# First time priming G10...

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#### jahall4

##### Well-Known Member
Typically the last prep I would do to a ply fin is sanding with 320 (maybe 400) before spraying it with a filler primer. On successive coats of Primer I would wet sand with 600 (maybe finish w/1000) before applying my next coat. Is there any reason I might consider something else?

The obvious difference with the G10 is youre making the surface less smooth. In fact it is so smooth I wouldnt think it would be good prime without sanding. So maybe just wet sand w/600 from the beginning?

#### Rex R

##### LV2
you need to give the paint something to grab onto, don't go higher than 400 grit. to be honest you could just 'scuff' up the G10 with 220 grit and still get good results, save the higher grits for between coats.
Rex

#### jahall4

##### Well-Known Member
you need to give the paint something to grab onto, don't go higher than 400 grit. to be honest you could just 'scuff' up the G10 with 220 grit and still get good results, save the higher grits for between coats.
Rex
Are you suggesting there is no chemical bond between the primer and the G10? And when I say chemical I mean adhesion similar to how a glue might work?

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#### Binder Design

##### Well-Known Member
Are you suggesting there is no chemical bond between the primer and the G10? And when I say chemical I mean adhesion similar to how a glue might work?
Any bonding with G10 is mechanical. There are no solvent glues or paints for G10 that I'm aware of.

#### jahall4

##### Well-Known Member
Any bonding with G10 is mechanical. There are no solvent glues or paints for G10 that I'm aware of.
... and Dupli-Color would agree, but the same is said for plastic, mechanical bonding only, yet we know that fiberglass provides a much superior substrate compared to most every plastic for paint. I&#8217;d love to hear an explanation on how the performance could be so different, but the properties be the same.

Another thing I have noticed is that Sharpies &#8220;stain&#8221; G10. It even appears to be in the surface. So if they react with the surface why not other solvents that might be in paints.

#### blackjack2564

##### Crazy Jim's Gone Banana's
TRF Supporter
jahall4;1607530 Another thing I have noticed is that Sharpies stain G10. It even appears to be in the surface. So if they react with the surface why not other solvents that might be in paints.[/QUOTE said:
I use markers of many types, when building. If left on tubes/fins they will "bleed" through many primers/paints.
So far I have been able to removes all traces of them with either denatured alcohol or lacquer thinner, before painting.

If they can be removed I would think the marks are "ON" the surface, not "IN" it.....

#### jahall4

##### Well-Known Member
I use markers of many types, when building. If left on tubes/fins they will "bleed" through many primers/paints.
So far I have been able to removes all traces of them with either denatured alcohol or lacquer thinner, before painting.

If they can be removed I would think the marks are "ON" the surface, not "IN" it.....
That's my point most of the mark is removed, but there remains a "stain" that even looks to be in the surface.

#### soopirV

##### Well-Known Member
That's my point most of the mark is removed, but there remains a "stain" that even looks to be in the surface.
I've seen that too, but think it's more "adsorption" around the neighboring glass fibers than true "absorption" into the matrix or substrate...but just my $0.02. This is why it's harder to clean off, since it's not just a surface mark, but around the fibers to a small extent. #### jahall4 ##### Well-Known Member I've seen that too, but think it's more "adsorption" around the neighboring glass fibers than true "absorption" into the matrix or substrate...but just my$0.02. This is why it's harder to clean off, since it's not just a surface mark, but around the fibers to a small extent.
That seems reasonable, but I have seen that, and this doesn't look that way. I'll try to get a picture.

#### crossfire

I have built a good number of FG rockets. Most of time all I do is wipe tube down clean after build is done and prime. I have not had paint stick to the FG parts. Sand a little after primed and move on to the color I am going to use.

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#### Nathan

##### ☢
TRF Supporter
...On successive coats of Primer I would wet sand with 600 (maybe finish w/1000) before applying my next coat...
There is no need to sand primer with anything finer than 400 grit. The abrasive particles on 1000 grit sandpaper are about are only about 10 micrometers. Your color coat is probably going to be at least 10 times that thick. And if you also spray several coats of clear then it will be a lot thicker. So save the superfine sandpaper for where it really makes a difference which is wet sanding the final coat.

#### jahall4

##### Well-Known Member
There is no need to sand primer with anything finer than 400 grit. The abrasive particles on 1000 grit sandpaper are about are only about 10 micrometers. Your color coat is probably going to be at least 10 times that thick. And if you also spray several coats of clear then it will be a lot thicker. So save the superfine sandpaper for where it really makes a difference which is wet sanding the final coat.
That has not been my experience. The difference only seen in close inspection, but if you will wet sand that last primer coat with 600 the first color coat goes on smoooooth, which mean less (or no) wet sanding of the color and clear coats that take longer to dry and are harder to sand.

#### Banzai88

##### Lvl 1,Wallet....Destroyed
TRF Supporter
You've seen Nathan's paint, right? I'm with him, especially since I started using auto paint and HVLP guns.

