The issue of streaks when applying synthetic sealants

[BS MXRacer]

Mr. Stoops and I were having an interesting discussion about synthetic sealants and the issue of streaking brought on by members' reported difficulties while applying the new Ultimate Wax. To allow the MOL users to benefit we decided to move that to a forum location.

This is a post I was going to make in the ultimate wax thread about the issue regarding the streaking and my understanding from comments posted by you (quoted below) that I believe would maybe help others, but I wanted to confirm that my assumptions were correct before posting it. Are my assumptions/points valid?

"Thought it might be relevant to relate the two cases of a sealant on top of a sealant to that of the sealant on top of a polish since this was also brought up earlier, which originates in the porous, non-uniform nature of painted surfaces.

You are correct in assuming that if you had a layer of oil on top of the paint that the wax/sealant would not adhere to it. But in order for that to happen you would need a perfectly flat, non porous surface to begin with. And paint is anything but perfectly flat and non porous. When you apply a pure polish you are, in fact, feeding those oils down into the pores of the paint. We know that in those debates on detailing forums many people insist that paint is "dry" and "impermeable" but that is flat out not correct. Even factory paint that has been oven cured still has some moisture to it in the form of whatever solvents, etc make up that paint. And over time, with exposure to the elements, that paint will continue to desiccate, sometimes to the point of failure.

That's why products like M105 that were designed to be used on fresh paint work best in that situation. Anyone who has experienced very fast drying and dusting of M105, or even gumming up of the product, needs look no further than the condition of the paint they're using it on. For me personally, I think back to that Ferrari 360 Modena I buffed out a couple of years ago where M105 did just that - it turned to a gummy mess almost immediately. Why? Because the paint (a clear coat, by the way, not single stage) was so dried out that it literally sucked the moisture out of M105 and into the paint. That can be a tough concept for those who believe paint to be completely "dry" to wrap their heads around. But switching to an oil rich product, in this case M80, did wonders for correcting that poor Ferrari. Spray a car, wet sand it a day or two later, then compound it with M105 and you won't see a ton of dust like you will when D/A correcting a used car that hasn't been pampered its whole life. And it's all down to the porosity and dryness of the paint.

So, what does that have to do with the question at hand? Simple - a pure polish applied to a paint surface, especially one that has experienced repeated exposure to the elements and is a bit more "weathered", will get down into those pores and effectively smooth out the finish. Applying a wax or sealant on top of that will actually give the wax/sealant a flatter, smoother base to lay over but still give plenty of paint surface for it to bond to. The rest of the final curing of the product locks it down over the polish. So the polish isn't actually creating a layer of oil on top of the paint, but rather filling the pores of the paint. A gel coat works the exact same way, but on a larger scale, so to speak. If you've ever worked on a dried out gel coat and applied a pure polish to it, you can literally watch that stuff get sucked into the finish. That is because gel coats are much thicker and far more porous than automotive paint, but the mechanism of what's happening is identical.

On a brand spanking new car fresh off the assembly line, a pure polish may make very little difference to the finish because the paint surface is still pretty "tight", meaning it hasn't yet aged, dried, opened up. Even applying a coat of wax often doesn't make a huge visual difference to paint that is that new. Now go to the opposite extreme - a badly oxidized single stage paint system, one where a red car now looks pink. A wax alone can make a huge visual improvement, but a pure polish will do much, much more. Obviously a proper paint cleaner is really called for in that case, but just looking at pure polishes it's obvious how much more dramatic the reaction is here compared to a fresh paint job. And in between these two extremes you'll find varying degrees of dryness, porosity, etc and the response to a pure polish will change accordingly. Clear coat systems may not be quite as dramatic, but the same sort of changes are still taking place.

It should also be noted that applying some synthetics over another synthetic may actually increase the chance of streaking since that first layer can make it a bit more difficult for the polymers in the second product to take hold. Let's be very clear here - this is not a terribly common situation, nor is it really a question of two products not being compatible with each other. It's sort of the nature of polymer products. Which is why some manufacturers stress that the paint be totally clean and devoid of any previous sealant.

