Pre-cat vs Nitro lacquer

[Brian Hale]

Which is better and why? I've sprayed gallons and gallons of nitro lacquer both as a "pro" cabinet maker and in my own shop and I really like the working properties and results I get. Never worked with per-cat lacquer but I keep hearing more and more about it. Supposed to be more durable than nitro? Better alcohol resistance.

Typically I’ll use it on dinning and end tables and chairs. Where can I get/who makes the good stuff?

Any input would be great!


Brian :)

[Steve Clardy]

All I use is Pre-cat. No mixing, use it right out of the can. Never used nitro so I can't do a comparision. Happy with the pre-cat. I use Star brand, purchased through Paxton's fine woods. $79.95 per 5-gallon. Star has a web site also.
Steve

[Brian Hale]

All I use is Pre-cat. No mixing, use it right out of the can. Never used nitro so I can't do a comparision. Happy with the pre-cat. I use Star brand, purchased through Paxton's fine woods. $79.95 per 5-gallon. Star has a web site also.
Steve

Thanks Steve!

When i spray nitro, i thin the first coat about 75% thinner/25% lacquer and spray a fairly light coat. Wait 10 minutes and knock the hairs off with 320 grit. The remaining coats are thinned till i get "1 drip per second for 4 seconds" (that my old boss talking) Typically i spray 3-5 medium coats and sand between when needed. The final coat is the heaviest.

Does per-cat not require thinning? Even the first "sealer" coat?

Brian :)

[Steve Clardy]

Use it right out of the bucket. You do need to use retarder to slow it down in hot and humid conditions, usually above 80 degrees. Also you can use reducer for cooler temps, so it will dry faster. 80 degree temps, I can sand and respray in 30 minutes usually.
I usually use two-three coats. They do make a sanding sealer, but I very seldom use it as I have to clean out the gun and keep track of whats sealer and whats lacquer, so I usually just use lacquer for all coats. I use the PC gravity guns and have good quality with them. Steve

[Steve Costain]

I have used catalized finishes but they were mixed right before i used them (Campbell finished) they have about an 8 hour life in the gun. it's like a automotive finish, really tough! I did a whole kitchen last year in white. Nice to work with, but stinks havbing to clean the gun after each use.

[Jim Becker]

One small comment about pre-cat lacquers...be REALLY careful with safety on these products. According to some finishing pros I know, you really have to pay attention to ventilation and respiration, etc...even more than regular solvent based lacquers. Nasty stuff...

[Todd Burch]

I used to spray nitro when I worked on cars. It is a fine product, and I feel you have better rub-out properties with it.

I use pre-cat today. Fewer coats are required for a good build, no mixing or thinning, except for the caveat Steve Clardy mentioned about retarder.

Steve Costain is refering to a post-cat lacquer, most likely Duravar - a fantastic product and more durable than pre-cat.

[Kirk (KC) Constable]

I use Sherwin Williams pre-cat, product number T77-F37 and T77-F38 (dull and medium). They also sell one that's already catalyzed, but I'm resistant to change and happy with what I'm using. I think the street retail price is somewhere around $30/gallon, cheaper if you buy the five gallon bucket.

I thin it a bit, but not measured...more habit than anything. I've shot it straight from the can with fine results.

KC

[Brian Hale]

Jim, Thanks for the heads up about the safety issue. I'm really really careful with finishes and the LOML is even more demanding than I. (environmental engineers ........ sheesh :rolleyes: )

Todd, can you tell me the difference between pre and post cat lacquer? If post cat is more durable then nitro or pre cat, shouldn't we all be spraying it or is there something bad i should know about it?

Kirk, thanks for the Sherwin Williams tip; I think there's a store about 20 minutes from me.

Thanks folks!!!!

Brian :D

[Todd Burch]

Brian, 4 quick differences are price (post cat cost more), pot life, durability, cure time (and, a salesman would probably also tout ease of use too for the precat, since an acid catalyst is not required to be added).

