| GeniX |
Okay well thats kinda it...
I was unable to get hold of decent F-clamps to clamp my project together, but tried to do my own 'stable' environment.
Anyhow, without 2 hands to hold the drill, I tried to screw my front baffle onto one of the side pieces as a start to my cabinet.
Needless to say I had to screw slower than normal, and the MDF started to seperate or rip apart into the thin layers it appears to be comprised of. Furthermore my screw on the other side was more successful due to better technique on my behalf, but still could not successfully screw into the other board - Ive realised that somewhat stable is not enough.. it *needs* to be clamped tightly, and I need to have both hands free for the drill.
So both screws are out. Im thinking of putting wood glue (small amounts) into the place where the MDF has seperated, and clamp it with my C-clamps until dry. I also plan to put filler into the screw holes, and do a little sanding on the surface to flatten it out... is this is best way I can correct my mistake without cutting another front baffle (which would involve buying more MDF)?
I have learnt my lesson - MDF needs to be securely clamped, and the screw needs to go in reasonably quickly to prevent tear through the layers, and to make sure that it does pierce into the next piece.
Any suggestions welcome. This is the part where I hate being new to woodwork - why can't I just realise these things without having to make the mistake first?
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| pinkmouse |
Hi Genix, sorry to hearabout your problems...:(
First rule of screwing into timber- drill and countersink pilot holes fo all your screws!
Second rule, use the correct screw- for end grain MDF, drywall or plasterboard screws are the best, because of their sharp point, narrow shank, and wide threads!
Ok, solving problems- yes, clamping and glueing the delaminated mdf will work, but you may need a bit more sanding when you finish, but as you are filling screw holes you will be doing that anyway. I find the best filler for mdf is car body filler, the two part epoxy stuff, it works much better than the plaster based fillers.
Do you have access to a B&D workmate or similar bench?. If you give me an idea of what you have available, I can suggest possible techniques to assist.:)
Don't give up... |
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| GeniX |
Thanks for coming to my aid again, PinkMouse!
OK well, heres the deal - the screws I bought are 1.5" brass woodscrews. It says 'countersunk' on the packaging.. I have no clue what that means.
I did drill short pilot holes - not all the way through into the other MDF sheet tho (I probably should have in hind-sight). I didnt really have a problem with guiding the screw straight as my pilot hole seemed to do that reasonably well.
Im not sure what a B&D workmate bench is, but Im quite confident that I do not have access to one. What I do have, though, are a couple of robust 'horses' (why i choose this word, I dont know, it seems to fit). Picture an upside down V shape. Now that shape is for each end - the place where the lines (legs) come together sees a plank of wood that connects them.
The constructs are a bit wobbly (I sat on one to help stabalize it while sanding).
---
Its a pity I didnt ask about filler earlier, as I have already bought some that seemed like it might work. Its called 'ezee Wood Patch' - just cheap stuff. Apparently it has no shrinking/cracking, is rapid drying, accepts enamel and acrylic paints.
Is the type of filler likely to make much of a difference if I am going to coat with a few coats of high-gloss black enamel paint?
Once again, thanks very much for your help! This whole forum has been about the best source of info for DIY I have found on the net.
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| diypole |
Hi Genix,
Five a.m. here in Vermont, so good morning.
Countersunk usually means the head of the screw is tapered and flat on the end so that it will come flush with the surface. You should drill pilot holes all the way or the screw will just "spread" the MDF apart. Make the pilot hole in the first sheet the same diameter as the screw WITH the threads. In the second sheet, make the pilot hole the same diamater as the central shank of the screw MINUS the threads(just eyeball it). In this way you will ensure the screw is tightening the joint by pulling the second sheet to it, because it can simply spin round in the first sheet. When you have pilot holes like this, you can put the screws in ahead of time,then hold the sheet with one hand and screw with the other. Make sure to glue the joint also.
best luck, Jason |
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| pinkmouse |
| The best screws for mdf:) |
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| pinkmouse |
| And a workmate style bench.. |
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| pinkmouse |
Genix,
I'm sure the filler you bought will be fine, though I am a bit worried by your use of brass screws, as they are very soft and may snap whilst driving.
| quote: | | What I do have, though, are a couple of robust 'horses' (why i choose this word, I dont know, it seems to fit) |
Quite right, they are called saw horses!!:D
Are you driving the screws in by hand, or using a battery drill/driver?
