The Spray Painting Thread

["Z" UTE]

Ok so from what you said before, the stage where im up to.....

So i've basically got my two coats of high fill,

Next spray a acrylic black guide coat...

Then sand wet 360 until flat with a big block ( what size?? i've got one that is about 7cm x 10cm)

Re- apply more highfill (only is needed?? or just apply anyway??) with final coat making it thinner (40%primer 60%thinners maybe???)

Spray guide coat again

Sand 800 wet ....

Please correct me if im missing something...


Thanks again...

Jeri

Jeri, you are on the right track. The guide coat is a "mist" coat just enough to give a haze over the primer, but not heavy enough that you can't see the primer. Use a can of black acrylic held about 600mm from the job and give it a very quick light coat. What you are looking for is a coat of small dots separated by about 1mm.

By long block I mean 30cm or longer, pick one up from your paint and panel supply shop.

You can do the 360 knock back dry if you wish, it is probably more time effective dry.

You will only need to apply more hi fill if you can not get the current lot flat, without rubbing through.. If you still have heaps of paint on the job after the initial knock back, you can then wet sand with 800 after applying another guide coat. Buuut if you think you are getting a bit thin stop and apply another coat of primer.

cheers Chuck.

[o_man_ra23]

The sander I bought was a 17" (sorry, thought it was 27" before, was mistaken) which works out about 43cm, and is a standard size. Was $25 from a paint/chemical supplier. It has a solid wooden handle most of the length of it, then an aluminium base, with a rubber pad on the paper side of that, and a toothed cam clamp either end to hold the paper on.

Also my last post mentioned metacryl2... that was a typo, it was meant to say metalux2

[DrNick]

I noticed you recommend to dry sand the primer.

I have tried this but the paper always clogs up after about 2 strokes and I find it impossible. Therefore I wet sand the primer and it really makes the whole process much slower as I have to wait a long time for the primer to be dried out before I can colour coat it.

What are you using to dry sand the hi fill or primer surfacer? I have P800 on a cork block.

[pac]

wet wet wet sand 400 at first finish off 800 before paint, only dry sand highfill 180-240 if recoating with highfill to perfect repair before paint

["Z" UTE]

Really depends on the quality of the primer, and the grade of paper as to whether it clogs. But for a quickish knock back of hi fill, to get the surface flat before a primer coat, dry is the way to go. On primer proper wet sanding is the only way to go.

cheers Chuck.

[o_man_ra23]

I have 80 to knock back after I have sent the orbital over (pre-primer), and 120 to rough back the first coat or 2 of hi fill. Need to get more paper for further sanding.

Something I was told by an old panel beater was that primer is porous, so should never be wet sanded. Is this no longer true?? I am using 2 pac primer.

["Z" UTE]

Owen, yes the primers are porous, verging on hydroscopic. That is why you will see the old timers with the panel on a stand out in the sun somewhere, doing the wet sand. (The sunlight and shading also shows up all the imperfections much better than fluro's.)

With modern ovens they just do the wet sand, and then bake the car for 20 minutes before laying any paint down.

You guys will have to decide on what grade of paper you are using for each of the stages.

From my experience:

Quick knock back of bog 80 grit,

Bog intermediate, and shaping hi fill, 120-240 grit,

Final bog and hi fill 320-360grit,

Primer 600-800 grit.

Last thing you want to do, is use too coarse a piece of paper before laying down some colour. I saw a TA22 in Sydney for sale, that had obviously been rubbed with 120-240, and then colour sprayed. The paint was great but you could clearly see the sanding lines!

Keep your paper sharp, and toss out the old worn down stuff. Worn 600-800 is equivalent to 1200, which is way too smoth, and will not provide a "key" for the paint to grip to, and yes the paint literally will fall off. If you have to push hard to get the paper to sand it is stuffed, change to a new sheet, and let the paper do the work.

Buy your sanding paper in bulk from your paint supplier, costs about 80 cents a sheet, compared to $1.20 plus at the automotive stores and Bunnings.

cheers Chuck.

