Spraying Primer – Avoid These Mistakes When Spraying Primer on a Car – DIY Auto Body and Paint

Spraying Primer – Avoid These Mistakes When Spraying Primer on a Car – DIY Auto Body and Paint

-Hey. This is Donnie Smith, and
welcome to this lesson on spraying primers. In the last video
in this series, we showed you how to mix
up some Epoxy Primer, now we’re going to
spray it on the car, and then we’re going to
mix up some primer-surfacer and apply that as well. First, before we start
to talk about spraying, I’d like to talk about
some of the mistakes, the common mistakes that I
see with spraying primers. And probably the biggest
mistake I’ve seen out there is trying to put too
much on, put it too wet, too many coats too soon. And that causes a
lot of problems. A lot of the problems
that you have in paint can come back to not
enough flash time or putting it on too thick. That’s why it’s important to
look at the technical data sheet, and find out exactly
what you’re supposed to do. And there’s technical data
information to the Epoxy and the primer-surfacer
at the end of this video for the ShopLine. Putting it on too thick, it
can cause a number of problems. But let’s talk about one of
the problems that can lead to. If you’ve ever seen
dry dirt or mud that’s dried and all the water
has evaporated out of it, it’s all cracked up, well,
you know, primers and paints, they do the same thing. If you put it on too thick,
too heavy, it’s going to dry, and if there’s a possibility
that some of these products can do that, and it could
actually crack on you and give you that cracked
look just like dried mud. Another thing that can
lead to is solvent popping. And what that is, is when
you apply it on too wet, the outside surface is
already kind of dried and what’s underneath can’t
escape, can’t evaporate. So you’ve got all those solvents
underneath and everything’s going evaporate sooner
or later, and what it does is, instead
evaporating the way it should, it later, after that
top film is dry, is it evaporates but it makes a
whole where that evaporates at. So there’s like a tiny
little pinhole in there. And sometimes those can
be very deep especially if it was the first coat of
primer or this is escaping at. And so it’s going to go
through all that surface and have a hole there. Another thing, if you put it on
too thick, too many coats too fast, it could shrink on you. So you might have it
sanded down, it looks good. And you paint it,
and it looks good. Then a couple days later,
even weeks later, that primer continues to shrink because
it couldn’t dry properly and then you see repair mapping
and sand scratch swelling from where you did
your body work. All those can be
eliminated if you’ll just follow the technical data sheet
and not put it on too thick. I know. Most of us are all the same. I mean, if a little
bit does good, we always think more is better. I mean, I’ve tried vitamins,
and well, I can’t really tell if that doing anything. Let’s try more. But just like with
medications, vitamins, more is not necessarily
better, and that’s the case in refinished products. So always read that
technical data sheet and follow the recommendations
because they’re there for a reason. Now, I know I mentioned allowing
it to flash the proper flash time, what’s the technical
data sheet say about that. Let me back up and tell you
exactly what flash time is. Flash time is the amount of time
it needs to dry between coats. So if you put a coat of
primer-surfacer down, and it says allow
to flash 5 minutes, you need to let that
sit for 5 minutes. Now, that is not an absolutely,
and let me tell you why. These technical data sheets
are written in a lab, in a testing environment. It’s usually 70 degrees. So when they do this, it
dries 5 minutes at 70 degrees Fahrenheit, and that’s the
amount of time it takes. Now, like today, out here
in my garage, it’s very hot. It might not take that long. It’s going to decrease the
amount of time it has to flash. And if it’s really cold, it’s
56 degrees in your shop, well, you’re going to increase
that time quite a bit. So always take into
account the temperature that that’s going to
affect that as well, but that’s a good starting point
is look at the technical data sheet, but remember
