Painting problem - how do I solve it?

[Mrowka 495]

I figured out why I have a problem with paint bleeding through at the edges of my lexan bodies....

It's because after I cut out my bodies before painting, I spend so much time sanding and filing the bodies that the edges of the clear plastic film backing the lexan come up. The result is that paint gets through where it's not supposed to. 

The question remains: what to do about it?

The obvious answer is to paint my bodies before I cut them out. Sheesh.

But since I have a cut out body waiting for paint, should I remove the backing film and then mask the outside of the body myself?

[Frog Jumper 3661]

I use Tamiya lacquer thinner to clean off my overspray.  Tamiya PS Cleaner likely works much better, but my LHS never has that in stock.

Terry

 

 

[Frog Jumper 3661]

To add to the debate, I have cut before paint, and cut after paint.  I don't really think it matters which way you go, but people will say you should cut prior to paint for two reasons:  the cut edge gets painted so you don't have a clear or white line along the cut edge, and cutting and sanding may scratch your paint.

Terry

 

 

 

[Mad Ax 9313]

I have this problem too.  Carson Paint Killer sprayed onto a contraband cotton swab works well for smaller areas.  Generally I can avoid large areas of the film coming away unless I'm really aggressive with the sanding.  In come cases, having to trim the lexan from both sides due to a really thick or awkward section (I'm looking at you, MAN TGS body) causes the film to lift up more.  If the lifting looks bad, I'll add some Tamiya masking tape to the outside.  Now if the film completely covers the area, this will do absolutely nothing, but if you fold it back or cut it off, the tape will stick down on the outside of the actual body and seal up the rest of the tape.

I've heard various arguments for cutting before and after painting.  I've tried both ways and each has its benefits, personally for me cut-before-paint works best.  I find the cutting process way more awkward than the painting process, and I'm far more likely to drop the body or slip with the knife while cutting, which could damage a fresh paint job.  That said, I often do the final sanding around the arches after the paint goes on, because I can't see how bad my cutting job is until there's some paint on there to show it up.

[Mrowka 495]

2 hours ago, Frog Jumper said:

To add to the debate, I have cut before paint, and cut after paint.  I don't really think it matters which way you go, but people will say you should cut prior to paint for two reasons:  the cut edge gets painted so you don't have a clear or white line along the cut edge, and cutting and sanding may scratch your paint.

Terry

That is why I always have cut and then painted. 

I have some paint eraser (HobbyKing special) but, frankly, it doesn't work all that well. Maybe steal some Tamiya lacquer thinner from somewhere. 

[Mrowka 495]

1 hour ago, Mad Ax said:

I have this problem too.  Carson Paint Killer sprayed onto a contraband cotton swab works well for smaller areas.  Generally I can avoid large areas of the film coming away unless I'm really aggressive with the sanding.  In come cases, having to trim the lexan from both sides due to a really thick or awkward section (I'm looking at you, MAN TGS body) causes the film to lift up more.  If the lifting looks bad, I'll add some Tamiya masking tape to the outside.  Now if the film completely covers the area, this will do absolutely nothing, but if you fold it back or cut it off, the tape will stick down on the outside of the actual body and seal up the rest of the tape.

I've heard various arguments for cutting before and after painting.  I've tried both ways and each has its benefits, personally for me cut-before-paint works best.  I find the cutting process way more awkward than the painting process, and I'm far more likely to drop the body or slip with the knife while cutting, which could damage a fresh paint job.  That said, I often do the final sanding around the arches after the paint goes on, because I can't see how bad my cutting job is until there's some paint on there to show it up.

I have always masked the outside edges of bodies as well, but with the film on and starting to peel away, the paint seeps underneath the film. 

Folding it back might help. There has got to be a better way than what I am doing.

[Juhunio 6830]

I always cut then paint...it's what the instructions tell you to do! I recently sprayed the light 'buckets' for an AMG GT3 shell before cutting them and experienced the issue of the cut edge being left clear. They get stuck on the inside of the shell so it's no biggy, but it was a clear (ha!) lesson on why the recommended way works best

I also occasionally experience a bit of overspray under the protective film if it starts to peel away a bit, but it's always very light and specific to the edges of the body shell. A wipe down with some Tamiya Polycarbonate cleaner always does the trick, it's great stuff if you can get hold of it 

[Gebbly 588]

I havent tried it but what if you cut first and sanded and then rolled a couple of mm of the overspray cover back all around the edge and stuck masking tape over it to cover the last few mm?

[Willy iine 18806]

1 hour ago, Gebbly said:

I havent tried it but what if you cut first and sanded and then rolled a couple of mm of the overspray cover back all around the edge and stuck masking tape over it to cover the last few mm?

That works fine, I do that on areas where the film had sometimes deteriorated from the prep.  I just make sure the tape does not curl onto the edge while masking.. not that there's a problem if the edge is masked but usually want the edge painted to prevent reflection/outline.

[Mrowka 495]

I had a brain wave last night - what if I use liquid masking tape to seal the edges where the film has come away? 

But that begs the question of how do I keep the liquid masking tape from getting onto the side to be painted? Regular masking tape, of course.

Any idea whether this will work?

[GeeWings 2830]

Could you not just peel a little more film away and then cover with tape on the body and over the film?

As for masking tape; just be careful, I’ve had bleeds with regular tape. As much as some supplies with Tamiya name on them can seem overpriced I think their tape is worth every cent. 

[Mrowka 495]

I am not the greatest paint and body man out there, but I know that not all masking tape is created equal.

I've had my best results using 3M frog tape.

[alvinlwh 5895]

2 hours ago, GeeWings said:

As much as some supplies with Tamiya name on them can seem overpriced I think their tape is worth every cent. 

I had been making static models for decades and (almost) all serious model makers I know of only use Tamiya tape and nothing else. They are the only one I had tried that masks cleanly and removes cleanly. 

If cost is a issue, only use Tamiya tape for the edges and cheaper masking tape for the "insides". 

[Mrowka 495]

FyI, I tried the liquid masking tape idea on a piece of scrap lexan, with one edge of the plastic film lifted.

Seemed to work.

[GeeWings 2830]

9 hours ago, Mrowka said:

FyI, I tried the liquid masking tape idea on a piece of scrap lexan, with one edge of the plastic film lifted.

Seemed to work.

That’s a result! Good luck and be sure to share pics once done.

[Mrowka 495]

Long story short, the masking was about the only thing to go right in that paint job.