote on a rocket. The main trick is to set your iron low so that it sets the glue on the back, but doesn't shrink the monocote very much. Again, ya still gotta paint the nose.

 

[AfterBurners]

One thing I really like to do with primers is changing the color from coat to coat. It really lets you know when you are
through the last coat. After final sanding, spray with primer *Sealer* instead of filler. It will really lay down flat and smooth,
and just a light sanding to get it ready for a color coat.

I agree I do the same thing

 

[Handeman]

One thing I really like to do with primers is changing the color from coat to coat. It really lets you know when you are
through the last coat. After final sanding, spray with primer *Sealer* instead of filler. It will really lay down flat and smooth,
and just a light sanding to get it ready for a color coat.

I used to do the same thing, but now I use the filler primer to fill spirals and flaws. I just sand each layer until the tube or fin shows through and do a final coat that is only sanded lightly. That works great for the base color coat.

 

[Mike TG]

+10 for all said here already. When it comes to fillets, I like to lay them down with glue and a wet finger to smooth them out. Let that dry and you're left with a strong fin joint. Want it better? I like to lay down a line of carpenter's wood filler from a tube, then use a very wet paint brush to smooth it in. If you put it on straight from a tube, it is pretty solid, but the wet brush will smooth over the outermost surface quite nicely. I usually need only a light sanding with 320 grit and some primer to be ready for paint. I have an anal streak, though,(skidmarks?!?), so some extra working here and there usually occurs. Of course, this is on LPR, as I am clueless as to the necessities of real power...

 

[Handeman]

+10 for all said here already. When it comes to fillets, I like to lay them down with glue and a wet finger to smooth them out. Let that dry and you're left with a strong fin joint. Want it better? I like to lay down a line of carpenter's wood filler from a tube, then use a very wet paint brush to smooth it in. If you put it on straight from a tube, it is pretty solid, but the wet brush will smooth over the outermost surface quite nicely. I usually need only a light sanding with 320 grit and some primer to be ready for paint. I have an anal streak, though,(skidmarks?!?), so some extra working here and there usually occurs. Of course, this is on LPR, as I am clueless as to the necessities of real power...

Check the threads on fillet techniques. I use what most around here do. I put a line of tape on the fin, about 1/4" from the BT and a line on the BT about 1/4" from the fin. (adjust distance for size of fillets) I then put epoxy on and smooth it our with a Popsicle stick. Once that is done, I pull the tape off. If you wait too long, you'll get a tape line where the epoxy met the tape.

 

[Nathan]

+10 for all said here already. When it comes to fillets, I like to lay them down with glue and a wet finger to smooth them out. Let that dry and you're left with a strong fin joint. Want it better? I like to lay down a line of carpenter's wood filler from a tube, then use a very wet paint brush to smooth it in. If you put it on straight from a tube, it is pretty solid, but the wet brush will smooth over the outermost surface quite nicely. I usually need only a light sanding with 320 grit and some primer to be ready for paint. I have an anal streak, though,(skidmarks?!?), so some extra working here and there usually occurs. Of course, this is on LPR, as I am clueless as to the necessities of real power...

I don't think wood filler fillets would be strong enough for HPR's or even some MPR's. I'm currently building a minimum diameter 29mm MPR. OpenRocket says it should go 866 mph on a G80 and I'm not sure that even the epoxy fillets are going to keep the fins on.

 

[Handeman]

I don't think wood filler fillets would be strong enough for HPR's or even some MPR's. I'm currently building a minimum diameter 29mm MPR. OpenRocket says it should go 866 mph on a G80 and I'm not sure that even the epoxy fillets are going to keep the fins on.

If your fin shapes are clipped delta or something close that minimizes flutter, it shouldn't be a problem. Unless you don't roughen the surface, use too small of fillets, use a poor epoxy, or any of a hundred other excuses I can give if it fails. Fly it!