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Thread: Do I need to use sealer

  1. #1

    Default Do I need to use sealer

    Getting close to finally spraying out my restoration. The P sheet calls for a DAS3037 (G6 dark gray) sealer to be applied prior to BC. I have read numerous threads where the sealer was deleted when applying an appropriate epoxy primer that was reduced and sprayed in an appropriate manner. It has always been my understanding that a sealer was used to hide "bleed through" of filler, under primers and any other material applied that could cause shadowing in the BC. On my project I applied a multitude coats of DP50LF primer(at least 3 coats) until absolutely nothing shows through. I have the called for sealer on hand to use if it is necessary, just not wanting to shoot a product if it is not needed. If I don't use the sealer will it change the final outcome of the color I am trying to achieve? If I shoot out control panels until I get the color I want, wouldn't this work without the sealer? Lastly, this is a tri-coat color, my first ever tri-coat spray out. I am not trying to cut corners, just not wanting to shoot something that is not necessary.

  2. #2
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    yes i would seal. either with epoxy or urethane dosent matter

  3. #3
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    Nov 2005
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    Default Are ready?

    Quote Originally Posted by Ronf View Post
    Getting close to finally spraying out my restoration. The P sheet calls for a DAS3037 (G6 dark gray) sealer to be applied prior to BC. I have read numerous threads where the sealer was deleted when applying an appropriate epoxy primer that was reduced and sprayed in an appropriate manner. It has always been my understanding that a sealer was used to hide "bleed through" of filler, under primers and any other material applied that could cause shadowing in the BC. On my project I applied a multitude coats of DP50LF primer(at least 3 coats) until absolutely nothing shows through. I have the called for sealer on hand to use if it is necessary, just not wanting to shoot a product if it is not needed. If I don't use the sealer will it change the final outcome of the color I am trying to achieve? If I shoot out control panels until I get the color I want, wouldn't this work without the sealer? Lastly, this is a tri-coat color, my first ever tri-coat spray out. I am not trying to cut corners, just not wanting to shoot something that is not necessary.
    Understand that you spray your sealer, allow it to dry and spray your base. Often, some may think they can spray sealer and a few days later begin the paint process. Also, if you have to sand your sealer for some reason, you'll need to reseal that section. About the best you can do with sealer is tack it off.

    What color(s) are you shooting, what colors are there on now (like red car with light gray primer scattered around)? My paint supplier advised me to shoot only 2 coats of 'pearl' over the base color (from him) for a best factory match of a blended area. If you are doing a complete you may want to write down how many coats of your second stage you put down in case of future redos.

    NOTE: Just found all sorts of pictures of this project in "WORKING WITH FILLER" section here. You need to take us for a ride in that machine when done.........or now!

    Henry

  4. #4

    Default

    Quote Originally Posted by PainterDave View Post
    yes i would seal. either with epoxy or urethane dosent matter
    Dave,

    Now I'm confused. I have 3+ coats of DP50LF Epoxy primer on the car now. So when you say epoxy is this what your referring to? Still hit it with the sealer? I know regardless if I seal or not I'll be wet sanding out to 600g to lay BC or sealer, mid coat, etc.

  5. #5

    Default

    Quote Originally Posted by Henry View Post
    Understand that you spray your sealer, allow it to dry and spray your base. Often, some may think they can spray sealer and a few days later begin the paint process. Also, if you have to sand your sealer for some reason, you'll need to reseal that section. About the best you can do with sealer is tack it off.

    What color(s) are you shooting, what colors are there on now (like red car with light gray primer scattered around)? My paint supplier advised me to shoot only 2 coats of 'pearl' over the base color (from him) for a best factory match of a blended area. If you are doing a complete you may want to write down how many coats of your second stage you put down in case of future redos.

    NOTE: Just found all sorts of pictures of this project in "WORKING WITH FILLER" section here. You need to take us for a ride in that machine when done.........or now!

    Henry
    This build (1936 Chevy coupe) was totally stripped down to metal bumper to bumper. It is a frame off nut and bolt restoration. After media blasting it was epoxy primed, dents repaired, body dollied out, patch panels, tons of fab work, etc., everything is straight as an arrow. After body filler and fab work it was then hit with DP50LF primer again, then 3 coats of G2 feather fill and blocked out with guide coat, again it was hit with PPG DP50LF epoxy primer. This is where I am at now, in epoxy primer state. My plan is to wet sand out to 600g then(all in the same day) hit it with sealer, bc, mid coat, cc. It is going to be a tri coat dark red metallic. My only question is do I need to use the dark gray G6 sealer the P sheet called for? This is not a repair, it is a total shoot. I have the sealer on hand, but why shoot it out if it is not needed?

  6. #6
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    Default

    Quote Originally Posted by Ronf View Post
    Dave,

    Now I'm confused. I have 3+ coats of DP50LF Epoxy primer on the car now. So when you say epoxy is this what your referring to? Still hit it with the sealer? I know regardless if I seal or not I'll be wet sanding out to 600g to lay BC or sealer, mid coat, etc.

    mix the epoxy as a "sealer" of the color of a good ground coat.like your G6 dk gray ?

    or urethane sealer. some guys on here spray over the sanded epoxy or sanded primer. but sealer promotes adhesion and better color coverage. make sense ?

