Noob Question: Titebond or Wood Filler for Balsa sealing?

(First let me say, you experienced guys use way too many abbreviations. It took me awhile to actually figure out what "CA" is, and that was only thanks to Google. Anyway....)

So I'm trying to get a good finish on the balsa wings of my Solar Warrior, and I've been reading a lot of posts here about different ways to accomplish it. The methods I've seen mentioned are papering, sanding sealer, CA and thinned-out wood glue. Papering is a little more than I want to get into at the moment, especially with the compound angle the Solar Warrior fins use. I'm not against CA filling, but I've yet to find a post that explains just how the heck you apply and smooth it without adhering yourself or the tools to the fin within seconds. That leaves the wood glue and the sanding sealer.

I'm prepared to try the thinned wood glue, as I have a bottle of Titebond II and some brushes. But the sanding sealer sounds like a more sure-fire method.

I went looking for some sanding sealer, but all I could come up with is wood filler paste. Is this the same thing? It seems awfully gritty/chalky, and dries as a try to smooth it in (on some scrap balsa). Am I supposed to thin this as well?

Thanks for any tips/feedback you can offer! I don't wanna screw this up.

I use DAP Lite Weight Spackling thinned with water. If the spackling you pick up at the store has any real weight to it that's not the right stuff, the container should feel almost empty. Thin to a paint like consistency and apply. I use cheap foam brushes. Clean it when your done and they last a long time. Sands real easy, too. They sell the same stuff in the hobby stores, I think it's Hobbyco filler, but you pay 3 x as much.

Dave,

I've mostly used either Aerogloss Sanding Sealer or Balsa Fillercoat to seal fins. Does the watered down spackle cause you any problems with warping? I'm assuming that if you coat both sides of a fin, it shouldn't be an issue.

Welcome aboard!

I prefer to use Avery full sheet label paper on almost all of my fins...trace fin, cut around with extra space around, stick on, trim off, do other side. It leaves a very smooth finish and also helps strengthen the fin itself. Have yet to see a fin break along the grain for any of the ones I've covered - they usually break at the glue joint instead. Also this avoids the issue of warpage which you may experience using CA or using something with a lot of water. In one case of CA warpage (I had used junk mail "credit card" plastic to spread on gel CA over fins) , the label paper helped keep the fins straight after I un-warped it.

For a few times aside from that, I've used Elmers' Carpenter's Wood Filler (https://www.amazon.com/dp/B001E5L19O/?tag=skimlinks_replacement-20) with good results. I mostly use it for filling tube spirals and fillets on low power rockets, but for filling fins, I use it straight (since thinning with water can increase chance of warpage) and for me, it's hardly any weight added since you just apply it on with a plastic scraper (like junk mail "credit card"), scrape off excess, let dry and sand. I also like it since it serves multiple purposes well, doesn't smell horrible or use solvents, easily sands and cleans up with water. Doesn't taste too bad either...just kidding!

KenECoyote said:

For a few times aside from that, I've used Elmers' Carpenter's Wood Filler (https://www.amazon.com/dp/B001E5L19O/?tag=skimlinks_replacement-20) with good results. I mostly use it for filling tube spirals and fillets on low power rockets, but for filling fins, I use it straight (since thinning with water can increase chance of warpage) and for me, it's hardly any weight added since you just apply it on with a plastic scraper (like junk mail "credit card"), scrape off excess, let dry and sand. I also like it since it serves multiple purposes well, doesn't smell horrible or use solvents, easily sands and cleans up with water. Doesn't taste too bad either...just kidding!

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This is basically the same filler I picked up, but I got the smaller version that comes in a tube. Guess I'll try this... thanks for the tip on using full strength.

And thanks to everyone else for their :2:. I'm amazed how quickly people respond to posts here. Shouldn't you guys be busy building rockets or something? Ha!

There's enough time waiting for glue to dry ... what better way to pass that time than on TRF?

I also use the Elmers carpenters wood filler. The tube is the same as the tub. I used the tube for a trial run then went ahead and bought the tub, cheaper that way. I usually go full strenght but sometimes add a little water, very little. I thinned it to the "thick cream" consistency once, applied to both sides of the fin and it warped like crazy. Then I had to straighten the fin. Just rubbing it in with your finger will work but its messy. Wet your finger tip and smooth it out. Then sand smooth. I also use it for filling spirals (thinned with water) and mix it with Mod Podge for low power fillets. For plain shaped fins, papering is the way to go..super easy and quick.

