Sport Bikes banner

1 - 20 of 57 Posts

·
Registered
Joined
·
148 Posts
Discussion Starter #1
Well I have a air compressor and pneumatic sander/buffer with a variable speed knob. Its handy. I started with 400 fine grit to get the paint off and its doing a good job. I need help with what I should use after I get all of the paint off. I want to sand and possibly prime the bodywork myself to soften the cost of my paint job. Has anyone done it on their own? Any help or links to threads will be greatly appreciated. Thanks :D
 

·
I own license2ill
Joined
·
5,679 Posts
there is alot more to it you got to wet sand fill and smoth it out fill (putty) where needed, prime it then wet sand it again,spray base coat after its been scuffed slightly,apply second coat,third coat (optional),then wet sand that after its tacked up, next you need to clear it,(optional) last if you like you can wet sand again then buff whan the paint is set.
you got to have a very good air compressor to keep enough air and pressure in the line
or the paint wont be smoth
you also need a water filter to keep the water out of the paint
my father and i own a body shop so if you have any more questions pm me
 

·
Registered
Joined
·
13,267 Posts
#1, you NEVER want to sand all the paint off.... theres no reason to unless there's been a lifting problem or similar. reason is: it's a waste of time, you will more than likely make a mess of it by making waves that will show up in the shiney finish.

#2 You don't want to put alot of primer on. Especially cheap rattle can primer. It will cost you more in the end when the shop has trouble because the paint they spray will make the cheap stuff lift or blister. Use only a 2 part uerathane or epoxy base/filler coat compatable with the top coat you or the shop is going to use. Also building up too thick of a coat just makes it chip that much easier and the chips will be deep and harder to fix.

#3 Don't use the single component type of putty. Use the 2 part Bondo filler when at all possible. The cheap single part stuff will lift and cause problems with the newer paints the shops use. Your much less likely to have problems if you use a two part compound thats reccomended by or made for the paint the shop will use, Dont matter if its under primer, the solvents will penetrate and still lift it.

#4 Compatability, thats the main thing to consider. If you use a product that isn't compatable with what the shop sprays you will end up wasting alot of time and money.
 

·
Registered
Joined
·
62 Posts
1) if the original paint was good then you should have just wet sanded it with 320

2) don't waste your time priming it with rattle can primer, body shop will just strip it off and charge you to do all the sanding again.

3) if you're going to paint yourself, make sure you've got a good compressor that can keep up with the flow rates required by the spray gun, has to have a water filter/drain, need a booth for best results.

4) after that you gotta figure it out on your own, body shops don't make money telling people how to do their work.
 

·
Site Sponsor
Joined
·
1,639 Posts
This is all assuming that you are using a Basecoat/Clearcoat (BC/CC) Urethane system over a previously painted surface that didnt' have any adhesion problems (the paint wasn't flaking off or hadn't seen 'Re-entry burn' like so many cars from the 80's). Some of this advice will apply for those using "spray can" painting, but the type of paint and technique used to spray from a can have many different properties than modern Urethane paint.

I'm assuming you're using modern spraying equipment:
-An air Compressor able to keep up with 8 to 20psi at .75 to 3 ft^3 per min. Except for spraying the polyester, most small "25 gallon, 5-horse" Craftsman aircompressors will work.
-Either an HVLP automotive-type spray gun, or an old-style Siphon-feed automotive-type spray gun with the correct sized tip (check with manufacturer's websites).
-A water trap and oil trap at the compressor, plus a disposable watertrap that screws on the base of the gun as last-chance-insurance against water getting in the paint

This is also assuming that you are shooting a solid color (or colors). I dont mean you can't put graphics or multiple solid colors on the peice, but that you aren't using "Transparent" or "Kandy" colors. The equipment, skill and knowledge required to shoot these with any success is far better left to someone who knows what they are doing. Putting a "run" in a solid color is easily fixed in a few seconds. Putting a "run" in a Kandy color usually requires starting completely over from Step 1.

First, to be able to do something correctly, you have to have a certain understanding of what you are doing. The Urethane paint is essentially a plastic in a liquid form. It is reduced (normally) 1 part paint to 1 part Urethane reducer (NOT laquer thinner). This type of paint adheres to whatever it is sprayed on in two ways: about 80% of the adhesion of a urethane paint is through a Physical bite. This means that the surface that you are spraying onto has to be ready Physically for the paint to adhere to it...usually it needs to be sanded by 600 grit or coarser (usually no more coarse than 320, or you'll see the sanding scratches after you are done). The other 20% of your bite is Chemical. That means there are chemicals in the paint that actually try to EAT into whatever your spraying onto and create a bond between the paint your spraying and the surface.

