Priming balsa parts

Well it seem what I had been using to seal balsa parts in particular balsa nose cones is no longer available (Sig sanding sealer). What is everyone using now?

SIG still lists their sanding sealer as available to order online.

https://www.sigmfg.com/cgi-bin/dpsmart.exe/IndexBuidlingMaterialsEquipmentF.html?E+Sig

I've used SIG in the past, but mostly use Pactra brand (formerly made by Testors), still called AeroGloss now by Midwest products.

https://midwestproducts.com/collections/paint

Jerome

For balsa parts I use glazing putty, usually found in the auto body/paint area of the store. It is basically thick primer. I squeeze a little into a dixie cup and using a home made paddle, scrap of thin ply, mix and apply the putty in very thin layer. Basically removing all but what fills the grain. Some grain will show and I want that.

Once putty is dry then I sand smooth and spray prime, and sand again. Then a final primer coat before painting.

I paper balsa fins with permanent adhesive label paper then do a thin CA soak.
For balsa nose cones I just use a thin CA soak and sandable filler primer that can be found in the auto section a Walmart or at auto parts stores.
Any big defects I fill with red glazing putty.
If you must have "sanding sealer" then try Minwax sanding sealer. It comes in a large can lasts a long time and doesn't shrink like dope based sealers.

CA soak? Like super glue? Wouldn't that be expensive for large nose cones? Where can I get glazing putty? Would autozone carry that? I swear I have never seen such a thing at Walmart.

sjh1 said:

CA soak? Like super glue? Wouldn't that be expensive for large nose cones? Where can I get glazing putty? Would autozone carry that? I swear I have never seen such a thing at Walmart.

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I get mine at walmart but any good parts store will carry it. As far as sanding sealer goes, I use DEFT spray can sanding sealer. Available at Lowe's or HD.It's lacquer based and dries fast. Honestly, I've gotten to the point these days where I sand my balsa parts with 360--400 grit paper to knock down the heavy grain and just use a high build primer and sand that down. ---H

sjh1 said:

CA soak? Like super glue? Wouldn't that be expensive for large nose cones?

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I'd say you need to look at my tutorial on doing it. You want to use super thin CA. Buying it in larger containers is cheaper than 1 ounce at a time.



Now for fins, I've got a tutorial on papering them (eliminating the need to fill them).

Pointy Side Up!
Jim

+1 to K'Tesh's method... I do something similar these days.

For most Balsa or basswood Nosecones there are a couple different methods of filling before priming.
I prefer spinning the cone on a dowel while holding a CA soaked paper towel to the surface. eventually this seals the surface and makes a great sanding base before a single primer coat.

While Pactra no longer makes AeroGloss sanding sealer. it is still very much available from Midwest. It is exactly the same formula stuff. That said I would NOT use "Sanding Sealer" trying to fill balsa or other wood grains. Sanding Sealer contains very little grain filling solids. Instead you might want to try Aero Gloss (Midwest) Balsa Filler. This material has the same wood penetrating vehicles along with very high amount of sandable solids. Makes filling deep Balsa grain possible in 2-3 coats rather then 6-10 While I have a good supply of this product in the basement I rarely use it anymore since it has such a strong odor. I've switched almost entirely to CA sealing then Cheapy grey automotive primer for my Babies butt smooth wood finishing. Most folks think my NC and fins are Plastic.

Minwax Wood Hardener is another similar method but this stuff Stinks to High heaven, use only in well ventilated areas. doesn't build up quite as well as CA but does indeed sink deeply into both woods making the sap wood as hard as the rings. Sands well and smooths out fairly well.

Fins can be done with any of the above or in combination depending on how you want to finish your models and how long you want to spend on the process.

sjh1 said:

CA soak? Like super glue? Wouldn't that be expensive for large nose cones? Where can I get glazing putty? Would autozone carry that? I swear I have never seen such a thing at Walmart.

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Yes Auto Zone should carry it. If your Walmart has a small auto body area that is where it would be. My local WM has that area near the headlight bulbs/fuses and trailer towing area.

A random selection of fillers, primers, hardeners, purchased at Wally World, Autozone, and/or your favorite big box home improvement store.

I haven't tried it on nose cones, but with fins I've had sucecss this way: I start with lightweight foam spackle. I use a flexible plastic straightedge (a credit card will do, something thinner is better, like last year's insurance ID card) to both press it into the grain and smooth it out. Nicks and dents are filled at the same time. As that stuff is quite soft, I follow it up with AeroGloss dope (not the filler, just the clear dope) once it is completely dried. Thin CA might work better for that last step, but I only have that in the 1 oz containers so the AeroGloss is a lot easier to brush on.

Incidentally, I also use the foam spackle for fillets if I want them large. Start with a regular glue fillet for the strength, but if the aesthetics and/or aerodynamics call for something bigger, then spackle works great on top of the glue. It can be piled on rough, easily shaped with 320 grit, then sealed with dope (or CA) for final sanding.