Mike

Just make sure you don't grab the Elmers Carpenters Wood Filler MAX, its evil to sand. Its got little chunks of stuff in it that are really hard.

rharshberger said:

Just make sure you don't grab the Elmers Carpenters Wood Filler MAX, its evil to sand. Its got little chunks of stuff in it that are really hard.

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DOH! The MAX stuff is what I have! Maybe I'll return it tomorrow and get the other stuff.

I've never had any problems with warpage. I coat both sides of a fin in the same session and so far never a warped fin. The Lite Spackling dries fast and you can scratch it with a finger nail but take a small piece and let it dry and see how much effort it takes to break it, it's very tough to do. I've used it on balsa, basswood and Birch ply, no warps. Creamy is the word for consistency, not runny, not too thick so it kinda crumbles on, creamy. Sand it to the wood and if you don't like it apply a second coat. If the sanding loads up the sandpaper the coat is still too wet. Let it dry some more, it doesn't take too long. Start another rocket if you have to do something

Hmm, well, I tried 3 methods today. First I tried the Elmers Wood Filler MAX. Total waste of time. It's practically sticky crumbs when it comes outta the tube, like it's already half dry. Total pain to attempt smoothing in the grain. I scrapped that idea immediately.

Next I moved on to the Titebond II, 3 parts glue to one part water, give or take. I did both sides at the same time. After drying, it had warped a bit and doesn't appear to have filled the gaps well. I'm trying a 2nd coat now, and I'll deal with the warpage when I have to, I guess.

Then I discovered some of that DAP spackling in my basement. We used it to fix some nail holes back when we repainted the walls, and the tube was still in great shape. It went on beautifully, but actually warped worse than the watered down glue! I certainly didn't expect that, because it didn't even seem wet. Not sure what happened there.

All in all, papering is looking better all the time. :sigh: Now I have to look up some directions on un-warping balsa. I'm getting a bit frustrated with how long it's taking to get this model going... half tempted to just spray it and be done, maybe trace off some nice foam core board or something for replacement wings.

re: warping, yeah, I use two big books (some coffee table art books) to press the fins together, and keep them flat (use wax paper between the fins and books).

Basically, any time you introduce water to wood, I would expect some warping, unless you take some precautionary measures.

The_Plummeteer said:

Hmm, well, I tried 3 methods today. First I tried the Elmers Wood Filler MAX. Total waste of time. It's practically sticky crumbs when it comes outta the tube, like it's already half dry. Total pain to attempt smoothing in the grain. I scrapped that idea immediately.

Next I moved on to the Titebond II, 3 parts glue to one part water, give or take. I did both sides at the same time. After drying, it had warped a bit and doesn't appear to have filled the gaps well. I'm trying a 2nd coat now, and I'll deal with the warpage when I have to, I guess.

Then I discovered some of that DAP spackling in my basement. We used it to fix some nail holes back when we repainted the walls, and the tube was still in great shape. It went on beautifully, but actually warped worse than the watered down glue! I certainly didn't expect that, because it didn't even seem wet. Not sure what happened there.

All in all, papering is looking better all the time. :sigh: Now I have to look up some directions on un-warping balsa. I'm getting a bit frustrated with how long it's taking to get this model going... half tempted to just spray it and be done, maybe trace off some nice foam core board or something for replacement wings.

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For most wood fin projects, I recommend self adhesive label paper (avoids using anything with water or CA and doesn't warp the fins...can actually help straighten already warped bare fins) and for small projects, you can just leave the fins as is and paint...adds "character".
Labels: https://www.amazon.com/dp/B000093L1J/?tag=skimlinks_replacement-20

KenECoyote said:

For most wood fin projects, I recommend self adhesive label paper (avoids using anything with water or CA and doesn't warp the fins...can actually help straighten already warped bare fins) and for small projects, you can just leave the fins as is and paint...adds "character".
Labels: https://www.amazon.com/dp/B000093L1J/?tag=skimlinks_replacement-20

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I've got some of that paper and might give it a try. I don't know why I'm not having a problem with warping wood but I can't explain why I'll do it just to try something different. One place I think it would work well is if you have a canted wingtip like a Quest Force 5. The tip just wants to bust off and I know the papering would help there. As it is it basically like that now with paper reinforcement glued to both sides. I can still cover the whole thing and I just might

Deft makes a spray sanding sealer. I get it at Lowe's in the wood finishing area. It dries quick and minimizes warping. I usually apply a couple of lite coats and after they are dry I put down one or two heavy coats. Sand and prime---that easy. My Coyote had a TON of wood to seal--Deft fit the bill.--

hornet driver said:

Deft makes a spray sanding sealer. I get it at Lowe's in the wood finishing area. It dries quick and minimizes warping. I usually apply a couple of lite coats and after they are dry I put down one or two heavy coats. Sand and prime---that easy. My Coyote had a TON of wood to seal--Deft fit the bill.--

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Wow! I'll have to admit that's an AMAZING finish! :clap:

To be honest though, I rarely go too far with the finish on the label papered fins since I don't want to devote too much time in case I get a CATO or lawn dart...kind of balance how much time to invest given possible loss (more invested=more it hurts to lose).

