Too Much Primer / Removing Primer

[Daniel Runyon]

Greets, YORF!

I'm building my first rocket, a Baby Bertha, and I've just realized that I put WAY too much primer (Plastikote gray) on the fins today trying to get the grain to fill. I then messed it up pretty bad trying to sand it too early... I've really made a mess! Any advice on trying to remove the primer and salvage it would me wonderful... I know I'm not the first one to make this mistake, but I really feel like a dodo after reading so many times of the fallicy of too much primer! I would rather have just let the grain show than wind up in my present situation!

Also, Hello people of the YORF! I've been admiring this fine little forum for a couple of weeks... very nice and homey vibe.

[EchoVictor]

Welcome!

Just be patient. Let the paint dry, and then sand away with successively finer paper until you see a little bit of the paper tube/balsa fins showing through, then paint.

Oh yeah, one requirement (as always)

PICTURES! :D

Later,
EV

[CPMcGraw]

Greets, YORF!

I'm building my first rocket, a Baby Bertha, and I've just realized that I put WAY too much primer (Plastikote gray) on the fins today trying to get the grain to fill. I then messed it up pretty bad trying to sand it too early... I've really made a mess! Any advice on trying to remove the primer and salvage it would me wonderful... I know I'm not the first one to make this mistake, but I really feel like a dodo after reading so many times of the fallicy of too much primer! I would rather have just let the grain show than wind up in my present situation!

Also, Hello people of the YORF! I've been admiring this fine little forum for a couple of weeks... very nice and homey vibe.

Welcome!

Depending on the degree of damage, you have several options. I believe there is a fin pattern for the Baby Bertha already on Ye Olde Rocket Plans, if you don't already have one handy. Cutting a new fin, or fins, isn't too difficult an option if you have a steel ruler handy. Baby-B uses 3/32" balsa sheet stock. One finishing technique we've started using is to apply blank white self-adhesive label stock to both sides of a bare balsa fin, and seal the outer edges (not the root edge!) with thin CA glue. This seals the wood and makes a very uniform surface for a thin-body primer. Kinda like MDO board for DIY construction projects; or foam-core board for the new Extreme 3D electric model airplanes...

If the damaged fins aren't too badly gouged and weakened, just smooth out the primer around those areas with a milder paper, and get yourself some KILZ. Use a brush (not the spray version) to apply straight KILZ into the gouges. This is a thicker primer, and will do a remarkable job of filling those areas. Let this dry overnight -- two days would be even better - and sand with 220-grit. Anything more aggressive would be overkill. If you see any gouges remaining, hit them again with spots of KILZ and resand. When the surface is smooth, spray one or two thin AIRBRUSH or AIRGUN coats of a less-thick primer, like Rust-O-Leum Bare Metal Primer (white). Don't use the spray can version of KILZ as it tends to introduce too much propellant gas into the mix, which causes crater-like pits to form under the surface when it dries. Too much added work getting the sanded surface not to look like the moon...

If, now, you need to replace just a leading or trailing edge from a fin, you could just add a strip of scrap balsa to the affected area. Sand with 220 to shape, fill the voids with Fill-N-Finish and let dry a day. Sand again to smooth out the rough spots, hit this with a coat of KILZ, and wait two days. Sand, inspect, touch up as needed, then hit the surfaces with Rust-O-Leum primer.

One of these methods should take care of nearly any state of damage those fins might be in...

[Daniel Runyon]

Thank you very, very much! I'm hoping to The Maker that I can just sand it out after it dries and add another layer, but one of these fins is pretty ugly!

I would be glad to share some pictures but I only have the miniDV camera that I use to do wedding videos and have to capture the footage and grab stills out of my editing system so I only go to that trouble when I have a LOT of time to light up and burn! I'm going to try to locate my low res Intel camera to take crappy stills for you photo loving rocketry folk though... I looked last night but couldn't find it! That fin is ugly enough to deserve a snap shot, no doubt!

MUCH appreciated!

P.S.
I'm DEFINITELY going to wait till I can get ahold of some sanding sealer before I build the rest of my rockets!

[barone]

I'm DEFINITELY going to wait till I can get ahold of some sanding sealer before I build the rest of my rockets!Sanding sealer cam get expensive. Just get some Elmers Fill n Finish, dilute with water to form a paste and rub it in. I like to rub it in with my fingers but I think you'll find that the majority of the folks here brush it on. Let it dry, sand, and apply again. Repeat until you're happy with the finish. It works great for filling the spirals on body tubes also.

