View Full Version : How To Prep My Car For Spraying

30-08-02, 03:44 PM
My new project shell is Red i want it to be changed to yellow (inside, outside and engine bay)

My question is

What do i need to do to prepare my car ready to be painted

Im looking to do all the prep work myself and just have the colour sprayed on top!!


30-08-02, 10:19 PM
im getin mine re-sprayed in a few weeks, same colour tho so im not sure how ud go about the inside and engine bay.... all im planning is to do all the repairs that need doin, get them in primer and then flat it all off with wet 600 paper, should check with whoeva's painting it as to which paper to use cos it depends on the heat of their gun and the mix's they use.
Hope that helps

31-08-02, 02:09 AM
To be honest prob best getting body shop to do it for ya all - check out below for reasons (I'd prob have paid for shop in long run for my project based on my experiences)
if yer planning on doing yer engine bay youll need to take out the engine otherwise it'll be patchy.

For the best job, you'll also need to remove ALL windows inc screen otherwise you'll have a red line running around the rubber area.

For the inside, you'll need to remove everything - prob be ok to leave the dash in but all else must come out so you can get access to all edges. Dont really matter too much about hidden areas (like floor plan) coz they can ne overlooked as they'll be hidden but things like yer boot etc will need spraying.

1st - give the car a really good wash - get in under all the arches etc. Use non wax based shampoo - washing up liquid for example!

Then remove all external panels - bonnet, hatch, doors, windows, wings, bumpers, lights, grill, trim, wipers etc.

Wash it again - now you can get access to all the nooks and crannies!

Strip out the interior and remove the windows and if you can roof lining. With car totally stripped all you have to mask is the dash and the engine area. Hoover the car and wipe the inside down with hot soapy water - especially around window edges - muck gets everywhere!

Once youve stripped car and bagged, labelled and taken photos of all bits (trust me you'll need to), you need to assess for rust and treat this 1st.
I started with the shell and worked round it starting at front using a black permanent marker (youre gonna overspray and sand so no probs). Youre looking for all rust, paint bubbles, scratches, dings, dents, weird bits etc.

Main areas are rear arches and boot - with car stripped u can check inside the panels aswell for the bubbly paintwork etc. Check under arches - get car on axle stands and remove wheels and have a ruddy good poke about. you're looking for damage on the lips, where the panels have started to come apart, expecially if theyve been folded or ground down. Check the sealent around the arch (like a rubber mastik) - if its loose and rust has got in, youre gonna have to remove all around it and then some coz it'll have spread under the mastik! heat gun and a sharp chisel good for this.

The do the same with yer doors, hatch, bonnet and wings - remove glass and dismantle doors (good chance to delock if u have the alarm for it)

get a pro to remove windscreen (save smashing it) - cost about ?40

Once car have been assessed, you need to make a plan of action. From sanding to priming and respray you need to set a timescale. The shorter the better. The reason for this is the weather is turning cooler and theres moisture in the air. If youre doing it in a garage and there no heaters and youre using body filler and primer, these items absorbe water - not good on a prepped car coz it will encourage rust befoire youve even started. the paint will merely trap the moisture - causing bubbles and rust later on.

Prepping yourself and priming is fine however you need to know exactly what paint you are using - cellulose and 2 pak dont really mix. So if you are priming yourself you need to use a 2 pak primer if you want to use a 2 pak top coat - likewise if you are using cellulose. you could do the respray yourself then get a body shop to polish it for ya (thats what I've done) but only if u feel confident in handling a spray gun and can get a really good dust free environment. If youre just getting it resprayed, you need to make sure your prep work is immaculate and have the necessary transport to ship yer shell and panels to the bodyshop (hire a flat bed truck) then back home again. Most shops wont touch a diy prepped car - especially if youre priming it yerself - many however will but then any flaws in the paintwork are made your responsibility coz paint will show every whirl, scratch, dent, ding faulty sanding line etc... (as I found out :evil: ) just make sure your primer is compatible with their paint - or better still buy the whole paint system and give the top coat to them to use!

To prep do the panels 1st - theyre smaller and can be stored easily. Theyre also easy to practice on! :o

The prep for the shell is the same as the panels but on a bigger scale.

During prepping - DO NOT use wet n dry WET. Youre essentially taking the car to bare metal and wet will promote rust. Use it dry. Only use it wet when the final coat is being applied to flat back between top coats. Dont even use it on primer or filler coz these absorb water.

