Tacking off

[norsa]

Interesting read. I'm trying some new clear so thought I would check the TDS.
I'm using polyester maxicar base.
Now maxicar supply my met/mica and as I'm only doing resto' I'll only use DG for solid.

Quote:
Substrates: maxi car, aquamax.

Allow maxi car to flash off for 20-30 minutes and allow aqua max to become completely matt.
Tack off with an appropriate cloth before the application of the clear coat.
??
Anyone?
Nick

 

[Parm]

I’m no painter but tack cloth on paint that isn’t fully dry doesn’t make sense to me

 

[Dcal]

Never got on with waterbased base coat, but I can't see it being dry enough to tack in 30 min unless you have great heat and airflow.
In a proper booth like yours it might be OK.

30 min would be more than enough for solvent based.

 

[norsa]

My point is, I was taught not to tack base coat and in fact to the contrary, add a drop coat esp with mica. Have the rules changed?

 

[Parm]

My point is, I was taught not to tack base coat and in fact to the contrary, add a drop coat esp with mica. Have the rules changed?

Your training is probably correct. Before you change your practice I’d verify the instructions are correct.

I’ve seen it too many times that TDS and MSDSs are incorrect. Way to easy to make mistakes with copy and paste

 

[norsa]

Indeed. I can see snail trails if it's not done correctly. Does anyone tack met/mica??

 

[Dcal]

I do but I've crap conditions.
Can't see the need in a proper booth where you won't have overspray settling on everything.

 

[norsa]

See, in my mind all you're really needing to tac is as you say, overspray. If that's the case, you could sink it especially if you're adding as I do for show cars, a flow coat.

 

[Dcal]

Yes I agree.
I'm nowhere near show cars, but the only way I can get half decient results is base coat and clear, let it cure, take all the nibs out flat with 2000 and a final coat of clear.
That way I only have to deal with the dirt and inscects from one coat.

 

[norsa]

I'm very fortunate to have an oven and unlimited air supply.

 

[Slowcoach]

Can the paint factor not confirm the need to tack off the base coat. Are you running a scheme, if so you should have access to the paint manufacturer surely.
Ive not done any spraying for a long time, is this water based or solvent basecoat.
I used to tack off basecoat if needed but it was 2:1 standox.

 

[norsa]

No, I can't justify running a scheme as we are classic restoration not crash rep and have a fantastic local supplier. Yes it's solvent base 1:1 and I've never in 40 years tacked 1:1 solvent. You suggest you would tack only for dust ingress? Did you use a drop coat?
Nick

 

[Slowcoach]

Used a drop coat, mainly when doing small blow ins I found it helpful to remove dry edge or needed from a dirt problem. I didn’t have an oven just a booth from studwork and plasterboard with proper enclosed lights extractor etc.

 

[norsa]

Ok. I'm lucky having the oven. However. I'm of the belief that these manufacturer TDS are prepared in virtual clinical conditions, which brings us right back to the original question. I have been known to get a reaction in base, flashed it off with the gun air, light flat back and re build but I've never flatted the final coat. As Parm said, why change my process. With the exception of a couple of intercoat adhesion issues, nobody has ever backed my met work. The other issue is FOMO. Could my met be better? By attempting to make it better, could I actually introduce issues. Strange isn't it. Whilst everyone is worrying about lockdown, Nobby here is worried about his tack rag.

 

[Slowcoach]

FOMO? Surely in clinical conditions a tack off wouldn’t be needed. I only did it if I needed to. Is this because you have now changed to a different paint manufacturer? What did your previous paint manufacturers TDS say.
Im not with you when you say you’ve never flatted the final coat. Do you mean the basecoat prior to lacquering. Surely there is a difference between tacking off and flatting prior to topcoat.
Complicated ain’t it.

 

[slim_boy_fat]

Are you running a scheme

Apologies for the slight diversion , but can you explain the term please? ( Purely for my 'headification', always like to learn new stuff...).

 

[norsa]

FOMO. Fear Of Missing Out. I used to use PPG but they didn't mention tack though I hadn't read any of their Tec for years. Now moved to max meyer. No my point is, I've never flatted pre clear coat as it would knock back the metallic or mica and I would assume to a lesser extent, tacking would have a similar affect.

 

[norsa]

Scheme is a paint mixing scheme where you have all the colours and you mix them yourself. It's normally mounted on a shaker system to agitate the paint.

 

[Slowcoach]

A mixing scheme, as in all the colours and binders to mix all shades of paint in a manufacturers range.

 

[slim_boy_fat]

@norsa and @Slowcoach - many thanks, gentlemen