How to.... Clear coat MDF

[Bruce Dorworth]

Has anyone been sucessful at spraying a clearcoat on MDF. I cut a lot of boxes and othe things out of 1/8" & 1/4" mdf. These items have been unfinished up to this point. I have tried spray shelac first and then a clearcoat, but after 2 or 3 coats of poly it still looks unfinished. There must be a magic formula.

I do want a clear finish not painted.

Thanks,
Bruce

P.s. I am also going to post this message in the finishing forum also...

[Chad Fitzgerald]

Hi Bruce, mdf will absorb alot of finish, its important to use a good finish. i use a post catalyzed conversion varnish from sherwin williams. It sprays nice and lays out relatively thick. 2 coaqts, seal coat, sand with 220 or 320, then finish coat. depending on temp/humidity dries to sand within an hour, finish coat to touch in about an hour. i like to leave it overnight before i pack it or do too much with it, or at least a good part of hte day. Campbells brand is also good. i have never used shelac so i dont know how it compares, not sure the clear coat you use, but the finish from do it yourself store often are very low in solids which means it takes many many coats to get anykind of decent finish. conversion varnishes have a relatively high solid content which provides for a very nice finish. post catalyzed provides for a very durable hard finish. i use this on all my cabinets, vanities, tables, bedroom sets etc.
i believe any sherwin williams store will have or can get you this, ldss near milwaukee carries the campbells brand. let me know if you have any more questions about it. glad to help
thanks chad

[Jim Dawson]

You need high solid content clear.

[Chuck Stone]

I use one of two things: either blond shellac flakes dissolved in alcohol
or i use scrap acrylic pieces, dissolved in acetone. With either one, you
can control the solids content by changing the amount of solvent you use.

MDF isn't all that pretty no matter what finish you use (if it's clear)

[Mark Maslonkowski]

Not applicable to this post but what settings do you use for cutting mdf I have a60 watt and can't seam to get it done without severally charring the edges

Thanks
Mark

[Bruce Dorworth]

Mark, you are not doing something right. I have an 80watt laser and I cut 1/8" at a speed of 31 and a power of 85. I cut 1/4" at a speed of 16 and a power of 90. Both of these leve the edge a brown color.

What laser do you have? Do you focus or use auto focus? Where are you located?

Bruce

[Mark Maslonkowski]

Bruce, I have a new June of this year 60watt epilog laser. I manually focus. I am located in central Minnesota.