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Old 06-08-2012, 16:22   #1
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Zen and the Art of Sanding

In preparation for topcoating a new build F-44SC cat, I am finding it surprising how quickly the sanding process consumes sanding discs. I am hoping that someone can tell me that I am doing something wrong because I only get about 6 to 8 sq ft. per pad until the resulting surface begins to show ever so slight tendencies of "glazing" . This cat has a fair amount of surface area so I could use some advice.

Here are the particulars:


I am currently sanding Awlgrip D8002 High build primer using P100 Festool Granat 6 inch pads on a RO 150 Festool sander set in between "1" and "2" speed. ( I've tried speed settings between 1 and wide open but slower seems to help ) The discs are NOT clogging; rather they just loose their ability to cut and produce a nice 100 grit surface. My concern is that I fear creating too smooth of a surface which would not foster good adhesion of the next product. ( 545)

The D8002 primer went on nice but I did have to thin it to it's maximum recommended amount because it's summer time here in Hood River, OR. Perhaps that could have caused the high build primer to resist sanding. Not sure. All I'm trying to do is knock down the coat so that it is uniformly flat and shows no "orange peel" so that 545 will get a good grip all the while without allowing sanding marks to show through the 545 primer that will go on next. Once the 545 is applied, I plan to block that with 220 ----> 320 grit prior to a three coat polyester polyurethane AWLGRIP topcoat.

What the heck am I doing wrong?. As if money was not an object, you would think that using a $900 sander with pads that cost $60 bucks a box would suffice.

Perhaps this is yet another reason why a cat paint job can cost upwards of $20k.

I am currently finishing up the build of the flagship ( Sail #1) F-44SC performance cruising cat which is scheduled to be launched mid summer 2013.


help!

Thanks in advance for any advice or words of sanding wisdom.
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Old 06-08-2012, 16:51   #2
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Re: zen and the art of sanding

Quote:
Originally Posted by vientoman View Post
In preparation for topcoating a new build F-44SC cat, I am finding it surprising how quickly the sanding process consumes sanding discs. I am hoping that someone can tell me that I am doing something wrong because I only get about 6 to 8 sq ft. per pad until the resulting surface begins to show ever so slight tendencies of "glazing" . This cat has a fair amount of surface area so I could use some advice.

Here are the particulars:


I am currently sanding Awlgrip D8002 High build primer using P100 Festool Granat 6 inch pads on a RO 150 Festool sander set in between "1" and "2" speed. ( I've tried speed settings between 1 and wide open but slower seems to help ) The discs are NOT clogging; rather they just loose their ability to cut and produce a nice 100 grit surface. My concern is that I fear creating too smooth of a surface which would not foster good adhesion of the next product. ( 545)

The D8002 primer went on nice but I did have to thin it to it's maximum recommended amount because it's summer time here in Hood River, OR. Perhaps that could have caused the high build primer to resist sanding. Not sure. All I'm trying to do is knock down the coat so that it is uniformly flat and shows no "orange peel" so that 545 will get a good grip all the while without allowing sanding marks to show through the 545 primer that will go on next. Once the 545 is applied, I plan to block that with 220 ----> 320 grit prior to a three coat polyester polyurethane AWLGRIP topcoat.

What the heck am I doing wrong?. As if money was not an object, you would think that using a $900 sander with pads that cost $60 bucks a box would suffice.

Perhaps this is yet another reason why a cat paint job can cost upwards of $20k.

I am currently finishing up the build of the flagship ( Sail #1) F-44SC performance cruising cat which is scheduled to be launched mid summer 2013.


help!

Thanks in advance for any advice or words of sanding wisdom.

IMHE that's pretty normal. You could go to a closed coat product but you would probably find it is too agressive for your present purpose, as well as more expensive. Many people (me included) do the blocking/fairing in the high build stage, not the 545 stage. 545 is a final primer and is harder to sand than high build, therefore it is usually faster to longboard the highbuild rather than vice versa. 545 is also not a high build product, it is meant to be a finish primer and therefore should be shot thinner than high build and will dry thinner still. For this reason if you fair in the 545 stage you are much more likely to blow through. If you blow through in the highbuild stage it doesn't matter, it will be covered by the 545. But if you blow through the 545 you must spot prime and re-sand, which can be very time consuming, especially when you blow through again right next to the spot prime you are sanding out. You should consider sanding the 545 with 320-400 (I prefer 400), as that is what the application guide calls for, and IME that is what works. So I am suggesting you 180 longboard the high build and then 400 DA the 545 with your Festool.

