Newbie Painting with HVLP Spray Gun

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PostPosted: Thu Dec 24, 2020 2:01 am
Hello,

I have been searching online and watching a lot of videos to try and get a straight answer. I recently inherited a 1997 Pontiac Firebird that needs a great deal of work. Having that said, the structural body of the car seems to be in excellent shape. There are no major dents, even a minor dent is hard to locate and there is no rust anywhere on the body.

Having this said, the paint has seen better days. There are places where the clearcoat has is just worn out. The car still looks good overall, but I am considering painting it. However, I have gotten a lot of varying opinions and feedback. I would have to guess this has been asked at least several times on this site already.

1.) I have a 20 Gallon Air Compressor that produces 5.0 CFM at 90 PSI and 6.0 CFM at 40 PSI. I was told that this was enough to achieve good results with most HVLP guns and tips but my tank would probably be constantly "catching up". I have also heard to simply not try to paint a vehicle with my current compressor.

2.) I do not have a garage to do this so I will be looking at doing it outside. I will also be waiting until the weather gets warmer as well. I know painting outside can create problems because of weather and mother nature but can I still achieve good results?

3.) If my compressor is good enough, or for future reference what HVLP guns are good choices? Should I get a separate gun for primer, paint and clearcoat?

4.) Can I use a rotary sander or belt sander to help sand down the remaining clearcoat and paint? What types of paper should I use?

I have a lot more to ask but I guess I will leave it at that for now. I am going to be in a pickle if my compressor is not up to the task because anyway as I only have standard power outlets in the area where I keep it. So if have to upgrade I may have to put this project on hold until I can figure out what compressor to get and how hard it will be to add in a 230v outlet or something.

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PostPosted: Thu Dec 24, 2020 9:00 am
Read the articles in the Info Center first and a lot of your questions will be answered.
I wrote the following: https://www.autobody101.com/content/art ... ould-know/ to give an overview of the tools, supplies and shop space needed for restoration work.

There is a section explaining the importance of the Air Compressor and filtration system, without which you will not get proper paint atomization.

Once you have read those articles, look for Sticky Posts at the top of each forum category. These are also great sources for "How To" instructions in particular areas of body work and painting.

The first thing I do with a restoration project is take pictures of everything inside and out. I also take pictures of wiring and hardware while dismantling the project.

You should keep lists of parts that are missing, need repair or replacing. Noting the color of parts can also be of help later on.

Proper body work and prepping for paint, using quality materials, are the key factors in producing a quality job.

Painting is actually the enjoyable part, IF you follow the air requirement suggestions and make sure you have everything set up and adjusted properly.
1968 Coronet R/T


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PostPosted: Thu Dec 24, 2020 4:41 pm
'68 Coronet R/T wrote:Read the articles in the Info Center first and a lot of your questions will be answered.
I wrote the following: https://www.autobody101.com/content/art ... ould-know/ to give an overview of the tools, supplies and shop space needed for restoration work.

There is a section explaining the importance of the Air Compressor and filtration system, without which you will not get proper paint atomization.

Once you have read those articles, look for Sticky Posts at the top of each forum category. These are also great sources for "How To" instructions in particular areas of body work and painting.

The first thing I do with a restoration project is take pictures of everything inside and out. I also take pictures of wiring and hardware while dismantling the project.

You should keep lists of parts that are missing, need repair or replacing. Noting the color of parts can also be of help later on.

Proper body work and prepping for paint, using quality materials, are the key factors in producing a quality job.

Painting is actually the enjoyable part, IF you follow the air requirement suggestions and make sure you have everything set up and adjusted properly.


Thanks for the reply, according to this first article, my units specifications are close but do will probably not meet the minimum requirements. Because the lower you go with PSI the greater volume of air produced or CFM correct? That means that when my compressor is dropped below 40 PSI the CFM will probably be greater than 6.0 correct? However, 9.0 CFM is definitely pushing it.

I realize it is about to be Christmas, so Merry Christmas. I will do some of my own reading on the rest of the threads here.



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PostPosted: Thu Dec 24, 2020 9:29 pm
My opinion
No to your air compressor There are some LVLP guns you might look at though. but even then I think it its too small for the task, asking it to run a DA will be asking too much from it as well.

Buy a DA and try it, You'll work for a couple min. and you'll wait five for it to fill back up! its has too small of a pump for the work at hand.
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PostPosted: Thu Dec 24, 2020 10:59 pm
This is what I have and for a one man shop it's the bare minimum in my opinion.
AirCompressor2.jpg

2StageAirCompressor.jpg
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PostPosted: Sat Dec 26, 2020 3:31 am
Doright wrote:My opinion
No to your air compressor There are some LVLP guns you might look at though. but even then I think it its too small for the task, asking it to run a DA will be asking too much from it as well.

Buy a DA and try it, You'll work for a couple min. and you'll wait five for it to fill back up! its has too small of a pump for the work at hand.


Thanks for the replies gentlemen. I was thinking about just getting one of these HVLP guns and trying it on a fender or hood or something from a scrapyard. I was hoping maybe I could find a hood at a junkyard to fit my hood and if the results turned out good I could just swap it out and paint the rest of the car. I also wanted to get a stencil or something and paint a hawk on the hood before applying the clear coat, I thought that would be pretty cool.

After reading your reply though a LVLP gun might be the route to start with given my compressor. It looks like many people are happy with the 3M brand but it is quite expensive at $200.00. Another plus to it is that many of the parts are disposable and easily replaceable but the reviews are saying even they are expensive on that stuff. If anyone has other recommendations I am open ears.

Also could you tell me what a DA is? Is it an HVLP?

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PostPosted: Sat Dec 26, 2020 10:34 am
DA = dual action sander. These are used a lot in auto body work from stripping paint to sanding clear coat.