Do you have access to luggage type ratchet straps?
How big will your clamps open?
What glue are you using?
What is your inside leg measurement?( :D Just joking!) |
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| GeniX |
First off, thanks ever so much for the info guys!
diypole: hey - that might actually work. How about tomorrow I place the boards together, mark off on the one the screws still have to go into where to make the pilot holes. Make small pilot holes the depth of the screw that will go in, and then I use the existing holes I drilled today to put the screws in (since they go pretty much all the way thru), and screw into the pilot holes.. make sense? If not, I apologise - Ive never done well at describing things (dont EVER ask me for directions :)
pinkmouse: I see what you mean about the screws. On the heads where the screw driver (actually electric drill with screw driver bit) kept popping out, Ive actually chipped some of the brass away. Showing that these are at least easily chippable screws (and thus probably more brittle than they should be). However, seeing as Ive spent more on this project than I planned, I am aiming to use what Ive bought unless it really wont do the job. I think the screws will hold as every side that adjoins onto another piece of wood will get 2 screws.
I dont have a workmate style bench, but just looking at the picture I reckon thats exactly what I would have needed to help this project! That, and a vice or two...
I probably dont have access (that I know of) to ratchet straps (not that I know what they are, but Im quite confident I wont have access to any). None of my friends possess any woodwork gear - they're all computer programmers (like me), and have probably never seen a woodworking tool in their lives.
The clamps I have are just a pair of 4" C-clamps. I really do need some large F-clamps.. but as said the store wont have any until this coming week.
The glue I have is just a generic wood adhesive. Apparently made for NZ native timbers, but Im guessing thats just a marketting gimick to get NZ'ers to buy it. I bought it because it came in a smallish container (thus Im not paying for lots that I wont use), and it was only NZ$4. Its apparently non-staining, fast setting, fast grabbing, paintable, resists heat, and non-toxic. Ofcourse most wood glues probably adhere to the above...
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Unless advice to the contrary is brought to my attention on this thread, Ill commence an attemp at diypoles idea tomorrow. Maybe I can get away without waiting for the store to get F-clamps in (although the salesman did say that when they do get them in this week coming, there will be a 2 for 1 sale on F-clamps, and other tools will be discounted).
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| BrianGT |
I like to use these screws and countersink/pilot bit:
--
Brian |
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| Peter Daniel |
| IMHO these are the best screws for woodworking. They are deck screws with square slot (Canadian invention, forgot the name;) ) instead of Philips, which makes driving them much easier. Also, the thread should not be on the whole length, but only on the part which goes throught the second piece. The length is way too big for MDF, since I was using them for framing.;) |
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| kelticwizard |
The ratchet clamps that Pinkmouse speaks of are called web clamps over here.
They are a strong strap with a fitting on the end. The free end of the strap goes around whatever two pieces you wish to clamp together and then returns to the fitting. The strap therefore forms a loop. The picture does not show it, but that fitting has a small handle that you toggle back and forth to keep tightening the loop you have made with the strap. As a result, whatever two pieces are in that loop get more and more pressure applied. You can apply just loose pressure if you want, but if you keep tightening, enormous pressure can be brought to bear as well.
Buy at least one. You might want to buy several. They are available in discount home-and-hardware type stores for 7 or 8 bucks. More expensive models are available in Sears and other stores where tools are sold. Once considered fairly rare, over the years they have become very common, not surprisingly. You can use these for pulling something, lifting, attaching things to your car-anything you can put that 12 foot loop around and want to clamp together. You'll love them-they're great.
LOL, even if you never use the loudspeaker, you'll find a million uses for those web clamps! |
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| kelticwizard |
| PS: If you are going to tightly clamp the pieces together, be sure to put some wood boards around the work. If the strap is made very tight, it will leave indentations in the particle board, MDF or whatever you are using. If you are just going to make it tight enough to hold the boards together so you can screw them together, then you won't have to worry about it. |
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| newmz |
| something i always find to be essential and useful when i work with mdf is plain old cheap and easy construction adhesive in the gun tubes, i mean those cartridge guns you get silicone sealant in. here in australia we have stuff called "liquid nails" plus lots of other generic versions. when it is applied it's very sticky and holds well enough to allow you to brace or add more panels, while still allowing you to move and adjust pieces/panels into position. sometimes i actually just use this stuff and lots of battens and bracing and dont bother with screws at all. |
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| Peter Daniel |
| I also never used screws on mdf when building speakers. For positioning and holding pieces together I use finishing nails sometimes. |
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| planet10 |
| quote: | Originally posted by Peter Daniel
with square slot (Canadian invention, forgot the name;) ) |
Robertson screws. I don't know why the rest of the world doesn't adopt them. Quality would go up, costs would go down.