[A Fish Named Wallyum]

Sanding sealer cam get expensive. Just get some Elmers Fill n Finish, dilute with water to form a paste and rub it in. I like to rub it in with my fingers but I think you'll find that the majority of the folks here brush it on. Let it dry, sand, and apply again. Repeat until you're happy with the finish. It works great for filling the spirals on body tubes also.

I agree. Just get a tub of the stuff, a paint brush, and a glass of water. Wet the brush, slop it around in the filler, then spread it on. Rinse the brush out when you're done, put the lid on the tub, and you're good to go the next time. :cool:

[Daniel Runyon]

Sounds good... I enjoyed working with the Elmers Carpenters Wood Filler on the spirals and want to use the Fill N Finish as soon as I can get ahold of some. We live in a wee little Mayberry in GA and have searched in every hardware store and Wal Mart around, and even made the trek to the big city to check at two Michaels and a Hobby Lobby for it (and other things) and have come up short! We never found that or sanding sealer (well, any sanding sealer other than the kind used on cabinets and things) and have had a heck of a time finding primer too! We finally found the two cans of plastikote at the last Michaels we went to, but that was all they had and it's not a practical place to go back to any time soon!

If only Discount Rocketry carried those items we could have had a one stop shop then and there! Just finding a meager set of startup supplies has been a bigger ordeal that I can truly describe within a reasonable word count. :) I so wanted that plastikote to fill those fins... it says it seals on the can, but they must have tested it on some mighty fine grain... I already had those fins pretty dang smooth.

Much appreciated!
Daniel

[CPMcGraw]

Sounds good... I enjoyed working with the Elmers Carpenters Wood Filler on the spirals and want to use the Fill N Finish as soon as I can get ahold of some. We live in a wee little Mayberry in GA and have searched in every hardware store and Wal Mart around, and even made the trek to the big city to check at two Michaels and a Hobby Lobby for it (and other things) and have come up short! We never found that or sanding sealer (well, any sanding sealer other than the kind used on cabinets and things) and have had a heck of a time finding primer too! We finally found the two cans of plastikote at the last Michaels we went to, but that was all they had and it's not a practical place to go back to any time soon!

If only Discount Rocketry carried those items we could have had a one stop shop then and there! Just finding a meager set of startup supplies has been a bigger ordeal that I can truly describe within a reasonable word count. :) I so wanted that plastikote to fill those fins... it says it seals on the can, but they must have tested it on some mighty fine grain... I already had those fins pretty dang smooth.

Much appreciated!
Daniel

Daniel,

Try locating either a LOWES or a HOME DEPOT for that Fill-N-Finish. The reason we recommend it over the regular wood filler is that it's much lighter, and is water-based. It cleans up easy.

I've come to appreciate Kilz more this past year, but I've learned the best way to apply it is with spray gun instead of the spray can. It's thick, and it tends to trap its propellant in the mix. With a spray gun, you get to thin it out slightly, so there's no excess gas and no bubbles under the surface. Kilz sands out very smooth otherwise, and covers the wood grain nicely. You might want to give this method a try on some scrap balsa to get the feel before applying it to a model.

[Daniel Runyon]

Try locating either a LOWES or a HOME DEPOT for that Fill-N-Finish.

We've tried two home depots, but we're going to be near a Lowe's this coming weekend a plan to check.

As for the Kilz, I'm pretty sure I've seen the cans around but we don't have access to a spray gun / compressor setup so we'd have to go canned!

I think it's going to live!

After a night of drying it sanded pretty well. I knocked out the worst of it and just applied the next coat. After seeing how well it worked after a FULL drying I'm a little more confident that it's going to turn out ok. My 5 year old son has chosen the colors that we're going to use and it's going to be pretty Crayola! I think it's going to be cool and he's going to LOVE it even if it does still wind up with a rough spot here and there... or even if it winds up being one big yellow red and blue wavy gravy!

[ghrocketman]

Sanding Sealer or Balsa Fillercoat may be expensive, but in my book, they are the only REAL way to finish balsa parts, part of this is me being a traditionalist, and part of this is because they provide a superior surface prep compared to any of the alternatives. They also weigh much less as the majority of the product evaporates as good ol' "Vapor Harmful" organic solvents. I still use vintage Aero Gloss color Dopes to finish/topcoat a lot of my rockets as well.

[Daniel Runyon]

I just checked out balsa fillercote as I've never seen reference to that... tell me more! Do you use it in conjuction with or instead of sanding sealer? What's the process?!

I just came in from checking on it... it looks MUCH better than last night, though still FAR from "perfect".

