Mohawk Duracoat Pre Cat lacquer

[woodlaker2]

Yep! Looks good.

 

[Panther Creek Woodworks]

Yes it is Ash and wormy white pine all from my property and my mill and kiln.

40% gloss

 

[Rwe2156]

Modern precat lacquers are the choice of most professional finishers of raw wood. Use the first coat as a sealer.
One finishing trick I've learned is to sand exposed end grain with 320 or 400 and the rest to 180 before applying the finish. That way, the end grain doesn't soak up the finish like it would when using only 180 grit. Once the lacquer is dry enough, then start with 320 and so forth.

Like others, I like the SW T77. I learned about that from this forum. I got the catalyst separate so I can mix only what I need at the time I need it.

View attachment 225473

I just had my first experience with lacquer and really like it. I was just getting my feet wet so I picked up a can of Watco.

I did not know you could use lacquer as a sealer. I thought you were supposed to use a vinyl sealer.

On that precat, are there any differences in how you mix with humidity & temp?

Some doors I sprayed with a cheap Husky HVLP. PS that not a run it’s the way the light is reflecting.

 

[bob vaughan]

On that precat, are there any differences in how you mix with humidity & temp?

No difference. Its like mixing epoxy: there's a ratio that activates things. Its usually 3 oz. per gallon for SW T77. T77 is an industrial finish generally used for kitchen cabinets by professional cabinet shops. Most shops get the 5 gal. cans already catalyzed because they'll use it up within the time limit.

Nice looking finish. Very professional looking.

 

[Rwe2156]

No difference. Its like mixing epoxy: there's a ratio that activates things. Its usually 3 oz. per gallon for SW T77. T77 is an industrial finish generally used for kitchen cabinets by professional cabinet shops. Most shops get the 5 gal. cans already catalyzed because they'll use it up within the time limit.

Nice looking finish. Very professional looking.

Thanks. And thanks for the info. I’ve got this table that the finish was a fail and I’m going to use lacquer.

 

[Rwe2156]

Another question: Can you build up a finish like you would with varnish, starting with a few coats of gloss and then a couple coats of satin.

Or is there no reason to do that with lacquer?

Do you have a preference for sheen? Which would show figured wood better?

Do you ever rub out lacquer?

 

[bob vaughan]

Lacquer, like varnish or shellac, is a protective film finish. It just dries faster. Built up coats gives the best finish for protection. Once the coats have dried, then treat the surface as you want to.
There are all sorts of ways to work a lacquer finish, depending on the time you want to put into it.
For most of what I do, three coats for the outside, and four or five for surfaces like table tops. Maybe one coat for the unexposed inside and two for drawer insides.
Prep the surface. Shoot. Scuff sand. Shoot. scuff sand if necessary, shoot again.
Caution: Let the surface dry and harden for a few days. It will shrink a little.
Once the surface is dry, sand and polish to suit if you want to.
I'll sometimes sand with 400 to smooth things then rub with maroon skotchbrite and wax. Polish and you'll have a smooth semi-gloss finish. This will expose figured wood to its greatest advantage without getting glossy light reflections.
Gloss finishes are the hardest but only slightly more so. The 'satin' finish is simply crushed sand mixed with the fluid. Skotchbrite achieves the same dullness.
If I were finishing that beautiful inlaid mahogany top, I'd go with the skotchbrite maroon and rub with a soft cloth buffer.

 

[Jasonfromhendo]

I tend to like the spray nozzle on Deft lacquer myself. I also seem to get more even spraying from the can (compared to Mohawk).

 

[Jasonfromhendo]

Lacquer, like varnish or shellac, is a protective film finish. It just dries faster. Built up coats gives the best finish for protection. Once the coats have dried, then treat the surface as you want to.
There are all sorts of ways to work a lacquer finish, depending on the time you want to put into it.
For most of what I do, three coats for the outside, and four or five for surfaces like table tops. Maybe one coat for the unexposed inside and two for drawer insides.
Prep the surface. Shoot. Scuff sand. Shoot. scuff sand if necessary, shoot again.
Caution: Let the surface dry and harden for a few days. It will shrink a little.
Once the surface is dry, sand and polish to suit if you want to.
I'll sometimes sand with 400 to smooth things then rub with maroon skotchbrite and wax. Polish and you'll have a smooth semi-gloss finish. This will expose figured wood to its greatest advantage without getting glossy light reflections.
Gloss finishes are the hardest but only slightly more so. The 'satin' finish is simply crushed sand mixed with the fluid. Skotchbrite achieves the same dullness.
If I were finishing that beautiful inlaid mahogany top, I'd go with the skotchbrite maroon and rub with a soft cloth buffer.