http://www.awlgrip.com/ProdLit/ApplicationGuideR.pdf


Read page 47 of the application guide I have linked to here. It is good it was hot when you shot high build, solvent retention can be a classic problem with it, often because the operator tries to stack on too many coats in too short a period of time for the ambient conditions in an attempt to get enough millage for fairing in one shoot.
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Old 06-08-2012, 17:29   #3
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Re: zen and the art of sanding

That stuff sands like a rock if you wait too long. I change paper every 5 min and don't wait until it quits cutting to change so 8 sq ft sounds about normal. The Festool paper is good stuff. Maybe drop down to 80 grit which what I would be using to begin with. The 545 will cover the 80 grit scratches and then go to your 220-320 finish sand.
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Old 06-08-2012, 19:48   #4
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Re: zen and the art of sanding

Quote:
Originally Posted by vientoman View Post
In preparation for topcoating a new build F-44SC cat, I am finding it surprising how quickly the sanding process consumes sanding discs. I am hoping that someone can tell me that I am doing something wrong because I only get about 6 to 8 sq ft. per pad until the resulting surface begins to show ever so slight tendencies of "glazing" . This cat has a fair amount of surface area so I could use some advice.

Here are the particulars:


I am currently sanding Awlgrip D8002 High build primer using P100 Festool Granat 6 inch pads on a RO 150 Festool sander set in between "1" and "2" speed. ( I've tried speed settings between 1 and wide open but slower seems to help ) The discs are NOT clogging; rather they just loose their ability to cut and produce a nice 100 grit surface. My concern is that I fear creating too smooth of a surface which would not foster good adhesion of the next product. ( 545)

The D8002 primer went on nice but I did have to thin it to it's maximum recommended amount because it's summer time here in Hood River, OR. Perhaps that could have caused the high build primer to resist sanding. Not sure. All I'm trying to do is knock down the coat so that it is uniformly flat and shows no "orange peel" so that 545 will get a good grip all the while without allowing sanding marks to show through the 545 primer that will go on next. Once the 545 is applied, I plan to block that with 220 ----> 320 grit prior to a three coat polyester polyurethane AWLGRIP topcoat.

What the heck am I doing wrong?. As if money was not an object, you would think that using a $900 sander with pads that cost $60 bucks a box would suffice.

Perhaps this is yet another reason why a cat paint job can cost upwards of $20k.

I am currently finishing up the build of the flagship ( Sail #1) F-44SC performance cruising cat which is scheduled to be launched mid summer 2013.


help!

Thanks in advance for any advice or words of sanding wisdom.
Well, first off, the Festool Rotex 150 sells for 525.00 new, not 900.00. Second, you should be using Festool Brilliant abrasives. I would start with 80 grit and finish with 100 or 120.

The Festool abrasives are without a doubt the toughest abrasives you can buy anywhere. I find sanding epoxy and LPU topcoats that Brilliant disks last and cut a long time compared to anything else.
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Old 06-08-2012, 23:39   #5
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Re: zen and the art of sanding

well, I went for the package deal which includes the dust extractor. I wouldn't recommend using an RO without one. I guess they went up in price, like the package is about $1k now.

Festool P26571810 Package Ro 150 CT 26 E

I am in no way associated with Festool but if you plan on doing much sanding, it will be the best investment in your health that you can make.
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Old 06-08-2012, 23:56   #6
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Re: zen and the art of sanding

Quote:
Originally Posted by vientoman View Post
well, I went for the package deal which includes the dust extractor. I wouldn't recommend using an RO without one. I guess they went up in price, like the package is about $1k now.

Festool P26571810 Package Ro 150 CT 26 E

I am in no way associated with Festool but if you plan on doing much sanding, it will be the best investment in your health that you can make.

Personally I do most of my finish sanding with pneumatics and think that a good respirator is the best investment for your health, but too each their own. I can see why that (pneumatics) is not an option for many.
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Old 07-08-2012, 00:32   #7
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Re: zen and the art of sanding

I'll try the "brilliant" type and report back.

I agree, it would be a life's work trying to do any sort of fairing at the 545 stage.

