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TR2/3/3A painting the body tub “inside”
- Thread starter sp53
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The Primer is called “Euro Primer” just about everything they sell is called Euro something. It has a 4:1 ratio activator and I used use 1 part reducer. I have found that, so far anyway, at 60 to 65 Fahrenheit their products are most friendly. Also, I am using 38 to 40 psi coming out at the gun. The primmer seems to come out strong at that psi, but seems to lay down well at that force.
Darrell_Walker
Jedi Knight
Offline
Would this be what you are using?
https://www.oreillyauto.com/site/c/....oap?ck=Search_N0472_-1_-1&pt=N0472&ppt=C0171
https://www.oreillyauto.com/site/c/....oap?ck=Search_N0472_-1_-1&pt=N0472&ppt=C0171
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CJD
Yoda
Offline
I make up the batch based on what I have to paint. For the entire tub, I'd likely mix the full 36 oz. cups. I have even gotten very lazy and actually mix the paint IN the cup, instead of in jars like I used to do. If I need more, I pop the top and mix more in the same cup I am using. Just remember to give it 15 minutes for the catalizer to start before you spray.
For spraying primer, use the largest tip you have. The smaller tips will tend to clog with the thickness of the primers. For finish, switch to a small tip for a finer spray pattern.
On areas that will require a lot of sanding and re-priming, I always spray a light primer coat of one color, followed immediately with a thicker coat of a different color primer. That gives you a sanding guide, so when the first coat starts to show through, you know to stop sanding before you hit metal. You cannot have bare metal under your color coat. It will not bond right.
I screwed up a batch last month while showing my son how to paint his fender. All 2-part paints have a pot life...so once mixed you have to spray within the pot life. I got talking to him, giving tips and such, and failed to realize we had exceeded the primer's pot life. I should have known when it wasn't laying right as we sprayed. Sure enough...it did not bond right, and the entire layer had to come back off and get re-sprayed from scratch.
Pot life is shortened in hot weather, or if you went a bit over on the mix ratio. Something to be aware of while you spray.
One of the beautiful things about the 2 part primers is they harden very fast. With most primers you can sand after just 30 minutes. Of course, read the spec sheet to be sure...
For spraying primer, use the largest tip you have. The smaller tips will tend to clog with the thickness of the primers. For finish, switch to a small tip for a finer spray pattern.
On areas that will require a lot of sanding and re-priming, I always spray a light primer coat of one color, followed immediately with a thicker coat of a different color primer. That gives you a sanding guide, so when the first coat starts to show through, you know to stop sanding before you hit metal. You cannot have bare metal under your color coat. It will not bond right.
I screwed up a batch last month while showing my son how to paint his fender. All 2-part paints have a pot life...so once mixed you have to spray within the pot life. I got talking to him, giving tips and such, and failed to realize we had exceeded the primer's pot life. I should have known when it wasn't laying right as we sprayed. Sure enough...it did not bond right, and the entire layer had to come back off and get re-sprayed from scratch.
Pot life is shortened in hot weather, or if you went a bit over on the mix ratio. Something to be aware of while you spray.
One of the beautiful things about the 2 part primers is they harden very fast. With most primers you can sand after just 30 minutes. Of course, read the spec sheet to be sure...
Not having any base line was my first problem/challenge. I did not know how much paint it was going to take, so I tried to stay calm and learn as I went forward, and used about 36 ounces, so now I know. All real knowledge belongs to the past anyway and Paying for that education never stops. Today I started going over the primmer I put down with some 220 and finding some shinny spots that are low and need more glazing, but all and all things look good. At least I am fooled. I plan on going over the whole tub with 220 and then wipe the primmer down with perhaps lacquer thinner, or do you think I need to use a chemical John? I mean there is only dust on the tub. I went back over the tub like you suggested with lacquer thinner before the primmer.
What sounds odd to me is that all these paint store guys what this sanded surface so I get this mechanical bond, but when it comes to the actual paint they want the primmer wet sanded with 400 and that makes everything very smooth? What happened to the mechanical bond? Is the actual paint a chemical bond? The logic they have showed so far would to me indicate I would but the paint over a rough surface and polish the paint.
These guys only carry gray primmer and I like the idea of using different colors. I might start buying the products on line because it is cheaper and I could get different colors. Plus I paid 22.00 dollars for a little can of activator. Now that I kinda know my way around I might buy stuff from that Eastwood outfit. Thanks for posting john I appreciate it.
What sounds odd to me is that all these paint store guys what this sanded surface so I get this mechanical bond, but when it comes to the actual paint they want the primmer wet sanded with 400 and that makes everything very smooth? What happened to the mechanical bond? Is the actual paint a chemical bond? The logic they have showed so far would to me indicate I would but the paint over a rough surface and polish the paint.
These guys only carry gray primmer and I like the idea of using different colors. I might start buying the products on line because it is cheaper and I could get different colors. Plus I paid 22.00 dollars for a little can of activator. Now that I kinda know my way around I might buy stuff from that Eastwood outfit. Thanks for posting john I appreciate it.
trrdster2000
Luke Skywalker
Offline
sp53, the different colors will help find the high and low spots. A spray can of compatible primmer paint from the same company should serve your purpose. Just a light coat in any area will do, it will take you one time to find out what works best for you. Most companies do a black and gray spray can of primmer.
Wayne
Wayne
Marvin Gruber
Yoda
Offline
A cheap trick I use is buy a rattle can of red, sprinkle spray the primer with it. Sand the car down, any red left shows low spots or sand marks. Reprime and do again until no red is left showing
Marv
Marv
CJD
Yoda
Offline
I know it sounds strange, but 400 grit actually makes a microscopically rough surface, so you do get a mechanical bond after using it. If you plan to lay more primer, then 220 is good for cutting the high spots quickly. I usually keep laying down primer until you see no "shiny" lows at all after sanding with 220 wet, and then lay one last thin prime coat just to be sure.
For the sanding right before your finish coats, change the paper to 400 grit. That will ensure you have no sanding marks show through.
Some panels may take several iterations of primer and sanding. Others may only take a couple. Always use the largest sanding block you can for the area being sanded...and don't cheat by pressing harder into the low spots.
As a general rule, you can lay a coat of paint over a previous one without sanding, if you do it within 24 hours. If the paint has been curing more than 24, then you have to roughen it in some way (scotch brite, or even 600 grit counts!) to ensure the paint will bond to the old.
For the sanding right before your finish coats, change the paper to 400 grit. That will ensure you have no sanding marks show through.
Some panels may take several iterations of primer and sanding. Others may only take a couple. Always use the largest sanding block you can for the area being sanded...and don't cheat by pressing harder into the low spots.
As a general rule, you can lay a coat of paint over a previous one without sanding, if you do it within 24 hours. If the paint has been curing more than 24, then you have to roughen it in some way (scotch brite, or even 600 grit counts!) to ensure the paint will bond to the old.
luke44
Jedi Warrior
Offline
Very very cool, I'm impressed. How did you attach the plastic sheeting to the plastic tubes?
I purchased some “Guide Coat” at the auto body shop. I am pretty sure the idea behind it is what Marv and others have mentioned by spraying some primmer on to see the low spots as I sand down. My concern is should I leave the Guide Coat on and put the other primmer over the top. This kinda bothers me because I have been working hard to make sure I have good bonds with the products and now they want me to spray some stuff that might not stick well, and they said I could take it off if I wanted with some lacquer thinner, but that I did not need to either???? This stuff does not make sense.