Your preferred method of sealing balsa wood
 

Items pulled from the 1st 20 pages of this forum.

Don't forget to vote even if it's "other". It'll be quick access data for us newbs :)

3 Coats of Pactra Aero Gloss Balsa Fillercoat followed by 2 coats of Pactra Aero Gloss Sanding Sealer.

I would vote for this as a preferred method. I like the way Balsa Fillercoat gets "sucked into" 40-50 year old balsa .... but have to admit lately I have been leaving out the two coats of Sanding Sealer and been using a coat of filler primer instead.

My preferred method has evolved over the years - and the exact method depends on how good the final result needs to be (e.g. display model vs. a frequent flyer). However I'm anal enough about it that I always do at least basic wood sealing and filling body tube spirals even for 'disposable' flyers.
My current primary method is a layer of Elmer's white glue (i.e. "Glue All"), sand, then a coat of thinned Elmer's Wood Filler, sand, then at least two coats of sandable primer (different colors). I like Krylon Industrial Tough Coat sandable primer.

I only fill tube spirals on Scale jobs and even those not often.
Wayyyyyy too much tedium.

I said I'm sort of anal about it. There have been times when I was building a simple rocket for some public launch (and didn't even expect to get it back after it flew) and I still couldn't stand not filling the fins and body seams...
Yea, I know, but it's sort of 'if it's worth doing, it's worth doing right'.

Quick and easy method for sure, and a shortcut that many modelers use, but makes for a heavy rocket with the resulting performance penalty.

So far, 25% have selected "other". How about posting a comment and letting us know what
works for you?

Rob, check the archives/posts here., this has been tossed around forever.

I usually use diluted Elmers wood filler but it depends on the situation. I have a Enerjet Hustler clone with it's long two piece fins that I used epoxy to fill and strengthen.

But to the point of the poll my preferred method is EWF since it is very easy to sand and doesn't react to any paint I've found yet.

EWF reacts to vintage Pactra Aero Gloss colored dope unless it's topcoated with sanding sealer first.

Rocketflyer, I read though almost half of the pages on this forum and noticed all the different opinions on sealing balsa. And they were numerous. I thought it would be useful to have all the data in one place.

I Suggested on FreeForAll a poll would help and was told I could make one. Its been useful to me because I had already bought EWF. :)

That’s good to know. Thanks.

I'm a teacher os middle school kids, and I have gone completely to Elmers Wood Filler. Cheap, easy to use, but the best thing is that it is water based and has no strong fumes. I was getting lots of students that were reacting to the strong oders of sanding sealer.

Label paper on fins
 

Here's this one from Way Back in the Day: ;) :D

https://forums.rocketshoppe.com/sho...904&postcount=9

I paper my find using regular printer paper and white glue. Details in my DR. ZOOCH build threads when pics, particularly the two stage X Prize Dr. ZOOCH rocket. I even weighed the bare balsa fins before papering then and afterwards, and the weight is minimal, actually miniscule, but the strength added is enormous and of course ease of finishing is wonderful.

Later! OL J R

When I was in the 8th grade, all science classes in my school district did a rocketry project.
Teams of 3 chose a rocket from the Estes catalog and built it over a couple weeks in the spring then launched it on a designated day.
I don't recall ANYONE complaining about Sanding Sealer fumes in 1984.
More mamby-pamby nonsense.

No doubt. My technique evolved.

Originally, I brushed on thinned Elmer's Fill'n'Finish directly on the balsa. But I found that didn't always fill all the grain. So I added a new first step of brushing on a primer of white pigmented shellac. It dries fast, and helps seal the wood. Plus, because of that, it's less prone to warping the wood versus the watered down FnF going straight on the balsa. Then apply the brushed-on, thinned FnF, and let it dry overnight.

Next I sand with 220 grit. If I then find any grain showing, I use an automotive product called body putty, I think, that comes in a squeeze tube. It uses a fast drying hot solvent, and is applied with a gloved finger. It goes on in a thin layer. It can be sanded in a short time.

Next, one or two coats of spray-on automotive primer (rattle can). If you don't get it on too heavy, it can be sanded 20-30 minutes after the last coat, then ready for a finish coat.

The reality off all this is that there is no sure-fire way to always get it done in the same number of steps. With each loop of applying a coat (and maybe sanding), you have to inspect for the grain showing, and be willing to re-do that step as necessary.

