MDF construction tips

You'd be FAR better off binning the MDF & using a good quality ply. You can make very strong boxes with 12 or even 9mm ply - they will be a lot stronger, longer-lasting, and lighter that any MDF box.

Your construction method seems fine, though I wouldn't bother with the glue in the screwholes - you may find it just makes the job harder. Glue & screw the joints as you describe, and if you want to make them extra-strong, put a 6mm fillet of epoxy resin round the inside of all the joints.

I know you've already bought the material, but MDF really isn't the best thing to use.

 

heeelllooo ham bone and welcome



as above ply is more robust
as you have to use mdf this how i do it with screws and mdf

[assuming its half inch-12mm]mdf i use 6x1.5"screws a 3 or 3.2mm drill avoiding the 30mm each end
http://www.screwfix.com/app/sfd/sea/searchresults.jsp?dyncharset=UTF-8&q=14525&pn=1&pd=1&pi=1&cn=1&cd=1&x=7&y=6

butt joint the components screws every 50 to 75mm pilot the full depth of the screw through both components
use the pozi srewdriver bit for your countersink glue and screw together hand tighten the last 2 turns

if the edge does delaminate slightly push glue into the crack ,unscrew the screw a few turns block and clamp then tighten screw

clear as mud

big all

 

Agree ply would be better. If I were making these I'd go along with the blocks idea but instead of using blocks I'd use full length 1"x1" pine, or similar, in each corner. Glue then screw thro' mdf into pine, that way you will not have to screw into mdf edge and have a greater glueing area.

 

i would also go with full length battons if you have the space

the 30mm is
when you butt join the two edges you drill your screw holes centraly in this case 7mm from the edge along the whole length
but as you get towards the ends they may start to delaminate hense avoiding the last 30mm
you can go closer to the end but the risk is then greater of delamination and also if your joining 3 bits together on a corner your screws may interfere with each other

would also suggest you place a couple of 20by44 planed timber battons on the bottom for protection if theres going to be any sliding or banging[but only if they would fit in ]as i dont actualy know what a d j box is!!!!!!
i am assuming its for records!!

big all

 

Havu=ing built kit boxes in the past I'd recommend using steel corner protectors and aluminium or steel L-profiles at least on the bottom edges.

Scrit

 

scrits idea is the way to go angled metal wide enough to accomodate all the bolts for the castors

i can see several possible problems
securing castors to the mdf is likly to pull the box to bits before the years out
so if you build an oblong frame[perhaps dexion type stuff] held together by the bolts securing the wheels on
then secure the frame to the boxes

dont forget mdf dosnt like getting wet it just swells up
try leaving a coffee or tea cup with a wet rim on it for twenty mins remove cup and dont dry it
tommorow youll have a raised ring
so make shure you paint it well and keep it dry

and oooooooooo the weight

big all

 

If you change your mind and use ply, remember this.

Ply don't like being srewed into anywhere near the edge, and that include going into it endways.

I definitely agree with the corner strips of some kind, and you are correct in thinking pilotholes(thread-size for the through-piece and a tad under shaft-size for the thread to screw into.

Not sure about the castors. I would put thin coachbolts down through the inside of the floor, then nut outside, then put a thin flooring on top inside to protect the contents from the boltheads.




Mr. HandyAndy - really

 

In that case make sure you get a good quality plywood - I'd recommend birch ply, not the cheapest but good - and specify a WBP or exterior grade. Also use steel or wood backing plates inside wherever you attach handles, castors, etc to safeguard against pulling through.

Scrit