So...in preparation, you need a surface that is made to accept this "Chemical bite", but that is also sanded correctly to give the paint it's "Physical bite".

The best surface for this is either an Epoxy Primer or a Uretane Primer. I wont go into the differences, but we only use High-build Epoxy Primer. There are many makers of this type of Primer, varrying in price from a $10 or $11 per Qt (you wont need more than a quart for morst bikes) to over $50/Qt. It will require an activator, and will require VERY HIGH amounts of pressure to spray. Unless you thin it considerably with Urethane Reducer, this stuff is like Liquid Putty. In fact, we use a type of Epoxy Primer that is advertised as a Polyester Coat, and goes on EXTREMELY thick. It is put on as if we were covering the entire bike in a layer of putty. It sands VERY easily, and we can do bodywork on top of it, or just sand this material flat and skip putting regular putty on.

Here is where things can get complicated. IF you have bodywork to do, AND you are going to be using a normal "Putty", you will need to put a "Sealer" over the top of all of your bodywork after you are done. Otherwise, the dyes in the "putty" can bleed through your color coat and it will show when you are done. So, if you plan on using "Putty" (always use a putty that requires a hardener..never use the types that "air-dry"..they are junk for anything but woodworking), make sure you pick up a Quart of any type of Sealer that you like. This will be the last coat ontop of your bodywork before spraying your base coat (color coat).

When I start on a bike that already has a good paintjob on it (no flaking, existing paint doesn't appear to be "falling off" in anyway), I just scuff this paint with 280 grit wet/dry paper and use this as my "pallette". I dont worry about taking all of the existing paint off, and if the peice had stickers..AND they were UNDER the clear (you can't use a knife to peel them off without cutting through the clearcoat), I dont worry about taking them off. IF the stickers were on TOP of the clear, you'll need to remove them first, and all of the glue residue that remains.

So, I've removed all of the stickers, used "Goo-Gone" or similar adhesive remover to remove the glue, then sanded the entire peice down with 280 grit wet/dry sandpaper (VERY WET). After I think I'm done sanding, I dry the peice off and look for any shiny areas...if there are shiny ares, that means that area was not sanded..the entire peice must look scuffed...dull...you'll know what I mean when you see it. If there is an area that you may damage with the sandpaper,or is difficult to get into, you can use Red Scotchbrite pads to scuff these areas. I dont use it for the main parts of the bike, but in really hard to sand areas, or delicate areas, it works well.

After sanding, you need to spray a good thick layer of Epoxy Primer or Polyester. Follow the spec sheet on mixing this, and on drying time. DO NOT try to sand it early. It may LOOK hard, but the underlying layers may still be mush and you'll only have to start over. Sometimes, on thick coats...I let the peice dry for 15 hours or more.

After this had dried. Use 320 or 400 grit sandpaper and sand down any runs that you may have put in it, and give the entire peice a quick "once over", just knocking the bumps and nicks off. You'll see what I mean.

After you've knocked it down....get yourself a can of black spraypaint. You want to "FOG" the entire peice. You dont need to paint it black..just hold the can back about a foot, and "FOG" the peice. What you are doing is putting a "Guide Coat" of black over the grey (or whatever color your primer is). Now, put a peice of sanding foam or something semi-rigid in the middle of your folded wet/dry sandpaper, and sand all of the black off. What this will do is show you the high and low spots that may need bodywork. If you sand and sand in one area, but the black spot wont go away...that's a low spot. It will either need to be sanded until the black dot goes away (hoping you dont sand through the Primer first), or you'll need to add more Primer or Putty in that area. If you see a ring of black that wont sand away..there is a high spot in the middle of the ring. You'll need to keep sanding it down until the black goes away, or until you go through the Primer..or use putty to bring the black areas "up" to meet the high spot.

After all of the bodywork is done...if you didn't use any "Putty", you can scuff the entire surface with 320 grit one more time, dry it, and use a cleaner/degreaser to get all of your finger prints and such off....you're ready for paint (finally). If you used putty, you'll need to shoot a coat of Sealer, wait for it to dry, then scuff IT with the 320 grit...degrease and get ready to spray your color coat.

When you spray your color...read the spec sheet on air pressure, flash times, time between coats, and time to clear. You dont have to put it on in one coat. Usually, I "fog" three to four coats on before I see complete coverage. If you shoot a super-thick coat (like you did with spray cans when you were a kid), you'll only extend the drying time by about a half day (instead of 10 to 12 minutes) and end up with that will have to be sanded out. Many dry, thin coats in the color coat are MUCH better than one thick coat. Also...the color coat of a BC/CC paint job IS NOT SHINY!! This stuff dries like concrete...its dull, coarse, and wont look the "final color" when you spray it. Trust in the paint, and plug on, with dry, even, "Fogged" coats. After you've got a solid color...put two more "fogged coats" on. If you're shooting a pearl or metallic (ask the paint rep whether there are metallics or pearl in the mix), after you've shot these last two "insurance" coats...over reduce the color paint by about 10%, turn your airpressure up about 3 to 5 pounds from what you've been spraying it, and put on two more VERY VERY DRY, COATS. These coats are going to evenly dispurse the pearl or metallic on the top layers. You shouldn't need more than about a quart of your color. Mixed correctly, a Quart of paint makes a half a gallon of Sprayable Material.