And, above all else, before spraying anything - primer or finish - use a frickin' tack rag to get the dust off. I've seen too many times where dust and dirt were showing thru the finish coat on somebody's rocket :(


Alternative: A couple coats of brushed-on hot solvent based model dope followed by sanding, then a couple coats of primer.

Either way, the key is getting the balsa stabilized/sealed with the first coat, so that the succeeding coats build up rather than soak in :)


Don't Like: Wood glue or thinned wood glue: This is a great adhesive, but it is way too difficult too sand. I avoid letting it build up anywhere. (While I apply glues fillets to fins, I don't let them get too fat, and always apply FnF over them to get the desired, smooth fillet.)

Doug

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Same here. I go for stuff that's easy to sand.

BTW, I counted and it shows you as YORF member #7. I was a slowpoke to sign up. I'm listed at #19, signing up the same day as you. :cool:


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Actually, Doug is 11 and you're 22. Just hover over your name and look at the link that shows at the bottom left of your browser (at least that's where it shows in Firefox). That shows the persons user record number.

:cool:

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Hovering over your name works in Internet Explorer too.
Not sure about Chrome.

Looks like I'm #19. When did YORF start up?

June 3, 2004 is when Scott and Buzz "joined" after building the site, but it really kicked off in Feb/March of 2005.

Well, I wasn't too late to the party then.

It didn't go fully live till the evening of March 8th, 2005.

John Brohm was my first user on 02/19/05. I believe I had him test some things before going live.

Kurt Schachner was next on 03/08/05 followed by Craig McGraw and Buzz McDermott on 03/09/05.

Hard to believe it's been 15 years, Scott, but very grateful for the hosting and archive services you and YORF provide the hobby. A treasure for sure.

Coming back on topic, I use sanding sealer and butyrate dope to seal nose cones, and Silkspan and Nitrate dope to seal fins.

+1 to what John said above.

Scott-
Thank you for hosting such a great and valuable site for us incurable BARs !

Cant beat good ole Dope based balsa sealer. My latest build with no primer, just colors. Not perfect, but good enough to fly. Oops, forgot to mention the process. Simple and fast, shaped and sanded fins smooth. Then I brush on one coat of Brodak sealer, let dry 20 min and brush on second coat. I let this dry 45 min and sand smooth and that is it. Since this new balsa is pretty hard I normally don't have to brush on another coat.

Other. Plastic, ply, fg, Al. The option was not given for laquer sealer with baby powder filler. Always sand balsa before you do the first coat of anything and never use CF!

I use diluted Elmers wood filler too. Sometimes I would get lazy and just use self adhesive label paper trimmed and then use CA around the edges. I located an old build that I started that I used Zinsser Bulls Eye water based primer. It's white and it is a Rust-Oleum product I picked up at either Home Depot or Lowes in a quart can. I haven't tried to sand it off yet so don't know how it worked but it did dry pretty quickly from what I remember ....

I've typically use Elmer's F&F, or white glue and paper.

I've been considering trying the Brodak Sanding Sealer. Can I apply this directly to the balsa or do I need to apply the clear dope first? And I've seen various references to thinning... I believe I've seen 50/50 mix and 1 part to 2 parts. Is that more a preference or what ? And can I use acetone from Home Depot or should I get the thinner?

Thanks

I brush it on full strength onto bare wood. I normally do not thin Brodak.

I just gave Elmer's wood filler a try. It's kind of dry and balls up. Not easy to spread. I added a few drops of water and that smoothed it out a bit.

Think I'll go back to full strength wood glue. It's easier to brush on.

Edit: Dang it, it warped my fins. They were off the rocket but i don't think it would have helped.They warped across, not longitudinally.

If you're going to use that stuff on fins, you need to do both sides at the same time. Don't use wood glue or Elmer's glue to seal fins. Very difficult to sand.

Allen

Yeah, just realized my mistake. Gonna have to get more wood and cut new ones.

Water based wood sealers= YECHHHHHH !

We'll, pressing them under a heavy flower pot didn't straighten them. Neither did coating the other side. Did find if you spread it with your finger you can quickly coat both sides.

I couldn't get balsa, had to use basswood. It's a PITA to cut.

The best result I've had with Elmer's wood filler is to thin it about 40% with water. Mix it well and paint it on thick with a small brush. It will look like stucco but will sand down smooth.

I had one fin glued on already and hadn't applied the sealer.

Coated it quickly, both sides, and got no warpage.