that’s at 70 degrees. So flash time is the
time in between coats. Now, the window is
how long you have before you can re-coat on top
of that without having to sand. For example, Epoxy
has a real long window of 72 hours, the one
I’m using anyway. Most of them do. So you have three days to come
back with your primer-surfacer or whatever you’re putting
on top of that to spray it. And during that time,
during those three days, you can spray right
on top of the Epoxy. It has a chemical bond,
a chemical adhesion, but if it goes longer than the
72 hours are to three days, you’re going to have to sand
that scuff it up lightly to give it a
mechanical adhesion. So when following the
steps in this video, we’re going to
spray the Epoxy on. We’re going to allow it to
dry the recommended time, then we’re going to come
straight on top of it with the
primer-surfacer, and then we’re going to allow it to dry. Then we’re going to block it out
and get it ready for painting. Again, if you want the
specifics, the technical data information on Epoxy,
on primer-surfacer, at the end of this video, there
will be some resources for you to click there where you
can get to those videos where I’ll go over the entire
technical data sheet for you. OK. Let’s get started. OK. We’ve got the primer mixed up. And the way this
works, you have to buy this adapter that
goes with the system. And you just push
this lid on here. And the nice thing about
this is, is when you’re done, you just take this off. You can throw the
lighter away, and then you just have your gun
to worry about cleaning. You don’t have to
keep a cup clean. What I’m going to do is wipe
this down with wax and greaser maybe one more time. Making sure that you are
working on a clean surface is an important part and
ensuring good adhesion and preventing problems like
fish eyes and things like that. We’ll let that flash off
for a little bit and dry. And then this is
the way we prime it. We just have an old tack rag. I wouldn’t necessarily
get a new one for it. So you can just slightly go
over it with the tack rag. Make sure some of
the dirt is off. Then also with
primer, you always want to make sure that
you do wear a proof respirator for
spraying, and you also want to be in an area like this,
in a prep station or a tank booth and that you
have your fans on. As you can see, we’ve
got our first coat on and it’s flashing off. Be sure and check
your procedure pages to see what the flash time
should be in between coats. And we’re going to go ahead
and put two coats of this Epoxy Primer on, the first coat we
went the full length of this, the second coat, we’re going
to come back a little bit and not go quite as far. And what that does
is allows a thinner build to be here so that you
don’t have a hard edge when you’re trying to
block sand this out. All right. We’ve got the gun clean
and now the washing down. We’ll go ahead and wipe
if off a little bit. And now we can get ready
to go ahead and put the primer-surfacer. In this particular
job, we’re going to use ShopLine, a JP202,
which is a primer-surfacer. And what that is used to
do is to fill the scratches and we block it out and
make a nice, smooth surface. So like I said, you always
want to be sure and look over your procedure pages. If you notice on this, it
shows that we put two coats on, so you might wait at least
30 minutes before applying your primer-surfacer. And you have up
to 72 hours, which is three days, to go ahead
and apply the surfacer. If you go longer than
three days or 72 hours, you’ll have to scuff
the surface to provide a mechanical adhesion rather
than the chemical adhesion. So we’re going to mix up
about the same amount. And if you look
over here on 202, and depending on
the products you’re using, wherever you
buy the products, be sure and ask for
these procedure pages so that you can look at
them, and it tells you how many coats should be
applied, the flash time, things like that. So here it shows that
you mix it 4 to 1, so it means 4 parts of JP202
to 1 part catalyst, which is 301 for this application. So we’re going to
mix this 4 to 1. So you look on here. Find the 4 to 1 and probably
we’ll just go 2 and 2, 2 parts here to the catalyst. So there’s our
primer-surfacer, catalyst in. It’s always a good idea to