Heck, I just apply a coat of Rustoleum Filler Primer, knock down the rough hairy stuff on the balsa, then start a basic sand-and-prime loop until I'm happy with the results. I put the first coat on in red oxide, then switch to gray; this makes it easy to see when I'm almost down to the material.

Here's Betsy, my camera carrier (which has yet to fly with the camera... maybe this year):



Done exactly as I described. I think it took a total of four coats of primer to get it the way I wanted it. I'm kind of obsessive about it.

What I do is use CA glue (thin) I found a way to apply it to nose cones that keeps it off your fingers and you get a uniform coating

Take a plastic sandwich bag and put a small puddle say quarter size diameter.

Starting with the tip of the nose cone careful roll / rotate the cone until you work your way all the way to the base of the cone. This method allows you to grip the cone at the shoulder and keeps the CA off your fingers.

Let it dry thoroughly before sanding. I start with 220 and repeat the CA process then follow with 320. Usually that's pretty good for me. Any other imperfections I'll use FnF or spot putty glaze whichever you prefer or have on hand. Sand again until imperfections are gone.

I follow with Duplicolor HBP

You guys are going way overboard on this.

I just squeeze a bit of Elmer's Yellow Carpentry glue into the bottle cap from a Two-Litter bottle of Pepsi or Coke... add a few drops of water from the tap, and stir until I have a thin slurry of glue. Then I take a cheap kid's paint by numbers paint brush and dip it into the slurry, and just paint it onto the balsa nosecone, or the fins, or any wooden part to coat it. The first layer will raise the grain, but then sanding it down to a smoother coat... prepares it for the second coating with more slurry. More sanding, and then another coating if it needs it. But after that, there's not much need to sand to get it smooth.

I find this much cheaper than going out and buying a separate wood sealer or primer.

Kirk G said:

You guys are going way overboard on this.

I just squeeze a bit of Elmer's Yellow Carpentry glue into the bottle cap from a Two-Litter bottle of Pepsi or Coke... add a few drops of water from the tap, and stir until I have a thin slurry of glue. Then I take a cheap kid's paint by numbers paint brush and dip it into the slurry, and just paint it onto the balsa nosecone, or the fins, or any wooden part to coat it. The first layer will raise the grain, but then sanding it down to a smoother coat... prepares it for the second coating with more slurry. More sanding, and then another coating if it needs it. But after that, there's not much need to sand to get it smooth.

I find this much cheaper than going out and buying a separate wood sealer or primer.

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I did this a long time ago... what a PITA! Way to much sanding and water warping for my tastes.

Most often these days, I still use Nitrate or Butyrate (SIG or Aerogloss) sanding sealers. It brushes on easy and sands smooth fast. Usually about 3 coats will do the trick. It also dries fast! You can get your fins done in a single sitting. Plus it smells good! lol

When I'm in the mood or really care about a build, a single layer (on each side) of light weight (0.75 oz) fiberglass cloth and finishing epoxy is the way to go! I do one side at a time with wax paper, peel-ply or mylar for a smooth finish. Very little surface sanding required. The balsa is still super light weight. Weighing less than basswood and stronger than ply. It does add an extra day though to the build time.

Jerome

Found only the Elmers Wood filler at Home Depot

After trying WEST system epoxy on a balsa cone, the only reason I'd ever do it another way is one of cost. I painted it with one coat WEST, did some other gluing with rest of that batch too. Sanded; where the grain was at a steeper angle I did manage to get a little bit of CA to soak in on top. One coat of spray paint and it really didn't need any more, except for opacity. No absorption and already smooth. P.S. I saw somewhere saying use sanding sealer before WEST, that would totally defeat the purpose, and epoxy (unless over-absorbed) is not only sealer against liquid, it seals against water vapor!

As to sanding sealers, never used them and am somewhat mystified. Usually I paint wood directly and let the absorbed part increase the surface hardness.

Any good high build primer is my route, usually use the Duplicolor as it is readily available at my local O'Reilly Auto Parts. Any big dings get a bit of Bondo glazing putty and after sanding and perhaps one repeat cycle, I'm left with a 'smooth as glass' surface for the finish coats.

I try to keep it simple. Rusto high fill primer, sand and paint. Sometimes, like on pointy conical nose cones I will harden the balsa with CA, but the the same filler primer, sand and paint.
My rockets are not museum quality, I don't have the skill to make them that way, so why get twisted in a bunch over the finish?

sjh1: The glazing putty everyone speaks of is in the automotive section. It is intended fill minor imperfections when using Bondo to make body repairs. Comes in a squeezable tube. Also happens to work for filling minor imperfections on rockets.

Isn't it odd, though, that "glazing putty" is automotive stuff. Actually, car folks adopted it from - who'ld'a thunk it? - glazers. (When you put a new pane of glass into an old fashioned window, the glass is initially held in by tiny sheet metal triangles called glazer's points, then the edges are sealed with putty.) In olden times, like fifty years ago when dinosaurs ruled the Earth, it was oil and lead oxide based - basically ultra super thick paint. Nowadays it's lead free of course, latex, acrylic, or something based, and called glazing compound to distinguish it from old lead based putty. The automotive stuff must be lead free nowadays too, and it's probably a different formulation from modern glazing compound, but weirdly the auto stuff kept the old name.