dave |
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| pinkmouse |
| As we're having a bit of a screw thread, here are my favorites, I didn't suggest them as as far as I know they are only available in Europe |
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| jag |
| quote: | | IMHO these are the best screws for woodworking. They are deck screws with square slot |
There is also another version available with hex slot, and they are indeed very easy to drive with something like this: |
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| Peter Daniel |
| When you driving 500 or more screws it's not easy anymore. You need a cordless drill gun.;) |
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| planet10 |
| quote: | Originally posted by Peter Daniel
When you driving 500 or more screws it's not easy anymore. You need a cordless drill gun.;) |
Easy enuff to get a hex head drill bit. The hexs are nice for driver mounting and such, but for regular work i'll stick with Robertsons (red usually).
dave |
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| GeniX |
Thanks all!
I tried the notion of drilling a hole wide enough for the screw thru the 1st sheet of MDF, and then aligning the two with one hand, I used a smaller bit to drill the pilot hole into the 2nd piece of MDF.
I then applied wood glue along the area they would join, matched my larger holes with the pilot holes by eye and screwed the screws. The result is quite a success!
No need for f-clamps and the like - this method is doable by hand alone, and the screws join the boards so that they're effectively clamped for the wood glue.
I will endeavour to do the rest of the cabinets a bit later on today (weather is really miserable.. wet and rainy).
Just a quick question tho (again sorry!) -- is it better to leave the back off for the eventual wiring of crossover & drivers, or is it better to leave a side off? So far as I can see, both have some merits later on, but the back does hide any visual issues if it is put on last..
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| Peter Daniel |
| quote: | Originally posted by planet10
Easy enuff to get a hex head drill bit. The hexs are nice for driver mounting and such, but for regular work i'll stick with Robertsons (red usually).
dave |
It may be easy but price increases with hex screws too (especially when it comes to 500 and more).;)
I've got at least 3 different types for ea size Allen bits, but for woodworking Robertson rules. |
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| roddyama |
Dave,
Robertsons drives are a Canadian thing. They’re not as available in the US, although you can find them with some searching. Sears has been including them in some of the power driver sets.
GeniX,
You can use a simple butt-joint with a brace inside like below. As long as you counter drill the holes for the size screw you’re using, it will not crack or chip the MDF, and it is very strong. Sink the screw heads below the surface and fill with wood putty.
Rodd Yamas***a |
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| jag |
| quote: | | When you driving 500 or more screws it's not easy anymore. You need a cordless drill gun |
Peter,
Have you diversified from building amp/speakers to building houses :) Or have to decided to live inside a speaker :bigeyes: |
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| roddyama |
Jag,
This sub-bass/end-table has nearly 150 wood screws in it and it is only half of the stereo pair. I wish I had the alternative drives (hex or Robertsons or torx or even a Philips wood screw) 25 years ago when I made them. Every screw is slotted and every hole was counter drilled. It’s not quite 500, but you wouldn’t want to do it all with a hand screwdriver.:bawling:
Rodd Yamas***a |
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| planet10 |
| quote: | Originally posted by roddyama
Every screw is slotted and every hole was counter drilled. It’s not quite 500, but you wouldn’t want to do it all with a hand screwdriver.:bawling:
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Yuk. I pull apart a lot of old hifi. The German ones have good salvage in them, but they use slotted fasteners. Even an electric drill/screwdriver doesn't work well. Those fasteners all go into the metal recycle. Canadian HiFis on the other hand don't have as good a content but are an excellent source for recyclable Robertsons.