SO, here's my mistake:

D8003 sanding surfacer is what I should be using at this stage rather than D8002. D8002 High build primer is exactly what it says it is......a primer not a surfacer and it isn't really optimized for sanding.

Admittedly, most of my experience with coatings have involved automotive paint systems for restorations where a "Primer surfacer" is the workhorse.

Awlgrip litarature: http://www.awlgrip.com/products/prim...xy-primer.aspx portrays D8002 also as a surfacer but I would hesitate to call it that at all.

I think it would be nice if Awlgrip offered a true "primer surfacer". I would use it.
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Old 07-08-2012, 00:49   #8
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Re: zen and the art of sanding

yep, but I find myself taking the respirator off when I'm just walking around the shop looking for another tool and it sure is nice to be able to rid the shop of dust while sanding.

I like air tools too because they can sometimes be smaller and more manageable but from an energy standpoint, they are horribly inefficient. The RO sander does a good job using 750 watts ( about 1hp) fed directly by a power cord while it takes a minimum of a 10 hp compressor do do any real sanding with an air tool.
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Old 07-08-2012, 11:27   #9
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Re: zen and the art of sanding

Quote:
Originally Posted by vientoman View Post
I'll try the "brilliant" type and report back.

I agree, it would be a life's work trying to do any sort of fairing at the 545 stage.

SO, here's my mistake:

D8003 sanding surfacer is what I should be using at this stage rather than D8002. D8002 High build primer is exactly what it says it is......a primer not a surfacer and it isn't really optimized for sanding.

Admittedly, most of my experience with coatings have involved automotive paint systems for restorations where a "Primer surfacer" is the workhorse.

Awlgrip litarature: http://www.awlgrip.com/products/prim...xy-primer.aspx portrays D8002 also as a surfacer but I would hesitate to call it that at all.

I think it would be nice if Awlgrip offered a true "primer surfacer". I would use it.

Our shop doesn't use any form of high build, seen way too many problems as a result. Solvent retention, a coating that is fairly soft going on under a coating that is very hard, etc. etc. Since we do a ten year warranty, we do all of our fairing in WEST with 407, and any final fairing in high grits in 545. Occasionally we have to re shoot 545, but we never have problems with blistering due to solvent retention down the road as a result. I don't like high build at all, I see it as a crutch for amateurs. Of the other local big yacht painting companies, one (Platypus) uses loads of high build and I have seen many problems in their work as a result; the other (Diamond) does as we do and their work is stellar.
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Old 07-08-2012, 11:52   #10
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Re: zen and the art of sanding

I think that you are absolutely right. Maybe it's a case where Awlgrip decided to give the people what they "want" and not necessarily what they "need".

I knew a old shcool "bodyman" in the automotive industry who said that "glazing putty was the bodymans crutch".

D8002 is the shipmates crutch.

I surely don't want to hurt anyone's feelings by questioning the awlgrip Gods, But I do agree that it is poor practice to rely on high builds as well and dang it if it doesn't hold true again that you just cant get there by doing things the quick and easy way.

so........along those lines. What I now realize more than ever is that the final 545 primer shouldn't go on until the boat is darn near perfect and ready to shoot the topcoat. That said, is it common practice to allow the 545 to cure for a specified amount of time before topcoating?

Since I am not in a hurry and I don't have to worry about billing or trying to get a boat back to a customer, what would be the ideal time frame or schedule between 545 and topcoat?
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Old 07-08-2012, 12:35   #11
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Re: zen and the art of sanding

Quote:
Originally Posted by vientoman View Post
I think that you are absolutely right. Maybe it's a case where Awlgrip decided to give the people what they "want" and not necessarily what they "need".

I knew a old shcool "bodyman" in the automotive industry who said that "glazing putty was the bodymans crutch".

D8002 is the shipmates crutch.

I surely don't want to hurt anyone's feelings by questioning the awlgrip Gods, But I do agree that it is poor practice to rely on high builds as well and dang it if it doesn't hold true again that you just cant get there by doing things the quick and easy way.

so........along those lines. What I now realize more than ever is that the final 545 primer shouldn't go on until the boat is darn near perfect and ready to shoot the topcoat. That said, is it common practice to allow the 545 to cure for a specified amount of time before topcoating?