Here are some pics of the label-papered fins on rockets I've built and almost all have flown...I basically paper any fins I can within reason now for low & mid power builds (you can paper a lot of small fins cheap, but they get more expensive as the fin requires two full sheets each):





Last pic is of a label papered Quest Lil' Grunt that despite having drilled holes into the bt (body tube) for glue "rivets", still popped a fin on a hard landing (this is a streamer recover rocket which I don't know why they didn't make ttw/through-the-wall fins). Note the smooth finish on the fin as well as this being an example of the fin popping at the joint instead of breaking...even with glue rivets and heavy fillets. It was easily repaired.

YMMV (Your Mileage/results May Vary)

Edit: The blue Indigo rocket is the one which had the middle fins warp like crazy when I followed the TLP instructions to coat the fins with CA (balsa was also very poor in the kit I got). I got it as straight as I could under books and weights (still slightly warped), label papered and then books again and they now hold true as far as I can tell.

I'm a new convert to the label paper. I had been using the papering technique from the Apogee video but I recently picked up a pack of Staple's brand label paper and used it on my Blue Max build. It worked so well that I doubt I'll use anything else on the rest of my builds. I will probably still use traditional papering on fins that I air foil but for square and rounded edges it'll be label paper. I also seal the edges with CA.

For balsa nose cones, I start with a coat of CA then sand. Then apply a couple of coats of filler primer, sanding in between coats. I really like FnF lightweight spackling for BT grooves. I think it works easier than wood filler, dries quicker and takes less sanding to knock it down. Less sanding is good, I do plenty of that on the finish.

I'm a fan of CA papering. Here is a thread where I discuss the technique. If you search based on the name "Marc_G" and the term "papering" you'll find a bunch of threads where I employ it. Some handy tips may be found.

https://www.rocketryforum.com/showt...d-fins-and-airbrush-finish&highlight=papering

https://www.rocketryforum.com/showt...atisfying-unrequited-love&p=514471#post514471



The best tip is to have some acetone (CA-debonder) handy...

Seriously, the main thing to watch out for is personal protection and ventilation. The technique itself is easy once you get the hang of it and gives great results.

Marc

KenECoyote: Any tips for what to do with the leading and trailing edges? Just curious how you treat those with the self adhesive paper. I've done a lot of papering and your method sounds like the very next thing I will try.

jeff_j_black said:

KenECoyote: Any tips for what to do with the leading and trailing edges? Just curious how you treat those with the self adhesive paper. I've done a lot of papering and your method sounds like the very next thing I will try.

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I've brushed on thin CA when the edges don't stick down too well, but for the most part, I just make sure to use a sharp x-acto knife to trim right to the edge and make sure I rub down any edges with a light touch. Then I spray Rustoleum Filler Primer all over the rocket (and fin edges), then I use Elmer's Carpenter's Wood Filler on the edges and sand if I really want a nice flat edge. Sounds like a lot, but it really isn't since I use the same Filler Primer on all my rockets to prime and then use the Wood Filler to fill spirals or imperfections, so it's just a bit more of what I would normally do. I've also used wood glue on the edges, but to tell the truth, I didn't really see any noticeable difference between using CA, wood glue or nothing.

Also you can use the label paper on airfoiled fins; however it's just more planning ahead of time - you cut the shape bigger with a fold at the airfoil, stick one side, trim that one side, fold on leading edge (precision is important), stick, trim other side.

Also with label paper the only big catch is to make sure you stick it down right the first time since it may pick up some small splinters if you make a mistake and try to lift up again...then the surface is no longer smooth. Good luck!

Thanks for all the tips guys! I just finished up my first papered fin, and I'm pretty pleased with the result. Used regular paper and some TitebondII, pretty much following the Apogee vid on Youtube. The only hiccups seem to be a dab of glue under one side that I apparently didn't get smeared off enough before applying the paper... I have a very slight mound.... and the joints are still visible. This Solar Warrior, for whatever reason, has two separate angled pieces you have to glue together to make a complete wing, and I'm having a hard time getting the glue leveled back down flat (I even used a rotary tool with a sanding wheel... still got a lump!). But yeah, papering is the way to go! I may give the sticky labels a shot as well... that'll basically be like applying a big decal, and I'm pretty good at that.