#### jahall4

##### Well-Known Member
You've seen Nathan's paint, right? I'm with him, especially since I started using auto paint and HVLP guns.
Nope, and unfortunately I don't have either so my experience with "sucky" rattle cans is necessarily going to be different. Right?

... but you can't go wrong getting you primer coat a little smoother than it has to be.

#### Banzai88

##### Lvl 1,Wallet....Destroyed
TRF Supporter
Nope, and unfortunately I don't have either so my experience with "sucky" rattle cans is necessarily going to be different. Right?

... but you can't go wrong getting you primer coat a little smoother than it has to be.
Never said rattle cans suck or that your experience is invalid or that auto paint or hvlp was required, just agreed with the point that effort, time, money, and supplies past 400 grit on primer was a technical waste. If going to 600 or 1k makes you happy.....sand away.

In fact, some rattle cans work very well. I'm a krylon fanboy myself, especially with aftermarket speay nozzles.

You're the one that inferred your own conclusions. I'm not looking for a flame war.

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#### jahall4

##### Well-Known Member
Never said rattle cans suck or that your experience is invalid or that auto paint or hvlp was required
I never said you did. "Flame war"? you brought it up. Please don't "infer" accusations.

#### Nathan

##### ☢
TRF Supporter
Nope, and unfortunately I don't have either so my experience with "sucky" rattle cans is necessarily going to be different. Right?...
There's nothing wrong with painting with rattle cans. The reason that I started using a HVLP gun and compressor was mainly just because I wanted a wider selection of paints that are not available in rattle cans. Here's the LOC Onyx that I painted several years ago using Duplicolor lacquer from a rattle can (I never miss an opportunity to repost a rocket pic) . . .

#### jahall4

##### Well-Known Member
There's nothing wrong with painting with rattle cans. The reason that I started using a HVLP gun and compressor was mainly just because I wanted a wider selection of paints that are not available in rattle cans. Here's the LOC Onyx that I painted several years ago using Duplicolor lacquer from a rattle can (I never miss an opportunity to repost a rocket pic) . . .

Very nice!

Well, I think rattle cans are pretty "sucky". I have not tried any lacquers, but the enamels "flash" to quick. In particular the clear coats dry so quick that it is impossible to avoid over-spray on large rockets.

Your fillets look as good (really better than mine) what is your technique?

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#### Nathan

##### ☢
TRF Supporter
Very nice!

Well, I think rattle cans are pretty "sucky". I have not tried any lacquers, but the enamels "flash" to quick. In particular the clear coats dry so quick that it is impossible to avoid over-spray on large rockets.

Your fillets look as good (really better than mine) what is your technique?
View attachment 298035View attachment 298036
I used to use enamel but have switched to lacquer because I get get better results. Most rattle can paint is enamel. If you want to try lacquer I recommend Duplicolor Perfect Match paint which is available at most auto supply chain stores. The only problem with Duplicolor Perfect Match is that it is only available in car paint colors, so that means mostly lots of silvers, blacks, reds, and whites. But it you want something like purple or green, forget it.

I did a build thread on that rocket, here is the post describing how I did the fillets. . .

Since I built that rocket I have changed my fillet procedure. I used to use just Bob Smith 15 minute epoxy, which makes nice looking fillets but isn't very strong and can crack from a hard landing. So now I do fillets using my normal structural epoxy which is MUCH stronger (Aeropoxy 6209) and then after it cures (24 hours) I cover with a thin layer of BS 15 minute epoxy to make it look nice.

#### Banzai88

##### Lvl 1,Wallet....Destroyed
TRF Supporter
For smaller rockets or accent colors where you don't need very much, the lacquers rattle cans from Testors work amazingly well.

#### jahall4

##### Well-Known Member
...If you want to try lacquer I recommend Duplicolor Perfect Match paint which is available at most auto supply chain stores. The only problem with Duplicolor Perfect Match is that it is only available in car paint colors, so that means mostly lots of silvers, blacks, reds, and whites. But it you want something like purple or green, forget it.
Exactly!

I used to use just Bob Smith 15 minute epoxy
Have you tried the BSI 30 with Micro balloons (started using the ballons when I was a kid)? So far has performed really well for me, plus gives you time to fill 2 roots at a time. Here a set on the Tomach I used for my L1...

BSI 30 is made for this type of application (https://www.bsi-inc.com/hobby/slow_cure.html)

#### manixFan

##### Not a rocket scientist
I have painted many G10 fin sets. I generally wet sand with 320 to take the shine off the G10 before I spray with Dupli-Color sandable primer. I start with gray, wet sand with 400, then cover with white and wet sand again. The 2 colors show the high spots really well (generally caused by stray epoxy on the fin). Once cured I finish with Dupli-Color paint and then wet sand with 600. The results have been very good and I've never had a problem with adhesion on the G10.

After trying a lot of different paints I now just suck it up and pay for Dupli-Color as several have already mentioned. There is a Napa distribution center near my house that has an attached retail store that has extended hours so I can generally get what I need. I also have been using the high-build primer in a can thinned with acetone which works wonders for filling fiberglass weave. It's also far cheaper than the spray cans. I just thin it and brush it on since I don't have sprayer. Works really well for large rockets.

