Sheet Rock Mud (ever use it on a cab ?)

[BUCKETHEAD]

Lately i have been working on my TRON.

After sanding it all the way down, I thought about using some SHEET ROCK MUD.

I have been using it in my house, We have been remodeling rooms.

I know how well it hides and fills up imperfections in sheet rock.

So i thought why not a cabinet also?

I have to say, So far it is working really well !

Anyone else use it before?

[shardian]

The problem with spackle is that it is not very durable. You can dent it with your fingernail most of the time. Most people use Bondo to patch their cabinets. Bondo is fiberglass based, and is very durable. So to make a long story short, spackle will work and give you a nice finish, but won't be the most durable solution.

[BUCKETHEAD]

I did also use Bondo.

But 4 the bigger area's that needed  it.

I had to use my belt sander to get all the original paint off the cabinet.

The original paint was a pain in the @ss !  to get off.

Much harder than any other cabinet i have done before

By doing that, It left alot of scrapes and tiny groves in the wood.

This Sheet rock mud,  Has fixed that very nicely.

This stuff gets pretty hard !

I would not recommend it to fix a large chunk missing out of the cabinet.

But small stuff i would.

To me, It is just as durable as wood filler.

But that is just me ?   

[shardian]

yeah it should be fine if all you are doing is filling screw holes and such.

[mcfreak]

Not a bad idea and it's probably a lot cheaper than Wood putty.  I'll give it a go when I start my tron.

[BUCKETHEAD]

Sanded down the Sheet Rock Mud today.

Wow! It came down to a super smooth finish !

This is the route i will go down for all my future cabs!

The Mud really fills in those little nicks and dents excellent.

But like i said, I used BONDO for the big stuff !

Here's what i used below.

[Paul Olson]

You can also use it on the edges of MDF. It will seal up the edge so it doesn't absorb as much paint. It can make the edges look just as good painted as the other surfaces.

[BUCKETHEAD]

Thanks for the tip!

Yeah i think this stuff works great !

[csa3d]

I'm definitely intrigued, but am left to ask.. when that stuff dries, wouldn't it be very soft and prone to chipping off?  The paint holds it on nice and tight?  Curious..

thanks
-csa

[mountain]

You can also use it on the edges of MDF. It will seal up the edge so it doesn't absorb as much paint. It can make the edges look just as good painted as the other surfaces.

Absolutely!

This concept works on the face as well. The key is to thin it with water and mix it until it is the consistency of mayonnaise. What it does is penetrate the MDF and bonds into the MDF. I would never use it as a wood filler, but it really helps seal the surface and prep it for primer. By the way, I always use automotive sanding primer. It sands easy, seals great, and leaves a very smooth finish.

[MPTech]

automotive sanding primer

Spray primer or brush on?

[prOk]

You guys gotta be nuts going anywhere near your cabs with drywall mud.   Do it right, sand properly and use a good primer to smooth the side.  Use a good filler like bondo to fix larger stuff.  Drywall mud is a lazy way out that will ultimately fail and when you come to painting, well, you'll see

[mountain]

automotive sanding primer

Spray primer or brush on?

I bought a quart at a local automotive supply store and sprayed it on.

You guys gotta be nuts going anywhere near your cabs with drywall mud.   Do it right, sand properly and use a good primer to smooth the side.  Use a good filler like bondo to fix larger stuff.  Drywall mud is a lazy way out that will ultimately fail and when you come to painting, well, you'll see

There is nothing there to fail when sealing the edge. The edge of MDF is much more porous than the surface, no matter how much you sand.  The goal is not to fill the area but to seal it. Go ahead and use Bondo to seal the edge and let me know how that works. It can be done but it is a lot more difficult and time consuming.

To repair or fill - Use Bondo

To seal - Use mud or primer-sand-primer-sand

[sstorkel]

To seal - Use mud or primer-sand-primer-sand

Actually, I've always heard you should use "glue size" to seal MDF. Glue size is basically a watered-down glue. I forget what the recipe is, but you can probably google it if you're interested. Something like one part glue to 10 parts water, I think.

[prOk]

Drywall mud is NOT a sealer and NOT appropriate for woodworking in any way.  If all you want to do is 'seal' the edge then use some polyurethane or thinned wood glue.  Drywall mud is softer and more porous than even the MDF itself, not to mention it's not an adhesive.  Not sure what you think you're sealing the mdf from with drywall compound as it absorbs water quite easily.  If you want to seal, use a sealer.. if you want to patch a hole in your wall, use drywall mud

[sstorkel]

If all you want to do is 'seal' the edge then use some polyurethane or thinned wood glue.

Actually, polyurethane is a poor sealer! Well, at least it is if you're planning to do anything else to the wood after sealing. The problem is that there are very few finishes, stains, or glues that will adhere well to poly. If you're not going to use glue size, de-waxed shellac is a better general-purpose sealer than polyurethane. It dries quickly, seals well, and is compatible with just about every other type of finish you might want to use.