Yes I have found that the satin finish puts odd spots of dull/matte finish on the piece and some spots that is more of a slightly glossy look. Thus I use gloss, and if one wants to take it down a notch, 000 or 0000 steel wool does the trick. I've seen Steve Ramsey on Youtube buff it with soapy water and (I believe) steel wool, and also scuff the surface with crumpled up kraft paper. BTW I don't sand between coats it is not technically necessary. Now, if you want to reduce dust nibs or the like, ya hit it once with 600 grit or maybe 000 steel wool, then use your tack cloth, then spray one final time. IMHO

 

[Willemjm]

Another question: Can you build up a finish like you would with varnish, starting with a few coats of gloss and then a couple coats of satin.

Or is there no reason to do that with lacquer?

Do you have a preference for sheen? Which would show figured wood better?

Do you ever rub out lacquer?

Pre cat cannot be built up in layers. Two coats is max after the seal coat. I find the seal coat with a very light scuff sand and a top coat more than adequate.

See the SW data sheet below. Personally I sand RO only up to 150 grit, the finish fills the sanding marks with the seal coat.

For uncatalysed lacquer, you can build up coats, as the layers dissolve into each other. That is not the case with pre cat. Uncatalysed lacquer cures to the touch 15 - 30 minutes, but a full cure can take several months depending on how many layers. You may find something which is left standing in the finish for a few weeks sticks slightly.

Uncatalysed lacquer is fine for furniture, but for a table top which will see a lot of use, it is a bad idea. Some solvents will dissolve the finish, standing water from a glass of ice water overnight will damage the finish.

Generally Pre-Cat is a professional industrial finish, designed for spray application. It needs a bit more skill to apply and is not meant as a finish which can be rubbed out. While a light rub out might work, the risk is exposing the next coat, which will show.

 

[Rwe2156]

Pre cat cannot be built up in layers. Two coats is max after the seal coat. I find the seal coat with a very light scuff sand and a top coat more than adequate.

See the SW data sheet below. Personally I sand RO only up to 150 grit, the finish fills the sanding marks with the seal coat.

For uncatalysed lacquer, you can build up coats, as the layers dissolve into each other. That is not the case with pre cat. Uncatalysed lacquer cures to the touch 15 - 30 minutes, but a full cure can take several months depending on how many layers. You may find something which is left standing in the finish for a few weeks sticks slightly.

Uncatalysed lacquer is fine for furniture, but for a table top which will see a lot of use, it is a bad idea. Some solvents will dissolve the finish, standing water from a glass of ice water overnight will damage the finish.

Generally Pre-Cat is a professional industrial finish, designed for spray application. It needs a bit more skill to apply and is not meant as a finish which can be rubbed out. While a light rub out might work, the risk is exposing the next coat, which will show.

View attachment 227286

Could you explain pre-cat, post -cat and uncatalzyed lacquer?

How do I know what I'm using? For example, Watco lacquer off the shelf at Home Depot - precat? uncat? I put two coats on those cabinet doors without sanding.

I thought all lacquer melted into the previous layer like shellac. I'm getting more confused!!

I can get this product locally. Gemini Ultramax Gemini Coatings

 

[Woodmolds]

I did not know you could use lacquer as a sealer. I thought you were supposed to use a vinyl sealer.
Watco lacquer off the shelf at Home Depot - precat? uncat?

It's not required but a Vinyl sealer will give a little bit more durable finish.
It should be on the label if it pre-cat. Absent any information on the label, assume it's conventional(uncat).

 

[Woodmolds]

Pre cat cannot be built up in layers. Two coats is max after the seal coat.

Generally Pre-Cat is a professional industrial finish, designed for spray application. It needs a bit more skill to apply and is not meant as a finish which can be rubbed out. While a light rub out might work, the risk is exposing the next coat, which will show.

Don't take this as criticism. Just my experiences here, but I used four to six coats of SW pre-cat on table and conference table tops with no detrimental effects.
There was level sanding between every couple coats. Basically using it as a grain filler.
This being over the course of the last 15-20 years. I'm not saying you should do this, but it has worked for me.

Personally I don't think it takes more skill to spray pre-cat. I actually think it harder to get runs with a high solids product.(Not that I never get any)
But maybe my years of spraying has made me forget some of the pit falls.

Lots of good information in this thread!

 

[Willemjm]

I did not know you could use lacquer as a sealer. I thought you were supposed to use a vinyl sealer.

For raw wood there is no advantage in using a vinyl sealer. In a wet moist environment, a vinyl sealer would give you a slight water resistance advantage. Vinyl sealers have better adhesion properties, so they are used over other coats, for items being repainted. They stick well to anything.

 

[Willemjm]

Don't take this as criticism. Just my experiences here, but I used four to six coats of SW pre-cat on table and conference table tops with no detrimental effects.
There was level sanding between every couple coats. Basically using it as a grain filler.
This being over the course of the last 15-20 years. I'm not saying you should do this, but it has worked for me.

Personally I don't think it takes more skill to spray pre-cat. I actually think it harder to get runs with a high solids product.(Not that I never get any)
But maybe my years of spraying has made me forget some of the pit falls.

