Cleaning models prior to painting

[Shockwave Rider]

Evening, chaps,

Acrylic paints.

Important bit, that. Whilst building the old Airfix Buccaneer, I had a wee problem with some Vallejo paint that I haven't had in yonks. I can't work out if it is something to do with the hot, humid weather or perhaps the Vallejo paints (which I am still dubious about) or the preparation of my painting surface.

However, whatever the root cause, I had stencil, low-tack masking tape lift the paint in certain parts of the model.

Now, I am thinking the following. The bits where the tape didn't lift the paint had received a coat of the good old Halfords grey plastic primer a day or so before I sprayed the Vallejo paint. The bits where the paint was lifted, had received a coat of the afore mentioned primer weeks ago, and in the ensuing period much remedial work was done on the model.

So, the old brain cell (I think I am beating about the bush here), is banging away, saying that the model was not properly prepared for receiving the Vallejo. (Another brain cell isn't too sure of this, as I sprayed some further Vallejo onto existing Vallejo, and still the paint showed signs of not gripping the surface properly - it is hot (28C) and humid, today.)

Regardless of my problems with Vallejo, what do the esteemed members of this forum us to clean their models before spraying acrylics?

Note, some of the cleaning will be on bare plastic, in preparation for Halfords primer; some of the cleaning will be of the Halfords primer; and the final lot of cleaning will be of acrylic paint, either between coats or camouflage patterns.

Hot cleaning fluids, like alcohol or white spirits, are a bit of a no-no, seeing as they will strip the thin layer of sprayed acrylic paint in next to no time.

Any advice appreciated.

Angus

[xlpainter]

hi do you give the primed areas a flat down with wet&dry i use 400 grit on halfords plastic primer then a quick rub over with revell colour mix never had any problems with either enamel or acrylic paints do you wash the model before it is built in fairy liquid and luke warm water to remove the release agent when molded hope this helps simon

[CliffB]

Hi Angus

I always use washing up liquid in water (as if you were washing dishes), but tepid water rather than hot of course. Apply with a soft brush (with mild scrubbing action), and then rinsed thoroughly (again by brush).

I never seem to have a problem with paint lifting (masked using Tamiya tape), but no doubt tomorrow.........

Cheers

Cliff

[kev67]

I think using baby wipes is a good idea, non perfumed ones that you can use to clean the models before painting

[Deon]

I wash my kits down with washing up liquid whilst on the sprues, give them a warm rinse after light sanding, air dry, tac cloth before every coat and a light sand after. i use Halfords grey primer and always wash my hands before touching the model during assembly and painting. Some paints are sensitive to tape, so I coat those with klear before masking.

[blimp]

Halfords primer is good stuff , but like most primers it is porous . natural oils from your hands will still impregnate the surface whilst handling . i do the usual fairy/ warm water prep , followed by a thorough rinsing as traces of the detergent can prevent paint adhesion . finally i give the surfaces a wipe with alcohol (meths) to remove any trace and degrease any oils that may migrate back to the surface . - windscreen wash is also good , being both 'soap' and alcohol . i havn't used Vallejo paint , so can't comment with any authority , but maybe age has affected it . some colours can have better propeties than others , even from the same manufactuer (or it might just be me )

[NickParker]

Hi Angus, i use Vallejo acrylics almost exclusively and one thing to note is they need a clean and ideally primed surface for good adhesion, also they can be quite delicate so leaving overnight before masking is a good idea. If you must mask quickly than a protective layer of clear works well, and use low tack tape, Tamiya tape has always worked for me, you could always de-tack the tape a little with your fingers. Hope this helped.

Nick

[Shockwave Rider]

Right chaps,

Thanks for the replies.

The culprit would appear to be oily, dirty fingers. After deciding to abandon all hope, and forge on with painting regardless, I was pleasantly surprised, on lifting the masking tape, to find that the paint had only lifted in about 4 places, and these were fairly small.

The Vallejo paint clung on like a limpet elsewhere. This is the experience I have had uptil now, so was most concerned to see it lifting. T'was quick work with a brush to touch up the errors.

Next time I shall apply the suggestions mentioned in this thread, aka clean Halfords with a water and a touch of washing up liquid, then clean with alcohol.

Thanks again,

Angus of Wokingham.

[Mike]

Finger oil is often the culprit in acrylic paint lifting - especially on non-primed surfaces. I'd be wary of cleaning your work with alcohol though, as IPA (Isopropyl Alcohol) will melt some primers - Mr Surfacer for certain.

I'd also be wary of using baby wipes, as a great many of them have moisturising ingredients in them, which equates to oil... not good

[Julien]

I can honestly say I have only ever washed one sprue in my life, this was an old easter eurlopean kit which posativly dripped mold release.

All I do prior to painting is wipe down with some kitchen towel.

Touch wood never had any problems

Julien