Acrylic Surfacer Primer for hairystick brushing ?

[AltcarBoB]

I am building a kit that needed a considerable amount of filing, sanding, filling and scraping. I thought a good session wet sanding with several grades of wet and dry would get the scratches out but a coat of Ultimate Primer showed up lots and lots of scratches. Short of smothering the model in filler and starting again with the sanding what can I do. 🙄

 

I was thinking of a Surfacer Primer to cover up the scratches, only model one I can find is Mr Surfacer but it seems to be a Laquer cellulose, I try to avoid anything with stinky nasty solvents in like the plague so is there an Acrylic equivalent that can be used. I prefer hand brushing but I airbrush or rattle can if its absolutely neccessary.

[bentwaters81tfw]

Halfords do a Filler Primer in an aerosol. Take a look at tomprobert's 1/32 Shackleton build, you will see how useful it is. I use it too for anything with warts.

[RJP]

Curious about the standing stage - how fine did you go with the sandpaper? I generally start with 400 grit or so for shaping and serious removals (think 1960s rivets) but get down to much finer grades to restore the surface.

 

I do recall the caution from a woodworker friend that worn out sandpaper isn't finer grade, it's just worn out.  How often have I tried that only to fail?😄

 

One other limited-use tip is to restore surface integrity using a very thin coat of liquid cement. Not for the faint of heart, that one!

[AltcarBoB]

7 minutes ago, RJP said:

Curious about the standing stage - how fine did you go with the sandpaper? I generally start with 400 grit or so for shaping and serious removals (think 1960s rivets) but get down to much finer grades to restore the surface.

 

I do recall the caution from a woodworker friend that worn out sandpaper isn't finer grade, it's just worn out.  How often have I tried that only to fail?😄

 

One other limited-use tip is to restore surface integrity using a very thin coat of liquid cement. Not for the faint of heart, that one!

I started wet sanding with a 400 pad, then 800 pad. 1200 paper and 6000 micromesh. I just seem to have ended up with smooth edged scratches 🤪

 

I will try the liquid cement trick. If it goes horribly wrong and melty do  you replace it under warranty 🤣

 

[AltcarBoB]

1 hour ago, bentwaters81tfw said:

Halfords do a Filler Primer in an aerosol. Take a look at tomprobert's 1/32 Shackleton build, you will see how useful it is. I use it too for anything with warts.

I will get some but not sure if Halfords open yet. I will try @RJPs suggestion of liquid cement on a small patch first.

[RJP]

9 minutes ago, AltcarBoB said:

 

I will try the liquid cement trick. If it goes horribly wrong and melty do  you replace it under warranty 🤣

 

Ha!  Think of me as a government telling everyone what to do during a pandemic and heading for the hills if it doesn't work. You are definitely on your own. 😄

 

I think of it as a heroic measure, the last attempt before the patient's inevitable demise.  Even if it goes wrong you are no further behind.

[bentwaters81tfw]

Yes, most Halfords are open. The stuff comes in a can with a matt yellow top. As usual, build up in layers rather than try it in one coat.

[AltcarBoB]

Just spoken to a friend who is in the motor trade to see if he could get me some hi build primer. When I described my problem he said try putting two or three coats of primer on let them go rock hard then sand back to the scratches again. Repeat if necessary, he said that should cover most scratches. 

 

I will try this first it's the safest.

[Steve Noble]

If you have deep scratches then I would suggest your filler/filling technique is not good. Trying to cover the scratches with filler primer may work, but it's far better to prep the filled areas better and not have the scratches in the first place. Paint can only hide so much. What sort of filler did you use in the first place? 

[Black Knight]

5 hours ago, AltcarBoB said:

I am building a kit that needed a considerable amount of filing, sanding, filling and scraping. I thought a good session wet sanding with several grades of wet and dry would get the scratches out but a coat of Ultimate Primer showed up lots and lots of scratches. Short of smothering the model in filler and starting again with the sanding what can I do. 🙄

 

I was thinking of a Surfacer Primer to cover up the scratches, only model one I can find is Mr Surfacer but it seems to be a Laquer cellulose, I try to avoid anything with stinky nasty solvents in like the plague so is there an Acrylic equivalent that can be used. I prefer hand brushing but I airbrush or rattle can if its absolutely neccessary.