be sure to put these lids on immediately, because this
catalyst is moisture sensitive, and you don’t want
that lid left open. Now, I can sit the Epoxy
Primer for the one that takes the induction time. This is primer-surfacer. There is no induction time
as soon as it’s mixed. Go on and spray it. Put your lid on. And you want to be sure and
always put this ring on. It has been left off before,
and without that, that lid is not going to stay on there. Put it on. Now, we’re ready to apply our
two coats of primer-surfacer. OK. As I mentioned, if we’ve
waited at least 30 minutes and not no longer than 72
hours, we can just come in, and we can spray
right over that. You can tack it if you want
to, but it is ready to spray, so we’re going to pick up our
paint gun, turn our fan on. OK. I just had a problem. I don’t know if
you saw it on film, but we had a drop that
dropped on the car, and I stopped to see
what the problem was. And what happened is
I had the liner here, and this will happen
if you’re not careful. And I popped this on and
wasn’t paying attention. And when I did, can
you focus in on that? I kind of caught the edge
of that and pushed it in. And this got kind of
pushed down in there just a little bit, which
didn’t make the seal. And then I put everything on. So make sure that this
does stay on top here. And that probably had I opened
the gun up and just put it back on top. Make sure. This doesn’t happen often,
but every once in a while if you’re not paying
attention, that will happen. So that was a mistake that
we can learn right here. Try to avoid that. OK. I went ahead and got the
first the first coat on. Let it dry for a little
bit, and then we’ll come back and put
our second coat on. Now, if you’ve been watching
my videos for a long time, you may realize these videos,
I shot a long time ago. However, listening to your
comments and your feedback, you really enjoyed
this series of videos. But there’s a lot of
complaints about them because the audio
wasn’t too good, and I tried to enhance that the
best I could, plus I’m putting in this intro and talking
about some of the question you had in the beginning
and ending of these videos. So hopefully, you
found that useful. Another question I got a lot
from this video from years ago is, what kind of primer
gun do I recommend? And there’s a lot of good
primer guns out there. You just need a
1.6 to 1.8 range. You know, it’s a
little bit bigger gun than what you’re going
to shoot base coat with. Base coat is going to
be like 1.3 to 1.4. And for primer,
I’d use 1.6 to 1.8. 3M makes some good primer guns. This is a DeVilbiss. They make some good ones. Me personally, I have started
using 3M’s Accuspray primer gun. Some people really liked
it, and some don’t. I’ve heard good
and bad about it. Me personally, I love the gun. It’s true that you don’t have
to have atomization quite as well as you do when
you’re shooting base coat or clear coat. But you still want a gun that
can spray it really nice. For example, in this
video, I showed you how to mask off and
back mask, but I mean, if you’ve got a small
spot in the fender, it’s possible that
you could just spray that fender and
maybe not even mask. What you’re going to do is,
you’re going to turn your gun. You’re going to fine tune
it to a smaller pattern, and then you’re going
to prime just that area. You’re going to keep that
repair area real small. And so you want a
primer gun that’s going to shoot good if
you need to do that, and a lot of times, that’s what
you may do rather than masking off the way we
did in this video. But if you’re a
beginner, I would recommend going ahead and taking
every precaution until you become comfortable enough to
know what your limits are. If you’re unsure, go
ahead and mask it off. Drop a piece of plastic
over the entire car just like we did
with this video, because it’s always better
to be safe than sorry just to save a few minutes. If you enjoyed this
video, I’d really appreciate it if you go
down below, give us a like, give us a thumbs up, and
be sure and tell others about this video. Thanks for watching, and
remember, if something’s worth doing, do your best and
have a blast doing it. Hey. Before you go anywhere,
be sure and check out some of our other
videos and playlists.