One thing I'd like to know... how do you folks handle primering and painting around the launch lug? There are now some pretty thick primer "fillets" on both sides of it. Would it be adventageous to save the mounting of the launch lug till after it's finished?

I keep doing a wide vascilation between "I have to remember that this is a 7 dollar model rocket" and "this is THE most important thing I have ever done in my entire life"!

[EchoVictor]

Be careful of mounting the lug after finishing. Most glue adheres to paint very poorly compared to the base paper or wood, so you run the risk of launch stresses popping off the lug at the most inopportune time.

I usually try to place my launch lugs out of sight (inside detail tubes, etc.) or in places where I won't have a paint color change.

Later,
EV

[ghrocketman]

I use my stockpile of Pactra Aero Gloss Balsa fillercoat (no longer available) for the first three coats on fins, nose cones, and balsa adapters. Sanding occurs between coats. Then I apply a final 1-2 coats of Aero Gloss Sanding Sealer on top of that.

Sig continues to make Balsa Fillercoat as well as Sanding Sealer. These products are available at most hobby shops. I know Hobby Lobby and Hobby Town USA carry both products. Online you can get these directly from Sig, or from one of the large hobby retailers such as Tower Hobbies. Purchase at LEAST a 4oz jar of each (I have them in Pint cans) along with at least a pint of Sig Supercoat dope thinner for thinning & cleaning brushes.

Balsa Fillercoat fills a little better than Sanding Sealer, that is why I use it for the first few coats. If you cannot find Balsa Fillercoat, you can make your own. This product is basically talcum powder (pure talc, NOT "baby" powder) dissolved in clear butyrate dope (available at any hobbyshop) optionally mixed with a little tan dope for color-matching with wood.

[tbzep]

Be careful of mounting the lug after finishing. Most glue adheres to paint very poorly compared to the base paper or wood, so you run the risk of launch stresses popping off the lug at the most inopportune time.

I usually try to place my launch lugs out of sight (inside detail tubes, etc.) or in places where I won't have a paint color change.

Later,
EV

Yep. If I forget to put a launch lug on before painting, I scrape a little strip of paint off down to the paper tube including the glassine. That let's me get a decent bond with the glue.

[Daniel Runyon]

I'm pretty sure on the next go round I wont have the launch lug issue because I wont be piling up so much primer and paint!

I've now got it painted and have to do a little touch up work to get the fin joints looking a little better, but it looks like Baby Bertha will be ready for flight tomorrow, assuming the wind is decent. Today it was about 11mph and blowing in the opposite direction for what is good for our field. The colors that my son chose turned out pretty good! I'll get some pics up ASAP... I still need to locate my little crappy Intel camera!

[Daniel Runyon]

My goodness!

I painted the body tube first with the fins taped up with blue painters tape, then taped the body as best I could and painted the fins. Then the fin joints didn't look so hot so I taped the fins back up and tried to put another layer on the body... now the blue from the fins is showing through the yellow of the body at the fin joints and as it stands I know of no doable solution other than painting more and more layers until the blue quits showing through... any advice would be super nice!

For the benefit of my next build, how do you go about painting the body and fins different colors and have the fin joints turn out nice and smooth? Using the method I have this go around whenever I remove the tape there's a hard line where the colors meet!

[barone]

.....One thing I'd like to know... how do you folks handle primering and painting around the launch lug? There are now some pretty thick primer "fillets" on both sides of it. Would it be adventageous to save the mounting of the launch lug till after it's finished?

The thing about primer or paint and launch lugs.......make sure you get any excess material from the inside of the lug or it could bind on the launch rod. Usually, it'll accumulate at the openings and can be easily removed by scraping the inside of the lug (at the ends) with an Xacto.

[barone]

My goodness!

I painted the body tube first with the fins taped up with blue painters tape, then taped the body as best I could and painted the fins. Then the fin joints didn't look so hot so I taped the fins back up and tried to put another layer on the body... now the blue from the fins is showing through the yellow of the body at the fin joints and as it stands I know of no doable solution other than painting more and more layers until the blue quits showing through... any advice would be super nice!

