Painting steps for epoxy primed tub, new inserts, and old fenders, grill and hood

[rjrobin2002]

I have a sand blasted and epoxy primed tub, new fiberglass door inserts, and a front clip that needs the crappy multiple coats sanded off to bare metal. My tub needs 3- 4 small Bondo repairs which I assume I do first.

Do I do Bondo repair the tub first, sand the front clip to bare metal and scuff the inserts, epoxy prime/seal the whole vehicle, high build prime, block sand, top coat, sand first top coat with a 1000-1500 grit paper and make any additional block sanding repairs , then spray the final coat, wet sand and buff?

 

[allenfahey]

I thought I replied to your PM but looks like it wasn't sent since it's not in my sent folder???

I assume you are doing all this in a garage out of the weather. I would remove the old paint from the front clip first. You may find more bodywork to do under there. A tip to remove paint with stripper is to gouge up the paint with a 40 grit disk on a grinder or even a DA pad. The stripper will be able to get under the multiple layers of paint and will strip faster and in less applications. Once you have the stripping done wipe it down with lacquer thinner and a red scuff pad. That will dry up the stripper and wash it away. Sand down the entire front clip to bare metal with 180. Sand the areas you are going to do bodywork with 80 grit and do your body work on the tub and the front clip. Final grit for the body work should be no coarser than 180. just the area surrounding the body work sand with 320 and a red scuff pad. If you have epoxy primer left over use that on the body work areas on the tub and the entire front clip. 3-4 coats should do it. After that is dry spray a guide coat and block sand the entire thing with 180. Spray 2-3 coats of high build 2K primer, and then guide coat it. Now you need to decide if you are going to spray sealer prior to paint or paint directly onto the primer. If I were you I would spray the sealer. Many 2K primers can be mixed as a sealer. Check the TDS (technical data sheet) for the mix ratio. If you are using sealer you can sand it down with 320 and follow that with a red scuff pad. If you are going directly to paint 400 or 600 grit is what you want to use.

What type of paint are you using? Single stage, base/clear? If you are using single stage you can't do any sanding between coats. If you are using base coat you can de-nib any dirt but you are going to have dirt no matter what you do in a garage. You can always buff it later. Spray the sealer, let flash, spray the paint, let flash, then spray the clear. Then your done!

 

[rjrobin2002]

Thanks for the great response and it answered my questions. I am doing a single stage paint, so what time frame do you wait between top coats?

BTW, I have a DA sander and Devilbiss spray gun. What should I do to make sure no water gets into my paint gun from my compressor?

 

[TwoDalesDad]

Use a throw away filter on your paint gun. before you plug in your paint gun....make sure to dain your compressor tank of water...

 

[bknbronco]

Allen helped me with my paint. I found a good single stage urethane (PPG) and had good luck with it. Follow what allen said. Sand to bare metal the areas that need filler. Work them areas out and wipe down and seal.

With my SS it is only like 15-30 minutes between coats. Depends on how you mix it and what reducers and hardners you use. For my paint there is like a dozen ways to mix it! The way i mix hardnens quick and still has a pot life of 48 hours i think. Read the data sheets with each paint product your gona use.

I use a devilbiss gun. My DA sander dont get as much use as my palm sander.

As far as the water....wwe dont have any fancy equiptment and not 50 feet of steel lines! We got about 4 feet of hose going from compressor to a cheep water seperator-regulator combo. I do use a "painting only" large hose with the large paint fittings on each end. Then a cheepo plastic water seperator (basically a tiny roll of toilet paper in a plastic housing) on the end of the hose that goes after the regulator, and another cheepo on the gun. I run like 60-80psi at the regulator and like 25psi at the gun.

The best thing you can do for water is not to paint the same day you do a ton of sanding. Let the compressor cool down completly, drain the tank and seperator, and let sit for a day. That way you wont get as much moisture in the lines as when the air is super super hot. Kind of depends on outside temps also.

Also might find you would like to clean up or add some seam sealor. Seam sealor gets applied over primer, in my case over the sealor.

