Sanding Sealer

A new kit I'm getting recommends the use of a "sanding sealer" for the wooden fins. Does anyone have experience using this? Can any primer or paint be used with it? I'm worried about brand compatibility so if anyone has success using a particular combination of sanding sealer, primer and paint products, I'm interested. Cheers.

In the good old days sanding sealer to fill wood grain was the norm (I'm talking about the 60's). Sanding sealer has been superceded by Carpenter's Wood filler (CWF). No volatile fumes, water cleanup. So go ahead and use CWF instead.
With superior products available, we no longer have to use sanding sealer, butyrate dope, fuses for ignition, flash bulbs, mercury switches, etc. etc. You young whippersnappers have it so easy. I won't even mention laser cut fins and 3D printed parts.
Cheers.

Aaaaah... So what I should is ask here first, and THEN buy the stuff. Got it!

I still like to use 1 coat of sanding sealer first made by SIG. Then I use the wood filler because sometimes I find it warps the balsa stock if used just by itself because of the moisture content in the filler. That's just me though. The wood filler also works great on the bt I use a old credit card to put it on and wipe it off then sand it takes away not only the spirals but also takes care of any minute bumps on the bt. Then of course prime and wet sand then prime and paint. smooth and glassy.

I've used sanding sealer (specifically the Minwax water based sanding sealer) on balsa fins before. It takes several coats and sanding in between to start to fill in the grain. I've used various spray primers (usually Rustoleum brand) and they all seem to be compatible. It takes some time to get a good finish with sanding sealer, and it adds a fair bit of weight, but it can be done.

I've also tried Elmer's carpenter's wood filler, it works very well, is very easy to sand, and takes fewer applications than sanding sealer. And I get better results in less time with less work.

My new favorite method is papering fins, light weight, fast, and adds strength!

I tried using Deft Lacquer Sanding Sealer for the first time on an Estes Sentinel clone I kitbashed from an Estes Vagabond. I cut tail and strake fins from 3/32" balsa wood.
I didn't want the warpage problem that might be caused by using wood filler. I am very happy with the results.



The rocket on the right in the photo below is the one that this product was used. I then sprayed Krylon White Enamel over the sealer. No problems. Sanded fins between each coat of sealer. I sprayed three seal coats.

Another alternative is papering the fins.
It is easier and faster and a lot less mess than sanding sealer or wood filler (cuts down or eliminates sanding, depending on how you do it.)
If you use actual glue rather than adhesive paper it adds a huge amount of strength to the fins
It does add a bit of weight.
Many posts about it, this is one of the more popular

https://www.rocketryforum.com/threads/papering-balsa-ply-fins-a-foolproof-method.65628/

Event Horizon said:

I tried using Deft Lacquer Sanding Sealer for the first time on an Estes Sentinel clone I kitbashed from an Estes Vagabond. I cut tail and strake fins from 3/32" balsa wood.
I didn't want the warpage problem that might be caused by using wood filler. I am very happy with the results.

The rocket on the right in the photo below is the one that this product was used. I then sprayed Krylon White Enamel over the sealer. No problems. Sanded fins between each coat of sealer. I sprayed three seal coats.
View attachment 384381

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+1 on the Deft sanding sealer. Used this to sand and bevel the fins for my Super DX3 for my L1 and L2, and they came out like glass.

I still have a few jars each of Aerogloss balsa sealer and sanding sealer. Love the smell. Brings back good memories!

I use the Deft sanding sealer in a can, it lasts a long time. Easy to brush on balsa (or ply) fins and nose cones. Does require a few coats and sanding in between, I usually go from 200 to 400 grit. I paint the Rusto 2X over it.

AfterBurners said:

Love the smell.

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Watch out for dain bramage.

kuririn said:

Watch out for dain bramage.

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Too late I'm already there

kuririn said:

Watch out for dain bramage.

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And be careful if you eat while you work. You don’t want to get this on your cooks and cakies.

Event Horizon said:

I tried using Deft Lacquer Sanding Sealer for the first time on an Estes Sentinel clone I kitbashed from an Estes Vagabond. I cut tail and strake fins from 3/32" balsa wood.
I didn't want the warpage problem that might be caused by using wood filler. I am very happy with the results.

The rocket on the right in the photo below is the one that this product was used. I then sprayed Krylon White Enamel over the sealer. No problems. Sanded fins between each coat of sealer. I sprayed three seal coats.
View attachment 384381

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sweet!!!

