# vinyl sealer 24% t67 f3 vs t67 f6 fast dry sealer



## kitchenfinefinish (Aug 4, 2017)

I have not used this product before but everyone keeps telling me to try it for MDF to seal the grain in. I have sprayed a good bit of laquer undercoater and hi build primer along with top coat laquer. My first question is. I went to sherwin williams and asked for the 24% sealer. When I got back to the shop they had put the nitrocellulose T67 F6 can in my box. I understand this is a different product than what I asked for but will it get me the same results as the 24% vinyl Hi solid (t67 f3)? 

Second question. Can I put undercoater on top of it or do I need to spray the undercoater first? The undercoater they gave me is not pre-cat. Will that hurt my top coat with Pre-cat laquer. 



I am starting to wish I hadn't deviated from my go process but the mdf grain killed my last job.

Thanks!


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## Steve Neul (Sep 2, 2011)

You could put a lacquer undercoater over T67. I don't think it would help your cause. The undercoater has more solids than the T67. There is an iron on like veneer tape which is paper you can put on the edge of mdf which makes it as easy to paint as the face. If I were doing it I would just spray a couple thick layers of undercoater on the edge first and then spray the whole thing. I think the vinyl sealer would be too thin to help you but you could put lacquer undercoater over vinyl sealer as well.


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## Rebelwork (Jan 15, 2012)

You need to call Sherwin & Williams for technical information...


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## MillerCraft (Aug 7, 2017)

I have been struggling with finishing mdf machined areas for about a year now. I used to use SW products too. I recently switched to ML Campbell finishing systems. They have an insanely high solids post-cat primer called "Clawlock" and it does the best job of sealing cut/machined mdf areas compared to anything I've worked with. Also good thing to remember about undercoater/topcoater: never put a post-cat on top of a pre-cat and you should be fine with a pre-cat going over a post-cat. 

Just my experience and what has worked for me.


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## Rick Mosher (Feb 26, 2009)

I agree with MillerCraft, clawlock is an excellent post catalyzed primer for MDF. No sealer required. I believe it is also available in white, black and grey which helps depending on what color you are painting over it with. It dries very fast and sands very well. My procedure was to spray a reduced coat of the white clawlock (50/50) to seal the wood and be able to see any voids in the substrate. Being thinned down it dried almost instantly and I would fill any imperfections, sand the filler flush and then spray a very heavy coat of primer (4-6 mils wet film thickness). Scuff sand 220 when dry and then spray on the pigmented finish. ( I used ML Campbells Pre Catalyzed pigmented lacquer but any catalyzed coating should be fine)


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## ColorStylist (Jul 19, 2014)

kitchenfinefinish said:


> I have not used this product before but everyone keeps telling me to try it for MDF to seal the grain in. I have sprayed a good bit of laquer undercoater and hi build primer along with top coat laquer. My first question is. I went to sherwin williams and asked for the 24% sealer. When I got back to the shop they had put the nitrocellulose T67 F6 can in my box. I understand this is a different product than what I asked for but will it get me the same results as the 24% vinyl Hi solid (t67 f3)?
> 
> Second question. Can I put undercoater on top of it or do I need to spray the undercoater first? The undercoater they gave me is not pre-cat. Will that hurt my top coat with Pre-cat laquer.
> 
> ...


Sherwin Williams support here! LOL

T67F6 and T67F3 are 24% hi build vinyl sealers. F6 is a faster drying hi solids sealer than the F3. F6 also drys to a flatter sheen than the F3 does......

You can apply 2-3 good even coats on the MDF, then apply your top coat of choice. You can apply lacquers and acrylics over this sealer with no problems.

If you apply a catalyzed product over the F6 or F3, (LIKE ANY OTHER CATALYZED SYSTEM) you must catalyze the sealer with 2% V66V26.

You can also tint the F3 or F6 sealers with the P63 vinyl basecoat colors as needed. So theoretically, you can get to a final solid color in 3 steps, and even be a catalyzed system all the way through. The P63 vinyl basecoats can be tinted to any color in the SW swatch book family.


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## Leo G (Oct 16, 2006)

Well, if you want to solve your MDF sealing problems, use the right MDF. Plum Creek double refined MDF is what you want to use. It's more expensive but that small increase in price will be offset by the time you have saved in the finishing department.

And then use MLC Clawlock.


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## MillerCraft (Aug 7, 2017)

Leo G said:


> Well, if you want to solve your MDF sealing problems, use the right MDF. Plum Creek double refined MDF is what you want to use. It's more expensive but that small increase in price will be offset by the time you have saved in the finishing department.
> 
> And then use MLC Clawlock.


Now is that Plum Creek doubel refined MDF something similar or better to what my suppliers have been calling "Rangerboard"? I used to start using "medex" but then was suggested to use "rangerboard." Not sure of the differences but this "rangerboard" was better for those cut and open areas compared to the medex. Again, not sure if it's the same or different from this Plum Creek refined mdf you're talking about? - always love learning something new


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## Leo G (Oct 16, 2006)

I think Rangerboard is about the same thing as the Plum Creek. I use it for beveled panels. The bevel is on the back side and is used because it forms a 1/4" tongue for the groove in the stiles and rails of my doors. I use to have to sand the crap out of the bevel and then put 2 coats of Clawlock on them with a good sanding between the coats to make it look descent. With the Plum Creek I mill the bevel and just spray one coat of primer, no sanding. Sometimes I do sand and it comes out a little better, but there's that time thing......


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