My paint spraying attempt

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Deano1712
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Joined: Sat 05 Aug, 2006 12:56
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  M roadster S50
Location: Leeds

My paint spraying attempt

Post by Deano1712 »

In years gone by I have done a few spray jobs on cars - panels and even full resprays. The quality was usually average at best due to lack of knowledge, experience or inadequate equipment. I have learned quite a lot having a go but never got to a point where the result was perfect, or even close. With my zed in need of some cosmetic attention I have been wanting to do the work myself but want a top quality job doing. To get to that point I needed to get a lot better at spraying and have been on a mini-journey over the last couple of months trying to get to there. The main lessons I have learned from spraying in the past is that poor gear, lack of preparation and/or being in a hurry to get done is a dead cert way to failure. I have given myself time in the last couple of months accumulating equipment, getting it setup properly and learning how to use it. There is lots to learn on the internet, particularly YouTube where there are countless videos of all states of paint preparation and application. I have also found http://www.autobody101.com/forums/ a useful resource.

With equipment its possible to spend lots of money – some spray guns are £300+ each and ideally you need one each for primer, base and clear! My budget was more restricted so what you see here has been put together for £700 total.

Starting with the compressor I went for an ebay special from China. Its 3hp which is as much as you can easily power at home. The tank is a large one – 200 litres and I have found it provides plenty of air for what I need. I built a mini shed for the compressor since my garage is full of gear and there is no spare room. This has the benefit of keeping the noise outside of the garage (although its a lot quieter than I expected anyway). So far the compressor has worked very well it seems to have been a good buy.

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For spray guns as stated above there is some expensive kit about. I used http://www.spraygunsdirect.co.uk/index.php and their recommendation of an Iwata AZ3 and also a Kestrel primer gun. The primer gun has a bigger nozzle, needed for spraying the medium. More expensive top coat guns are no doubt better but for my purposes and ‘learner’ status the Iwata has been great and performs well. Note that both guns have a regulator fitted so gun pressure can be set accurately. The HVLP top coat gun needs 29 psi at the inlet.

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This part may be a bit OTT but I took an idea from a spraying forum and made a air manifold to bring air into the garage from two compressors ( I have another smaller compressor which I have been using for an air-fed mask). The manifold has concentric pipes so the incoming air can be water-cooled. This condenses any water and also delivers nice cool air to the mask :)

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Before I painted something important I wanted to do a test panel. I bought a z3 door on ebay for £100 and used that to try the gear out. The door on my car has a scratch on it so the plan was the new door may end up on the car if it went well, otherwise I could sell it on the bay for what I paid.

Here is the door as I got it and then after sanding. It was in fair condition with a few chips and blemishes. I was hoping to sand these out and just apply top coats (no primer). However it soon became clear it would need primer since many areas were sanded back through the base in order to get it smooth. I sanded it back using 800 grit (wet), which is fine enough for top coat to go on, but could have used a coarser grit if I had planned on using primer.

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Before applying top coats I wanted to get the garage in a clean state so lined it out using a tarpaulin and got a couple of powerful halogen lights. Good lighting is important when spraying to see the paint going down.

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The door was first covered in three coats of 2-pack primer. This goes on easily and is a good way to practice spraying. The primer gets sanded back so any mistakes (runs etc) can corrected. After it dried I used a thin black coat from a rattle can to provide a ‘guide’ coat. This gets sanded off using 800-grit paper. When all the guide coat is removed you know its a completely smooth surface ready for the top coats.

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I got 2-litres of base coat paint which should be enough to do what I want on my motor (bonnet, bumper, front wings, sills and doors). Lechler paint is seriously expensive! To ensure the paint is prepared right I got a viscosity cup and filters. When mixed the paint should pass through the cup in 14-15 seconds. This worked out right first time. To paint the door I used 250ml of paint with around 80% of thinners in addition. There is no activator with base coat.

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The base coat goes on in 4 layers. First layer is a light dust coat which dries and forms a good adhesive layer to the primer. Two heavier wet coats are then applied with 5-10 mins between coats. The last coat is a lighter coat with the gun further away from the panel. This helps to make the paint colour more even.

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After an hour or so the base is dry enough for the clear coat. Clear is a 2-pack paint with activator and a bit of thinners. This is applied in 3 wet coats with 10-minutes between coats. Its sticky stuff and its best to get away from the area after the final coat is on. Its also toxic hence the need for an air fed mask.

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So we are all done. Sadly not! Pro’s may be able to stop at this point but there are always a few blemishes and/or inclusions in the paint in a diy workshop so the paint was now sanded down smooth using a very fine 2500 grit paper (wet). This was surprising quick to do since the clear went down very smooth. Here is the panel complete after 30-mins of sanding.

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A further 30 mins polishing with a rotary polisher using medium and fine compound and we are all done. Happy days for a first attempt its worked out really well. Its a good result for around 8-hours work. There are a few blemishes but its 95% good and the next job will be better still.

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Here is the next job for next weekend...
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Boysie
Joined: Sat 23 Apr, 2005 14:24
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Re: My paint spraying attempt

Post by Boysie »

Great write up
I was glued to the pc screen reading
I did think the hardtop would appear at the end
Great job Deano, I love your dedication to detail

I have always admired people who can spray
"Preparation" is the answer
I can put my hand to most things never tried spraying
I had a client who sprayed all his internal doors in his house, the finish was amazing


I wish you were my neighbour, well maybe a few days away lol :lol:
Ray

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janijoeli
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Re: My paint spraying attempt

Post by janijoeli »

This is DIY gone pro! :) Awesome job Deano! I am slightly jelly about your garage and setup.

