Would a primer help hide some or all of the sanding marks from sanding the model from gap filling.I sanded my Maz 537 tank transport but it looks alittle rough and I thought it might help if I put primer on it but not sure.Before I put the prime on and waste my time I thought I would ask you great folks first.

Happy Modeling
Tom

Tom,

what grit sandpaper did you use? Try using a finer grit sandpaper over the same area and see if the sand marks come out first.

I used fine grit sandpaper but still has those scratch marks. Will the paint cover them up or will the primer be thicker than paint and cover it better.

Happy Modeling
Tom

Primer (or paint for that matter) will not cover up the sanding marks. But a good primer will fill them in, which allows you to so some additional sanding to even out the surface. Your best bet would be to sand the bare plastic as well as can be done, then use a primer. After the primer coat has hardened, then wet sand the area again using progressively more fine grades of sandpaper until the marks are smoothed out to your satisfaction.

HTH,

mr. surfacer 500 is said to cover somewhat deep scratches and is sandable

fine grit is different than modeller fine grit. I would recomend you take a trip to an automotive store and look in the paint section. I found a pack of sandpaper that has grades from "fine" to super, super fine! it helps because they give you one of each, and keep them in order, so you can use the different degrees of fineness. But, because im lazy, the second most finest sheet, and there are no sanding marks visable. Hope this helps!

If you use at least 600 grit wet/dry sandpaper the scratchs should not show.

You can use primer on the rough spots, just wait overnight and sand it down the next day.

Keep a bowl of water to wash the paper as your sanding and it will last longer.

cheers

Hi Tom

As already been said you should be using wet and dry for fine sanding.

I'm in the UK but I imagine it's the same for any country.

Generally speaking there are two main types of abrasive materials in sheet form available for smoothing and sanding surfaces (not just models) , finishing prior to painting.

Sandpaper and wet and dry. Both are normally sold at most DIY stores etc. The really coarse stuff is sandpaper and whilst not made from sand it looks pretty much like it and is that sort of light colour. Aimed at wood or painted surface preparation.

Wet and Dry on the other hand is very fine and prone to clogging, hence the wet part.
It is normally a dark grey colour and has a cloth/fabric or stronger type of backing.

If you wet normal sandpaper with it's paper back it becomes useless.

W&D on the other hand with it's backing is made for getting wet. Indeed if you don't use water it will clog very quickly due to its fine abrasive surface and become less efficient.

It's used mainly for finishing hard surfaces such as metal or paint when you need it really smooth like a cars paintwork.

There is normally a number printed on the reverse of the sheets which denotes the grade, or in other words how fine or coarse it is. The higher the number the finer the abrasive.

I have 1500 grade which is very fine and will leave the surface smooth as the proverbial baby's bottom.

An alternative to the D.I.Y shop and you may find carries the much finer grades, is auto repair/spares shops as already mentioned.

Regards

Alan

My primer problem is the enamel primer I used to cover PE and metal barrels didn't get mixed properly or was old or something, because it has stayed "gummy" and tacky on the model. Do I just wait it out (already waited 3 days) or should I spray it with another coat or a coating of sealer?

And will an acrylic sealant work over tacky enamel?

If this primer is from a spray aerosol can, it may be old stuff.
Or it is non-sandable primer/filler.
I suggest waiting it out longer before adding anything on top. Apply heat, but not enough to damage your model.

Thanks, I'll try the old hair dryer and see what happens!

Primer will hide scratch marks .......... and most of the detail. Use a piece of #000 Steel wool to remove any scratching on the styrene, if that doesn't work try #0000 Steel Wool. Your base coat of paint will cover most of the scratches anyway, gouges it won't cover.

Hope that helps,
razorboy