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.