If you've sprayed any metallics or pearls, DO NOT touch the peice's surface. You cannot wipe on these peices, as you will disturb the metallic particles. If you've sprayed a solid color, you dont NEED to, but if you think there may have been some oils that got into your gun when spraying, you can wipe down the solid colors with a semi-damp cloth with cleaner/degreaser and tack-wrag them before spraying your clear coats.

Your clear coat is the final coats that give the paint it's shiny appearance, and seal off the soft-easily scratched base coat. The clearcoat has some very nasty things in it...and although you SHOULD have been wearing a charcoal mask during the entire process..if you can only borrow one for one stage..this is the stage. Clearcoat can cause all kinds of nifty cancers that you dont want, and can cause death even from one time spraying. Wear a mask at the least! A full body suit and air-fed respirator would be better, but for backyard painters, it's just unrealistic.

Follow the spec sheets on the clear coat. Dont worry about putting on a super-thick coat and making it shiny on the first pass. I personally dont see a solid, shiny-coat until my third coat of clear. The first two are very dry, fog coats. I put on 4 to 6 coats, fogged of clear, then for my last two coats, I over-reduce the clear by about 5% and spray with a little more airpressure and a bit more distance from the peice. if a peice of dirt, fly, kid sister gets in the clear..dont worry. It'll sand out.

Let the clear dry as long as the spec sheet says. I personally dont touch the clear for at least 12 hours. Then, I start the sanding/polishing processes.

If you have any runs, sags, or bugs in the clear, work on those areas first. Get them flat using 800 Grit Wet sandpaper. Put a couple of drops of good dishwashing detergent in th bucket, this will help keep your sandpaper from sticking. After you've gotten those areas sanded flat, sand the entire peice with 800 grit paper. After sanding, if I think it's done, I dry the peice off and look for shiney areas. if there are shiny spots, (even tiny little specs of shiny-ness), I go again with the 800. After the entire peice is dull with 800, I get some 1000 grit, and sand the entire peice really well, then I use 1500 grit, then 2000 grit. The balance here is that you want to sand all of the peice flat, without sanding THROUGH the clearcoat. If you sand through, you have to re-spray the clear, costing time and materials. Try to not sand through.

After you've got the whole thing done with 2000 grit sandpaper, you need to use a polishing system to make it "shiny" again. I use 3M's Perfect-It II compound/polish system. You can get the materials at any O'Reilly's auto store, or at most paint-suppliers. Doing a peice by hand is a very labor-intensive job, but it CAN be done. Using a buffer is a much better way to do the polishing, but, again..you have the ability to ruin the entire thing if you buff through the clear.

If you've made it this far, and you've not sanded or buffed through anything...congratulations. I hope everyone attempts this at least once. It a very difficult process that takes time, mechanical ability, artistic ability, understanding of materials and quite a bit of money. But it can be fun and make your bike stand out from everyone elses if done right. There are many books out on custom painting, and just because it doesn't say motorcycle on it, doesn't mean the processes inside dont apply. $25 at Barnes and Noble may save you $400 at the paint shop if it can keep you from screwing up once or twice.

[shameless plug]
Afte all this typing..I gotta put in a shameless plug for my custom paint shop. I run Grasshopper Custom Paint. We've been doing bikes, street rods, helmets and custom stuff for the better part of 10 years. You can see some of the stuff on my outdated website at www.grasshoppercustompaint.com.
[/shameless plug]

Anyways, hope this helps. If anyone needs more help, PM me.

The 'hopper
 

·
Registered
Joined
·
1,057 Posts
Hell yeah, that was the most detailed instructions I've seen.
 

·
Registered
Joined
·
148 Posts
Discussion Starter #11
I have never seen any thread that detailed. I'm glad I asked. This thread will be printed and put in an clear protective sheet for reference. I couldnt be any more grateful. Thanks grashopr! This thread should be locked at the top!
 

·
Registered
Joined
·
57 Posts
This should be a sticky! Excellent info. I took some auto body classes at tech school and I could've just read this and saved me some cash!
 