 

[bknbronco]

how bad is everything? Are you positive you need to block everything? Skipping the high build primer and the blocking can save you some coin and tons of hours. If you want to win a car show trophy then block, but my hood and tailgate turned out good with just scuffing, sealing, and 2 coats SS. No blocking on either.

With that said i will someday redo my paint and get the waves out of my glass tub by blocking, at that time i will glass or weld up my body gaps but for now it looks pretty nice to everyone that has looked at it.

 

[rjrobin2002]

'Spray 2-3 coats of high build 2K primer, and then guide coat it. Now you need to decide if you are going to spray sealer prior to paint or paint directly onto the primer. If I were you I would spray the sealer'

What is the time frame between the 2k primer coats and when can I spray the guide coat?
Is there any sanding between or after the high build coat or after the guide coat?

 

[allenfahey]

TwoDalesDad is refering to the orange canister filters you attach between the gun and fitting.

Bknbronco has good advise about draining the compressor and on filtration. My compressor at home is a large Ingersol Rand 7.5 horse 80 gallon tank. When I paint at home I too drain the compressor. I have a 3 stage Devilbis desicant filter system but they are too expensive for what you will ever need. The larger the compressor, the less it is running, the less moisture you will get. Cool air= less moisture. A few good tips keeping water out of the air lines.
1. paint in the morning when it's still cool out. Less bugs out anyways.
2. Plumb the metal lines out of the compressor into a large "U" with a water spigot on the end. I had these at the dealership and they caught alot of water in them.
3. If your compressor is a large one like mine you can keep the petcock on the bottom off the compressor cracked a little. Water will settle and trickle out the bottom. If you have a small marginal compressor you can't do it because you will need all the CFM you can get with spraying paint.


BknBronco also mentioned hose fittings. HVLP guns need alot of CFM to operate correctly and get the proper atomization. He is referring to special fittings called HVLP fittings. You will need a HVLP hose coupler on the end of the line off the compressor. A HVLP fitting on the hose end to plug into the fitting. A 3/8" ID hose. Another HVLP coupler on the other end of the hose, and another HVLP fitting on the gun. You can use a regular "M" or "A" style fitting but you will get a better job if you use the fittings the gun was designed to use.

Flash times.... Depends on the temperature, air flow, hardener, and reducer. I like to use a bit slower reducer and hardener than the temp I'm spraying in especially for the clear or in your case single stage. Slower hardeners and reducers will be easier to run too. If you use too fast of a reducer/hardener you will can get solvent pop (trapped solvent that escapes and create bubbles), orange peel, and have it die back some (look dull). Especially in a garage with little to no air flow. Flash times are about 10-15 minutes. Flashed off means it has tacked off. If you touch the masking paper and it leaves a finger print and is stringy you are ready for the next coat. Once it's done and the overspray is out of the garage you can use a heater to help dry it. I use a salamander heater in the garage to dry my paint. Quicker the paint dries the less dirt there will be but too fast while spraying it can produce a bunch of problems.

 

[allenfahey]

Is there any sanding between or after the high build coat or after the guide coat?

Spray a coat of primer, wait to flash off (see above post) spray another coat, ect.
When the primer is dry you apply the guide coat. I like to use some left over base coat. You can buy a can of guide coat in an aerosol can from the paint store. Don't use paint like Rustoleum. It will clog and gum up the sand paper.

 

[nboost]

This is some good info.
Thanks

 

[rjrobin2002]

Just got back from the auto paint supply place and 600 bucks later I am ready to go. Thanks for pointing me in the right direction.

 

[allenfahey]

Just got back from the auto paint supply place and 600 bucks later I am ready to go. Thanks for pointing me in the right direction.

$600 is all? You aren't done buying stuff yet

 

[rjrobin2002]

$600 is all? You aren't done buying stuff yet

I am sure I will be making more trips there also. I am also not sure if you are saying I over payed either though. I am very new to this.

 

[bknbronco]

What brand you goen with? Gona shoot epoxy over everything, then high build?

$600 bucks will get you goen! Thats alot of crap! But you havent bought paint yet! I had alot of fun painting my stuff and cant waite to paint the body again.