Part of a sealant's bonding ability comes from the availability of the pores in the paint surface and the subsequent filling of those pores. So when a sealant is already present on the surface filling most of the pores the newly applied sealant can occupy the remaining available space as well as bond with each other. When not allowed to fully cure this can result in streaks."

Well, yes and no.

The streaking really comes from a less than uniform application of a product that has the ability to darken the appearance of the paint. If you try to wipe it off too soon you do a lot of pushing around of the polymers, sort of making the unevenness even worse for a bit. So your last sentence "When not allowed to fully cure this can result in streaks." but that's true whether there's already a polymer on the surface or not.

Response:

Your response more clearly explains the issue and cause of streaking as others are experiencing it, having never had an issue with any Meguiar's sealant myself. I am still relatively new to the detailing world and I envisioned them differently, which I pictured more like a paint run. Instead of variations in the darkness of the paint caused by differing thicknesses in the layer of sealant present on the paint surface.

Guess I still have some questions:
1.) if one layer of sealant being present on the surface can adversely affect the application of additional layers what quality contributes to the negative impact on the bonding of those subsequent layers? Is it the filling of pores on the paint surface?

2.) As well as what can be done to avoid bonding issues if a person decides to place a second coat of sealant or wax on a surface? Ensure that maximum cure time is allotted before attempting to remove the sealant maybe?

3.) Could a wipe down with a high lubricity quick detailer like Last Touch at full strength, UQD, or M135 also have a negative effect on the bonding of any additional layers of sealant?

[Michael Stoops]

Re: The issue of streaks when applying synthetic sealants

Mr. Stoops and I were having an interesting discussion

You can call me Mike, you know? My mom calls me that and it works pretty well. No need to be so formal - I'm a pretty laid back guy.

Guess I still have some questions:
1.) if one layer of sealant being present on the surface can adversely affect the application of additional layers what quality contributes to the negative impact on the bonding of those subsequent layers? Is it the filling of pores on the paint surface?

A really fresh layer of sealant on the paint (like a matter of days fresh) can cause a subsequent application to take a bit longer to fully crosslink and bond, but it won't prevent it from happening. You can do a little experiment when wiping off the residue after applying the sealant -

• hold your swirl finder light up high, shining down on the paint after you've wiped off the residue
• wipe your towel so that it passed directly over the reflection of the light and observe the "streak" that's created
• now wipe your towel over the same area, but at 90° to the first wipe and observe the "streak" once again - it should have shifted by the same 90°
• come back 12 hours or so later and do the same thing - you may or may not see that streak, but if it's there it will be much shorter in length and you may actually be able to watch it disappear before your eyes - but timing is everything here so a little luck is called for

It is important to note that this "streaking" really only shows up under strong lighting but it does not manifest itself as dark patches or visible smearing. So what's happening with these streaks? The polymers you've laid down are not yet fully crosslinked and bonded to the paint, so you are literally pushing them around a bit. We've all heard that synthetic sealants need 12 to 24 hours to fully crosslink and bond, and this is a visual example of why.

If you have a fairly fresh layer of polymer on the paint then a secondary layer may take a bit longer to fully crosslink. This is essentially because you've already got a super slick, super smooth surface due to that first layer. Brand spanking new paint out of the factory is pretty "tight" as well, compared to older paint that has dried out a bit after exposure to the elements. If you looked at new paint versus old paint very closely you'd see the older paint surface appears "rougher" - that roughness gives almost anything more surface area to grab onto and bond to. At least more easily, or more quickly - not that old paint is a "better" surface. That's also why we get a lot of phone calls from people with paint in decent shape, but not polished to perfection like MOL members (or other forum enthusiasts) are used to doing, who rave about the huge improvement in appearance after applying something like NXT Tech Wax 2.0. We all know that prep accounts for the vast majority of shine, but these more casual users don't. And since their paint isn't "perfect", it can gain a surprising amount of gloss and clarity just from having a polish/wax like NXT fill in and smooth over that surface roughness.