If you plan to get serious about restoring or painting cars the primary tool is the air compressor. It is literally the hub and heart of shop.

I started with a small compressor like yours and it was the most frustrating experience of all that I have dealt with over the years.

My DA would run for about 2 minutes and then not have enough power to continue until the compressor would catch up. I couldn't use air tools (impact hammers, chisels, cutoff tool, sanders, grinders, drills, etc.) for the same reason.

Then when I started spraying paint it was such a hassle. The gun would spray perfectly for a minute but then the compressor would kick on and run continuously. This causes pulsating, excessive moisture and poor atomizing of the paint.

As I wrote in the article, you compressor should "exceed" your spray gun's CFM requirements. Without the correct volume of air you are asking for and will have issues.
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PostPosted: Sat Dec 26, 2020 1:50 pm
I think Jim said it best when asked for advise on shopping for a compressor when he said Buy the biggest baddest air compressor you can afford!
As Jim says A compressor is the Hub or The center of your Shop.

A small compressor like your is great for filling tires on your car or running a Nail/Stapler gun stuff like that. But Any tool that requires constant use or a Lot of CFM to operate that little guy just isn't going to cut it.

When a Compressor runs continuously it get really HOT! really really Hot this shortens its life considerably! Heat is any compressors enemy. In fact Most are not rated for continuous use if you read the fine print.


As a compressor cycles the air pressure fluctuates most smaller cheap air compressors have very cheap air pressure regulators that don't respond as quickly or as accurately as well as higher quality ones do resulting in pressure fluctuations at the gun which causes a lot of painting problems. Just buying a Hi quality Pressure regulator is not the answer.

Too make matters worse Air compressor mfg mislead the general public with grossly over stated HP & CFM claims! Compounding this Air tool mfg do the same thing! claiming their tool uses less CFM than it actually uses.

Here is some math for the subject that kinda explains things I was gonna try to explain.
https://www.vmacair.com/blog/sizing-air-receiver-tank/
Dennis Barnett
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PostPosted: Sun Dec 27, 2020 4:38 am
Yeah the thing that sucks is I have been able to solve most of my problems with batteries. As in anytime a need for something pops up I can purchase as nice Milwaukee tool to take care of the job. For instance, I got sick of taking off my mower blades by hand (I do this often because of my landscaping business) and caved and bought a M18 Impact Wrench. It is hands down one of the best purchases I have ever made.

At the time I only had about 20' of air hose and the shop where the mowers are is separated from the air compressor. Plus I was seeing that my compressor was limited. I know I am getting slightly off subject here but it has been a game changer. I no longer have to wedge a piece of wood under my mower deck to remove and install mower blades. The tool is worth the price just for this purpose in my opinion. If I have a sharp set of blades ready to go this job now takes a couple seconds rather than minutes of agony.

Anyway I guess I have finally hit a roadblock to something I may not be able to solve. I have been looking into the LVLP guns and people are recommending them for primer and especially clear coat but recommend a HVLP for base coat.

I have been detailing cars on the side for years, never got into it because it was never profitable for me personally. I just always saw how hard it was to rake people in for hundreds of dollars for a job that was worth that price just not worth it to them. It is the logic of 'why would someone pay me several hundred dollars to wash, clay bar, wax and possibly even polish their car when you can get it down in a fun little tunnel for $20?'. Even though the job is worth that much money and people think the job was well worth it after they see the results, it is just most people have the previously mentioned logic.

Anyway I have always wanted to get into restoring fully restoring the exterior of cars, but my skills have always topped out at polish. So once your clear coat is gone there is not much I can do anymore.

This post is already getting long winded but right now I was only planning to do this Firebird. Is painting cars a profitable side job? I realize anything is profitable if you put your mind to it but generally speaking? Then is it more profitable to paint vehicles for people or to buy vehicles, paint them and resale them??

I may look at larger compressors later, but my budget cannot handle it. It looks like something that is probably going to cost me $2,000+ and I cannot even consider that right now. A larger compressor alone is much more expensive, then I need to figure out how to route a 240v power supply to it and finally select my painting equipment. I would love to do this but right now cannot even think about it.

By the way this car is a work in progress. I need to do a lot to it before it is fully road worthy. The engine and transmission seems like it is in good shape so far, so if I can solve the other problems I would love to give it a new paint job.

As I said I may go to a junkyard and see if I can locate a hood that fits this car. Then paint it with a LVLP or something and see what happens. If I like the results I can use it as my new hood and if not I can scrape it and start figuring out how I am going to upgrade my setup.

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PostPosted: Sun Dec 27, 2020 8:03 am
TheFoxRocks wrote:Is painting cars a profitable side job? I realize anything is profitable if you put your mind to it but generally speaking?


Unless you're well set up and experienced the costs of making mistakes will kill any hope of profitability that you might have had.

This, from me, who's had a repair shop for nearly 20 years and has moved operations to a home based business. But....I already have all the paint, the guns, the tools and years of experience. Could someone new to the trade expect to make a living from it? Unlikely.

Then is it more profitable to paint vehicles for people or to buy vehicles, paint them and resale them??


That all depends on the customer and the vehicle. Some people want a $500 respray while others don't bat an eye at $30K. They're the ones with the vehicles that can take that kind of investment and still represent a profitable venture for the customer. Unless you're highly experienced and knowledgeable on what a vehicle can be worth and the costs of taking it from a rusty wreck to concourse condition then you're better off leaving those decisions to the customers who know what they're doing, or have the resources to be able to absorb the cost of a mistake.

If you think that you'll be able to buy something for $2K, paint it and sell it for $10K then you're sadly mistaken.
Chris
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