How to seal mdf edges?

[Acrobat]

Hi, I've scoured the net as you do, and there are rather a few conflicting ways and various methods to deal mdc edges for spray painting.

I read that some use 50-50 mix of pva and water and paint this on the edges, let dry, sand with fine grit 320, then prime, and finally paint top coats.
I would have thought adding any water to the edges of mdf would likely make the swell? I'd be sceptical if this is ok?
But since I have both pva and water on hand would be willing to try it.
Otherwise any other advice on sealing products is welcome.

I have many oval shapes-all edges to paint, so not a typical flat edge like a bookshelf. I just want a lovely smooth finish all over when done and not to be able to easily tell the edge from any flay surtace. (Imagine a pair of sunglasses).

 

[Brandon]

Which variety of mdf did you use? If putting a profile on mdf I'd suggest using a "double refined or premium" mdf. My suppliers use different names for essentially the same thing. It's a much denser product and takes paint well with only a some minimal sanding. I use it as an inexpensive alternative for painted raised panel doors.

 

[bkharman]

Get a small can of Zinnser BIN shellac. It is paint and shellac in one. I use it on MDF as it is alcohol based and therefore no water to swell the edges up. It dries very hard and is also sands to a powder. My steps would be:

1. Prime the edges with BIN (you don't have to be perfect as it will sand easily.)
2. Sand lightly with a soft sanding block or profile to reduce the fuzz and BIN.
3. Clean up dust and coat again.  Do as many as you feel get you the edge you want.

A couple of notes. Buy a bunch of 1" foam brushes. It is a lot cheaper than trying to use denatured alcohol to clean things. Use the brush then toss.
BIN will dry to the touch in a matter of minutes. Generally between 5 and 15. You have to work quick.
Don't work out of the BIN can... Pour a little in a working jar and keep the main can lid tight when not pouring. I use a mason jar and put the lid on loosely as I work. The alcohol starts evaporating immediately. Once I forgot to put the lid on the mason jar and put a foam brush in it. 30 minutes later I had a almost hard goopy jar with a foam brush stuck in it.

I love the stuff but it has a slight learning curve. The good news is if you mess up and have drips and such, it sounds out easily and to powder.

Don't hesitate to ask if you go with it and have any more questions. I prefer this method over the glue mix EVERY time.

Cheers. Bryan.

 

[tjbnwi]

I've used the water/glue combo, it works well.

As Bryan posted, BIN is a great product for your application also.

I now use Kem Aqua Surfacer when I spray anything MDF.

Tom

 

[Billedis]

I have had good results with just plain old drywall mud.  put it on, let it dry and sand it off.  Bill

 

[monstrol]

You can also use bondo glazing putty. It comes in a tube and can be found wherever bondo is sold. It dries quickly, sands well and I apply it with my finger. It is also red, so you will end up with red fingers.

 

[sae]

You can also use bondo glazing putty. It comes in a tube and can be found wherever bondo is sold. It dries quickly, sands well and I apply it with my finger. It is also red, so you will end up with red fingers.

[member=5893]monstrol[/member]

There's so many less volatile fillers in this world, I don't know what the obsession is with woodworkers and Bondo.

Bondo contains just about all the things that will end your life in a hurry, yet people continue to flock to it (and recommend it).

Read the MSDS, and then throw it all away. And certainly don't use your fingers to apply it.

http://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSuUn_zu8l00xM8tvmxm95v70k17zHvu9lxtD7SSSSSS--

 

[tjbnwi]

You can also use bondo glazing putty. It comes in a tube and can be found wherever bondo is sold. It dries quickly, sands well and I apply it with my finger. It is also red, so you will end up with red fingers.

[member=5893]monstrol[/member]

There's so many less volatile fillers in this world, I don't know what the obsession is with woodworkers and Bondo.

Bondo contains just about all the things that will end your life in a hurry, yet people continue to flock to it (and recommend it).

Read the MSDS, and then throw it all away. And certainly don't use your fingers to apply it.

http://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSuUn_zu8l00xM8tvmxm95v70k17zHvu9lxtD7SSSSSS--

He's calling it Bondo, but it is really automotive glazing compound he is recommending.

Could be worse, I still lead body seams.

Tom

 

[NL-mikkla]

Up here there are a few brands that have a specific product for that, it's usually just called edge sealer.
They work really well, create the edge you describe, dries within 15 min or so and sand to dust.
Pretty sure your local painstore can help you with that.

 

[Acrobat]

Thank you guys. I've gone to the paint dept and got some zinsser BIN sealer. Will try it tomorrow after work. Not cheap stuff but if it works better than primer paint I have tried previously It will be worth it. The other stuff seems to need a heap of coats on the edge and if I can avoid that it will save time and top coat wastage.

 

[bkharman]

Thank you guys. I've gone to the paint dept and got some zinsser BIN sealer. Will try it tomorrow after work. Not cheap stuff but if it works better than primer paint I have tried previously It will be worth it. The other stuff seems to need a heap of coats on the edge and if I can avoid that it will save time and top coat wastage.

It is very thin material so make sure you have a drop cloth under the work.

Ain't cheap but I love the stuff!!

Oh, the smell. It will have a real strong smell but it disappears pretty quick.

Cheers. Bryan.

 

[John H]

You can also use bondo glazing putty. It comes in a tube and can be found wherever bondo is sold. It dries quickly, sands well and I apply it with my finger. It is also red, so you will end up with red fingers.

^^^^ +1

Bondo 907 Glazing and Spot Putty
http://www.amazon.com/gp/product/B0002JM8PY?psc=1&redirect=true&ref_=oh_aui_search_detailpage

 

[Cheese]

Could be worse, I still lead body seams.

Tom

Seriously???

 

[w802h]

I know a guy who builds a lot of cabinetry and decided to buy an edgebander for taming MDF edges. 

 

[tjbnwi]

Could be worse, I still lead body seams.

Tom

Seriously???

Yes...

I thought my oldest daughter how to body solder.

I'll get some picture of the paddles, files, tallow and bars.

Tom

 

[Cheese]

That's pretty cool Tom...a forgotten art.

 

[monstrol]

Also....Mohawk makes a water-based grain filler that is a pain to use but gets the job done...
you know for those that are kinda shy of aromatic hydrocarbons.

 

[Dbn107]

Thinned Timbermate works pretty well too.

 

[Acrobat]

Thank you guys. I've gone to the paint dept and got some zinsser BIN sealer. Will try it tomorrow after work. Not cheap stuff but if it works better than primer paint I have tried previously It will be worth it. The other stuff seems to need a heap of coats on the edge and if I can avoid that it will save time and top coat wastage.

It is very thin material so make sure you have a drop cloth under the work.

Ain't cheap but I love the stuff!!

Oh, the smell. It will have a real strong smell but it disappears pretty quick.

Cheers. Bryan.

Bryan, it worked well. Think I will use it from now on. And yeah, man that does have a strong smell. Job came out with a much better finish than previously so am very happy. Thanks again for the advice and everyone's input.

 

[bkharman]

Bryan, it worked well. Think I will use it from now on. And yeah, man that does have a strong smell. Job came out with a much better finish than previously so am very happy. Thanks again for the advice and everyone's input.

The smell is strong but doesn't linger too long. I use that on MDF all of the time. If you can deal with the smell and the price, it will treat you very well!!

Glad it worked out for you @Acrobat.

Cheers. Bryan.