[prOk]

Yea, you don't want to paint over poly no..  but for that matter, what's the point of doing anything beyond paint to 'seal' the edge of MDF anyway?  you're putting tmold over it before you are done so who cares if it's fuzzy?  Either way, my point was drywall mud and wood don't mix, shouldn't mix.  The crap doesn't seal anything and won't hold long term so i'd hate to see people suddenly decide it's a *good, cheap and/or easy* way out of doing things the right way.

[Wade]

I agree 100% with prok on this.  Cabinets flex with movement and expand/contract with humidity.  Drywall mud will likely just chip or crack off in the long term.

Wade

[jcoplin]

I use joint compound on the edges of MDF that I am going to paint all the time.  It is the only way I've found to make the edges match the surface smoothness.  I have done this on *many* sets of cabinet doors that have been in kitchens and bathrooms (both far more materially hostile environments with more use than any MAME cabinet) and I have never seen it fail.  I wouldn't use it for patch, but to smooth edges, it works perfectly.

[mountain]

Right on!

If I was making a cab that had an edge, say an admin panel, and it needed the same finish as its face, joint compound will smooth it out nicely.

Drywall mud is NOT a sealer and NOT appropriate for woodworking in any way. 

A lot of woodworkers would say that about Bondo too. They may also say that MDF is not wood. However, in a custom hobby such as this, whatever works, works. Have you ever worked with MDF and tried to finish the edge with paint? I have. Bondo takes forever in this application. Using joint compound to fill all of the little voids in the middle of the MDF is fast, cheap, and does the job. You will never see the mud crack under these conditions because the final amount used after sanding is minimal.

[Sir Auros]

Well damn, I guess this explains why all the walls in my house are full of cracks and won't hold paint. I should've used Bondo instead of drywall mud. 

[prOk]

Drywall mud to smooth edges of bondo.. bizarre.   It's easy to polish the edges of bondo, just use 600 grit paper on a sanding block.  If I really didn't want to sand, I still wouldn't use drywall mud. I'd probably use rotted wood arrester or polyurethane.  Both of those will actually physically bond with the MDF and will be sandable smooth easily.. Drywall mud is not appropriate.  Heck for that matter if you're just painting it, prime the edges heavily and sand smooth. Why go through all the filling excercise in the first place.

[mountain]

Drywall mud to smooth edges of bondo.. bizarre. 

I can't seam to find where this was mentioned.

[nostrebor]

Pr0k,

It is an accepted, and documented practice to use joint compound for smoothing the edges of MDF in the woodworking world. The first time I heard about it, was in an article in WOOD magazine. I've seen different methods demonstrated at the big WW show that runs through the country every year as well. Of course in all cases, using joint compound is only acceptable under painted finishes, where the goal is to give the machined edges the same texture as the faces of the product.

Do note that I used the word "smoothing". It will not seal, or protect the MDF from anything. That is the top-coat's responsibility.

Edit: found a quote from ShopNotes on the subject.

from Vol. 15 Issue 86 of ShopNotes, page 23 – an excerpt from an article on using MDF to make a thickness sander…

“Just like glue, the edges of MDF readily absorb paint. What you can end up with is a noticeable contrast between the smooth faces and rough edges… To solve this problem, I take a couple of simple steps. First, I seal all the exposted edges with drywall joint compound… It looks like a mess, but it actually goes on easily with a putty knife or even your finger. And when dry, the excess sands off with a minimum of effort. Then, before applying the topcoat, I seal everything with a coat of primer. The top coat will then build quickly to a smooth durable, film.

[BUCKETHEAD]

You guys gotta be nuts going anywhere near your cabs with drywall mud.   Do it right, sand properly and use a good primer to smooth the side.  Use a good filler like bondo to fix larger stuff.  Drywall mud is a lazy way out that will ultimately fail and when you come to painting, well, you'll see

Well, I can say that the 2 cabinets i have been using the mud on.

Have been outside in my shop for the last 3 months and the mud is holding up fine!

I have no climate control out there either.

And the cabinets still look great!

I have painted both of them black and they will soon be in my gameroom!   

Like i said, I used bondo on the big stuff!

Mud on the tiny dings and blemishes!   

[javeryh]

You can also use it on the edges of MDF. It will seal up the edge so it doesn't absorb as much paint. It can make the edges look just as good painted as the other surfaces.

Absolutely!

This concept works on the face as well. The key is to thin it with water and mix it until it is the consistency of mayonnaise. What it does is penetrate the MDF and bonds into the MDF. I would never use it as a wood filler, but it really helps seal the surface and prep it for primer. By the way, I always use automotive sanding primer. It sands easy, seals great, and leaves a very smooth finish.

I'l second this.  I used it to seal the edges on 2 bookcases I built out of MDF - works great!