For the benefit of my next build, how do you go about painting the body and fins different colors and have the fin joints turn out nice and smooth? Using the method I have this go around whenever I remove the tape there's a hard line where the colors meet!
Well, as you've discovered, light paint doesn't cover dark paint very well. Some of the other guys can probably give you better advise for fixing this but here's what I'd do (keep in mind, I'm not a master modeler....) Tape (on the blue) where you want your paint joint to be. Then start lightly sanding (gee, I bet you've been doing alot of that lately) the overlap area. You'll end up removing some of your yellow. Once the blue is gone, reapply the yellow in light coats. You may need to wet sand between coats to get it to blend in with the previously applied yellow. By the way, the only way I know of to get rid of the hard line between paint colors is to wet sand it with 800 or 1000 grit sand paper (automotive section of Walmart). Also, the line can be minimized by using a modeling masking tape. It's usually thinner than regular masking tape and has less bleed under, but it can be expensive. I get mine from Hobby Lobby (I used about $20 worth of the stuff on my Saturn V).

[Daniel Runyon]

Much appreciated!

Is this (http://www.hobbylinc.com/htm/par/par40257.htm) anything like the masking tape you mention?

or maybe this (http://www.hobbylinc.com/htm/pac/pacmt102.htm)?

And thank you VERY much ghrocketman!

[CPMcGraw]

...Also, the line can be minimized by using a modeling masking tape. It's usually thinner than regular masking tape and has less bleed under, but it can be expensive. I get mine from Hobby Lobby (I used about $20 worth of the stuff on my Saturn V).

Back when I worked at one of the LHS, there was this one model builder who said he preferred vinyl pinstriping for automotive detailing as edge masking tape. He said it would lay down on the surface flatter than regular masking tape, and it had less tack (stickiness) than regular masking tapes. Being a vinyl, it could form curves that you couldn't do with paper tapes.

I've tried it myself, and can't honestly say I saw any real improvement, but then I may have been doing it wrong myself. This fellow was sold on it, and would tell others who came into the shop about his methods. It didn't hurt our sales of tapes, because he would point them over to the model airplane covering section and show them the same stuff on our shelves, just under a different brand name.

It's not the first thing someone might think of for this purpose, but I can't argue with his underlying logic. Maybe it just takes some practice to lay it correctly, or some nimble fingers that still have their youthful dexterity... :(

[Bob Thomas]

It's not a solution, just an alternative. I have become quite fond of running a black marker border over fin-tube color transitions. It looks like a design choice and masks any over-run and bleeding. Or choose the fin color if its available as a piant marker and surround the joint. It works great especially when a fillet blurs the joint between fin and tube.

Bob

[Bob Thomas]

Here's a pic

[tbzep]

You've learned a valuable lesson...Light colors first, dark second. If you go back with a light color, the dark underneath will show through.

I've used scotch magic tape for sharp paint edges in the past. It's not as thick, so the paint won't build up as high against it. I usually stick it to my hand first, to cut down on the adhesive's stickiness so it won't pull the paint up when removing.

However, I've been using Scotch brand blue painter's tape the last few years and usually get nice transition lines with it too. I try to make sure to use really light coats and let them dry longer between coats to prevent as much buildup at the edge. The painter's tape isn't as sticky, so it won't pull up the first coat. However, it isn't very good for curves and small spaces. Automotive painter's tape in 1/4" width works great for curves if you can't find the Taimaya stuff that has been mentioned.

Just noticed the vinyl penstriping post. IIRC, you have to stretch it a bit as you apply to get it to make nice curves and lay down real flat. I've never used it for masking, but I've put it on R/C planes when I didn't want to drive for two hours to get trim monocote.

[Daniel Runyon]

Thank you all VERY much... yes, I've learned MANY valuable lessons!

Bob

You've just led me right to the perfect solution... bless you sir! I'll show the results as soon as they're in... and I can located that danged little crappy Intel camera I KNOW I still own!

[Daniel Runyon]

Ok... here's my ROUGH lookin Baby Bertha!

http://www.isarapix.com/pix23/1171466509.jpg

It's taking me a WHILE to sand it back down, but I'm not in a hurry... do a little on it every day... or not! I've already built my Big Bertha and flown it (unfinished) since I started sanding! Heck, it's been flown itself about 10 or so times since I started sanding. It looks rough but flies good with the exception of one flight after it got an Estes Dent (top left fin, leading edge) that I didn't notice till the next flight took WAY off to the side! Filled it with Elmers Wood Filler and flown it a few time since.

Originally it was sun yellow with blue fins and red cone, and that's what its going back to hopefully!

[barone]

Well, by the time you get done, there certainly shouldn't be any wood grain showing. ;) Actually, I kinda like the rough look.

[Daniel Runyon]

Actually, I kinda like the rough look.

I do too! My son doesn't dig it though... he wants it to look the way it did before I messed it all up. But I really do think it looks cool all roughed up... looks about as old and worn as that old Big Bertha with the broken fin that dude keeps trying to sell on Ebay for a fortune!