McFeely's sell Robertsons screws in the US, and if Sears starts selling more Robertson drives maybe they'll catch on. You certainly won't go back once you switch.
dave |
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| Peter Daniel |
| quote: | Originally posted by jag
Peter,
Have you diversified from building amp/speakers to building houses :) Or have to decided to live inside a speaker :bigeyes: |
I bought a house in 1996 and spend good few years renovating it. That's when I lost a touch with my Audio interests. I just came back to do Audio full time beginning this year, and I can honestly say, I'm better than ever, thanks to the internet. If only I had enough motivation and excitement I used to have before. But when you digging out the basement with your own hands, to make it two feet deeper, you may loose more than that.;) ;) |
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| GeniX |
Rodd,
When you say fill with wood putty with regards to screwing, what do you mean? What is there to fill with putty? (unless you mean any cracks and seams - which Im already planning to do)
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| roddyama |
GeniX,
After you have counterdrilled, drive the screw so its head is about an 1/8" below the surface. This is what you fill with wood putty.
Rodd Yamas***a |
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| diypole |
Whoa, This screw thread took off. Genix, glad the trick worked. Growing up on a farm, necessity was always a mother(of invention). Dave and Peter, those square drives are catching on with those in the know, but still must be ordered as local hardware stores don't stock. I have a square drive bit for my gun, and rarely use anything else if I can help it. Even without a magnet they stay attached to the bit and NEVER slip.
Mistakes are the best teacher life has, if one is willing to make them. I've learned as much putting old **** drivers in different baffles as I have reading about theory.
regards, Diypole |
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| pinkmouse |
Genix, I'm glad its all coming together, can't wait to see the photos:)
If all your crossover components will fit through the hole for the woofer, just pre assemble them then glue them inside with silicone sealant, that way you can build and finish the boxes first, as some solvents used in finishing products can attack the varnish used in insulating inductors.
Otherwise, just leave off the backs, as you say, it will be less cosmetically revealing. |
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| Stew320 |
I use the collated drywall screws meant for the auto feed screwdriver (the ones with the coarser threads), I get them surplus from my work for free.
Pink I see Screwfix is keeping you in screws! I've not tried the T-star screws as yet, do they grab better than the drywall type?
One thing I find a pain in the *** is having to change from a 4mm drill bit to 2.5 then change to a countersink bit then change to a screwdriver bit, So I use my 18v de-walt for the screwdriver bit drill press for the countersink bit, chepo power devil for the drill bits. this speeds things up and saves getting into a blind fury/red-mist situation because of losing the bits every time you set them down ;-)
Stew. |
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| pinkmouse |
Stew, yup Screwfix are a great company, been dealing with them for about 7 years, I think the first catalogue was about 32 pages, now it's about 300!
The Spax screws grip very well in end grain, and seem to have a greater shear strength than drywall screws, so they break less often. The Spax head also virtually removes the problem of cam-out when driving, so, all in all, a much better product.
As we are going through the screwfix catalogue, try these, they should reduce your frustration level a little, and lead to greater productivity
:) |
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| BrianGT |
Just went by home depot, and they had some green screws that Peter posted a picture of above, but only in the larger diameter size. I found some Deck Mate (c) with Phillips Square-Driv(tm) ends on them and they include a bit to use. They seem just as good as square drive. Home Depot carries all sizes of these screws.
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Brian |
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| capslock |
| quote: | Originally posted by newmz
something i always find to be essential and useful when i work with mdf is plain old cheap and easy construction adhesive in the gun tubes, i mean those cartridge guns you get silicone sealant in. here in australia we have stuff called "liquid nails" plus lots of other generic versions. when it is applied it's very sticky and holds well enough to allow you to brace or add more panels, while still allowing you to move and adjust pieces/panels into position. sometimes i actually just use this stuff and lots of battens and bracing and dont bother with screws at all. |
Both speaker builder magazines here in Germany recommend using the stuff. There are at least three brands here, Bison, Pattex and Uhu. When dried, its a lot like contact glue, but you should not let it dry for more than a minute before joining pieces. You can still move pieces a little, but if you don't touch, parts won't move. The stuff is perfect both for building cabinets without braces, screws or anything as well as for attaching tiles and damping mats on the inside. Only nasty thing: the glue won't stop coming out of the nozzle unless you unlock the piston.
It's probably not as rigid as wood glue, but maybe it is even preferable to have 0.5 mm of something slightly elasting and damping between the individual boards. Haven't used screws since unless I want to be able to exchange things.