The_Plummeteer said:

Thanks for all the tips guys! I just finished up my first papered fin, and I'm pretty pleased with the result. Used regular paper and some TitebondII, pretty much following the Apogee vid on Youtube. The only hiccups seem to be a dab of glue under one side that I apparently didn't get smeared off enough before applying the paper... I have a very slight mound.... and the joints are still visible. This Solar Warrior, for whatever reason, has two separate angled pieces you have to glue together to make a complete wing, and I'm having a hard time getting the glue leveled back down flat (I even used a rotary tool with a sanding wheel... still got a lump!). But yeah, papering is the way to go! I may give the sticky labels a shot as well... that'll basically be like applying a big decal, and I'm pretty good at that.

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Great to hear you've found a method you like that works! This is what is great about model rockets...so many techniques and helpful opinions! Also don't worry about the imperfect results...it's part of the learning process and each time you do it, it'll become much better. My early models only stand to testify that I've made good improvements in my technique. :wink:

Rockets with long fins which extend up along the body tube often are made in two (or more) pieces. I think it is so that the small piece has the most end grain along both the body tube and the top of the bottom fin (seems to be a stronger construction...almost like a bracing piece). Also it's possible that it is done this way so they can be cut out of a smaller piece of balsa. The large finned/winged rockets I have built (ex. Dynastar Snarky & Firefox) were both done this way and it seems pretty strong.

Post some pics of your finished rocket when you get a chance!

Yep, will do!

I changed up my method just a bit papering the other fins last night. Instead of trying to smear the glue on and then rub it off with my finger (messy!), I dabbed the glue all over in small spots and used a $0.39 foam brush from Walmart to spread it across. To remove the excess, I flipped the brush around to the dry side and smoothed it again. Worked pretty darn well! I think my paper is a little thin, because even after sanding the balsa and papering I can see a hint of the grain in the finished surface. Need to invest in a ream of nicer, heavier printer paper... what I have is the cheapest of the cheap. But it's all good... can't expect my first rockets to be masterpieces, right?

The_Plummeteer said:

Y... can't expect my first rockets to be masterpieces, right?

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Yup! Otherwise it wouldn't be as fun to actually launch them! :grin:

BTW - try the cheap junk mail "credit card" (looks like a cc but isn't) to spread the glue on...you may be surprised how well it can work and it's cheaper than cheap!

Ken,

Do you paper the fins with the labels before you glue them on or after? I would think before but wouldn't that effect the strength of the bond?
Thanks
Joe Kipp

joekipp said:

Ken,

Do you paper the fins with the labels before you glue them on or after? I would think before but wouldn't that effect the strength of the bond?
Thanks
Joe Kipp

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Its much easier to apply paper of any type with the fin off the rocket, then you can apply more pressure/squeegee easier.

joekipp said:

Ken,

Do you paper the fins with the labels before you glue them on or after? I would think before but wouldn't that effect the strength of the bond?
Thanks
Joe Kipp

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Like Rich noted above, it's much easier before. I do it before gluing to the body tube and haven't had any issues with the strength of the bond. Maybe it decreases the strength a bit since the glue likely does not permeate the label paper through the adhesive, but I think the fins are plenty strong and would rather have the fin break off at the body tube joint than break in the middle. The prior is an easy fix, the latter not so much.

Thanks Ken and Rich. I'm starting an upscale of the Estes Bullpup AGM 12D and I think that I'll use this a test of papering the fins with labels to see how they turn out.

The finishing of balsa parts has been a sore spot for me for a while. I seem to cause more issues than I solve at times.
Thanks
Joe Kipp

One way to get around rough paper edges is to "butterfly" the paper over the leading edge.
Here's how I papered the fins on the Flutter-By.

https://modelrocketbuilding.blogspot.com/2013/12/centuri-flutter-by-build-part-4-paper.html
https://modelrocketbuilding.blogspot.com/2013/12/centuri-flutter-by-build-part-5-paper.html
https://modelrocketbuilding.blogspot.com/2013/12/centuri-flutter-by-build-part-6-paper.html

Before making the next model, try papering using a glue stick.
It's not as messy and allows you to re-position the paper skin before burnishing.
Just be sure to get a name brand glue stick, like Elmer's. The Staples brand glue stick was a mess.

Papering fins is nothing new, I first saw it done in an old Estes Model Rocket News.

You shouldn't have any problem with adhesion unless you've CA'd the root edge.