Tools you'll need for prepping -

DIY compressor & airgun kit - ?99 from B&Q - excellent for blowing dust off panels and cleaning up clogged paper from the sander - will pay for itself in a day (on saved paper alone!) no good for spraying a car though
2 packs of dust masks (4 in a pack) B&Q - ?5
Orbital sander (about ?30 from B&Q) get a powerful one
plenty of wet n dry (packs of) in 1x80, 4x120, 4x240, 3x400, 4x600, 3x800, 2x1200, 1x1500 grit (depends on state of body mind - usually 4 sheets per pack and these can be cut into threes for the sander)
set of thin to fat chisels, heat gun, hammer - for removing "stuff"
body filler P38 for dents etc...
fibreglass P40 bridging compound (fibreglass body filler - ok for small holes)
knifing putty (cellulose putty) -
** make sure these are compatible with paint system being used (may react badly!)
fibreglass resin and matting sheets (Davids fastglas) for bigger holes etc.
Sanding block - dont use fingers unless intricate areas
panel wipe (paint supply shop)
anti rust stopper, rust remover, jenolite rust sealer etc for killing rust
Hammerite (for them hidden areas)
flat area to work on (couple of work benches with a board over them)
bubble pack or soft sheets to prevent panels getting damaged when standing on the floor or when you turn them over to do the other side
rubber gloves (dust dries out yer skin something rotten)
There are other bits n bobs - it all depends on the severity of the shell. If its mint you may not need some of the above.

1st you need to clean up all rust areas and those bits to be undented - strip back tha area and 4" around it to bare metal using 80 - 120 grit on an orbital sander or block. You must get all paint out even in the ding centre in areas to be filled - this helps with excellent bond. 80 grit will allow an excellent key for the filler/fibreglass but 120 is ok for light dings and roughing up the surface immediately around a dent. Sand away as much rust and loose debris as possible - then sand a bit more. Treat with rust killer and leave for required amount of time - lightkly sand back to flat any runs if liquid based. Some rust removers are water based so read instructions (remember water promotes rust!)

If using fibreglass/filler u really need to allow 24 hours to harden fully before applying filler/knifing putty over the top - I did all fibreglassing in one go after getting car dings stripped to bare metal. Saved time

When filling dents/holes etc, try and knock the dent out 1st using light taps with a hammer and a support the other side (called a dolly) - theres a real art to panel beating - youre looking at reducing the dent as much as possible - you dont want tons of deep filler everywhere
In order, fill using fibreglass or P40 (if necessary), but not to top - allow to harden (24 hrs). Then sand back roughly (80 grit), clean all dust off (air gun great for this). Then apply layer of filler - if deep, do in stages allowing to dry between each. Cover area with filler immediately around aswell (up to 4"+ around). This allows to be sanded back using 120 dry to get basic shape then 240 dry for more detail. By allowing 4" stripped lip around ding, you can see when youre getting close to being level coz the metal will start to show - you'll end up sanding most of filler away. Use orbital sander where possible and keep it moving/clean with air gun

To flat back all areas with no dings (inc shell), you dont need to remove all red paint - simply need to key it and feather in the filled areas. The best way to do this is using 120 grit on orbital sander/block to take top surface off. Keep sheets clean and sander moving to avoid clogging and swirls. You can take paint right down to black primer layer but try and avoid breaking this if you can (no deal if you do - its just more that then needs etch priming and this layer has been baked on so is v tough ).
Once sanded in 120 dry, lightly oversand the area with 240 dry. The area should be smooth, have no visible dings or scratches - treat if there is. During sanding back, use your outstretched hand to feel the surface, you want it really smooth. Your fingers will also assess where there are bumps or dents in filler which need to be addressed.

This is now ready for 1st stage priming. Really you should - plan to have all panels and shell prepped in this way ready for priming within at least a week to 10 days. If its raining, keep panels dry and away from moisture - especially those bites with exposed metal.
Before priming, make sure you replace all sealed areas where mastik has been removed - including around door hinges, under the car etc... Dont worry about wing mastick as these can be applied when wings are to be fitted.
Priming will show up any additional faults allowing you to address these.

There are several stages to priming. these are etch primer, primer filler and primer surfacer.

If spraying yourself, you need a suitable spray area. A clean, empty double garage is ideal. You'll need to ensure its spotless though and that you have at least 3 ft around the car from all angles expecially above.