Eric |
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| Redeye |
I've just been through similar levels of grief with the glue/screw method of building my new active studio monitors. It's been very time consuming doing all the drilling, filling, sanding and all the rest although I've ended up with (IMHO) a very good pair of cabinets.
Next time I think I'm going to get some frame clamps and just glue the things and save myself a load of time. Has anybody got any advice on this method? I presume that it will make just as sturdy cabinets given that the wood glue is usually stronger than the wood? I guess the only problem is the fiddly/messy nature of actually applying the glue and getting the clamps on so that it all makes right angles and lines up straight. |
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| pinkmouse |
| Try milling rebates in your timber ( see below). You can use a router or a table saw, and if made accurately, the cabinet will all line up and hold together during assembly. You will only need ratchet/webbing straps to hold it together whilst the glue sets, or perhaps a couple of panel pins, as Peter suggested |
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| Redeye |
| Thanks pinkmouse. I was thinking of milling rebates to get the centre support in the right place, but you're right - if I do that for the end pieces as well then it should all line up (in theory at least). |
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| GeniX |
How would one do rebates with a table saw? Given the 'L' shape (well if you rotate it a bit)...
PS: Your suggestion of making the cabinets whole, and wiring the drivers and such up with crossover last is growing on me, PinkMouse. Provided the crossover can fit thru the drivers hole, it may prove much easier for the finishing of the cabinet as Im not stuck with a back piece to put on last.
Im also thinking of trying a 2nd-order crossover just for the hell of it. They arent that much more difficult than 1st order (and I think it suits my driver/tweeter overlap better)
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| pinkmouse |
Genix, first or second order, don't know without seeing the driver curves, but hey, why not:)
Cutting Rebates with a table saw
YOU DO THIS AT YOUR OWN RISK!!! Do not attempt if you are unfamiliar with the use of power tools!
:att'n:You have to remove the blade guard for this operation, so it is vital to keep your hands out of the way of the blade, and to use eye protection:att'n: |
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| Schaef |
Holy cow!!! The weekend comes and a thread totally explodes all over the place!!!
Here's a couple of thoughts. First, GeniX, I can offer quite a few solutions for you on the box construction front. An easy answer to your problem would be to use a small piece of scrap wood placed on the inside angle side of the two pieces to be joined. Now take two of your C-clamps and attach one such that it clamps the piece of scrap to a panel, now take the other C-clamp and clamp it so that it clamps the other panel to the scrap as well. (Use the same idea as the person showing the screws into a piece of 1x1, except use the clamps instead of screws) This should be good enough to hold until you get a screw in that end. Then flip and do it again. It also helps to have a large flat work surface. I use a piece of plywood on two or more sawhorses. Its cheap, pretty stable, offers a huge work surface and stores flat when not in use! (And gets used when I need pieces of playwood that I don't have on hand at the time)
As to the square-drive screws, sure they can be found in the U.S. - you just have to know where to look! In addition to McFeeley's (great source) there's also Rockler (www.rockler.com) and Home depot, if you look at the deck screws. As to type of screw, you want a coarse threaded screw, not those fine-threaded ones. (Look at the screw, see lots of threads really close together, that's fine thread, if you hold one of each side-by-side, the difference is VERY obvious)
Also, GeniX, I would recommend you use at least three screws per side, even if you are glueing. The sides can bow out in the middle, so I always put one on each end, and one in the middle. (Unless of course, your sides are really short, like 10" or less)
Everybody's recommendation on pre-drilling is an absolute must when working with MDF, otherwise you'll run into tons of problems (as you're finding out)
I hope this helps out and you aren't completely done yet!
I almost forgot, PinkMouse, another way to do that rabbet, which is slightly safer in my opinion, is to rotate the piece 90 degrees and nibble away. It takes longer, but you don't have a possibly long piece dangling in the air just waiting to fall into the blade and kick back!
My way of doing the same thing:
Set the saw fence at the width of the rabbet, (probably about 3/4") set the blade to the depth of the rabbet. Now using the sliding miter gauge, and the piece against the fence, slide through the blade. Next, pull the piece a blade thickness or less away from the fence, and repeat. Keep doing this until you have the complete cut done. Its slower, but much safer. (Its how I do tenons when I either don't want to use my radial arm saw, or the piece is too wide for it) Please work safe, you want all of those fingers! |
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