Wouldn't it be weird if the world weren't so odd? Maybe I'll try glazing compound on balsa some day.

K'Tesh said:

I'd say you need to look at my tutorial on doing it. You want to use super thin CA. Buying it in larger containers is cheaper than 1 ounce at a time.

Pointy Side Up!
Jim

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I started work on two BNC-60AH nose cones tonight. Using two different methods on them. One is something I learned recently using Elmer's wood filler. Darn wood feels like plastic once it's done. It's great. I'm trying K'Tesh's CA method on the other. Granted, it's my first try, but so far it's not turning out as well as the wood filler option. But I'm not giving up yet. By tomorrow night they'll both be finished one way or the other and I'll know what works for me.

K'Tesh, what do you do for the shoulder? Just leave it plain or do you CA is also? If it's CA, what sanding method do you recommend? I want to give your method every chance before I decide which to use primarily.

I still use Aerogloss sanding sealer. 3-4 coats and it's good.

I don't have aeroglass. I have minwax sanding sealer. Work about the same?

Kruegon said:

I don't have aeroglass. I have minwax sanding sealer. Work about the same?

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Not sure about Min wax. Aerogloss is basicly model airplane dope with baby powder to fill the voids. Adds almost no weight.

I have tried everything, and nothing beats old fashion Aerogloss Balsa Sealer.

The wood filler method is working out amazingly. Feels like plastic when finished. I'm curious about the durability. I wonder just how tough it'll make it. The nosecone is noticeably firmer. The fins turned out better than I could have hoped. They even shine like dull plastic. And the CA on the edges took every notch and nick out leaving it smooth. The primer and paint will tell the tale though.

Hi Kruegon, hope you're finding some good info here. Everybody has their favorite method, and they all have some merit. I use different ones depending on how big the model is and how much of a hurry I'm in. CA onto bare balsa wins hands down for pure speed. You can have a small NC ready for primer in 5 minutes or less. For bigger ones (say BT-55 and up through 3" which is about the limit I would go for balsa cones) I use a coat of West, Aeropoxy, US Composites or similar good quality thin epoxy. If I made the cone myself I'll coat it while it's still on the lathe so I can machine-sand the resin. I wouldn't recommend using cheaper epoxy like Bob Smith or hardware store stuff; they are a lot gummier and harder to sand.

Long ago I used sanding sealer, which as someone said above you can make from clear dope and baby powder, but quit because the newer methods seemed a lot easier and better. You need numerous coats of sealer with drying time in between, and it keeps shrinking for years and will eventually crackle. I still use clear dope with no filler on glider wings sometimes. I've never tried the Minwax sealer nor the Wood Hardener, which some people like.

I tried the wood glue method once, a long time ago. For me it took too long to dry, caused some swelling, and was hard to sand. For a really cheap way I'd use Elmer's wood filler instead. Though I did a few models with it, I think the Elmer's CWF is too soft, but it's great if you have soft landing areas or are your teaching your kids since there's almost no way to hurt yourself with it.

Thanks caveduck. I've found a ton of info and even found that I have some reliable info to share as well.

I've played with the Minwax sanding sealer. Doesn't seem any better than any other sanding sealer I've tried. I still have the boys using it for ease.

So far the wood filler seems pretty awesome. Again, the durability is still in question but time and flights will tell. I'm still playing with epoxy options. The Bob Smith epoxy works beautifully, but I'm finding it to be a little rubbery once cured. But it does beautifully if your good at fillets.

I'm playing with the CA option now. Technique is proving to be more elusive than I had hoped. But I'm not giving up yet.

Kruegon said:

I started work on two BNC-60AH nose cones tonight. Using two different methods on them. One is something I learned recently using Elmer's wood filler. Darn wood feels like plastic once it's done. It's great. I'm trying K'Tesh's CA method on the other. Granted, it's my first try, but so far it's not turning out as well as the wood filler option. But I'm not giving up yet. By tomorrow night they'll both be finished one way or the other and I'll know what works for me.

K'Tesh, what do you do for the shoulder? Just leave it plain or do you CA is also? If it's CA, what sanding method do you recommend? I want to give your method every chance before I decide which to use primarily.

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Personally, I leave it w/o CA (except close to the actual step from the shoulder to outside (visible) edge). I protect the shoulder with a short section of body tube while I'm sanding (NOT while I'm applying glue)

One method I'd like to try someday would be to figure out a way of putting my nosecone on a medium speed rotisserie (with some kind of way of angling it to prevent it just collecting into a single point/ring) and "painting" it with epoxy. Then allow it to cure while spinning. It'd add weight, but it may reduce the amount the amount of weight needed for rockets that need nose weight.