Help - paint crinkles --> removal - DONE!

jcdenton · Post by **jcdenton** » Sat Dec 15, 2007 1:09 pm

Hey,

I've already posted this over in the Star Trek modeling section in my thread about my Deep Space Nine project, but I wanted to get it in here too, as probably not all of you read all the forums. (I for my part am hardly ever anywhere else but in the ST part

)

So I've got the fiber optics DS9 station. it's mostly complete and I've come to painting. I've given the entire station a base black coating and started to give it a second layer of copper spary paint after that. I only got to a few parts in copper last week, but had everything in black. up to that point everything looked great! so today I continued with the copper and after I left it sitting to dry a bit I came back and found to my horror that the paint is somehow crinkling. Take a look:

http://www.weiss.tw/DS9/15122007.jpg

sorry for the bad picture, but I only have my smartphone as a digital camera. what you can see is that most of the surfaces should be smooth, but they aren't.
so my problem is, how should I procede? I certainly don't like the looks too much, but I'm afraid that if I soak it in some sort of dissolving agent to get the paint off, I dissolve the fiber optics with it. I don't want all those holes and optics to have been drilled in vain. but I clearly don't like the result right now

any advice? it's greatly appreciated!!

cheers
JC

DX-SFX · Post by **DX-SFX** » Sat Dec 15, 2007 10:12 pm

This is usually the result of putting a paint based on a strong solvent on top of a paint that uses a weaker solvent base. You might have got away with the first coat if the first coat flashed off quickly but the second coat bonding with the first could've retained sufficient solvent long enough to react with the black coat. There are specialist paint strippers that won't harm plastic kits. It's hard for me to reccommend a US brand as I'm in the UK but I'm sure someone here can offer some suggestions.

Kolschey · Post by **Kolschey** » Sat Dec 15, 2007 10:22 pm

Thermodynamics (expansion and contraction based on temperature) is also a factor.

Spray or hand paint in cold weather (below 50 degrees Fahrenheit)and you are almost guaranteed a crackle effect on your paint.

Lt. Z0mBe · Post by **Lt. Z0mBe** » Sun Dec 16, 2007 1:29 am

It is outgassing. The base coat was not fully cured, and, as such, continues to vent solvent fumes through the also-still-curing top coat.

I hope this helps.

Kenny

jcdenton · Post by **jcdenton** » Sun Dec 16, 2007 7:14 am

First of all, thanks for all of your replies!

@Lt.Z0mBe
the base coat was left to cure for 6 days before I applied the copper yesterday. I'm not an expert on paints, but shouldn't that have been enough time for it to cure?

@Kolschey
That were my thoughts at first, too. But I painted indoors with the temperature around 67°F. Do you think that would have been low enough?

I tend to think that DX-SFX comes about as close to my problem as it gets. When I first applied the copper on top of the fairly fresh black coat, the black was not fully cured and thus could react better with the copper. So please go ahead and recommend a UK or European brand as I'm not in the US myself either. I'm in Germany.

Thanks again for all your help! I really appreciate it!!

Cheers
JC

DX-SFX · Post by **DX-SFX** » Sun Dec 16, 2007 9:32 am

Let's first establish what type of paints they are? Cellulose, enamel, car (xylene) acrylics, model (alcohol/water) acrylics?

jcdenton · Post by **jcdenton** » Sun Dec 16, 2007 10:38 am

Well, it says that the copper is Acetone-based. The black doesn't really say a lot about it's ingredients, but as it says that it's supposed to be hard surfaced and very durable and not dilutable with water it should be an enamel paint, right? Sorry for being so inprecise, I'm figuring all of this out right now. I'm not an expert on paints (yet)

DX-SFX · Post by **DX-SFX** » Sun Dec 16, 2007 6:59 pm

Any acetone/cellulose/xylene based paint should go on first. It's the most potent of paints you're likely to encounter in a rattle can so I'm not in the least surprised you had the problem if the black coat was an enamel. You can overcoat any paint with the same type of paint or with one with a less strong solvent base but not the other way around. If you put a strong solvent paint on top of a weak solvent paint, it will pickle. It does sound like your black coat was an enamel.