2.) As well as what can be done to avoid bonding issues if a person decides to place a second coat of sealant or wax on a surface? Ensure that maximum cure time is allotted before attempting to remove the sealant maybe?

Ensuring max cure time is important, but proper application 9ie, uniform application) is also very important. This is easy enough to do when applying your sealant with a D/A, but it takes a bit more technique and care when doing so by hand. But regardless of application method, don't rush things too much. It's a good idea to cover every square inch a few times when applying, just to try and even things out as much as possible. If you've never applied a paste wax with a 4" finishing pad on a D/A, you owe it to yourself to give it a shot - you can lay that wax/sealant down so fast, so easy, and so uniform. Heck, even good old M16 spreads beautifully this way, and wipe off is a piece of cake.

3.) Could a wipe down with a high lubricity quick detailer like Last Touch at full strength, UQD, or M135 also have a negative effect on the bonding of any additional layers of sealant?

The lubricity of the mist and wipe isn't so much the issue as is the polymer load of the product. UQD and M135 have a much higher polymer load than Last Touch, but nowhere near what a liquid or paste wax does, meaning not so much that they would have an adverse effect on the bonding of a sealant. Interestingly, however, they can have an adverse effect on the cutting ability of a compound if used frequently in your correction process. That's why our pro guys stick with M34 Final Inspection during that process. But there is a huge difference between trying to cut through something and simply laying another layer of something on top of it.

[BS MXRacer]

Re: The issue of streaks when applying synthetic sealants

You can call me Mike, you know? My mom calls me that and it works pretty well. No need to be so formal - I'm a pretty laid back guy.

Mike it is. I would rather be overly formal until told otherwise in the hopes to not offend anyone as I am dealing with professionals like yourself and others who choose to share their knowledge.

[BS MXRacer]

Re: The issue of streaks when applying synthetic sealants

I always try to apply as thin and uniform a layer of sealant as possible, usually by D/A, which is why I think I've never had any issues. I'm not arguing that proper application won't prevent streaking, but why does it matter how uniform the layer is? Given that any layer no matter how thinly applied is far thicker than any sealant that remains once the drying has occurred and we wipe off the residue.

[wifpd4]

Re: The issue of streaks when applying synthetic sealants

Granted I have very limited experience, I haven't experienced streaking with M21 (if M21 is one of the products being discussed) with the last few, very few, cars I've done. I understand this discussion up to a point and this one sentence has thrown me a bit of a curve. Well, okay, several sentences:

...

Interestingly, however, they can have an adverse effect on the cutting ability of a compound if used frequently in your correction process. That's why our pro guys stick with M34 Final Inspection during that process. But there is a huge difference between trying to cut through something and simply laying another layer of something on top of it.

In a hypothetical example, related to this paragraph, I've just applied a layer of synthetic sealant, had some streaking and used either UQD, M135 or Last Touch to assist in adjusting or removing this streaking and some given time in the future when I decide to clean the finish(paint) again with a compound, I will have difficulties. Therefore, I should stick to M34 for streaking adjustments of synthetic sealant to avoid difficulties in the future doing paint correction? I just misplaced my GPS and have gotten lost. Solid brain freeze here, please clarify. Thanks,

[BS MXRacer]

Re: The issue of streaks when applying synthetic sealants

Granted I have very limited experience, I haven't experienced streaking with M21 (if M21 is one of the products being discussed) with the last few, very few, cars I've done. I understand this discussion up to a point and this one sentence has thrown me a bit of a curve. Well, okay, several sentences:




In a hypothetical example, related to this paragraph, I've just applied a layer of synthetic sealant, had some streaking and used either UQD, M135 or Last Touch to assist in adjusting or removing this streaking and some given time in the future when I decide to clean the finish(paint) again with a compound, I will have difficulties. Therefore, I should stick to M34 for streaking adjustments of synthetic sealant to avoid difficulties in the future doing paint correction? I just misplaced my GPS and have gotten lost. Solid brain freeze here, please clarify. Thanks,

This is just a general discussion about sealants, so yes M21 applies here.