  7. #7
    Join Date
    Sep 2006
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    Default

    I almost always use reduced epoxy as a sealer before BC on anything of importance. Started doing that nearly 20 years ago when I had back to back issues on repaints. some BC's can mess with the underlying products especially in repair work where you don't know what products are underneath. I have had something go seemingly perfect, then later as the solvents where nearly gone I could see something reacted a little on a feathered edge. Has a hobbiest, it wasn't worth the risk anymore & I never had a probably with using sealer. Only downsides are more expense, possibly extra peel if not sprayed & reduced well, one more layer of potential dust nibs.

    Another habit I have is not only dust tacking between BC's like many do, but going over my 2nd coat of base & carefully wet sanding any nibs off with 1000 grit & re-apply. So easy to get rid of those in most BC's & they really make a mess out of the clear if you leave them. Nibs in the 2nd or 3rd coat of clear not as big of a deal & those are untouchable of coarse. If you miss one in the BC it looks pretty nasty by the time your done with clear. Just my opinion of coarse, they are many ways to get nearly identical results in the end

  8. #8
    Join Date
    Nov 2013
    Location
    olympia,wa
    Posts
    428

    Default

    Quote Originally Posted by Ronf View Post
    This build (1936 Chevy coupe) was totally stripped down to metal bumper to bumper. It is a frame off nut and bolt restoration. After media blasting it was epoxy primed, dents repaired, body dollied out, patch panels, tons of fab work, etc., everything is straight as an arrow. After body filler and fab work it was then hit with DP50LF primer again, then 3 coats of G2 feather fill and blocked out with guide coat, again it was hit with PPG DP50LF epoxy primer. This is where I am at now, in epoxy primer state. My plan is to wet sand out to 600g then(all in the same day) hit it with sealer, bc, mid coat, cc. It is going to be a tri coat dark red metallic. My only question is do I need to use the dark gray G6 sealer the P sheet called for? This is not a repair, it is a total shoot. I have the sealer on hand, but why shoot it out if it is not needed?
    i think things would be different if you had shot a 2k urethane primer over the dp50. in my understanding, the dp50 wants to be re-coated for best adhesion. if you had a 2k urethane primer over the dp you could count the sealer as optional.
    the good news though, is dp50 is great sealer, and sticks to itself very well.
    thats my understanding anyway, these guys may have a different opinion.
    b marler

  9. #9

    Default Now it makes sence

    Quote Originally Posted by PainterDave View Post
    mix the epoxy as a "sealer" of the color of a good ground coat.like your G6 dk gray ?

    or urethane sealer. some guys on here spray over the sanded epoxy or sanded primer. but sealer promotes adhesion and better color coverage. make sense ?
    Thanks Dave for the reply,

    After reading your post and an earlier post from Len it does indeed make sense now. I'll go ahead and stick with PPG's P-sheet and hit it with the sealer prior to BC.

    Earlier post from Len in response to another subscribers question on using sealers,
    "What most sealer accomplishes is to stop the top coats from being absorbed by the substrate and make the substrate all the same color. If you have areas of primer that can absorb your top coat differently than other areas it can change the look slightly especially when applying metallic base coats. If you're using "good" primer and your base coat covers well then it's less likely you need a sealer but when we want to insure a top quality, long lasting job we will usually seal it."

    Thank you to all that replied, y'all are making this a much easier project to get through

  10. #10

    Default

    Quote Originally Posted by 68ragtop View Post
    I almost always use reduced epoxy as a sealer before BC on anything of importance. Started doing that nearly 20 years ago when I had back to back issues on repaints. some BC's can mess with the underlying products especially in repair work where you don't know what products are underneath. I have had something go seemingly perfect, then later as the solvents where nearly gone I could see something reacted a little on a feathered edge. Has a hobbiest, it wasn't worth the risk anymore & I never had a probably with using sealer. Only downsides are more expense, possibly extra peel if not sprayed & reduced well, one more layer of potential dust nibs.

    Another habit I have is not only dust tacking between BC's like many do, but going over my 2nd coat of base & carefully wet sanding any nibs off with 1000 grit & re-apply. So easy to get rid of those in most BC's & they really make a mess out of the clear if you leave them. Nibs in the 2nd or 3rd coat of clear not as big of a deal & those are untouchable of coarse. If you miss one in the BC it looks pretty nasty by the time your done with clear. Just my opinion of coarse, they are many ways to get nearly identical results in the end
    68ragtop,

    You actually hit on several points in your response as to why I was asking if the sealer was necessary. As I said earlier I have the sealer on hand but wasn't wanting to shoot it out if it is not needed, just one more step to cause those pesky nibs or de-lamination in the layers! I have a spray booth but it is nearly 35 years old and certainly not up to today's standards and anybody that has a booth, modern or not, will tell you they still get nibs. My idea has always been to do all that is needed to achieve the results I'm going for but do nothing beyond that as it just increases the chances for problems. Like you, I consider myself an extreme hobbyist in that I have continually done body work over the last 40 plus years of doing frame off restorations but am by no means a professional. I have seen some extreme changes over the last several decades in coating products(almost always for the better) and those in the business have surely had their work cut out for them trying to keep up with this changing environment. Thank you for your reply, it helps me to go forward.

