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Waterborne finish on MDF without raising the fibres?

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Forum topic by 404 - Not Found posted 949 days ago 1477 views 0 times favorited 7 replies Add to Favorites Watch
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404 - Not Found

2544 posts in 1566 days


949 days ago

I don’t spray a lot of mdf but when using waterborne paint, I haven’t quite managed to get away from the fibres raising on the surface. I can get the finish right in the end with maybe 2/3 primers and 2/3 topcoats, flatted between coats. Has anyone found a technique to eliminate the problem of fibres raising that isn’t quite so time consuming?
I always put a good coat of emulsion on the cut edges first to bind the fibres and sand back smooth which works well, it’s the fibres on the surface which have always been a problem. Is there a sealer or should I use cellulose primer for the mdf?

Any advice would be appreciated


7 replies so far

View hObOmOnk's profile

hObOmOnk

1380 posts in 2724 days


#1 posted 949 days ago

Dewaxed shellac.

-- 温故知新

View Alan Robertson's profile

Alan Robertson

66 posts in 2515 days


#2 posted 949 days ago

Agreed. I cut mine 50/50 with denate alch. 2 to 3 coats, light sand, tack. Dries very quickly.
Good luck.

-- MrAl

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Rick

6455 posts in 1630 days


#3 posted 947 days ago

I use this for Pine also to seal it, ONLY if a Natural Finish though, as it blocks the stain.

50/50 Methyl Hydrate and Regular White Shellac. Dries very fast, Quick “Sanding” with 000 Steel Wool, Wipe off and a Good Vaccuming to get the Steel Wool Remants is a MUST!!

If it’s a “Not All That Fussy” of a Project i.e. Personal Use, I just brush on Water Based Poly, Maybe a One Hour Dry and sand it with 100 Grit, Vaccumn, Maybe Steel Wool or 150 Grit and Vaccumn again. Another Coat Of Poly, maybe two.

I’m assuming you have Stained your Project before all of the above.

-- COMMON SENSE Is Like Deodorant. The People Who need It Most, Never Use It.

View Viking's profile

Viking

857 posts in 1792 days


#4 posted 947 days ago

I just did a project with MDF and used KILZ water base as a primer and sprayed 2 top coats of enamal. No raised fiber issues. I also use MinWax water based Polycrylic on unprimed MDF all the time and again no issues.

Good Luck!

-- Rick Gustafson - Lost Creek Ranch - Colorado County, Texas

View NiteWalker's profile (online now)

NiteWalker

2699 posts in 1174 days


#5 posted 946 days ago

+1 for dewaxed shellac. I use Zinsser SealCoat.

-- He who dies with the most tools... dies with the emptiest wallet.

View Greedo's profile

Greedo

465 posts in 1557 days


#6 posted 946 days ago

the first coat of water based finish will always raise the grain or at least give a rough finish, i just sand after the first coat of acrylic varnish with nothing lower than 220 grit, and apply another coat. 2 coats are enough with acrylic to get a glass smooth surface if you use paint that is thich enough. Spraying it may not be the best option, i use a roller for mdf.

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404 - Not Found

2544 posts in 1566 days


#7 posted 946 days ago

Interesting reading, thanks for all your input. Some of the products mentioned above are just not available in Ireland, the paint store I go to has just started stocking Zinsser stuff, so I might check that out the next time I’m painting mdf. There’s nowhere in this country where you could walk in and ask for dewaxed shellac flakes, but Rustins Shellac Sanding Sealer is sold in the above mentioned paint shop and my local hardware store, so that’s an option too.

Thanks again

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