Practicing spray painting…?

[ArAKern]

Sylvia phoenix?

Yes it is a Phoenix from Stuart Taylor Racing (believe he brought the writes to produce them from Sylvia) but now produced by RAW.

 

[stuvy]

Yes it is a Phoenix from Stuart Taylor Racing (believe he brought the writes to produce them from Sylvia) but now produced by RAW.

He did a long time back, we used to rave one about 19 years back

 

[gt6s]

I practiced on a horse box. First job I did with a compressor i built costing THREE QUID Needless to say not a very good compressor.

 

[The Z'eer]

You could be throwing a lot of paint from the gun

I've got a feeling that might be so. I used a 50 % overlap, kept the gun at a right angle from the panel and 7 inches distance.

 

[The Z'eer]

Its important to strain your paint.

It was strained

 

[The Z'eer]

when panel wiping ...always new paper towels , soak one so its almost dripping and wet the panel , follow behind quickly to dry it with another towel , dont let it dry on the panel , if the panel is suspect for grease etc throw the towels and repeat

Thanks Steve, will do

 

[The Z'eer]

The 2 bar needs to be set with the spraygun trigger open, the fluid needle shouldn't need to be wide open for that paint. Have you checked the viscosity of the paint with a viscosity cup?

I set the pressure via the gun regulator with gun trigger gently depressed, no paint delivery.

 

[The Z'eer]

When I mixed the paint I filled the cup on the spray gun about two thirds to three quarters full. Nearly all the paint in the cup was used on that first coat for that one panel. This is considered too paint for one coat ?

 

[carbon]

So here's my first attempt at spray painting via my DeVillbiss GPG...
View attachment 341770

... Lechler 29107 onto bare steel. As a first attempt it was ok, although on inspection...



View attachment 341771View attachment 341773

...some of these imperfections look like tiny craters and others tiny bumps/pimples for want of a better word.

Would these be dust particles? Other than that it "appears" ok, I guess. Complete novice.

View attachment 341770 View attachment 341771 View attachment 341773

Is this one coat of expoy primer?

I haven't used any thinners

I would have expected you to use some thinners for this

When I mixed the paint I filled the cup on the spray gun about two thirds to three quarters full. Nearly all the paint in the cup was used on that first coat for that one panel. This is considered too paint for one coat ?

According to the data sheet for the Lechler 29107 the 'Theoretical coverage: 1 l mixture = 4.5 m² at 100 μ' from that I would have expected at least two coats from the quantity you had

 

[steveo3002]

i think alot of this will boil down to pratice , you can be told so many times and read all the books , but you will get the hang of it with more practice

are you wearing a paper suit and wetting the floor?

 

[The Z'eer]

Ok, so I'm still practicing and using the practice panels and so far there seems to a bit of an improvement. Getting used using the gun and getting the paint on with no runs and less orange peel.

I've experienced some dust in the primer but I've cut that out with 600 grit when I keyed the surface for the application of the top coat (direct gloss Mipa Super Black).

The top coat has gone on rather well except for a little orange peel and dust in the paint which I'm happy to cut out.

My question are these:

1. What grit of paper should I go in with for this job?

2. I'm guessing I ought to continue block sanding with this process?

3. Should I be dry sanding or wet?

Thanks

 

[MetalMonkey]

Ok, so I'm still practicing and using the practice panels and so far there seems to a bit of an improvement. Getting used using the gun and getting the paint on with no runs and less orange peel.

I've experienced some dust in the primer but I've cut that out with 600 grit when I keyed the surface for the application of the top coat (direct gloss Mipa Super Black).

The top coat has gone on rather well except for a little orange peel and dust in the paint which I'm happy to cut out.

My question are these:

1. What grit of paper should I go in with for this job?

2. I'm guessing I ought to continue block sanding with this process?

3. Should I be dry sanding or wet?

Thanks

Everybody has their own method - I can only tell you what works for me.

Primer I finish dry with 400 straight off the DA, block with 400 as required - then spray base/clear or direct gloss.

To deal with any peel, runs, bits or get a mirror finish, I wet sand the topcoat with a block. It is imperative to keep it wet and keep washing the paper so you don't leave any scratches.