100 Replies to “Spraying Primer – Avoid These Mistakes When Spraying Primer on a Car – DIY Auto Body and Paint”

  1. I painted and did body repair back in the 60s and 70s but materials are different now and I haven't kept up with the technology, Your Videos are a great help. Thanks.

  2. It would be really great if you have a playlist which covers every step from stripping the paint to repaint and polishing. Love your videos. 😉

  3. i have a question , I spray epoxy primer..should i spray a 2k primer top of it?? .primer all place or just on top of the filler?? im confuse to use primer.

  4. Another mistake I was always taught was that "overmixing" could cause the primer to kick much faster. Thank you for doing what you do to help the people that simply don't know how any of this works. Wish this was available 10 years ago I had to go to a technical school or get yelled at by an older tech just to learn something. This would've been much easier.

  5. The audio on this was perfect. Many are simply too low volume or include so much background noise that it is difficult to understand them.

    I don't know what is meant by 'Use a gun in the 1.6-1.8 range for primer; 1.3-1.4 range for base coat'. Clearly I'm not among the unwashed regarding spary painting!!

    Is that gallons per minute, meters per second or some Klingon measurement of which I am unaware?

  6. I had that same problem with the cups so now when I press the top on I pull it out and check that's it's on all the way before I put the black cap on.

  7. Excellent job. Sir, I painted my car's bumper, but it's made wrong color. So how I can repaint my bumper? Shell I need to remove clear or paint, and what no of sand paper I need to remove it and how please. I am not professional. Thank you

  8. so is it bad if one would use a spray can primer and just straightforwardly spray on it on the car without the epoxy primer?

  9. Can you spray primer one day come back next day break it open let it sit than spray your polyester surfacer on before the 72 hours?
    Would that help reduce solvent pop?
    Love your videos, thanks for sharing your knowledge

  10. Very helpful. I have a vw camper, I am paint the entire van at home in the garage. Can you tell me the steps to take from the start, the old paint is still on in places,and there are a few new metal panels, should I etch prime the entire van, then sand it all first, ,is it ok to fuse filler over raw metal, and then paint.. Could do with your advice here. Cheers


  12. i should've watched this man's video from his experiences. I just got done sanding, bonding and then spraying primer on my car parts. It looks nice now, but I'm scared of what awaits. His video''s make sense to me from my experiences so far.

  13. Back in the day I painted cars in a body shop and used lacquer based primers especially using Du Pont.Are these lacquer primers still available or have they been replaced. thanks

  14. Cool tips on primer. I can't seem to get an answer from anyone including companies that sell paint guns. I'm on a tight budget and don't want to spend more than $200 for a paint gun. But I also need something that is compatible with my Craftsman 6hp 150psi 30gal compressor.
    I was looking at devilbiss flg 670 because it has multiple tips and isn't too high of a price to be a one gun does it all. Do you have any recommendations on what would be a good mid range gun that can do all paint types? Thank you!

  15. Please Donnie I love your videos and have learned a lot. BUT keep yourself safe. Like a breathable air system for 2 part paints. Also would be good to have full painter suit with hood and at least painters goggles… Also arm length butyl rubber gloves . What I have read to be the best protection, we want you around to do more videos…

  16. hello, i'm doing a used plastic bumper respray. I sanded down on some areas all the way down to plastic and on some areas I have to use filler for plastic. Before I apply filler I will spray the the areas with adhesion promoter (plastic primer) where filler will be applied. When I sand down the filler I will again spray adhesion promoter but this time all over the bumper. What primer do you suggest to spray before primer surfacer?

  17. Body work done, now about ready to spray some panels. Oh yeah, this is the first auto(my personal vehicle) I've ever painted and I want to thank you for your excellent, easy to follow videos. I tried watching videos from several other posters but most had me searching for something better for whatever the reason just minutes into them. I very much appreciate how you developed a library by steps in the auto body and paint process. My confidence and knowledge quickly and dramatically increased once I found one of your vids. Thank you for sharing your expertise and experience with the world of us DIY. I would have not started this project yet without your help. I have to admit, my body work looks as good as shop pay work at a mid level shop. It took me a decade(no not really)but it's tight and right. Many thanks sir

  18. Awesome videos, like your casual approach to them! By no means a master but those pps cups when you put them on you're supposed to rotate onto the next notch of the adapter! Had a cup come loose once because of this, hopefully can save someone from this with a comment!

  19. You're right about people putting on too much paint or primer. I've watched a lot of Youtube videos on painting cars and I don't know how many times I've heard someone say " I'm just going to put a light coat on for the first coat " and then they go ahead and put enough paint on for two complete coats !

  20. Do you have to use two part primer and two part primer surfacer when re-coating a car panel with two pack base coat and perhaps non two part clear?

  21. I am experiencing (swelling /mapping) on my car. Is it possible to resand my car again with 600 grit and just base over it? or do i need to reprime it again?

  22. Hi,great video very informative,can you tell me if you can paint your top coat straight on top of the epoxy primer or do you have to apply primer surfacer on top first ?….Many thanks

  23. one thing ypu do I never will do. never paint to a paper edge. I dont know how many time I did it and even after blocking you risk stll seeing a line where you taped. remember your boat scenario? same applies. rolling the edge is a good idea but move it back further so you have a larger blend

  24. Great videos… when you say "technical data sheet' do you mean the directions on the product label or is there an official source of information that you are drawing from?