Since I am not in a hurry and I don't have to worry about billing or trying to get a boat back to a customer, what would be the ideal time frame or schedule between 545 and topcoat?
Sounds like you may be planning to chemical bond the topcoat to the 545. This is rarely a good idea. 545 doesn't flow like topcoat, so a certain amount of peel is inevitable. If you hot coat this will be reproduced and actually magnified by the topcoat. Let the 545 come to a full cure, sand to 400 grit, then topcoat.
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Old 07-08-2012, 17:00   #12
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Re: zen and the art of sanding

I was actually planning on allowing the 545 to cure then working it back down to a level surface and will honor your experience by bringing it to a 400 grit.

Given 75 to 80 degree days w/ approx. 20% humidity, what would you consider to be "full cure" for 545?

Thanks.
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Old 07-08-2012, 23:54   #13
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Re: zen and the art of sanding

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Originally Posted by vientoman View Post
I was actually planning on allowing the 545 to cure then working it back down to a level surface and will honor your experience by bringing it to a 400 grit.

Given 75 to 80 degree days w/ approx. 20% humidity, what would you consider to be "full cure" for 545?

Thanks.

24 hrs., though in those temps you can probably start to sand in 12 or less. Many people like to start sanding as soon as possible while the primer is still a little soft because it sands faster like that. I prefer to give it more like 48 hrs to come to a full cure and finish shrinking. I believe premature sanding can cause problems like swirlies from gumming grit discs, and sometimes it does strange things to the grit profile if it shrinks a lot after sanding. Maybe I'm just a glutton for punishment, but I don't like to take risks with quality.
If you are using a quality DA like the Festool with a clean new pad, you can use 320 discs for the majority of sanding and it won't show through at all. But make sure to use 400 dry for all your hand sanding, hand sanding leaves coarser scratches and there is no random orbit so they really stand out. I start with these grits and never touch the 545 with anything else, if you start with a coarser grit and then move up you will not only have to remove much material and risk blowing through or a very thin primer coat, but you will probably also fail to get the coarser profile out and will end up with visible scratches. Unless you guide coat with a dye like we do. Even then it's just too risky, and really doesn't save you much time. You will be surprised how quick a nice 545 shoot sands out with 320 and 400, not much slower than a coarser grit at all, though you will use more paper. If its convenient to your color selection, shoot 545 grey, it changes color when you sand it so no guide coat is needed.
I shot loads of AwlQuick (D8003) back in the early days. I hate it, too many problems. It sure sands out fast and nice, and if you are a pro outfit looking to get a good looking job out the door quick without a warranty I can see why some find it irresistible. I sanded so much of it I can still taste it years later, tastes like banana flavored candy-gross!
You might consider instead of going to a more expensive abrasive a move to a cheaper one can also be wise. When I'm looking at a big sanding job I often go this route because I have a huge backlog of materials bills on similar jobs to compare, and I find it is often substantially cheaper that way. You use more paper but it's much cheaper paper. I like Mirka, but that is in part because they sell a lot of abrasives that work great with dust extracted pneumatics, like Abranet. The low end Mirka is high quality Finnish grit, but cheaper than many other options. Check Fisheries Supply...
Search for the thread "Pics From the Boatyard" if you'd like to see a few pics of boats I've painted, I'd link to it but I'm presently out cruising and haven't figured out how to copy and paste on an iPad yet, LOL!!
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Old 11-08-2012, 03:48   #14
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Re: zen and the art of sanding

Can anyone offer comments regarding the effectiveness of the new "Abranet" sanding discs?

Abranet?

The claim is that they offer 4x the lifespan of a traditional abrasive pads but at $1 to $1.50 a sheet ( 4x the price of conventional abrasive pads ) when used for sanding primers, gelcoats, painted surfaces etc, are they worth it?
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Old 11-08-2012, 09:15   #15
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Re: zen and the art of sanding

Quote:
Originally Posted by vientoman View Post
Can anyone offer comments regarding the effectiveness of the new "Abranet" sanding discs?

Abranet?

The claim is that they offer 4x the lifespan of a traditional abrasive pads but at $1 to $1.50 a sheet ( 4x the price of conventional abrasive pads ) when used for sanding primers, gelcoats, painted surfaces etc, are they worth it?


They've actually been around for quite a while now. I really like them for dust extraction. The longevity is great, to the point that I sometimes have to stop guys on the crew from using Abranet discs for hand sanding because they last so long and don't gum up at all. The only drawback is that they are a little aggressive due to their three dimensional nature. Not a problem as long as you are aware.
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