This year for BALLS I'm am going for altitude on a couple of flights so I plan to try and clear coat and then wet sand up to 1000 grit. I've never gone beyond 600 before so I'm not sure how it will work out. But they are small rockets so it shouldn't be too bad.

Tony

#### jahall4

##### Well-Known Member
I have painted many G10 fin sets. I generally wet sand with 320 to take the shine off the G10 before I spray with Dupli-Color sandable primer. I start with gray, wet sand with 400, then cover with white and wet sand again. The 2 colors show the high spots really well (generally caused by stray epoxy on the fin). Once cured I finish with Dupli-Color paint and then wet sand with 600. The results have been very good and I've never had a problem with adhesion on the G10.

After trying a lot of different paints I now just suck it up and pay for Dupli-Color as several have already mentioned. There is a Napa distribution center near my house that has an attached retail store that has extended hours so I can generally get what I need. I also have been using the high-build primer in a can thinned with acetone which works wonders for filling fiberglass weave. It's also far cheaper than the spray cans. I just thin it and brush it on since I don't have sprayer. Works really well for large rockets.

This year for BALLS I'm am going for altitude on a couple of flights so I plan to try and clear coat and then wet sand up to 1000 grit. I've never gone beyond 600 before so I'm not sure how it will work out. But they are small rockets so it shouldn't be too bad.

Tony

View attachment 298043
Our processes are pretty close except I'll sand that last coat of Dupli-color primer/filler with 600. I like your idea of brushing the canned product. I'll try that for all but the final primer coat. If you are going to start wet sanding you color coats you'll have to try Trizact 3000/5000 sheet (https://3mcollision.com/3m-trizact-hookit-foam-sheet-p3000-30290.html) 1000 won't be fine enough particularly for the clear coat.

#### manixFan

##### Not a rocket scientist
Our processes are pretty close except I'll sand that last coat of Dupli-color primer/filler with 600. I like your idea of brushing the canned product. I'll try that for all but the final primer coat. If you are going to start wet sanding you color coats you'll have to try Trizact 3000/5000 sheet (https://3mcollision.com/3m-trizact-hookit-foam-sheet-p3000-30290.html) 1000 won't be fine enough particularly for the clear coat.
Wow, I didn't realize it would take such fine grit for the clear coat. Thanks for the tip. I ordered some Trizact from Amazon already.

Dupli-color does make an adhesion promoter for plastic, chrome, and vinyl. I've never tried it on a G10 or a plastic nosecone but I suppose it would help:

The Dupli-Color primer in the can says to use their 'specialty reducer' which is pretty expensive. I looked at the MSDS sheet for it and it is 97% acetone and 3% Ethyl 3-Ethoxypropionate. I figure for my use straight acetone works fine.

https://www.paintdocs.com/docs/webPDF.jsp?SITEID=DUPLI&prodno=BG906&doctype=MSDS&lang=2

Sometimes I wonder why I bother though. Last year I used a tower launcher on a 3" minimum diameter and it was brutal on the finish. This year I'm trying fly-away rail guides with 38mm, 54mm, and 75mm diameter rockets at BALLS. I hope they are easier on the finish. But once the rockets hit the playa it's almost always time to refinish anyways.

Thanks for the tip,

Tony

#### jahall4

##### Well-Known Member
Wow, I didn't realize it would take such fine grit for the clear coat. Thanks for the tip. I ordered some Trizact from Amazon already.
It doesn't necessarily have to but it comes in really handy for leveling across color transitions or decals/vinyl or buffing out over-spray. Even if I have a perfect base of color I'll still go to the Trizact 5000 before spraying the clear.

Dupli-color does make an adhesion promoter for plastic, chrome, and vinyl. I've never tried it on a G10 or a plastic nosecone but I suppose it would help:
We'll I'm getting ready to do just that later today. I have talked to Dupli-color and they said it should work fine on fiberglass. I have been using it under their primer/filler on plastic nose cones. So far no peeling paint even when we buried a 4" cone into the ground 7", although we try to avoid that. ;-)

This year I'm trying fly-away rail guides with 38mm, 54mm, and 75mm diameter rockets at BALLS. I hope they are easier on the finish.
I am a BIG fan Mayhem rail guides and have used them extensively and exclusively on 38mm. We have seen and instance or two where you can get a nick in the paint on a fins leading edge, but I suspect the substrate, which in this case was ply, contributed. Regardless it was easy to touch up. We have used them from C11s through H133s here are some pics and video:

https://dl.dropboxusercontent.com/u/6960195/DVR Test.wmv

https://dl.dropboxusercontent.com/u/6960195/MVI_3349.wmv

#### jahall4

##### Well-Known Member
The Dupli-color adhesion promoter appears to be working very well underneath the primer. No peeling, separation, or chipping almost like it is part of the fiberglass surface. In fact I can sand away enough primer to make it translucent, but there still be a haze of primer color.