MDF splitting from wood screws, what do you use? (1 Viewer)

[JohnA]

As I posted in my "Maelstrom finally started" post, I am facing some obstacles screwing into the MDF panel for my Maelstrom subwoofer. I don't have any clamps to build the box and my first attempt on screwing and glueing some internal braces ended in near disaster with the MDF splitting.

In the end, I switched from wood screws to sheetrock screws and used a much larger pilot hole than I thought should be used.

What exactly is everyone using for screws? What type and size screw are you using? What size pilot hole?

Thanks for your response.

-JohnA

 

[Jon Torres]

I used to use screws when building boxes, but experienced splitting also. Lately I just use wood glue. I think if your cuts are good, you wouldn't need clamps either. I just place heavy things such as other boxes or tool boxes on the wood to press down till the glue dries. Once the glue dries, you're good to go. Now that I have clamps, it should be easier to keep things together.

 

[Cam S]

I had great succes using brads and a brad gun. It isn't as strong as screws but if you use glue as well then it can be just as strong if not stronger than screws alone.

 

[Ron D Core]

I've built everything with drywall screws and a 1/8" pilot hole. As long as the whole is deep enough for the entire screw and you don't over tighten, it shouldn't split. Just put a screw every 5 or 6 inches, it should be more than enough.

 

[Clayton_M]

try wafers?

 

[Chris Tsutsui]

* Predrill the screw in the MDF long enough.

* Don't put a screw close to the ends of the edge. Start 2 inches from the end.

* wax or put soap on the screw if you have trouble driving it in

 

[Pete Mazz]

If you use the right screw. #8 x 2" flat head coarse thread with shank.

And use a countersink bit like this, with a 9/64" bit.

You should have no problems.
Pete

 

[JohnA]

Thanks for all the quick replies.

Jon

The cuts are good, a friend who is a finish carpenter did all the cuts for me with professional grade tools and great care.

However, the way the box goes together, I don't feel comfortable without clamps or screws.

Cam and clayton

Thanks for the tips, for now, I am trying to do this on the cheap. I don't have access to brad guns or anything to use wafers.

It looks like I will use the tips from Ron, Chris and Pete.

Thanks for the many good, quick tips. I will be sure to follow up with my progress.

-JohnA

 

[Robert_Gaither]

A pair (or 3 if you want an additional bolt in the middle) threaded bolts, nuts, washers, and 2" x 4"s (holes drilled for the threaded bolts) is a cheap and dirty clamp that can be made for such a project and the bolts might can be recycled for a future project (DIY rack or Sonosub end cap holders).

 

[Justin Bowser]

Another thing you might consider would be using threaded inserts and machine screws. You drill the appropriate sized hole in the oiece you want to attach to and press in the insert then attach the two pieces with a threaded machine screw.
You can get inserts and T nuts and other hardware at www.rockler.com.
Good luck,
Justin B.

 

[Hank Frankenberg]

John, I don't use screws. Since you have good, accurate cuts, your joints will be tight. Carpenter's glue will give you a joint that is stronger than the MDF itself, so screws don't add much except additional time/labor to your project. I'm currently turning 4 sheets of 3/4" MDF into two 70" tower cabinets that will weigh 200# each and there are no screws in them.

With that said, if you have a particular assembly/panel that is awkward and the best solution is screws, then Pete's post is the answer.

 

[Patrick Sun]

Hank, but can you do your cabinets without clamps?

 

[Hank Frankenberg]

Of course not, Patrick! Cabinet-building RULE #1: You cannot have too many clamps. And you know I like those MLCS Merle band clamps: http://www.mlcswoodworking.com/shops.../merlclmp.html
ps: nice new sub project you've got - probably the ultimate and last one you'll build, right?

 

[Patrick Sun]

Screws are for the frugal enclosure builders. Me, I just borrow my buddy's clamps when I build enclosure. It took 8 clamps for my latest project. And I doubt it's my last project (I do have one more sub driver left...)

 

[JohnA]

Thank you for all the excellent ideas.

I am trying to borrow some clamps for the external panels. Until then, I will try screwing and glueing the internal braces and Amp Box.

Thanks again.

-JohnA

 

[jeff lam]

I've used the gold wood screws at HD and predrilling small holes I haven't had any splitting problems.

 

[Patrick Sun]

If you get the clamps, you won't need screws for the internal bracing.

My latest SBS box was all done with glue-n-clamp. The only screws are for the drivers, plate amp, port, and legs.

 

[Tim Hood]

As stated before, if you're too close to the edge, it will split...

I even split MDF using nails from a finish nailer???

But #6 course threaded screws (for sheetrock) I've found work the best.

Tim

 

[JohnA]

Well

I managed to get a hold of eight pistol grip clamps, six capable of clamping on 24" and two on 36".

My plate amp is less than two miles away at my local UPS, to be delivered tomorrow and I have a free day this weekend.

Looks like I will get to assemble the box and install the AMP.

I am pretty excited. I will post some pictures as soon as I have something worth posting.

Thanks for all the input from the people on this board as well as Dan at Adire Audio.

-JohnA