There are several things you can try to strip the paint. In no particular order you can try a caustic oven cleaner spray or brake fluid or one of the specialist model paint strippers like "Microstrip". Conventional DIY paint stripper like Nitromors will work too but not being familiar with what's on the German market, you might have to experiment a bit just to make sure that whatever you choose doesn't damage the plastic. None of the above should but I don't want to say go for it and then ruin your model. Luckily enamel can be stripped fairly easily so assuming your stripper can get through the top coats, you should find the paint lift off without too much trouble (famous last words).

jcdenton · Post by **jcdenton** » Mon Dec 17, 2007 3:21 am

Alright, thanks DX-SFX! I'll go and get me some oven cleaner right after work today. That'll be my first try. I'll let you know how it went!

jcdenton · Post by **jcdenton** » Mon Dec 17, 2007 1:12 pm

Well, I tried it on a piece of plastic that I tried the paint on last weekend and after about an hour of soaking I can scrape off the paint with my fingernails. It comes off in small skin-like pieces. I'm trying to let it soak in for another few hours and see if that helps it any further. If not, it's going to be really tough getting everything off the station, but at least it's coming off without harming the plastics or the fiber optics! I put some excess fiber into the cleaner as well to try the effects it has on it. Thank you so very much for helping me out! I'll let you know when I get to the station itself.

Cheers
JC

DX-SFX · Post by **DX-SFX** » Mon Dec 17, 2007 10:17 pm

If you have any stubborn areas, try spraying the model with oven cleaner and then putting it in a plastic bag. Failing that, move up to a proper paint stripper, the caustic type that looks like wallpaper paste. You'll see this doing it's work and then you rinse it off with water. Wear rubber gloves though as it can give you skin burns.

jcdenton · Post by **jcdenton** » Wed Dec 19, 2007 12:54 pm

An update on my oven cleaner experiments. I had it soaking for about 24 hrs and tried what the paint would think about that after I got back from work yesterday. While still damp I could use a toothbrush to get the paint off. After I let the test-part dry out, the paint came off in pieces. So I'm confident, that it should work on the station as well. My experiments also showed no influence on the fibers nor on the styrene itself. Unfortunately I can't try it on the model until January as some other stuff came up that needs to get done before I can work on the model again. Thanks again for your advice and I'll let you know how it'll eventually turn out.

Cheers
JC

DX-SFX · Post by **DX-SFX** » Wed Dec 19, 2007 2:06 pm

As long as you get there in the end without spoiling it, that'll be good. I hope the rest strips easily.

jcdenton · Post by **jcdenton** » Wed Jan 09, 2008 12:51 pm

Hey,

Happy New Year! I'm back working on the station

I have so far given a part of the station a good soak of the oven cleaner. The paint is coming off, but not as well as I had hoped for. I'm worried that I'll break off the fibers when scrubbing it with a toothbrush. And it really takes a lot of scrubbing for that stubborn stuff to come off. Is that to be expected or should it come off easier from your experience?

jcdenton · Post by **jcdenton** » Sun Jan 13, 2008 11:13 am

Alright, I've tried different soaking times now. From 20min, to an hour to even a day. It's useless. The paint softens just enough so I can scratch it off. If I'd do that to the entire station, all my lighting efforts will be rendered useless because I'll have broken off all the fibers.

Now, to get some better paint remover than oven cleaner... I've looked around local stores and the only thing that I can find that would probably take off the paint always states "Do not use on plastics!". Now I've looked into buying stuff like Nitromors. It's not sold in Germany. Henkel Germany (whose UK daughter sells it in the UK) stopped making this kinda stuff about 10 years ago. Too much of a health risk because of the methylene chloride. So I thought about buying it directly from the UK. Right, no UK-retailer will ship that stuff outside of the UK. Not via webstores and not even through ebay. Great, huh?