I use 'Liquid Green Stuff' from Warhammer/Games Workshop

As it comes its slightly thick and cannot be wet sanded.

I thin it with Klear/Future/Astonish which makes it water resistant when dry. It also makes it dry quite speedily.

I use a small paint brush* to paint it over where I've sanded and it fill in the scores nicely, then I use a very fine grade - 800 or 1200 or 2000, w & d to sand the LGS down.

A tub costs between £3.50 and £6, depending on where you buy it but it lasts a very long time, I've been using my current tub for several years now

 

* I should devote one paint brush to the LGS but I keep forgetting and just wash my brush out in my brush cleaner, just like paint

[AltcarBoB]

@Black Knight thanks that sounds like handy stuff I have ordered some, even if it doesnt get used on this build it will be useful.

[colin]

5 hours ago, AltcarBoB said:

Just spoken to a friend who is in the motor trade to see if he could get me some hi build primer. When I described my problem he said try putting two or three coats of primer on let them go rock hard then sand back to the scratches again. Repeat if necessary, he said that should cover most scratches. 

 

I will try this first it's the safest.

I use Mr Surfacer primer this way, build the coats up and wetsand back

[Steve Noble]

If you want something better than any filler primer just buy some Impa Finissage as shown below. It's a one part filler, just squeeze a little from the tube and apply sparingly over the area where you have scratches. It dries in 10-20 mins and is dry or wet sandable. It produces a very fine surface ready for primer and paint. I've had a tube over 5 years and it's still perfect stuff. It works particularly well over all areas of filler that have scratches or sanding marks still present..

 

[colin]

6 hours ago, Steve Noble said:

If you want something better than any filler primer just buy some Impa Finissage as shown below. It's a one part filler, just squeeze a little from the tube and apply sparingly over the area where you have scratches. It dries in 10-20 mins and is dry or wet sandable. It produces a very fine surface ready for primer and paint. I've had a tube over 5 years and it's still perfect stuff. It works particularly well over all areas of filler that have scratches or sanding marks still present..

 

Have this and agree it''s very good, squeez a small blob onto a piece of plastic, if the blob skins over just mix it around or add a drop of Mr levelling thinner to make it more like a thick Mr Surfacer.

That's the only problem I find with it, for the small amounts I need it skins over very quickly before you can use it. But it does sand down very nicely and sticks like the saying '---t to a blanket'

[Giorgio N]

7 hours ago, Steve Noble said:

If you want something better than any filler primer just buy some Impa Finissage as shown below. It's a one part filler, just squeeze a little from the tube and apply sparingly over the area where you have scratches. It dries in 10-20 mins and is dry or wet sandable. It produces a very fine surface ready for primer and paint. I've had a tube over 5 years and it's still perfect stuff. It works particularly well over all areas of filler that have scratches or sanding marks still present..

 

 

 

Interesting, never heard of it before but sounds like something I have to try ! I see that it's also quite inexpensive compared to most modelling fillers. I should check with the local car accessories shop if they have it

[Giorgio N]

On 6/10/2020 at 6:18 PM, AltcarBoB said:

I started wet sanding with a 400 pad, then 800 pad. 1200 paper and 6000 micromesh. I just seem to have ended up with smooth edged scratches 🤪

 

I will try the liquid cement trick. If it goes horribly wrong and melty do  you replace it under warranty 🤣

 

If you still have scratches after having gone through the various grits, I wonder if you have followed a circular motion while sanding or just a linear one ?

If the latter, then you can try to sand the area again, this time in a circular motion, starting with the 400 pad and then down to 6000

[Steve Noble]

It depends what filler you used in the first place? Some fillers are poor and never sand back smoothly. I tend to use automotive fillers, not model filler. Model filler shrinks when drying and often doesn't sand too well. I find automotive products are far better in general for modelling use.

[AltcarBoB]

Three coats of primer left to cure and then wet sanded back to the plastic has filled the scratches nicely. 

 

It would still be nice if a manufacturer came up with a brushed acrylic hi build primer for modelling.

 

I have got an aerosol hi build primer for cars and a bottle of Liquid Green on the way. I will have a play with both.