  25. Use the Revo Accelerated curing system to make sure your primer or paint is fully cured to avoid sinking or solvent popping. I have laid on 2k primer very heavy and was able to cure it fully sandable in 3 minutes. You can also Revo your bodyfiller.

  26. I have a part that has bare metal around where the windshield where urethane seats, can I just put some coats of a VHT epoxy paint on the bare metal, and don't paint it and then just replace the windshield and the urethane is going to stick well to this VHT epoxy paint? Please help!

  27. I am going to ask Acid Etch Primer over J/B Epoxy weld? or should I remove the J/B weld first? and Thanks

  28. Thanks for answering my question about mandatory primering first before topcoating one single panel. I have a decent hood, which just wanted sand up and spray, Not wasting time or money priming the entire hood, there is no filling involved and no bare metal. I just remember the days back in the '70's when I used to pull the car under a cool tree and sand and spray it then go out in the same car later that day!

  29. What vitamins are you adding to your primer? I was thinking about adding some B12 for that energetic look, you know get a speeding ticket when parked look…

  30. I’m spraying a truck with ShopLine epoxy and 2k primers right now. I’m trying to double a triple check all my info. These videos have helped a lot. Thank you

  31. Hey donnie! I just finished spraying a polyester primer, I know I need to spray a urethane over it but it wont arrive till next week. Is it okay to let the polyester sit that long? could i bake it before urethane to take out any moisture?

  32. Hi Donnie, can you use a hair dryer, or heat gun to speed up the process of evaporating solvents between layers in cold conditions, or you would need to use the infrared equipment. I mean when using just heat gun will the solvents still be trapped under? Thanks. Merry Christmas

  33. I like the accu spray gun the only thing I don't like about it I was clearing a town car when the gun was 3/4 s of the way through it started starving for material

  34. Can you apply primer on non gloss paint? I apply primer let it dry than apply the paint but I notice scratch marks. I was wondering if I can re apply primer to cover scratchers or would have to sand and prime again?

  35. Hey I bought two different sandable primer grey colors and was wondering what do I do to even the colors out or does it matter?

  36. I see that you're putting epoxy primer over the bare metal and the filler, but why across the rest of the print painted surface and not just your work area? I thought epoxy primer only needed to be for the spots that needed to be sealed. Thanks for the great videos

  37. Don't spray too heavy of a coat, let it cure "flash" between coats, proper temp in the room, don't let the paint sit too long between coats, remove all wax and grease from surface, keep gun clean, don't leave the paint or curing agent open, careful you get a good seal on the spray gun, so it doesn't drip, 1.6 to 1.8 size gun if you are spraying primer.. there.. I saved you fifteen minutes.

  38. Get your FREE checklist with step-by-step checkpoints to inspect and repair and paint your project. This list will help you from missing many of the important steps. https://mailchi.mp/fb2e14bc0285/checklist

  39. Ok. Im restoring my frame. I'm sandblasting it. Now, that same day I want to paint it. So tell me exactly how to do it. I'm thinking of going epoxy primer and then industrial acrylic enamel both 2k with hardener. Do I pressure wash the frame or just air clean. Do I apply one nice wet coat of epoxy and the let it dry but not all they way just tacky and then spray my top coat. Also if I pressure wash it and there is flash rust, can I apply the epoxy over flash rust. How many coats of primer and Can I just put one nice one or what. I don't want to mess this up I want to do it right. I'm gonna be spraying at around 65 to 70 Fahrenheit temp, outside. PLEASE TELL ME EXACTLY WHAT AND HOW AND WHEN TO DO IT. Also is urethane primer better than epoxy for this job. Thanks

  40. Hi . Im going to paint a tailgate and I have some bare metal spots but no dents or scratches. Can I just apply the base coat on top of the epoxy primer? Or I need another primer on top before the base coat?

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