·
Site Sponsor
Joined
·
1,639 Posts
NP....I didn't know that there were people on here who were wanting to do their own paint...if the board wants to host it, and they have a knowledge base, I could easily do a photo-how-to. I've always got the material to shoot to show anyone how to do this type of stuff, but I would rather not hold up my limited amount of webspace doing it. I'll volunteer the time if someone will volunteer the space.


The 'hopper
 

·
SBN SuperMod
Joined
·
1,394 Posts
lewisville said:
This should be a sticky!
DOH! I thought I had stuck it! :)

Grashopr - If you'd like to post pictures & such, please feel free to do so, or, if you would like a dedicated thread, I'll stick & close it. If you've something more in mind, let me know & I'll talk to the big guy.
 

·
Registered
Joined
·
13,267 Posts
The best thing you can do is check with your local suppliers. Ask when the factory reps are coming down to show how to use there new shit. There almost always free and it will teach you more in a few hours than you would imagine.
I learned from a friend that has been spraying show cars and working for the MB dealer here. He's amazing how he does some things. Won 5 best paint in show awards in the last 8 years or so.
One thing though not just the clear but ALL the new paints today are nasty ass shit. Wear a paper suit (cheap protection) and a air fed respirator (if you can rent a booth chances are there may be a mask you can use, you don't want to be breathin that crap at all..) My friend's lungs look like he's been in a coal mine for 20 years..
He also has pancreatic cancer from that shit. But he's been doing it for almost 40 years and for the longest time never even wore a normal respriator...
Try and go with a solid color if you haven't done much. The metallic/candys are a real bitch to spray. The hard thing is not ending up with dark and light aeras. Getting it even and consistant is way harder than you think. Like Grasshopper said the basecoats look like crap so it can be hard to tell if it's right with some colors.
If you have access to a decent booth or can rent one for a day it will be a huge help (also when taking into condersation you will have a fair amount of $$ in materials it is worth it if you can get a booth) If you got it together and find a clean booth and get lucky you shouldn't need to touch the clear... but that takes a ton of practice..
I always have waterfalls and rivers that need taken out!
John can lay it down so it looks like glass...
 

·
Registered
Joined
·
3 Posts
Painting advice

Well I work as a auto body technician and I have a few questions. First are you going to strip the paint right off and start over. and will there be any need to do any repair work on the body before painting. Anyway the way to prep for paint is as follows: 1) to strip all the paint completely off use 80 grit sandpaper this will take the paint off very quickly so be careful. next if there is no repair needed use 180 grit and sand the entire thing. then you can prime the bike. if repair is needed it should be done after you have sanded with the 80 grit this will ensure proper adhesion. after you have the bike in primer allow it to dry for an hour or so then you block the primer smooth with 320 grit or 360 grit I prefer 320 once the whole thing is blocked smooth you are ready to spray sealer wich is pretty much the standard procedure for painting today anyway allow the sealer to dry for 15-20 minutes then you spray your base coat lay the first coat on fairly heavy wait 10 minutes spray the next coat a little less heavy wait 10 min then spray your last coat on . wait 15 min. and spray on a medium heavy coat of clear and you may want to put on as many as 5 coats of clear but at least 3. when that is dry like the next day sand the whole thing with 1500 grit sandpaper and then buff to a shine with medium buffing compound be careful not to burn through the clear. my suggestion is to set the buffer on 2 or 3 and move fairly quickly then switch to a polish pad and polishing compound and repeat the process.
 

·
Site Sponsor
Joined
·
1,639 Posts
Kay, all....I've been workin with the Mod's on setting up a much more 'instructive' how-to on painting bikes. Last weekend we got Gixerking's bike done, but we didn't get many pics taken. As the season goes on, I'll be taking pics and writing up how-to's so hopefully by this winter, you all will be able to strip and re-spray your own bikes with wreckless abandon! Anyways...I'm taking offers now. If anyone would like to see how to do a specific step (you're in the middle of something right now and need to see it soon), request it. Please dont ask for Clearcoat how-to's...I have already begun the pics for that one, and will be working on the sanding/buffing how to this weekend...any others that are high-priority for you guys?

The 'hopper
 

·
Registered
Joined
·
95 Posts
graphic artist for the bike masses anybody want to know more
about complex graphics for bikes just say it

something a bit hard or higher level then routine stuff i will give all
i know just pm me but i think there are enough people here that can help
with prep work

but i like the different styles or techiques for prep
its good to for even me just to hear someone else take on
that stuff


sketch,
Master airbrush and tattoo artist
 

·
Registered
Joined
·
459 Posts
After you spray on the basecoat, should you sand before you put on the clearcoat? On all the tv shows, after they paint, they wet sand the hell out of the car/bike before they put on the clearcoat. So far, I haven't seen it written that you should wetsand before clearcoat.
 
1 - 20 of 57 Posts
Top