GUIDE : Spraying with aerosols

[JSeaman]

Disclaimer : I'm not a sprayer or bodywork specialist but I've done this stuff a few times. I don't know if this is 'the done thing' or considered good practice but I base it on the results. I'm happy enough with the work I'm doing to put this up as a guide and if you like the results then use it.

Obviously this isn't being done on a Supra - it's actually a Stringer trike but the principles are the same across the board

Step 1 - If possible, remove the item you are going to spray completely. If you are doing a small section on a larger panel then you need to suitably mask off the area. Be sure that no excess spray can fall on bits you don't want painted (If you are doing a small area, it is sometimes helpful to cut out a hole in a piece of card and spray from behind the card - this directs the spray more centrally so you don't paint any more than you need)

Step 2 - If you are using paint stripper then apply it liberally following the instructions and get rid of the softened paint with a wallpaper scraper. For my purposes, I just wanted to flatten the arch surface so skipped this stage.

Step 3 - Wet sand back the surface until it is smooth. To wet sand:

- Get a (or several) medium/fine wet sanding sponge (Wilkos ~£1)
- Dip in water and then wipe it over the surface a few times to build up a film of water
- Sand the surface as normal but regularly stop to dip in clean water

The water will prevent cutting into the surface and give you a much smoother finish but it takes a lot longer to smooth down so if your area is badly damaged you might want to dry sand it first. One side of your sponge will be medium grit (which isn't as coarse as it feels when you have a surface of water so don't worry!), and the other is fine. Start with the medium then flip over to the fine side

Put time in here, if you have a surface scratch it WILL show through. Get as much light on the panel as you can and try and find the scratches by catching it in the right light

Step 4 - Once you have completed the wet sand, dry it off with a cloth/kitchen towel and leave it for a few hours

Step 5 - Now go back to it fresh and wet sand it again. You will find more defects and do a better job if you do this

Step 6 - I'm not going to cover filling large areas but I did need to use a substantial amount of 'stopper' which is a fine surface filler. Basically this can be applied to cracks, dints, chips etc anything small that is going to show through the finished surface. The first picture shows the most substantial area I covered which was a large lightly pitted area, it almost warranted the use of a P38 style filler but the stopper is actually a very fine layer so I decided this would be adequate. Try and apply your filler in an even manner and smooth the edges where it meets the paint - Oh, use your finger for it because you'll be able to mould it properly and smooth it better than anything else you can buy

If necessary, build up the stopper/filler with several layers (Shown in picture 2 with one layer applied. In this case standard filler could have been justified)

NOTE : When stopper starts to dry (Very quickly after you apply it) you won't be able to re-work it so apply it at a steady pace and don't get ahead of yourself. Work a small area at a time and concentrate on making it as smooth as you can. Saying that, don't get carried away - you'll be sanding it to get the finish you need and if you keep prodding it then it'll start to solidify and rough up the surface (If this happens, move on to the next part and don't touch til it dries)

Step 7 - Leave the stuff to dry for whatever length is advised - I always leave it overnight. Now get cracking with the wet sanding again - take your time and make damned sure you've got two things

1. A smooth blending where the filler meets the paint work - and I mean VERY smooth
2. No huge lumps! Seems obvious but it isn't. When you are concentrating on smoothing out the filler it's very easy to miss the fact that it stands proud of the surface of the paint. Look at it from a shallow angle and make sure your filler is level with the surface of the paint itself

Once again, take your time and if necessary leave it and come back a few times - you cannot make up for short cuts taken at this stage, make it as smooth as you want the finished article to be

Step 8 - Ensure the surface(s) are thoroughly free from dust and dirt then get yourself some primer. Depending on what you are doing you might want plastic primer, metal primer, fibreglass primer etc etc. The colour will also influence the top coat so speak to your local auto factor (or wherever you are buying the paint from) and confirm what base colour should be used with the top coat.

I HIGHLY recommend Hycote. It is a make of paint I have used a couple of times now and they are cracking products, easy to work with, good spray patterns, good price etc. I used filler primer because the surface I was working with was not the greatest (A hand painted, neglected trike arch!). I wanted this to build up a thick base layer so I could sand out any surface scratches etc that I didn't get with the initial stopper/wet sand.

Note - by the time I finish I'll have used the best part of 10 cans on the stuff I'm doing. Admittedly I'm probably doing a larger area than any of you will consider but take this into account. Oh, and I got 12 cans for about £30 off ebay so it's not too bad for cost

Step 9 - Lay your part(s) out on a surface (picture 1) you can afford to get paint on and start shaking your tin of primer. Mix the paint well because you don't want colour imperfections or inconsitent spraying. Start to spray ...

Spraying :
1. Keep the aerosol min 20cm away from the surface. Seriously. Don't be tempted to move in close because you WILL screw up the finish.
2. Move all the time - if you hold the can still you will have massive build up of paint and it'll look crap. Constantly move across the surface in long sweeping strokes. Don't point the aerosol at the surface then press the nozzle, start spraying before you are over it and then spray evenly across the whole part until you pass over it completely
3. Do lots of very thin coats. If you start putting a thick coat on it'll look awesome ... for about 10 seconds until you realise you've got high/low points, running paint (drips), and just generally a bad result.