I don't see much, if any, orange peel effect on your finished door. :thumb: Did you have any before the final sanding and polishing? I am asking because my car's bonnet has some orange peel effect I'd like to take care of, preferably myself. I just don't know if simply sanding and polishing would do the job, or if it would need to be re-re-painted...

Cannot wait to see that Hamann roof painted :)
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Brian H
Joined: Tue 16 Dec, 2008 19:55
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Re: My paint spraying attempt

Post by Brian H »

Well done Deano, I was like boysie, glued to the screen and hoping there was more when reading :thumb:

Now awaiting the finished hardtop pics.
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Badman gee
Joined: Sun 14 Nov, 2010 10:45
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Re: My paint spraying attempt

Post by Badman gee »

Excellent effort
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Del
Joined: Sat 19 Nov, 2011 18:35
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Re: My paint spraying attempt

Post by Del »

Looks better than what professional body shops in the Bristol area have done for me over the years. :x
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
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Re: My paint spraying attempt

Post by Southernboy »

Impressive dedication to detail...well done on a superb effort and a great write-up...Looking forward to "next weekend's results"... :cheers
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z3bedee
Joined: Fri 24 Jun, 2011 10:57
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Re: My paint spraying attempt

Post by z3bedee »

Hey Deano that looks like an excellent effort and a brilliant write up. Don't be paying for anymore panels to practice on I've got a bonnet and front bumper that I'm more than willing to let you have a go at :lol:
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Deano1712
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Re: My paint spraying attempt

Post by Deano1712 »

Thanks for the comments. Its certainly all about preparation, there is actually not much skill involved in the spraying part. As i said its not perfect. It was a windy day and there are a few bits in the paint. Most are tiny and ok but there is one that is bigger and spoils it. I may try an experiment with a dremmel. :roll:

janijoeli - with orange peel its usually possible to sand it out. Its just hard work to do so if its thick. There wasnt much on the door here, just a bit around the edges. I need to apply a bit more paint around the panel edges next time.
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pingu
Joined: Fri 30 Apr, 2004 16:01
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Re: My paint spraying attempt

Post by pingu »

Excellent job. How will you match the paint with the rear of the car? Have you got a paint colour meter (they don't come cheap)?
Pingu
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Gazza
Joined: Tue 04 Oct, 2005 20:58
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Re: My paint spraying attempt

Post by Gazza »

pingu wrote:Excellent job. How will you match the paint with the rear of the car? Have you got a paint colour meter (they don't come cheap)?

The paint suppliers will have the colour test meter although that doesn't guarantee a perfect match.
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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Deano1712
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Re: My paint spraying attempt

Post by Deano1712 »

pingu wrote:Excellent job. How will you match the paint with the rear of the car? Have you got a paint colour meter (they don't come cheap)?
I just got standard code 309 paint and I cant tell yet what the match is like to the rest of the car. I will know when the hardtop goes on. I was hoping there will just be one blend line at the door rear edge at worst. That would just need rear 1/4 panel blending at the front. If the hardtop shows up bad against the area above the boot lid then I will probaobly have to spray the whole car. No problem if so its just a longer job. All of the panels come off and I can paint them all at my leisure.
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Gazza
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Re: My paint spraying attempt

Post by Gazza »

Just remove the fuel flap and the paint shop can match to that.

Avoid just ordering paint by the code number, as an example I was told there are 15 shade variants on Estoril Blue :shock:
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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pingu
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Re: My paint spraying attempt

Post by pingu »

As you have gone this far, I'd definitely do the whole car, especially if the car has been kept outside. Panels that are on the top (bonnet, boot and roof) would get more UV than the sides, so they wouldn't fade at the same rate.

There's also bound to be scratches, etc. on the rear, and that would be really annoying if you hadn't done it when you had all the kit out.
Pingu
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Jonttt
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Re: My paint spraying attempt

Post by Jonttt »

Great job deanno, looks like you have been having fun. Looks like you have got to the point of quality of finish were only an eagle eye would spot defects.

Makes my efforts at colour coding my rear grill look feeble lol

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Deano1712
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Re: My paint spraying attempt

Post by Deano1712 »

Gazza - good point about the fuel cap. Lesson learned :?

pingu - yes I may just end up spraying the whole car. There are defects on every panel to some degree so its a way to get it all right and the colour match right too. I may not have enough paint though, but if I get another litre from the same vendor it should mix in fine. Im planning to get a new bumper and sills from bmw. The bumper has lost some of the tags that mount the grill. Getting replacement panels makes the spraying an easier job since the prep and paint can be done in slow time without needing to strip the car down.
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Southernboy
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Re: My paint spraying attempt

Post by Southernboy »

Really admire your determination to become adept at this...Your door looks great in the pic you posted...obviously you get a closer look, but the pic looks like a professional finish..I can see the entire car being repainted... 8-)
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Robert T
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Re: My paint spraying attempt

Post by Robert T »

Good stuff. You planning on going into business?

Cheers R.
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