Tools needed -

Spray gun, air line and compressor (HSS - turbine air hvlp gun - about ?100 for a week)
fresh air powered respirator (?90 for a weeks hire from HSS - safe n sure - includes powered unit, 3 A2 filters and a full head mask). If your using cellulose primer, you can use normal paint spraying masks and filters
Tarpaulin - 5x4m B&Q - enough to build a spray booth - I used 4 sheets and managed to cover the roof aswell.
cable ties to help assemble it
wooden beams to make frame to support the tarp - unless you have totally empty garage to attachd tarp to walls.
Masking take - proper car type stuff (car paint supplier)
Masking paper or good quality broadsheet newspaper (paper is better quality).
Bin bags to cover wheels with
Paint - if final coat is celly use celly primers (as with 2pak...)
etch primer and etch thinners - if lots of bare metal get about 1.5 ltrs. I used 2 ltrs but covered the entire car before realising just need to treat bare metal and immediate area
primer filler 2ltrs(2pak or celly based)
primer surfacer 2ltrs(2pak or celly based)
thinners/hardner to go with the above
Plastic primer 500ml (1k) - for all plastic bits n bobs - very thin - can do all plastic bits inc bumpers
mop and bucket of water to mop spray area down with
decent lighting - some of those halogen security spot lights (?20 B&Q)
Tack cloths
Panel wipe
Good quality clean soft cloths
plenty of rubber gloves or latex ones
Stiring sticks
measuring cups,
measuring stick,
paint filter seive
proper thinners for the above
you could also get the top coat you wish in the same format (2pak or celly) to give to the body shop. That way you know you have a compatible match. 2pak need about 3-3.5 ltrs if doing inside aswell.

(paint mounts are based on 2pak - celly you'll need more coz you have to apply more coats to good result)

Before spraying, make sure the spray area is really clean and away from dirt or direct draughts. Use muslin over vent holes (if using a garage) and make sure the tarp overhead has also been loghtly mopped down (dont over wet as you dont want water dripping on yer paint!)
Between each stage of priming, make sure the booth is cleaned and keep sealed off if you can when you sand back layers - move car outside if you can.
You must ensure the panel/part to be sprayed is clean and free from silicone, greese, dirt and dust.

Make sure all areas are masked off inc wheels, engine bay, dash steering wheel etc... Dont worry about inner arches you bac black them out later (bitumen paint is good for that!)
With the exception of plastic parts (see later), you must 1st wipe the panel down with panel wipe. This disolves greese dirt, silicone etc... Wipe on with a cloth then off with another. once done, do it again!
Then use a tack cloth over the panel - this is a special cloth designesd to pick up loose lint, dust debris etc - its slightly sticky. You MUST panel wipe and tack cloth all panels that have been sanded back before spraying. Most sprayers tack cloth just before spraying to ensure they get all specks.

If bare metal is exposed, you must seal this properly. Use an etch primer which basically burns into the metal sealing it. You dont need to sand this layer and it should be left as it is where possible (its a thin membrane)
To smooth the body properly, you can then use a primer filler which is basically a thick primer that smooths any fault lines, deep scratches etc. Once dry (24 hrs), it can be sanded using 400 grit dry on an orbital sander or block, very gently to get a nice smoothish surface - watch edges though - you dont want to go down to bare metal. You can apply another layer but dont go too thick.
Once gently sanded smooth (remove rough feeling) The last layer is the primer surfacer itself. 2pak primer (2k) is the best as it is very hard wearing, however does contain cyanoacrylate vapours so you'll need a fresh air powered respirator (?90 for a weeks hire from HSS - safe n sure - includes powered unit, 3 A2 filters and a full head mask). If your using cellulose primer, you can use normal paint spraying masks and filters however celly primer as with celly top coat requires more prep and flatting between coats takes alot longer (usually about 4 coats) - 2pak doesnt - its also more forgiving of faults and only needs about 2 coats.
Primer surfacer (the 2pak stuff is a vanilla yellow colour!) can be sanded between coats using 600 dry on a sander/block within a couple of hours.
When you have sprayed on the last coat of primer surfacer, before you sand it back using 800 grit dry, spray on a speckle coat of paint. This is just an old can of spray paint sprayed at a distance (matt black is great for this) to form speckles of paint all over the primer. the idea is that once you start sanding the speckle coat is sanded away, so you know that area is smooth, leaving only those areas that are still to be done, dented or where there are dips showing the speckle coat on them. Decisions can then be made as to whether to flat these back or strip back to bare metal and fill! If you wish you can give the panels/body a final sand over with 1000 dry. Use yer fingers to feel the body - remember smooth is the key to a nice shine. 2pak sets in about an hour so all sanding can be done within 2 hours!
If using 2 pak - 2 coats should be sufficient

Once the final primer surfacer layer has been smoothed back and the speckle coat has gone (dont worry of there are still bits of speckle showing as long as its smooth), youre ready for the car to be sprayed with its top coat.