Maybe you don't need as durable a finish as postcat provides. Let's say you are a manufacturer kicking out 100 cabinet boxes a day, and for the market you are in, precat not only is cheaper, but it provides sufficient enough protection for the grade of cabinet you are making. If so, no need for postcat and the extra expense.

On the other hand, if after you are spraying, you have only 30 minutes of time available before an item has to be wrapped and packed with up to 400 lbs of weight on it, then precat won't cut it, but the postcat will. Plus, with precat, it takes 3 coats. Postcat is only 2 coats. And on and on and on...!

Something I've learned over the last year, is that it is a waste of money to spring for the expensive postcat when most people wouldn't know the difference if a can of it hit them in the head.

[Brian Hale]

Brian, 4 quick differences are price (post cat cost more), pot life, durability, cure time (and, a salesman would probably also tout ease of use too for the precat, since an acid catalyst is not required to be added).

Maybe you don't need as durable a finish as postcat provides. Let's say you are a manufacturer kicking out 100 cabinet boxes a day, and for the market you are in, precat not only is cheaper, but it provides sufficient enough protection for the grade of cabinet you are making. If so, no need for postcat and the extra expense.

On the other hand, if after you are spraying, you have only 30 minutes of time available before an item has to be wrapped and packed with up to 400 lbs of weight on it, then precat won't cut it, but the postcat will. Plus, with precat, it takes 3 coats. Postcat is only 2 coats. And on and on and on...!

Something I've learned over the last year, is that it is a waste of money to spring for the expensive postcat when most people wouldn't know the difference if a can of it hit them in the head.

Thanks Todd!

One more question....... If durability is the main concern (cost and dry time are non issues) Is post cat best? It souinds like it has the longest shelf life (before mixing) and about the same dry time as the others; as in start to finish 3-4 coats in half a day.

Am i correct??

Brian :)

[John Parker]

Brian,
If you are spraying small lots at home. You should consider water based products. I use Target coatings and really like it. Alot safer to spray with alot of the advantages of solvent based products. Clean up is great, just water.

[Todd Burch]

Brian, almost correct:

"One more question....... If durability is the main concern (cost and dry time are non issues) Is post cat best?"

Yes.

"It souinds like it has the longest shelf life (before mixing)..."

Wrong. Post Cat has a short pot life, and a shorter shelf life than precat.

"...and about the same dry time as the others; as in start to finish 3-4 coats in half a day."

The first coat of postcat has the same dry time as the first coat of precat, but post only needs 2 coats. You can do two coats in less than a hour in the right temperture setting.

[Richard McComas]

Hi Brian,

I haven’t actually sprayed pre-cat lacquer but I have done a fair amount of research on the subject, mostly on Jeff Jewitt’s Homestead finishing web site, the professional finishing form over on the woodweb.com site and some of the web sites that sell pre-cat lacquers.

The general consensus is, Pre-cats dose not allow you to put on an infinite thickness of finish as does regular NC lacquer, too thick of a coat of pre-cat can/will crack, you need check the manufacturer's recommendation for their product.

[Kirk (KC) Constable]

I think there's some confusion as to 'pre-cat', 'post-cat', etc.

Don't know about other manufacurers, but the Sherwin Williams stuff I shoot is labelled like this: "T77-F37 Catalyzed Lacquer (Pre-cat)". Catalyst must be added before use, which then begins the 'shelf life' of that batch (3 or 6 months, can't remember which). They'll add the catalyst for you at the store, or you can buy a bottle and do it yourself. This is what I call 'pre-cat'.

They also sell a lacquer that's ready to shoot straight from the can with no mixing required. This is what I call 'catalyzed'.

I have no idea what 'post-cat' is??

KC

[Todd Burch]

OK, for ML Campbell, for pre-cat, the factory adds the catalyst. Whne I buy a gallon, the store hands it to me and I pour it straight into the pot. 6 months shelf life (although I've gone 18...)

For postcat, the store sells me the gallon of finish and a separate container of catalyst. I add the catalyst to the finish when I am filling the pot. 8 hour pot life.

[Kirk (KC) Constable]

All righty then...maybe it's just different manufacturer's lingo. Sounds like the same idea.

KC