For those of you that are still using sanding sealer and balk at the high prices for a tiny little bottle, here's a blog post from a BAR for a recipe for homemade sanding sealer.
https://fdsailor.blogspot.com/2011/08/how-to-make-sanding-sealer.html
I have tried it. Think liquid plastic. One or two coats on ply, and two or three coats on balsa, sanding in between, and you will have a nice substrate for a beautiful glossy finish. I use Styrofoam packing peanuts, just because it's free and I have so much from my orders. Don't use the soy based packing peanuts, they won't dissolve in MEK.
Also there is a safer substitute MEK on the market. I haven't tried that yet, so don't know if it works.
Be careful choosing the container for this, MEK will dissolve some plastics as well as the synthetic rubber gasket on metal lids.
Use in a well ventilated area, or wear a fume filtering mask.
Disclaimer: I provide this as information, use at your own risk.

I ended up using the Minwax sanding sealer I got before even posting here. 2 coats with sanding after each one. I have enough of it for many, many, and many more fins, so I'll probably be using it for a while.

I got Bondo spot putty for the tube spirals, and sanded the nose cone, so for the next step, I'll try Duplicolor sandable primer (grey) for the entire rocket all at once.

So here's where I'm at with:

- Sanding (100 grit)
- 1st coat of brushed-on Minwax sanding sealer
- Sanding (220 grit)
- 2nd coat of brushed-on Minwax sanding sealer
- Sanding (220 grit)
- Duplicolor sandable primer
- Full dry
- Duplicolor sandable primer
- Sanding (600 grit)

My goal here is just to see what's best finish I can get, given my current level of patience. The photo zooms in details I can't see with my bare eyes, but the result is still better than I could hope for. Finger tips can't feel roughness whatsoever.
(Yes, these are LOC Park Flyer Hawk fins.)

I might try wood filler next time, but the ones I'm familiar with seem thick for this kind of job.

I think wood filler would probably work better. I think I would probably use the sanding sealer when working balsa wood. Just saying. All in all they look nice. I think after a couple more sanding steps and primer they will be even better.

Euclid said:

So here's where I'm at with:

- Sanding (100 grit)
- 1st coat of brushed-on Minwax sanding sealer
- Sanding (220 grit)
- 2nd coat of brushed-on Minwax sanding sealer
- Sanding (220 grit)
- Duplicolor sandable primer
- Full dry
- Duplicolor sandable primer
- Sanding (600 grit)

My goal here is just to see what's best finish I can get, given my current level of patience. The photo zooms in details I can't see with my bare eyes, but the result is still better than I could hope for. Finger tips can't feel roughness whatsoever.View attachment 384586
(Yes, these are LOC Park Flyer Hawk fins.)

I might try wood filler next time, but the ones I'm familiar with seem thick for this kind of job.

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The pics still show grain showing. It will be more visible when topcoated. instead of the Duplicolor sandable primmer, may I suggest you try their filler primer. two medium coats let dry a few hours, sand with 320. Repeat as necessary. BTW, 600 grit is too fine for cutting initial primer coats. It just burnishes the surface instead of leveling surface.

This is the product I used ("Filler", "fills deep scratches"):

Unfortunately, I only noticed the grains once I had that photo, and used up the entire can (also used for the nose cone and tube, which look great). The spray was rather liquid, squirting out droplets even after plenty of spraying and shaking (unlike normal paint aerosols I'm used to), so maybe I had a defective can. I also thought 600 grit was fine, but decided to blindly follow the directions on the can. I suppose that's for automotive surface.

I'll think about doing extra steps over the weekend. I might just save the extra effort for a bigger kit and consider this one as a test bed.

Event Horizon said:

I tried using Deft Lacquer Sanding Sealer for the first time on an Estes Sentinel clone ....
I didn't want the warpage problem that might be caused by using wood filler. I am very happy with the results.

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I'll second that recommendation. I apply three coats of the Deft Sanding Sealer, then wood filler, and finally a high-solids primer.

Euclid said:

This is the product I used ("Filler", "fills deep scratches"):
View attachment 384631
Unfortunately, I only noticed the grains once I had that photo, and used up the entire can (also used for the nose cone and tube, which look great). The spray was rather liquid, squirting out droplets even after plenty of spraying and shaking (unlike normal paint aerosols I'm used to), so maybe I had a defective can. I also thought 600 grit was fine, but decided to blindly follow the directions on the can. I suppose that's for automotive surface.

I'll think about doing extra steps over the weekend. I might just save the extra effort for a bigger kit and consider this one as a test bed.

