How to use clear as a sealer?

[basshead]

Can anyone tell me how to use clear instead of vinyl sealer? I've read it on the forum before but can't find the thread now. Basically, I need to know what PPG clear to use and the mixing ratio...

[basshead]

Anyone? It was something Paul wrote, if anyone can provide a link. Or chime in yourself Paul?

[Wiker]

Could it be some of these links

"I like the Behlen Sealer. RIC uses thinned down conversion varnish as sealer and it bonds even better than Behlen. All sealers must be scuffed BTW."
viewtopic.php?p=208224#p208224

"Use DuPont 480S for sealer, or vinyl sealer from StewMac or ReRanch. PPG DBU for color or tints. PPG 2021 or 2042 for clearcoats. Follow manufacturer's directions for reduction and curing times. Spray as cleanly as possible, carefully flatten the clearcoat after it's cured, and buff, buff, buff."
viewtopic.php?p=167052#p167052

viewtopic.php?p=713892#p713892
viewtopic.php?p=379133#p379133

I don’t remember ever seen Paul giving any specifics about mixing ration.


Without actually knowing much about this, my own reasoning when using the automotive clear as sealer is to thin it down enough so that the sealing coat does not just lie on top, but gets transported into the surface of the wood (just a micro millimetre).
But, if sprayed too heavy all that reducer will not get a chance to flash off before the clear starts to set, and some reducer will get trapped in the wood. Sealed in reducer will try to lift the finish off the wood trying to escape.
Light mist coats for the first coats should solve that.

Just for reference . . .
The Glasurit 923-335 clear I’m using has a standard mixing ratio of 2 : 1 clear and hardener + 10% reducer.
Standard mix for PPG DCU2042 (the clear Paul has mentioned several times) seems to be with 20% reducer
https://buyat.ppg.com/refinishProductCa ... 6e3798ff1f

My own schedule for sealing will be:
mist coat with finish + 100% reducer, wait 1-2 hour
second mist coat with finish + 100% reducer, wait 1-2 hours
very light coat with finish + 50% reducer, wait 3-4 hours
light coat with finish + 20% reducer, wait 24 hours
sand flat with 220 to prepare for colour burst coats

For the colour burst to look as good as possible I will build up a sealing coat thick enough to be sanded completely flat. I don’t think this is critical for an opaque colour coats.

[basshead]

Bingo, got it. Thanks Geir.

I'd recommend PPG 2042 or EC-700 and their appropriate catalysts...

[basshead]

Does anyone know for sure if PPG 2042 has to be baked or can it air dry?

[Wiker]

Select the hardener and reducer that match the temperature in which you will be spraying.
https://buyat.ppg.com/refinishProductCa ... 6e3798ff1f
For DCU2042 it seems you will need the general purpose DCX61 hardener. (Other finishes, like the Glasurit I’m using, have different hardeners for different temperature ranges.) Then you select the DT8xx reducer that matches your spraying temperature (see table in the .pdf).
Simple as that

[Wiker]

Btw, do you have 3M PPS for your spray gun?
If not I would recommend get it as it simplifies some of the hassle spraying solvent (and other) based finishes. I’ll put up more info if you need.

[basshead]

Thanks for the info, I didn't realise there was a different catalyst per heat range. As for the PPS, I have a ruler looking thing with all the mixing ratios on it. I've had it for years and used it no problems. I googled 3M PPS and was pretty impressed with what's available now. I can't say whether the PPG shop in town will have any of that gear though, it's pretty 3rd World out here. Post some more info though please.

[Wiker]

3M PPS:

http://www.youtube.com/watch?v=hcTRlfesS6E

Three things I like for using the 3M PPS:

1) I find cleaning the paint cup for the spray gun is a big hassle, especially with solvent based finishes. With 3M PPS that job is gone as you simply just toss away the liner cup, and only have to clean the gun itself.

2) With 3M PPS on the gun the gun can be oriented in any direction for spraying, even upside-down if needed. VERY useful.

3) You probably know but, automotive finish should be strained through a 200 micron filter before sprayed. I didn’t know at first when finishing the fret board last autumn, and got lots of small imperfection in the finish I thought was dust. The I started to filter the finish and got a near perfect result.
3M PPS have filters integrated in the lids so a separate filters aren’t needed, so one doesn’t have to do any straining as it’s done automatically in the cup.

I find these three things (mostly the first two) such a relief I can’t imagine going through with my own refinish without it. On top of this, for some reason my gun seems to perform better (atomizes better) with 3M PPS than with an ordinary cup.


