How to avoid hard paint edge?

General Discussion. Make yourself at home...read, ask and answer!



Settled In
Posts: 53
Joined: Sat Jun 01, 2019 11:56 pm

Country:
Canada
PostPosted: Wed Mar 31, 2021 11:04 pm
Ok so I'm painting my wheels with acrylic enamel paint (auto store spray can paint so please don't bash, I know 2k stuff is better but just wheels) and my issue is that, I'm painting my whole wheel, inside barrel and face so I need to do it in 2 stages, I need to let the paint reach a handle time so I can switch it around. The issue with enamel is that it has recoat window, if I wait 1 hour (which is dry handle time), I need to wait 48 hours or even 7 days if I apply the clearcoat as well.

So I figure let's mask the inside of the barrel when I do the face, and when I do the inside I will lay it flat. My question is, will it do a hard line or it won't be noticeable?



Top Contributor
Posts: 6214
Joined: Tue Sep 16, 2008 1:17 pm
Location: Pahrump NV.
Country:
USA
PostPosted: Wed Mar 31, 2021 11:09 pm
Pay special attention to #4

chris wrote:Credit goes to Han for this suggestion:

There are a few fundamentals that folks new to auto body / painting and new to using resources like this board should know. I'd like to document these in this thread and after a period of time I'll pull all the key points into the first post, and we will sticky this. So, here are a few to get the ball rolling:

1. Everyone here comes from different backgrounds. In this field there are often many ways to achieve the same end result. Sometimes the difference in advice is based on the perspective of an experienced technician who is "on the clock", versus a serious hobbyist or restoration expert who is going for a "six nines" (.999999 perfection) result. Sometimes the difference in advice is based on the way we were taught. The new person here needs to read and examine all advice given, and decide for himself which is the lowest risk/highest reward approach. If someone posts advice that is flat out wrong, the community here will quickly (and hopefully, kindly) point out the flaw, and offer alternatives.

2. You can hurt yourself doing this stuff. Anything learned here is to be employed at your own risk. Research and learn how to protect yourself -- especially when it comes to your lungs. If you are unsure about any safety aspect of what you are about to attempt, ask/research first. Lungs are very expensive to replace.

3. There are three things you need to have under control when spraying (assuming your prep work was done correctly): The environment, the material, and the gun. If you don't get all three right you will likely have a problem. Good lighting is a must. Reading and understanding the tech sheets for the products you are using is a must. Dialing in your gun and your technique is a must. This is not a venture you want to rush into. Spend 90% of your time preparing and 10% of your time applying.

4. Rattle can products at your local auto parts retail store are best to be avoided. We see a lot of guys here mistakenly use aerosol primer under a catalyzed color coat, then wonder why they have adhesion problems later. That rattle can stuff is a type of lacquer (that's the only way it can have a shelf life for so long). It can work if used under acrylic enamel or other rattle-can finishing products -- but typically not what the community here gets involved with. No time like the present to get rid of those aerosol cans and move up to a real spray gun and compressor, and learn how to use a modern urethane (or waterborne) finishing system.

5. Sandpaper. Leave the home improvement stuff at the big box store, and get yourself a variety of top quality automotive sandpaper. Norton makes great paper, as well as 3M. It may seem expensive at first but the time savings and lifespan of the paper will more than pay for itself. There a thread here that discusses the various grits and usage.

6. Rust-stop, Rust-conversion, Rust-anything. Some people will swear by this stuff, most people will say that it's a joke and causes more problems than it's worth. I'm in the latter camp. I can see where maybe on an old truck frame you might want to try it -- but I'd never recommend it on sheet metal. If you are doing a restoration the right answer is to remove and replace the bad metal. If you are doing a $50 quickie for the used car lot down the street...then let your conscience be your guide.

7. Metal Prep, Etch, Soda Blast. Any of these things introduce a layer of unknown chemistry on the surface of your sheet metal. I say "unknown" because the pH and penetration of this stuff is never really under your control. Best bet is to avoid any metal prep or etch products -- modern epoxy primers don't need them. For soda blasting...it can be done but you need to have your blackbelt in neutralizing the stuff afterward -- and pray that you got it out of every nook and cranny on the car. I don't touch anything that has been soda blasted and I wouldn't do it to any car I'm working on.

8. You can never have enough compressed air. If you are using an HVLP gun or a D/A sander, you will quickly find out if your wheeled Craftsman tire inflater is up to the task (it won't be). Be sure to determine the greatest CFM (Cubic Feet per Minute) tool you have, and then pair that with a compressor that has at least 25% headroom above that number. It doesn't matter how many horespower, gallons, cylinders, color or weight of the compressor -- the critical spec is the delivered CFM rating at the PSI you need.

9. You've learned everything, prepped your car, have a new gun and compressor, garage is all set up - you are ready to paint, right? No! Practice on a couple of old hoods and fenders from the junkyard, first. Your prized car project is not the place to work out kinks in your technique...trust me on this one. Shoot the junk parts first and you'll be much more confident moving to your real project. Some junkyards will give away stuff that is unlikely to sell. Make friends with your local salvage yard. Practice priming, sealing, color, clear...anything involving your spray gun.

10. Learn how to use a mixing cup. Click on this thread for a great discussion regarding this topic.

11. Get the tech sheets or product (p) sheets for the paint products you are using! Every manufacturer I've come across has these product sheets available for download from their respective websites. These sheets boil down years of product development and research into the environmental and mixing conditions the chemical engineers intended for their products -- don't play "junior chemist" -- follow the directions, instead.

12. Finally, if anything begins to go wrong while you are painting - stop. Fisheyes will not get better with time. Drips coming out of your gun will not magically fix themselves. If you are getting orange peel, try to dial the gun in (first step - increase pressure a notch) before you continue with your clear. There are a ton of things that can go wrong when painting -- don't feel bad if any one (or a few) happen to you. That's what the website is here for, to help you sort this stuff out. A wise man once said "A true mark of a craftsman is his ability to fix mistakes". That's very true when it comes to auto body and paint!

Don't forget to check out the articles we've assembled -- especially the "newbie" and "beginner" articles under the General Articles section found at the page here: AutoBody 101 Info Center
Dennis B.
A&P Mechanic, FCC General radio Telephone Operator
Line Maintenance A&P Mechanic and MOC Tech specialist.

User avatar

Top Contributor
Posts: 2762
Joined: Sun Dec 16, 2012 4:46 am
Location: Canberra
Country:
Australia
PostPosted: Thu Apr 01, 2021 2:57 am
If you have to use spray cans, don't use enamel. You can already see the ridiculous tape free and dry times. On a wheel there is usually a line or join or something that you can tape along for a hard edge - if you place it properly and tape carefully you'll never see it.
Chris

Return to Body and Paint

Who is online

Users browsing this forum: Google [Bot] and 136 guests