  11. #11
    Join Date
    Nov 2005
    Posts
    9,111

    Default Consider...

    Quote Originally Posted by Ronf View Post
    68ragtop,

    You actually hit on several points in your response as to why I was asking if the sealer was necessary. As I said earlier I have the sealer on hand but wasn't wanting to shoot it out if it is not needed, just one more step to cause those pesky nibs or de-lamination in the layers! I have a spray booth but it is nearly 35 years old and certainly not up to today's standards and anybody that has a booth, modern or not, will tell you they still get nibs. My idea has always been to do all that is needed to achieve the results I'm going for but do nothing beyond that as it just increases the chances for problems. Like you, I consider myself an extreme hobbyist in that I have continually done body work over the last 40 plus years of doing frame off restorations but am by no means a professional. I have seen some extreme changes over the last several decades in coating products(almost always for the better) and those in the business have surely had their work cut out for them trying to keep up with this changing environment. Thank you for your reply, it helps me to go forward.
    Before seeing your car in another area I commented that I thought you might have a blotchy surface of like red paint with light gray primer. Then I might be more inclined to seal just to have a better chance of outcome for the new (expensive) 3 stage paint. However, since your car is completely in primer and the same color you may not need to use a sealer if you've met certain conditions as follows:

    1. First off, what does the data sheet for the paint call for?
    2. What did the first coat of primer look like over your repair areas (filler & metal). Did you look closely?
    3. Did you use a 'good' epoxy primer and how many coats?
    4. Is all the primer you used noted for color and adhesion?

    I don't use sealer and don't see any nastiness in the final topcoat even after a few years. Does this mean you don't have to or are you here waiting for someone to convince you it's OK not to? I personally don't think with the prep you've done you need sealer, however, there are those who would strongly disagree.

    As you've done, keep us posted.

    One last thing, please. How are you going to paint this car? In its entirety to include jambs, dash, firewall, fender and body or are you planning multiple sessions? My guess is multiple in which case you'll get to see what the finish product will be before the entire thing is shot. Look closely at each coat you apply for any potential problems. I would also guess you might be taking the body off of the frame for paint...yes?

    Henry

  12. #12

    Default Paint procedures

    Quote Originally Posted by Henry View Post
    Before seeing your car in another area I commented that I thought you might have a blotchy surface of like red paint with light gray primer. Then I might be more inclined to seal just to have a better chance of outcome for the new (expensive) 3 stage paint. However, since your car is completely in primer and the same color you may not need to use a sealer if you've met certain conditions as follows:

    1. First off, what does the data sheet for the paint call for?
    2. What did the first coat of primer look like over your repair areas (filler & metal). Did you look closely?
    3. Did you use a 'good' epoxy primer and how many coats?
    4. Is all the primer you used noted for color and adhesion?

    I don't use sealer and don't see any nastiness in the final topcoat even after a few years. Does this mean you don't have to or are you here waiting for someone to convince you it's OK not to? I personally don't think with the prep you've done you need sealer, however, there are those who would strongly disagree.

    As you've done, keep us posted.

    One last thing, please. How are you going to paint this car? In its entirety to include jambs, dash, firewall, fender and body or are you planning multiple sessions? My guess is multiple in which case you'll get to see what the finish product will be before the entire thing is shot. Look closely at each coat you apply for any potential problems. I would also guess you might be taking the body off of the frame for paint...yes?

    Henry
    Henry,

    I will paint the peripherals in multiple sessions but the main body will be removed and shot in one session to keep from tiger stripping it. Jambs, backside of fenders, and running boards in one session and the body and dash in another and finish up with a few odds and ends in a separate session.

    If I follow the P sheet I would be using sealer. Len hit on a statement that convinced me to go ahead with the called for sealer, PPG's(G6 gray) DAS3025 and 3027. The primer I used was a good epoxy primer, PPG DP50LF. P sheet states I could shoot my base coat(Deltron DBC2000) directly on the DP50LF surface but I have too much time and expense already laid out to omit something on a chance and yes, I was waiting for somebody to convince me it would have been fine without the sealer. It wasn't that I wanted to cut the sealer out in terms of expense as I already have those products on hand. I just didn't want to do an unnecessary step that had the potential for something to go wrong(peeling, extra nibs, etc). My only apprehension in this shoot is it being my first tri coat. Ive shot plenty of single and 2 stage as a hobbyist and I have high quality guns(Sata 4000 B rp and Sata 4000 hvlp), I'm just doing the extra research to make sure I have everything down before I step in the booth. Thank you for your reply, it very much gives food for thought!

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