Paint question...

I am painting the Mustang II and everything looks good except I am having a devil of a time with the nose cone. The first coat of grey primer went on fine. Then I put the second coat which was glossy grey paint. Then I sanded with 240 and put the third coat on. BTW: I waited 24 hours between coats. This time the third coat "bubbled up" at the base of the nose cone. (You know, the widest part) Disappointed, I sanded it down the best I could with 240 grit and repainted it. This time, the part that bubbled up is hardly noticable but the non-bubbled portion of the base is now bubbled. (BTW, Now I'm only waiting 1-2 hours between coats). So I sanded again, and painted. This time, no excessive bubbling. But now the rocket looks pock marked. I'm thinking about 100 grit and starting over.

So, 2 questions for all the technique masters out there:
1) Why did the paint "bubble up"?
2) What did I do wrong?
3) Suggestions for making it right?

Oh, I used Rustoleum glossy enamel for the paint. Which brings up an interesting note: Lowe's doesn't sell Krylon any more. At least there were no spots for it at my Lowe's. Does anyone know for sure?

Well technically that is 3 questions but who is counting.

-- could have been bad paint.
-- could have been the humidity.
-- could have been the heat.
-- it is possible that the paint doesn't go on well over itself (ie doesn't like a second coat)

I paint my parts in my basement where the temperature and humidity stay pretty constant or seem to anyway.

I'm thinking about buying an airbrush myself. You get much better control over the application of the paint. Spray cans are just to cumbersome for the type of finish we rocketeers expect of our rockets.

I painted the top half of the rocket with the same grey over gloss white (same brand) and had no issues.

It sounds like your primer and paint are different brands (Krylon and Rustoleum). That's why it doesn't work as it's supposed to... If you use primer and paint of the same brand there should be no problem.

Oliver

I didn't think about that. I think the primer was Velspar and the gloss was Rustoleum. That may be it.

I tend to agree with Oliver. Something else to consider, your nosecone may have had an excessive amount of oil still on it from the release agent the mfgr uses during the molding process. This is more pronounced in LOC nosecones, but still a possibility. My Recommendation:

Sand the nose cone down, primer and all

Scrub it with white vinegar and a scotch scrub pad (the acid breaks down the oil)

Wash off in HOT soapy water and rinse

Use either Rustoleum or Krylon White primer, both seem to be compatable with eachother

Use MORE than one coat of primer...my nose cones have at least 3-5 coats or more ( Just ask Ken, he has seen me in action and hates when I say..."needs more primer!")

Let the primer dry overnite

Wetsand with 400-600 grit wet/dry under warm water

Let it dry

IMPORTANT: Wipe it down with a TAC cloth, just before painting(Again Ken P has seen me look all over for a TAC rag, rather than paint without it)

Paint...one to two light coats followed by a heavier final coat. I use Krylon and Testors for the most part

It should be fine by then

Yea, it's a bit more work, but you have already spent alot of time building, why not treat the finish the same way?

It does sound like an incompatability problem with paints vs primer. As a matter of fact, I have never heard of that brand of primer before.

I like white primer and others actually use white and gray, alternating coats so they can see how it is shaping and how far to sand. Remember, a good primer base coat that is compatable and smooth as glass will give you a great top coat. The finish is the primers job....paint should be used just for color.

Cya,

Carl

That's a lot of paint. How much weight do you think you add to the rocket giving it this much? You definitely can't go by what's printed on the box for rocket weight.

That's quite a technique.

Vinegar is also good for giving your car an acid bath to remove hard water spots. That stuff is great for everything.

It sounds like the first coat had a poor bond. When the later coats were added, the first coats soaked up the solvents, swelled, and then shrank, breaking the bond.

E Miller

You bet! White vinegar is a godsend for us, especially in the nosecone and fiberglass tube area. It really cuts through release agents.

Regarding weight, I know that I built one rocket that was rated by the Mfgr at 4.8lbs and mine was 7.56 lbs...I do extra glassing and big filets for strength plus the finish I noted, so I am sure the paint does add some extra weight.

Another good point you made, you can never go by the MFGR's recommended weight as everyone builds differently. Always try to weigh your rocket before doing any sims on it so you can get a better reading.

Carl

Jeez.... where do I start?

First of all, anyone reading this needs to understand that Tulanko is a hyperactive insomniac perfectionistic paranoid.

Some of the things you'll NEVER hear Carl say:

"That's too much epoxy, bubba."
"Don't use so much paint."
"I only have one can of primer."
"Tack rag? What's that?"
"No, I only use one coat of clearcoat after I finish painting."
"Decals? We don't need no stinking decals...."
"Clean my rocket? I kind of like the 'it landed in the cowpile look'."
"I never repaint my rockets between launches."