So now I'm looking into real model paint strippers like the mentioned "Microstrip". I've also heard about "Easy Lift Off". So now my question is to you who have experience with either one of them. Do you think I could apply those to my current problem? As ELO is specifically for removing paint from plastic surfaces, I think it should be alright with the fibers as well or am I mistaken there?

This is really beginning to be a pain...

DX-SFX · Post by **DX-SFX** » Sun Jan 13, 2008 5:49 pm

Microstrip will take off (water based) acrylic and enamels but it struggles with car sprays. It's mildly caustic like oven spray but it's in the form of a heavy paste that you apply and then stick the smothered model in a tied polythene bag overnight. The advantage is that the stripper stays in contact with the paint for much longer than an hour so might be worth trying.

If the model is well sealed, i.e. no chance of any liquid getting inside, hydraulic brake fluid will work but needs cleaning off carefully afterwards.

jcdenton · Post by **jcdenton** » Mon Jan 14, 2008 9:45 am

Yeah! Great! Next problem! Nitromors, Microstrip or Easy-Lift-Off are not being shipped internationally. They are under HAZMAT regulations and not to be shipped over here. Any Germans around that could point me to an equivalent product on the german market? I found paintstrippers from Molto and Scheidel and I've contacted Molto and asked them if I could use their stuff on my problem. No answer so far... I'll keep you posted though...

Lord Darth Beavis · Post by **Lord Darth Beavis** » Tue Jan 15, 2008 11:47 pm

JC--see if you can locate Castrol Super Clean. It is a purple, super-strong degreaser type cleanser, that will take the paint off of just about anything. Dunno if it is available in Europe, though. You might check at your local parts houses or autop supply stores to see if you can get it there. Just make sure you wear gloves, because it will do a number on your hands.

Don't ask me how I know...

jcdenton · Post by **jcdenton** » Wed Jan 16, 2008 4:51 am

Alright, thanks for the hint. I'll see if I can find it over here. Right now I'm working on it with 70% Ethanol. It doesn't work as well as I had hoped it would, but it seems to be better than oven cleaner.

And I'll remember the gloves

jcdenton · Post by **jcdenton** » Thu Jan 24, 2008 10:30 am

To keep you updated and in case anybody runs into this problem as well.

I'm cleaning it using 70% Isopropanol. I let it soak for about 20 minutes and then scrape it off with a wooden toothpick and a hard toothbrush. It's a pain to do, but it works. I'm done with about 50% of the station and hope to get everything off by the weekend so I can start repainting next week. Only downside off Isopropanol is that it is so volatile. You have to keep on putting more and more on the model because it dries away so fast... Ethanol didn't do that, but is a lot harder to come buy and more expensive as well.

Cheers
JC

modeler1964 · Post by **modeler1964** » Thu Jan 24, 2008 2:24 pm

I too can attest to Super Clean. It comes in a gallon size for about $5 USD. It comes in a purple container. I used it last night on a model that had been painted for over ten years with enamels. Within 2 hours of soaking the parts, the paint was dissolving and I could rub it off with a finger (wearing gloves of course). It does not attack the plastic in any way. Tonight I will be taking it out of the super clean bath and I will post pics. Its the best stuff I have seen for this purpose.

Link to Castrol German website:

http://www.castrol.com/castrol/castrolh ... oryId=3210

jcdenton · Post by **jcdenton** » Sun Feb 24, 2008 11:36 am

I'M DONE!!!! I can't believe it! I just spent over 2 months to get the station back into shape. I finally got the last cleaning done this morning and now she has a smooth black primer once again. So this week I'll finally get to painting her again and this time I'll use a brush. No more spray-experiments

I'm so glad that I got that crappy paint job off of her again and I just had to share my joy!

Thanks again for all your advice on paint stripping.

Cheers
JC