[Jeri]

Chuck...

Mate if i get the whole car to the stage where my doors are upto at the moment (2 coat of hi fill/primer)
can it be left untouched for 6+ months?

is it possible to fix (weld) the rust after this stage?


Only reason is because i might be buying another house in the next few months, which means full concentration on the house (renovations), and i just thought that if the car is at that stage at least it'll protected from surface rust and it can be transported to the new place..

Thanks..

["Z" UTE]

Jeri, you can leave the car in primer for 6 months or so, provided that the car is stored indoors.

Before application of any paint, the surface would have to be scuffed back, as a hard surface film will develop on the primer over time, and again the paint will not stick to this surface.

As mentioned by others, primer is quite porous and will reatin, and even draw in moisture laden air. So the car will have to be indoors. Park it under a tarp outdoors for 6 months, and you will have to take all the paint off and start again.

Rust repairs, will necessitate the removal of any paint that you already have in the area of the repair, unless it is ZINC weldthrough primer.

cheers Chuck.

[Jeri]

So basically as long as its indoors its ok.. i would have to start sanding anyway, because when i get back into it in the future, i would have to start from the guide coat sanding.`....

and as for the rust repairs i would have to:

rub back to metal around the area

weld new plate

bog... sand to shape

etch primer where i can still see metal

hi fill the area

then i should be ready for doing the guide coat sanding for the whole panel

Plz correct me if im missing something....

thanks

["Z" UTE]

Jeri, /\ sounds good to me. You have done well so far. It is great to see someone having a go at a task which can give a great deal of fullfilment. Best of luck, and I hope the house reno's do not keep you away from your Celica for too long.

cheers Chuck.

[Harreh]

Ok so I've got the spoiler for my car which desperately needs to be painted before it goes back on.

I have about 500mls of the paint that the car was repainted in and its a 2pack, I've never worked with 2pack before, done a bit with acrylic though.

My understanding is I'm going to need to get the primer, clear coat, hardener and thinners but I cant for the life of me online find a decent guide of mixing and what ratio's are required, also what types are needed, do I just use a generic 2pack primer? If someone could shed some light on this for me it would be great.

Also if someone could advise a good place on the Central coast or in the north sydney area to pick these things up it would be great.

[love ke70]

just a question, have you asked a shop how much it would cost for them to paint it if you gave them the paint and the spoiler off the car? may find that for cash it wouldnt cost much more than what you would spend on all the bits and peices you will buy, and you dont have to worry about the safety factor of using 2pac...
if you do wanna, you can get a mixing stick from the paint place that gives you the ratios.
and im pretty sure its all been said in here already

[Harreh]

I've had a look through but 36 pages

Yeah unfortunately it looks like its gonna be a fair bit, most the places in my area have quoted between $400-700 for spraying and fitting which is fucking ridiculous with me supplying paint.

I wouldnt mind doing it myself as I'd like to learn and I wanna be spraying some FG parts soon.

["Z" UTE]

Harreh, what brand of 2pak is the paint? Is it an ISO free paint? If not, bite the bullet and find a spray shop. The Isocyanates in the other paint are deadly carcenogens. You need to wear a full suit and respirator when using them. The air supply for the respirator can not come from your compressor, due to oil contamination, which will coat your lungs and kill you.

Do you need a claer coat?, as most solid 2Pak colours are gloss, and do not need a clearcoat. If your paint is a special effects paint such as pearls, you will need a clearcoat.

If you are using Iso free 2Pak, any acrylic primer will do.

2Pak over acylic works.

Acrylic over 2Pak can fry, particularly on sanded edges.


Match the brand of hardener to the paint brand, as mixing brands can lead to problems. The ratios are on a data sheet, you ask the paint supply shop for the data sheet, or it will be on the can of paint.


If you spoiler is plastic, you will need plastic primer, primer, colour and clearcoat, plus thinners. Do not buy general purpose thinners, just use the 2Pak brand of "reducer" for all the thinning.

cheers Chuck