Sealing MDF

[kc10flteng]

Guys help!!!! I gotta seal about 60 sheets of 1 inch MDF ...and fast - with something sprayable (HVLP). I've searched the forum but can't seem to nail down any product that has gotten good feedback from the group at least on an economical level. I'm in California & some of the products that seem to work well for some are not available to me. This is what happens when ones "bot" eyes are bigger than ones "bot" (operator) capabilities. You warned me!!!! Thanks in advance!

[jay_p]

Ron,

What is the bigger picture here? Are you talking interior or exterior, clear or colored, primer/sealer or finish coat?

Jay

[patricktoomey]

I don't know the specifics of what you're looking for but if you're just trying to seal it to keep out atmospheric moisture and stabilize it for another finish, I might recommend Shellac. I roll it on to seal my MDF and Trupan, for example my vaccuum hold down plenum board. I have also sprayed it after a little thinning with a Binks pressure pot system using the widest needle they have. I've also sprayed it using a SATA LM2000 with their widest needle but needed to thin it a little more. I find rolling 1-2 thick coats sometimes faster than spraying 2-4 thinner coats.

Again, not knowing the specifics of what you need I may be way off base but that's my story and I'm sticking to it.

[gene]

I dont know if you have access to m l cambel magnaclaw primer or not but if you do its worth using. we use it often and have good results on mdf cabinet doors. if not you can use tightbond wood glue and water mixture to seal it . mix enough water to make it sprayable ONLY. Water is the enimy of mdf . It will cause fuzzing if too much is used , the secret of sealing mdf is to sand with a high grit sandpaper 180 220 320
The idea is to close the poors in the mdf before sealing it . With 60 sheets to do i would consider a pressure pot . harbor freigt has them for around 60.00 Good luck

[beacon14]

I think Gene means Clawlok (http://mlcampbell.com/pages/starpage.asp?star=CLA)

[jay_p]

Gene,
Would you use the yellow glue spray under a clear finish? Seem to me that you would get that yellow haze look that shows up when you fail to sand away excess glue. I have heard of people using dilute Weldbond for this as well.

Jay

[itoolfred]

Gene/David,
I do a lot of work with mdf and have never heard of the Clawlok. Looking at the web page is says it is a "post-catalyzed (amino-alkyd) primer". What does this mean?
Thanks,
Fred

[bleeth]

That means it is an oil based primer that you need to mix a catalyst into which activates the chemical process by which it dries quickly (basically).

Campbells as well as SWP, Mohawk, and all other furniture finish products come under the typical heading of "pre-cats" and "post-cats". Pre catalyzed means no mixing but usually shorter shelf life and a softer finish. Post cat will last on the shelf longer and result in a harder finish and is usually a bit pricier than pre-cats. They each have their own plusses and minuses depending upon the application.
If you have a decent size Campbell's distributor near you they have regularly scheduled seminars on use and application for clients that are free.

Once you decide to start learning about professional grade finishes you are in for a lot of information and another great learning curve in your life.

Dave