Plastic bits MUST be sprayed with a plastic primer BEFORE the primer filler and surfacer are applied. Etch primer is not needed on plastic so following the guide above, swap the etch part for plastic primer instead. This usually comes ready mixed. You CANNOT however use panel wipe on plastic primer - I discovered it melts it - just make sure its dust free using tack cloth and keep away from greese/silicone based stuff once plastic primed. Once primer filler/surfacer are on - panel wipe is ok to use. Flat back in the same way as rest of the car using same grit dry.

It can be quite expensive to do it all yerself (the paint alone will cost you ?200+) but if youre priming, you may as well paint the top coat - especially if youre using 2pak. Just make sure the spray area is totally free from dust grit etc...wash down the spray area using mop - inc roof.
Make sure the car is panel wiped (inc plastic bits).. You'll 1st need to spray the panels and body with one quick coat - mainly to ghet the edges of things - door edges, hatch, bonnet edges etc. once dry flat these back using 800 grit dry. If necessary flat back using 1000 grit very gently all dry. By giving all panels and the body a quick one off complete coat, you can save time flatting back.

Once edges and one coat has been sprayed onto shell and parts, reassemble panels back on car - hatch doors, bonnet, bumpers etc.
No need to mask off areas as already done. Sand the outer skin using 100 wet n dry (dry) - being very careful where you sand - dont apply too much pressure with the sander and stay away from edges (you can use sanding block)
Once reassembled (loosely!) you can apply the 1st proper top coat.
After car has been flatted back after loose reassembly make sure body is panel wiped and tack clothed.
Now you can spray car as one whole complete usit. remember yu still need tpo spray edges but 1st coat will help hide any erors. Be fvery aware of where doors are etc in relation to yer air hose. I walk around the car with gun and line attached beforehand to get a feel of what I need to do. The roof is the hardest - as uis the bonnet - if you have one, use the sun roof soace to stand in and be prepared for cramp in yer hand!
2 pak paint only really needs 2 coats but I applied 4 to mine, flatting back between coats using 1500 wet n dry WET with hot soapy water - ensureing the car was properly dry, panel wiped and tackj clotrhed between sabded coats.

2pak top coat - sets in 1 hour, flat back in 2-5 hours (assess paint 1st though - leave it as long as you can - same for primer layers)
sand back using 1500 wet n dry wet in hot soapy water.

If you get orange peel, this can be flatted back gently.

If you get runs, you will need to smooth these right back and respray otherwise you will see them (darker deeper colour).

The paint you have chosen colour wise will let you get away with murder because its a light colour therefore will not show any problems as much as a red or black car will. Red is bad coz if done wrong will result in 10000000 shades of pink (as happened to me 1st time round)

Hope this helps m8! Sorry about length. If you want, pm me & I'll send you details of pics I have of me doing my car.

The books for ref are - how to paint your car - haynes, how to restore your car - haynes, from panel beating to spraying - free with subscription to Car Mechanics magazine. check out www.haynes.co.uk


31-08-02, 08:31 AM
Ffs Ade, u do love hogging all of the webspace dont u! :wink:
Cant complain, at least ur helpful!

31-08-02, 03:51 PM
christ Ade, i was trying to sound like i knew something and u come back with a novel :roll:

Ford :lol:

Ben (lurk75)
31-08-02, 04:27 PM
Ade- no wonder your misses moans you dont spend time with her! after reading that lot i feel like i could restore just about anything!

Fair play to you, you are dedicated!

31-08-02, 04:28 PM
lmao cheers Ade

I read the first paragraph and the printed the rest out for when i got a few hours spare to go through it proper

But ill point out, ill be strippin the car completly as im reshelling one so engine will come out as will all running gear and interior etc so it will be havin a pukka job done. My mate is putting the topcoat on but i plan to do the rest myself as i have rebuilt the whole car on myown and would prefar myself to do it to gain that satisfaction from rebuilding my own car. :)

cheers for the info fellas ill let you know how i get on and ill post pics when its goin off for spraying and when i get it back!!!


01-09-02, 10:28 PM
lol! I'm practising for my book!

If u need help m8, let me know or send me a cd & I'll give u all me pics on what I did


(all I want is a shiney car - cannae wait till shes polished!)