The Airbrush Forum

Whiplash · #1 (**permalink**) 07-03-2009, 09:56 AM

If we all owned a body shop or could afford to get our stuff professionally clearcoated, we wouldnt be doing it out of our sheds, garages, backyards, etc. I do suggest that if you are not a professional, that you do get someone who is pro to clearcoat for you... but lets face it, some are gonna do it anyways.... So I have some tips and tricks for you all who are going to do your own clearcoating.

There's so much that can mess with a clear coat: dust, contaminates, interactions between chemicals, solvent popping, fisheyes, etc etc etc... My goal is to help you reduce these problems.

These are some of the materials you will need:

Clear product (make sure its compatible with your base), tack rag, mixing cup, measuring stick (if your cup doesnt have measurements), filter, rubber gloves, degreaser, masking tape and masking supplies, respirator mask and paint gun.

Step 1: CLEAN CLEAN CLEAN... it is important to clearcoat in a clean environment. Do not spray anything that contains silicone (ie: WD40, Armor All, etc) for at least a day or two before you plan on clearcoating. Check the chemicals you use and ensure they dont contain any silicones. Silicones do not allow adhesion and if they are sprayed, they float in the air for some time before they settle. If you already have your project in the area, those particles land on it and when you go to clear, it repels the clear .. so you get an area void of clear... looks like a fisheye...

Also you will want to sweep the area and blow it out the day before. Dust particles in the air take a long time to settle and if you sweep just before you clear, those dust particles will land on your project and make nibs in the clear (bumps).

STEP 2: So the magical day arrives for you to clear your project (this part is always exciting for me...)... The first thing to do is wet down the floor with a hose. Basically just sprinkle it on so you don't raise any dust that has settled there. Wetting the floor helps dust that comes into the area to stick to the floor as well as it prevents the possibility of kicking up dust as you walk around while clearing. Also, wear clothing that does not have alot of lint/thread so your cloths dont contribute to the problem.

STEP 3: Position your project(s) so you are able to walk around them, plan out the way you are going to clear ... what angles you need, almost pretend you are clearing the project so you know you have room to access every angle. This helps prevent dryspray or nospray on parts of your project.

STEP 4: Mask off any parts you don't want cleared. If you masked it off for the prime and sanding part, replace that mask with clean stuff. Dust and particles can be blown out of creases and land on your project. Don't use anything like wax paper or plastic that clear wont stick to because after your first coat of clear is put on, when you go to spray your second coat, it will blow off the dried clear from the plastic and.. yup, you guessed it... right onto your project. Cheap alternatives are meat wrapping paper or just use straight masking tape.

STEP 5: Now you have everything laid out, you will want to degrease the project. Put on clean latex gloves (stops you from contaminating your project with the oils from your hands). Depending on the degreaser, you may need to wipe/spray it on and wipe it off. I use Wash n' Wipe, it is a solvent degreaser and does not pull up waterbased paints, very good to use with Autoair/Createx. Spray it on and then wipe it off with a soft blue shop towel. Don't need to scrub it off, just gently wipe it off. Do that to the entire project.

STEP 6: Mix your clear. Usually 2 part urothane clear has a pot life of 2 hours (how long it can sit in the pot before it becomes hard). Then put on your mask (IMPORTANT!!!!!) and you still have your gloves on. Set up your spray gun (I setup my clear gun with two full rotations of the needle control), and put the filter in the cup and pour the clear into the gun through the filter... yet another step for preventing contaminates. Then do some test sprays to make sure your pressure it right (I use approx 30psi, but I go more more on feel that on an actual #). Now take the tack rag (which is a slightly sticky rag that picks up dust off the project). If you pull back on your spray gun only a little bit, you will get air and not clear. I use this to blow the project while I run the tack rag over it. Do this lightly, all you want to do is pull up any loose dust... be careful not to rub as you will leave the resdue from the tack rag on the project.

STEP 7: Okay, so now your about as clean as your gonna get at this stage. Go ahead and start spraying. for larger projects, start spraying in the centre and then towards yourself, helps so you don't lean in the clear to get the middle part, smaller peices you can just start spraying the one side and work your way across. Spray in lines holding the gun about 10"-12" from the project (this varies to the person/ gun/ product/ pressure... find what works). You want to cover the last pass 50% on the next pass. This takes some practice. This stage is a dry/wet spray. You dont want to lay the clear down too heavy or you will get sags/runs (the clear has nothing really to bite to at this stage) and you dont want to lay it down to dry or you just get dryspray and no adhesion...

NOTE: you can see the mist the clear makes, if you don't get rid of that and the car stays in this environment, it wont allow the solvents to be released and then your clear starts making bubbles and pinholes which are called solvent pops. This can also happen if you lay down clear to quick and dont allow flash time (dry time).

STEP 8: Wait the required flash time (approx 10 mins depending on your product). Make sure the previous layer has flashed off before laying down your next layer. I usually test this by touching a piece of the masking to make sure that it is dry. Now your clear has some 'bite'... you can lay down your next layer wet. Make sure to cover every peice, checking all sides, looking for dry spray....

STEP 9: Wait flash time... then spray again. This should be your third and final coat. You don't need layers and layers of clear, 3 coats is usually adequate... Really watch your dryspray at this stage. If something lands in the clear or you get a run/sag, your better of leaving it and sanding it out rather than to try to fix it at this stage (unless its a big bug!).

STEP 10: Now you can clean your gun, and let the clear dry. If you can, don't move the project until the next day. Make sure you have good airflow and that the solvents can be released.

have a beer...

Next day, unmask and your done!

Now keep in mind this is a short simple list. There will be a lot of little things you will learn along the way that will help improve your technique.

Good luck and happy spraying!