For the second question about detail sprays:
First I would say Last Touch doesn't really affect sealants as it doesn't have the polymers that UQD or M135 do. UQD or M135 can have an affect on compound cutting ability when used as a pad lubricant, if used during the correction process to remove product that for whatever reason is being difficult to wipe off, or as I wipe between steps.

The polymers left behind from UQD or M135 don't remain present on the paint for an extended amount of time when compared to a wax or sealant so by the time you return to do any correction work the polymers are already gone.

Hope that helps.

[Michael Stoops]

Re: The issue of streaks when applying synthetic sealants

I always try to apply as thin and uniform a layer of sealant as possible, usually by D/A, which is why I think I've never had any issues. I'm not arguing that proper application won't prevent streaking, but why does it matter how uniform the layer is? Given that any layer no matter how thinly applied is far thicker than any sealant that remains once the drying has occurred and we wipe off the residue.

There are a couple of slightly different things at play here:

One is the appearance of some streaking or smearing after wipe off, which is essentially the polymers being pushed around before they have a chance to fully cross link. Step away from the finish and you can not see this streaking.

Second is an uneven blotchiness, which is due to an uneven application of a product that has the ability to darken paint. While this usually settles out on its own in a day or so (part of which leads some people to feel that a sealant looks better a day or so later) it can be hurried along with a wipe of a very slightly damp microfiber towel.

In a hypothetical example, related to this paragraph, I've just applied a layer of synthetic sealant, had some streaking and used either UQD, M135 or Last Touch to assist in adjusting or removing this streaking and some given time in the future when I decide to clean the finish(paint) again with a compound, I will have difficulties. Therefore, I should stick to M34 for streaking adjustments of synthetic sealant to avoid difficulties in the future doing paint correction? I just misplaced my GPS and have gotten lost. Solid brain freeze here, please clarify. Thanks,

The key here is "some time in the future", by which point a good deal of the product you've applied has degraded away. Remember, waxes and sealants are sacrificial barriers that do just that - degrade over time. If you apply a good solid coat of a quality polymer sealant (and we're talking in general here, not strictly Meguiar's products) and then even try to wet sand a day or two later, you'll struggle to cut through it immediately. It's just so darn slick that even the abrasive particles on 1000 grit paper will struggle a bit at first. But put that same coat of product on today, then drive the car for a few months, wash it, expose it to rain, etc and that layer of product has degraded to the point where it's no longer quite as tough, quite as resistant, and you can get through it with a compound pretty easily.

[wifpd4]

Re: The issue of streaks when applying synthetic sealants

...

The key here is "some time in the future", by which point a good deal of the product you've applied has degraded away. Remember, waxes and sealants are sacrificial barriers that do just that - degrade over time. If you apply a good solid coat of a quality polymer sealant (and we're talking in general here, not strictly Meguiar's products) and then even try to wet sand a day or two later, you'll struggle to cut through it immediately. It's just so darn slick that even the abrasive particles on 1000 grit paper will struggle a bit at first. But put that same coat of product on today, then drive the car for a few months, wash it, expose it to rain, etc and that layer of product has degraded to the point where it's no longer quite as tough, quite as resistant, and you can get through it with a compound pretty easily.

Thank you for the clarification. I was trying to envision in my small world, why I would be putting on a sealant and within a "short" time frame being applying compound and worrying about the possible negating effects of a spray detailer. A situation perhaps common in the professional world. Thanks again for the additional explanation. I need to think more globally!!