Why is my primer pooling?

[Tromance]

Hello all. I've started a new Revell model of a McLaren, and today went to primer some small parts. I've already sprayed the undertray with no issues.

For some reason though, the Vallejo primer is pooling on these parts and won't go on properly. I'm at a loss to understand why. I've stripped and cleaned the airbrush, washed all the parts (twice) with detergent and rinsed, and brushed them down again with alcohol to get rid of any grease, and made sure I've shaken the primer well. I can't think of what else could be causing it. Any ideas?

[Radleigh]

Too much on? Not shaken/mixed properly?

[chadders]

Something on the plastic?

[Tromance]

I don't THINK I've done anything different to the whole previous model, but now you've got me doubting myself. I'll wash everything again and give the primer extra shakes.

[snapper_city]

If it is still pooling try not to spray too much in one go. Just mist the first few layers on and by then it will have something good to bite against.

[colin]

Second the above, light mist coat to start with, if you go too heavy this is what happens, same with the paints

[noeyedears]

i used to use vallejo primer but gave up on it due to the same problem, and it sanded awful too. could hav ebeen a bad bottle tho' i suppose.

[Tromance]

Thanks to the assembled masses - the mist technique seems to have sorted it.

While I'm at it, I'd be curious to hear what other people favour for primers - I'm still at the phase of trying all sorts of things. So far I've discovered that Vallejo is considerably better than Ace Hardware's own brand...

[Radleigh]

Tamiya here, I don't use nothing else since trying it.

[prowler0000]

Got a big bottle of Vallejo Primer here, but still working thru the last few cans of Halfords primer. Good stuff, Halfords!

Am wary of the Vallejo stuff, but will give it a try & hopefully get better results than you did.

[Julien]

My first coat of Vallejo white plastic primer does go on looking like that but not as bad, I was really worried at first but when painted over it looks great.

For darker colours the Vallejo dark grey air stuff is excellent, best primer I have used.

Julien

[Fazer]

Alcad fine surface primer for me as it is cellulose based & gives a good bite into the plastic / resin which I mostly use. It leaves a good surface with minor preps for top coating....believe me, I have gone through a lot of different primers...

Mark D

[Rick Brown]

Alcad fine surface primer for me as it is cellulose based & gives a good bite into the plastic / resin which I mostly use. It leaves a good surface with minor preps for top coating....believe me, I have gone through a lot of different primers...

Mark D

Seconded.

The Vallejo does give a nice surface for their MA paints but it's a little bit delicate imho and comes off easily.

The Alclad needs to be built up slowly or else it will dry to a very rough surface that'll need a good rub down before applying the top coats.

Watch out for build ups in places like wing routes on Spits etc. Drying time is pretty quick too.

Sticks like muck to a blanket!

Rick.

[SaintsPhil]

Alcad fine surface primer for me as it is cellulose based & gives a good bite into the plastic / resin which I mostly use. It leaves a good surface with minor preps for top coating....believe me, I have gone through a lot of different primers...

Mark D

Third'd, I couldn't get on with the Vallejo stuff either, except the model air one mentioned above. Finally settled on Alclad and ill never go back! Only issue is as its cellulose based its nasty stuff, extractor and mask are a must!

[Scarlet]

Halfords plastic primer for me. Tamiya stuff is good but by the time you factor in postage it works out expensive. No shops near me now to get modelling supplies from.

[Tromance]

Thanks chaps. Tamiya seems to get universal acclaim but you can't get the cans here in the Middle East, and it's illegal to fly with them. I model in a room without windows and don't (yet) have a spray booth, so might have to hold off on Alclad for now. Seems Vallejo might be my best bet for now!

[Will Vale]

+1 for Alclad in the airbrush or Tamiya in the can. The Duplicolour sandable primer is good too, as is GW Chaos Black in a rattle can.

I tried the Vallejo primer recently and it went on exactly like that. It's deceptive though - it takes a long time to fully dry during which it shrinks down. I also tried spraying a wet coat and that gave a terrific finish but peeled off in big chunks when I tried to sand it. Maybe it's best for figures or other stuff where you don't do anything to the primer other than paint over it?

Will

[noeyedears]

alclad grey

halfords grey (decanted) goes on a bit "dusty" but polished up good.

mr surfacer grey and white

tamiya grey and white

all these are top notch primers.

[treker_ed]

I tend to use halfords primer or tamiya fine primer. The halfords grey plastic primer is ideal for large areas and darker colours. The tamiya fine primers are good for when you want a flawlessly smooth primer surface.

[SleeperService]

Hi There

That paint finish is what you get when the paint beads like a drop of water on wax paper, instead of pulling the paint flat it rolls under and tries to make a sphere. Think of it as capillary action in reverse if that helps.

Misting will get a finish but it won't adhere strongly to the surface hence the poor results when sanding. Basically it leaves tiny blobs of paint so you get a finish like a cobbled street on a tiny scale. The top-coats will flatten out but will need to be thicker.

So what to do? Probable culprits are:

Silicone based release agent, detergent doesn't have much effect, get it off with a soft brush loaded with meths before detergent for anything else like wax deposits and then meths rather than alcohol at the end.

Alcohol with evaporation retarder in. This leaves a slight oily deposit behind replacing the gunge you've removed.

Oil from your fingers, some people have rusty fingers which leave marks on metal, others have oily fingers which leave grease smears. If that's you then you need to wear gloves.

Lower grade styrene leaving a very smooth almost polythene like surface. Getting more common nowadays unfortunately. Trick here is to roughen the surface up so it looks like it's been lightly sanded, fibre glass pencil will get into the corners. If you know what you're doing a bead blaster works great.

Halfords plastic primer is designed for the latter as it's the material used for car bumpers and body trim. For normal styrene the standard Halfords primer is better. To get a good finish with either fill a jug kettle to just over half way, make a cup of tea or coffee, fill the kettle with cold water and drop the can in. Drink your drink. Take the can out (it should be just too hot to hold without a rag) and give it a good shake for the full two minutes. Spray your part from about 18 to 12" away depending on temperature warmer is further. Give as light a coat as possible. That should give you a nice smooth finish.

The heat makes the can pressure a little higher and the paint a LOT freer flowing so the droplets are much smaller. I've been using their paint since I were a lad in the hobby and in a car body-shop or two. I've only found two-pack that wouldn't go over it and the sooner that stuff is banned the better. Lethal doesn't begin to cover it.

As part of my advert for Halfords I'll add that it's made in Manchester by a factory that really knows it's business, and I don't and never have worked for them.

HTH and sorry for rambling. I know how frustrating it can be when things don't work and you can't work out why.

[Nigel Heath]

For big areas like (essentially) a complete model Tamiya white and grey primers in spray cans. For small parts; Alclad grey and black (micro filler and gloss) applied with an airbrush. I use Tamiya metal primer on the odd metal part as its in a can and is convenient - it is clear in finish. They all work well.