For a bad run I might drop down as far as 320 to level it out or slice it back with a razor blade - and then switch through the grits, 600/800/1200/1500 and then finish off with a trizact 3000 just to cut down the buffing time.
Buffing with a rotary, I prefer 3M or Menzerna. Farecla G3 works ok, but I prefer Menzerna.

 

[The Z'eer]

Everybody has their own method - I can only tell you what works for me.

Primer I finish dry with 400 straight off the DA, block with 400 as required - then spray base/clear or direct gloss.

To deal with any peel, runs, bits or get a mirror finish, I wet sand the topcoat with a block. It is imperative to keep it wet and keep washing the paper so you don't leave any scratches.

For a bad run I might drop down as far as 320 to level it out or slice it back with a razor blade - and then switch through the grits, 600/800/1200/1500 and then finish off with a trizact 3000 just to cut down the buffing time.
Buffing with a rotary, I prefer 3M or Menzerna. Farecla G3 works ok, but I prefer Menzerna.

Once again, thank you for imparting your knowledge, certainly appreciated

So just to confirm you're dry sanding at 400 grit via a dual action sander? Can I ask why I would be block sanding afterwards with 400 as well?

I have used Menzerna products for metal polishing, I was quite pleased with the results

 

[MetalMonkey]

So just to confirm you're dry sanding at 400 grit via a dual action sander? Can I ask why I would be block sanding afterwards with 400 as well?

Dry sanding the primer, yes.
Traditional primer tends to absorb water, so I prefer to sand it dry. Some people will wet sand primer, but then you really need to bake it afterwards to ensure it is dry before spraying your topcoat.
If you are using epoxy primer, its not a problem, obviously – although you do still need to ensure any water doesn’t get trapped in any crevices that might later be blown out when you spray.

The DA sander will level to a degree, and finish quickly - but it has a tendency to follow the surface it is on, especially if you are using an interface pad.
That’s fine if your panel is flat, but if you have a lump or a bump in the panel (from a repair or filling a ding etc ) it will still be there after you have run the DA over – blocking it working at 90 degrees strokes and some guide coat will level it out.

 

[steveo3002]

for sanding defects , use the least aggressive paper you can , most of my small defects come out with 1500 or finer , maybe 1200 for the worst bits

 

[The Z'eer]

On one of the practice panels, painted in Mipa direct gloss (black) around a month ago, I tried the finger nail test. Unfortunately if I press quite hard and indentation is left. Is this this to be expected with direct gloss paint?

I made sure I used the correct ratio of 2:1 and followed the data sheet, I am using regular hardener and left the paint to cure naturally.

Oddly if I rub my finger across it, repeatedly with some pressure the indentation can (not always) disappear, no paint appears on my finger when I do this.

 

[steveo3002]

On one of the practice panels, painted in Mipa direct gloss (black) around a month ago, I tried the finger nail test. Unfortunately if I press quite hard and indentation is left. Is this this to be expected with direct gloss paint?

I made sure I used the correct ratio of 2:1 and followed the data sheet, I am using regular hardener and left the paint to cure naturally.

Oddly if I rub my finger across it, repeatedly with some pressure the indentation can (not always) disappear, no paint appears on my finger when I do this.

no not normal , id expect it hard next day or 48 hrs max

funnily a mate painted something the other day and thats stayed soft ish

 

[The Z'eer]

no not normal , id expect it hard next day or 48 hrs max

funnily a mate painted something the other day and thats stayed soft ish

Trying to work out what May of causes this.

The paint and hardener is about four years old, albeit only opened once. Possibly this is the cause?

If a little too much of the thinners we’re added, could this be the cause?

 

[carbon]

If a little too much of the thinners we’re added, could this be the cause?

As long as the ratio of paint and hardener is correct then the amount of thinners shouldn’t make any difference, as once the thinners has evaporated the paint should cure. The problem with to much thinner is you are more likely to get runs

 

[The Z'eer]

As long as the ratio of paint and hardener is correct then the amount of thinners shouldn’t make any difference, as once the thinners has evaporated the paint should cure. The problem with to much thinner is you are more likely to get runs

Ok, thanks for clearing that up. At least I know it’s not the addition of thinners