Lots of good information in this thread!

If it works for you great. I was just following what they have on their data sheet, plus the input from their Rep.

Where the challenge is, begins with heavily
pigmented coatings. The dark colors, I find difficult at times, especially getting a perfectly uniform finish on a 8 x 4 sheet of Ply.

We had one project with a dark grey finish, where after a week, the finish remained soft. Had the technical Rep out and his opinion was that the two coats were too heavy, not allowing proper curing.

I think their thickness spec is probably aimed at factories, where the painting and curing process is around 30 minutes.

How long did you wait with applying 2nd, 3rd, 4th coats?

Troubleshooting Pre-Cat Cracking

Heavy cracking in a pre-catalyzed varnish finish appears to indicate too thick a build. March 26, 2009

woodweb.com

 

[Willemjm]

Could you explain pre-cat, post -cat and uncatalzyed lacquer?

How do I know what I'm using? For example, Watco lacquer off the shelf at Home Depot - precat? uncat? I put two coats on those cabinet doors without sanding.

I thought all lacquer melted into the previous layer like shellac. I'm getting more confused!!

I can get this product locally. Gemini Ultramax Gemini Coatings

Just my opinion:

The lacquer you purchase at the big box stores is just nitro, there is no catalyst, easy to use, but offers limited protection to moisture, stains from things like ketchup etc. The coating is cured by evaporation of the solvent carrier. Shelf life is years.

Pre—Cat the catalyst is added to the finish at the time you purchase it. After 3 months the product is no longer useable. I think it is a money making business, so I purchase it uncatalysed and add the catalyst to my spray cup at time of spraying. Curing is both by evaporation of the solvent and chemical curing. After full chemical curing 3 days, the product is not dissolved by a solvent, which is why a subsequent coat won’t melt in. Durability is far superior.

Post-Cat is normally only available to industrial customers. Catalyst is added on the job site and then the pot life is 8 hours. Most cabinet factories use post-cat, it is the most durable. It has to be applied under correct conditions, temperature, humidity and needs to cure above 68F.

 

[Woodmolds]

If it works for you great. I was just following what they have on their data sheet, plus the input from their Rep.

Where the challenge is, begins with heavily
pigmented coatings. The dark colors, I find difficult at times, especially getting a perfectly uniform finish on a 8 x 4 sheet of Ply.

We had one project with a dark grey finish, where after a week, the finish remained soft. Had the technical Rep out and his opinion was that the two coats were too heavy, not allowing proper curing.

I think their thickness spec is probably aimed at factories, where the painting and curing process is around 30 minutes.

How long did you wait with applying 2nd, 3rd, 4th coats?

Troubleshooting Pre-Cat Cracking

Heavy cracking in a pre-catalyzed varnish finish appears to indicate too thick a build. March 26, 2009

woodweb.com

Well, I hadn't considered colors. I could see that being more of a problem. I can't put my finger on it, but colored lacquers do give more problems.
I've had chipping with colors especially darker colors(usually under sinks(moisture?)), but not clears.
I agree the specs are best practice for a reason.

Generally not being under a time construct. I would wait to sand 36-48 hours. The longer I waited the better it sanded.
But I have light sanded and re-coated within 30-45 minutes for build. On walnut I have sprayed two wet coats back to back, waited 1-2 hours, scraped with a razor sharp scraper to grain filler. It scraped much easier before curing than after. Because I have removed product sanding and sometimes scraping, it would be interesting to know what my final build is.

Per SW- "Maximum cure and chemical resistance is attained after 10 days air drying."

 

[bob vaughan]

waited 1-2 hours, scraped with a razor sharp scraper to grain filler. It scraped much easier before curing than after.

Scraping off the top coat and leaving the pores filled is a great tip for when a show room transparent finish is indicated. Thanks for that. I may never do it that way, but I'll know what I should have done.

 

[Rwe2156]

I am refacing our bathroom vanity with Cherry and plan to use lacquer. I would like to build up several coats.

I am going to check with my SW store, but I’m not very hopeful I can buy their product at least in any small volume.

@bob vaughan I’m confused about the SW product. Why would you add catalyzer to a precat lacquer?

I’ve been very happy with other Mohawk products so I’ll probably go that route since @Panther Creek Woodworks had good results.

 

[bob vaughan]

@bob vaughan I’m confused about the SW product. Why would you add catalyzer to a precat lacquer?

That does read kind of silly. It would be more accurate to say catalyzed lacquer only gets the catalyst added when needed in circumstances when the supply would possibly last longer than the predicted pot life.
When I first started using the precat back in the mid 1970s the dealer would add the catalyst before shipping to insure the product was correctly mixed. He didn't trust a bunch of rookie kids not to screw up the mixture. Wise move on his part.
Precat is easier to say and write than catalyzed lacquer.