Carl is the only person I know that has had a rocket come in under ballistic flight that totally destroyed the component structures, but he still had a perfectly good paint shell left....

One last tip for y'all: Don't EVER ask Carl if your rocket "looks OK" unless you can REALLY handle the truth.

OK, Buckeye-boy, just remembered, you asked for it.....

Moderator's Note:

These guys know each other very well. Normally we wouldn't tolerate such slander.

Very funny!

Jeez.................................you are right Milo, I am still laughing...

I think Ken is still a bit PO'ed about the fillets I suggested when he was building his L1 bird. He was sanding for hours afterward.......

but, in my defense...he did ask!

And it flew successfully first time!

...and yes, we are best friends seperated by several states. Spooky, huh? Make sure the Misses has those cookies ready for next month Ken!

As for ballistic...you had to admit, the parachute still worked! Safety first!!!

Man, am I really that bad?????

Boy, I really like that idea of the alternating colors of primer. I can see where that would make the sanding process alot easier to see what affect you are having.

Well, the plan was to sand it all down, clean it, and then do the repaint thing. As I was pulling off the trim tape (that was around the section of the nosecone that goes into the rocket) a bit of paint "popped loose". Very interesting I thought. Then I pulled on it. Folks, that paint just slid off like the shell of a cracked boiled egg. 50% was complete when I finished pulling. 25% came off with additional pulling. And 25% came off with a razor. Very strange. Anyway, what the heck caused that to happen? I gave it 24hrs of drying time.

Well, the next steps are to sand it lightly, clean it up as was suggested by Carl above and then repaint. Here is a question, should I have sanded the nose cone before I primed it the first time?

Sanded the nosecone........uh.....Yea!

Use some 220 grit on the nose cone; it should rough it up enough...

Definitely sounds like release agent wasn't cleaned off....good luck

Oh, now I'm really pissed. I did the Dr. Glass method of nose cone painting. I got the grey part of the Mustang nose cone perfect. Then I went to apply the black. Immediately the black paint went on.... and cracked!!! It looks horrible!!! I think that the temperature had something to do with it. So now what? Sand and start again? Come on guys, I need some words of encouragment....

BTW: The rest of the Mustang II is compete and it looks great. The nose cone is killing me...

Did you paint the entire nose cone gray, then paint over the tip part black? if so, you probably didn't wait 24 - 48 hrs to let the gray paint set. Another reason is paint incompatability or you put it on too thick. The first two coats should be almost a dusting; just enough to look semi transparent.

If you painted over primer only on the nosecone tip, you have me stumped, unless you had oils from your hands on it, but that would only effect spots that you touched.

I am betting you put it on too thick and too soon, possibly with different brands of paint. One of the biggest causes of Orange Peal is the solvents/thinners in the spray when put on too heavily attack the lower surface. The other cause of orange pealing is surface oils from your hands.....still betting it was too thick.

If it has been at least 48 hours since you painted the gray, mask it off, sand the orange pealed black section off to the primer, then re-spray.

More info please.....

the 24-48 hour thing is probably the cause. The black was Krylon and the grey was Rust-o-leum. I have done second coats with those two cans in 2 hours and haven't never seen this before.

Well, what I did was sand down the whole nose cone and reprimed... But, this time I was prepared. I went to Home Depot and bought new paint. This time a grey can of primer, white can of primer, and colored cans all from Rust-o-leum. I alternated the white with the grey and now the nose cone is sitting downstairs drying with 5 coats of primer. Tomorrow, I will sand and coat. I will let you all know... Wish me luck.

Here's a story for ya.

That was a great file!!!! Where did you get it from? Thanks for sharing.

Now the results of the Mustang II nose cone. 24 hours have passed, the tip is now painted a beautiful black. I mask it, and paint the rest with the grey. Immediately the bubbles start showing up. I'm pissed, but they are small bubbles and so I said, I will sand them down and apply another coat. But after 30 min or so, almost all the bubbles disappear leaving about 3 raised areas that are hardly noticable. At this point I give up. It is not perfect, but it is acceptable. So, mission is complete. Once it is dryed and I get my hands back on my digital, I will share the picture.

Thanks for everyone's help. I laughed, I cried, it became a part of me.

I'm only too happy to have made it available for your edification. If you'd like to look at it on a Web Site, go to www.arsabq.org and click the button for newsletters.
Thanks and Respects