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Thats great primer. I use it all the time, but as always just primer alone will not fill all the scratches and cost wise it run more money. I would try using a good sanding sealer and then primer afterwards to get the desired results.

Euclid said:

So here's where I'm at with:

- Sanding (100 grit)
- 1st coat of brushed-on Minwax sanding sealer
- Sanding (220 grit)
- 2nd coat of brushed-on Minwax sanding sealer
- Sanding (220 grit)
- Duplicolor sandable primer
- Full dry
- Duplicolor sandable primer
- Sanding (600 grit)

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Everyone has their preferences, but that seems like too much work to me, and you still have plenty of grain showing. One good coat of CWF, sanded down, followed by a good coat of filler primer, sanded down, and you'll have a much better result.

Occasionally CWF will miss a spot and you'll need to do a bit of touch-up afterward (again, I paper my fins nowadays, but I have done my share of CWF-ing.)

I might try wood filler next time, but the ones I'm familiar with seem thick for this kind of job.

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Plain Elmer's Carpenter's Wood Filler (not the "Max" stuff!), thinned down with water to the consistency of mustard. I used to apply with a brush, but eventually just switched over to using my fingers, since it's non-toxic, cleans easily, and that way I can (a) rub it into the grooves better, and (b) thin it out to a more even layer, for easier sanding.

Good old fashioned shellac works great as a filler, too. Dries super fast and sands well. And there's the added bonus that it is multipurpose and you can use it to finish wood projects, as well.

Two coats of Deft Lacquer Sanding Sealer on Midwest Products 3mm plywood home cut Sentinel fins.

You can buy good old fashioned sanding sealer on ebay. Use it and sand then Elmer's wood filler applied with a credit card put on wipe off, dry, sand. If you try papering still use the sanding sealer first then paper applied with Elmer's all purpose or school glue. Papering alone still shows a lot of variations.(it seams bumpy) You could put on a coat of sanding sealer over the paper and sand. Finally gray primer(you don't need the expensive auto primer)(Rusto 2X) let dry overnight and wet sand 400 grit. Baby's Butt.

nelie61 said:

You can buy good old fashioned sanding sealer on ebay. Use it and sand then Elmer's wood filler applied with a credit card put on wipe off, dry, sand. If you try papering still use the sanding sealer first then paper applied with Elmer's all purpose or school glue.

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I am not understanding the above.

Why would you use sanding sealer before OR in addition TO Elmer’s wood filler?

Why do you need sanding sealer before papering?

BABAR said:

Why do you need sanding sealer before papering?

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I certainly don't seal before papering with adhesive label paper. I can imagine that having a less porous surface might help label paper adhesion, but the way I do it I've never had one lift on me. On one recent occasion I tried to peel off the label paper from a fin and actually gave up because it was too difficult.

I've never used adhesive label paper and I have found that putting paper on without a little smoother surface than just the plain balsa shows a little too many variations for my tastes. Basswood and ply are different stories(not nearly as much grain). Also Sanding sealer before the Elmer's wood filler helps keep the moisture away from the balsa and definitely helps from warpage because of the water content in Elmer's wood filler. To each his own But if you want glass fins try it. And I think I'll try the adhesive paper I've only used printer paper. If you have a kit that has a full sheet of laser cut fins try this: Leave the sheet whole un-cut apply Sanding sealer and sand, Then paper one side of the whole uncut sheet then let dry then run your blade thru the other unpapered side so you know where the fins are then paper the other side of the whole sheet and let dry. Now some of the glue with seep into the pre-cuts but cut the fins out and then stack and clamp them together. Take your dremmel with a barrel sanding attachment and run it across all sides until they're all uniform and the same. Unclamp and take a file to chamfer the leading edge of each fin you will not know that any paper is even on there it is tight all the way around the fin then use some sealer on the edges and the leading edge chamfer and like I said before... Baby's butt. We all know it is hard to get all the grain from balsa stock and I find that this works for me and I'm never in a hurry I just like a nice job.

There are many ways to skin the cat. If you have a technique that works well for you, that's great. My label technique is probably a bit different from most others' (I think), but I'm quite comfortable with it and get good results. The label paper is fairly rigid, so it doesn't conform to the very fine ridges in the balsa. At the same time, it adheres well because I go to great lengths to remove all the dust from the balsa grain before applying the paper.

Gluing on paper with Elmers is a significantly different process from using label paper, so I have no doubt that different techniques are called for.

There is no "best" here, it's all preference.