What you need:

1) An adapter to fit your gun. Find an adapter with a threading that fits the threads on your gun.
http://solutions.3m.com/wps/portal/3M/e ... BL0BRFN3gl

2) Then you need a cup and collar.
http://3mcollision.com/products/paint-a ... system/pps
If your gun uses a pressure cup you’ll need one of the pressure cups. I went with the mini size 6 oz cup – conveniently small but still large enough for guitar finishing.

3) Finally a box or two of lids and liners.
http://3mcollision.com/products/paint-a ... and-liners
For a mini size 6 oz cup, the #16114 kit contains 50 liners and 50 lids with 200 micron filters for solvent based paint.

4) I didn’t bother with the mixing ration inserts myself.
http://3mcollision.com/products/paint-a ... io-inserts

Couldn't find a shop selling 3M PPS here in Norway. Lots of adapters on ebay but the #34 adapter I needed was hard to find. The pressurized mini size cup was also hard to find for some reason. And, hard to find a shop that ships internationally.
Eventually found everything I needed at
http://www.janecosales.com/3MPaintPrepSystem.aspx
http://www.tcpglobal.com/3m/3m700.aspx also caries 3M PPS but didn’t have the adapter and cup I needed.



Myself I’m finally done removing the old finish out of every little corer. What a job – puh. A bit of final sanding and I’m ready for the sealing coat.

[cjj]

Good info on the PPS stuff. I'm gonna have to look into getting that system!

[basshead]

My own schedule for sealing will be:
mist coat with finish + 100% reducer, wait 1-2 hour
second mist coat with finish + 100% reducer, wait 1-2 hours
very light coat with finish + 50% reducer, wait 3-4 hours
light coat with finish + 20% reducer, wait 24 hours
sand flat with 220 to prepare for colour burst coats

For the colour burst to look as good as possible I will build up a sealing coat thick enough to be sanded completely flat. I don’t think this is critical for an opaque colour coats.

Geir, what's your process for painting a bare bass? Seal the fingerboard and body as you describe above? Then mask the fingerboard to shoot the colour? How many coats, rubbing back between coats etc? I'd appreciate any info mate.

[Wiker]

Geir, what's your process for painting a bare bass? Seal the fingerboard and body as you describe above? Then mask the fingerboard to shoot the colour? How many coats, rubbing back between coats etc? I'd appreciate any info mate.

Huh. You almost made it sound like I know what I’m doing - I haven’t done it yet though
Comments from those that have actually done some finishing would be great.

Anyway . . .
Yes, I will seal everything including fretboard.

While test-spraying I seem to get a very good bonding between coats, without sanding, when there is not too much time between coats. Long enough for the previous coat to have set enough to be almost non-sticky, but not yet fully set. 1.5 to 3 hours seems to work for me (probably depends on temperature, how much reducer etc.).

I will build a sealing coat thick enough so that I can sand the surface completely smooth (with 220 grit) without sanding down into the wood. As I’m doing a Fireglo for the burst to fade from color to no-color as smooth as possible the surface needs to be smooth or else it can get blotchy.
I don’t think this will be so critical with a solid finish, but still some sanding to get a good bind between sealing and color coat.

My plane is: sealing coat(s), sand with 220 grit (not the fretboard), mask fretboard, color coats, un-mask fretboard, top coats. Sanding after sealing coat I will not be sanding the fretboard. Better to sand the fretboard later just before the next coat (top coat) goes onto the board.

As I’m spraying a fireglo I won’t be sanding between color coats or I’ll ruin the burst. I have to do some more testing, but I won’t bore you with the detail as you’re doing a different style finish.

One aim though is to get away with as thin a color coat as possible to avoid building a too thick finish. With a solid finish that shouldn’t be so hard.
Thin down the finish as much as possible. The TransTint I’m using mixes very well with Glasurit finish itself but not with the reducer, so I can’t thin it down too much or the dye will not mix properly. Adding 100% reducer seems to still be ok for me, while 200% gives me problems.
You’ll have to test this yourself with the PPG and the tint you’ll be using. But with a solid finish you shouldn’t have the need to thin it down so much anyway as you can add much more tint/dye and get away with fewer color coats. (A burst finish is different because one wants to get that fading transition as smooth as possible, and therefore can’t add too much dye or it’ll start to look blotchy.)
For a solid color I guess you can just add as much tint/dye you need to get good coverage maybe even with one coat. You’ll just have to do some experimenting with this to see what works.

[jingle_jangle]

Just saw this thread. I use 3M PPS exclusively. A real time and material saver. You don't have to bake 2042 or EC700. Thanks, Geir!

[basshead]

I'll be using PPG Paul as that's one of the few things this place does have, lol.

[basshead]

Damn! I went to the local PPG shop this morning and they don't have any 2042. They only have D800, D880, D8120 & D8122. Before I trawl the net to find out if any of these will work, has anyone else tried any of them?