Have a look at the fuel tank in the second picture. It gives you the best idea of how thin the coats I put on were.

 

[JSeaman]

Step 10 - Go to 9 for at least 3 or 4 coats. I decided 8 coats to start with, then some more stopper/filling then another 8 coats. That's just the primer of course. Hycote stuff allows 10-15 minutes between coats so within a couple of hours you can have built up a nice covering. Afetr 8 coats it'll look something like this:

(Note the use of rocks - make sure you get all the edges as much as you do the main surface of whatever you paint)

Step 11 - After 24 hours, return to your parts and prepare to transform them completely. The surface should be even but pretty rough to touchcompared to how it was after wet sanding. Guess what we do? That's right, wet sand this and it will suddenly become amazing. You will find out how good a job you did during your filling stage as well because all those surface defects are going to show through. If you've done a perfect job (You almost certainly won't have) then you can skip the next stages

Step 12 - Once you've wet sanded everything you can finish fixing the paint surface. In my case I knew I was going to have to spray it before doing some more serious work on the surface because I couldn't do much due to the red, white and black paint (made it very hard to properly look at the surface of the paint). Anyway, tidy up all the edges you didn't sand well enough and flatten back any bits that stand proud of the surface. In my case I had LOTS of small dents on the surface (see the picture for the extent of the damage), which all needed filling with stopped

Step 13 - Get busy with the stopper, don't skimp and make sure you get all of the imperfections. Now is where you build on your earlier work, don't see any stage as a waste of time - you have to have some patience to get an excellent end result.

Step 14 - At this stage I treated it like I had just started the arch, I got some normal medium grit sand paper and roughly smoothed down the surface of the filler so it was pretty much a flat even surface across the whole arch. Don't press too hard or sand too deep unless you want to get filling again! It's much easier to take off filler than apply it so go easy with the dry sanding

Step 15 - Once rough sanded, the surface will look something like this

Step 16 - Once wet sanded and clean it'll be more like this

Step 17 - I'm now going to switch between panels now, I had some pc problems which mean I have less pictures than I'd have hoped and this will let me demonstrate things more easily. Here's a picture of the state of everything so far, all has been prepped to the same level

Step 18 - Once you are all wet sanded back, apply more primer (I did 4 coats)

Step 19 - It kills you to do it again but apply any more stopper you need

Step 20 - Sand, wet sand, prime again and go to step 18 if need be. Eventually you get this

Step 21 - Here's the surface I ended up with on the fuel tank, pretty smooth

Step 22 - Make sure you have enough paint! Always better to have a can or two left over at the end than run short during a spray session. Note you need much less lacquer than top coat due to the fact you'll do fewer (but thicker) coats. The pic shows what I used and you have seen the area I'm covering. I had less than a can of lacquer left and 2 of top coat by the time I was done (I'd allowed plenty of extra and used most of it!!)

Step 23 - Start applying your top coat. I've showed a pic of the front arch here because it bests demonstrates how patchy the paint is allowed to be. Don't 'colour it in', just apply an even layer over the whole surface and don't worry about the patchy look. Keep the aerosol at a fixed height above the piece you are spraying and don't stop moving.

Step 24 - After 8 coats of top coat, the fuel tank looked like this

Step 25 - You see on this picture that the surface was really mottled and bumpy so it gets wet sanded smooth. I do this half way through the top coat spraying so we end up with a nice flat finish by the end

 

[JSeaman]

Step 26 - Another 6 or so coats later and it's like this

Step 27 - Another wet sand to get the surface finish we are after

Step 28 - Always dry the bits off after wet sanding with some clean kitchen towel. This will prevent staining from watermarks

Step 29 - Sadly I lost a lot of pictures here but I find the key to lacquering is a two stage process

1. Apply about 8 coats in the same manner as when you spray top coat (First picture shows after this stage is reached)

2. Wet sand it back and it'll look awful (See picture 2)

3. Wipe it down with some kitchen towel (will start to look much better) - see pictures 3 and 4

3. Now you need to spray again and give a further 4-10 coats (I did about 6), this time you do it differently though. Move the paint can so it is SLIGHTLY closer to the surface (If you were 20cm away, go to 15cm for the lacquer), spray as before with the can constantly moving but making slow sweeping movements so you leave a thicker layer of coverage. Picture 5 shows roughly how far away I was. The key here is to have a constant slow movement so you get a really nice distribution but a thick enough coat of lacquer so that it doesn't leave the rough surface you got with the top coat.

Hycote lacquer is excellent, some are very poor for dripping and poor spray patterns but this stuff is highly recommended. You shouldn't need to sand the lacquer once you have applied your last few coats and all being well your stuff should look like this:

One final tip, if you find that an aerosol starts to splutter and produce thick drips in the spray pattern then take the spray cap off, throw it away and use one off another can. By turning the can upside down and spraying for a couple of seconds after every use it reduces the chance of this happening but it does happen from time to time and rather than attempt to unblock it with a pin then mess it up further you should just swap.



Number 1 rule, take your time if you want a good finish - you cannot take shortcuts I'm afraid (believe me I have tried before!)