How long does a good paint job take? Well, that depends. . .
It depends on how "good" you want it and how long each coat takes to dry enough.
Lacquer drys very quickly and you can sand it in about an hour, but it typically makes pretty thin coats, so you need more coats to get it smooth.
Urethane takes at least overnight to dry, and is harder to sand, but does some "self leveling" and makes thicker coats. You could get a way with one coat of primer and one or two coats of color, especially if matte.
My last project was a set of dining room chairs. Two coats of catalyzed primer, sanding the first day, then three coats of automotive catalyzed lacquer on the second day. It's as smooth and glossy as a car finish. Yes, I have spray equipment, and automotive lacquer is killer expensive. 1 quart cost me over $200.
It depends on how "good" you want it and how long each coat takes to dry enough.
Lacquer drys very quickly and you can sand it in about an hour, but it typically makes pretty thin coats, so you need more coats to get it smooth.
Urethane takes at least overnight to dry, and is harder to sand, but does some "self leveling" and makes thicker coats. You could get a way with one coat of primer and one or two coats of color, especially if matte.
My last project was a set of dining room chairs. Two coats of catalyzed primer, sanding the first day, then three coats of automotive catalyzed lacquer on the second day. It's as smooth and glossy as a car finish. Yes, I have spray equipment, and automotive lacquer is killer expensive. 1 quart cost me over $200.
what was the total elapsed time for the prep and finishing of that time - and yes, I mean including the time waiting for each coat to dry / cure as might be required? I assume you didn't bake the auto lacquer in a booth?
I had 8 chairs to spray, taking about 20 minutes per chair.
Dry time, about 1 hour.
Sanding, about 30 minutes per chair, per coat. Sand between all primer coats.
Finish coats, spray time about 15 minutes per chair. Catalyzed lacquer does not require baking, old fashioned automotive enamel is really no longer used, and water-based products as used by manufacturers can use "accelerated" drying at medium heat. Not for the DIY user.
It again takes about 1 hour for the stuff to dry enough for the next coat. I did not need to sand between the final coats, it was smooth enough. It took most of the daylight hours of two days.
Dry time, about 1 hour.
Sanding, about 30 minutes per chair, per coat. Sand between all primer coats.
Finish coats, spray time about 15 minutes per chair. Catalyzed lacquer does not require baking, old fashioned automotive enamel is really no longer used, and water-based products as used by manufacturers can use "accelerated" drying at medium heat. Not for the DIY user.
It again takes about 1 hour for the stuff to dry enough for the next coat. I did not need to sand between the final coats, it was smooth enough. It took most of the daylight hours of two days.
Well I only bothered measuring the internals of the enclosure. The vent was supposed to be 3.5cm throughout the box.
The lower opening is actually 4 or 4.2cm, and the the distance between the upper sheet of MDF and the lower one that make the port is ******* 6.5cm. How did he get it wrong by 3 cm??? :\
I had a gut feeling the first time I met him that he's just an amateur, telling me that I "worry too much" as I was explaining the importance of the small details.
What does this awkward, inconsistent port mean to my subwoofer? I'm afraid it moves the tuning frequency way up, to 25hz or so, which turns this entire DIY project into a freaking $100 Polk sub.
EDIT:
So I measured partially wrong. The first, long part of the port is actualy 3.45cm, which is close enough to 3.5cm.
However, the second (upper, shorter) part is bloody 5.2cm. What. The. F. How can someone be wrong by 2 full centimeters... Anyway, I was thinking that it might be a pain in the **** to remove the upper piece, so maybe I should make another one just like it, with 1.7cm thick MDF, and stick it right below the existing piece.
So 5.2 - 1.7 = 3.5. I'll lose some internal volume for the piece that was placed at the wrong height, but it shouldn't be too bad.
Your thoughts? 🙂
The lower opening is actually 4 or 4.2cm, and the the distance between the upper sheet of MDF and the lower one that make the port is ******* 6.5cm. How did he get it wrong by 3 cm??? :\
I had a gut feeling the first time I met him that he's just an amateur, telling me that I "worry too much" as I was explaining the importance of the small details.
What does this awkward, inconsistent port mean to my subwoofer? I'm afraid it moves the tuning frequency way up, to 25hz or so, which turns this entire DIY project into a freaking $100 Polk sub.
EDIT:
So I measured partially wrong. The first, long part of the port is actualy 3.45cm, which is close enough to 3.5cm.
However, the second (upper, shorter) part is bloody 5.2cm. What. The. F. How can someone be wrong by 2 full centimeters... Anyway, I was thinking that it might be a pain in the **** to remove the upper piece, so maybe I should make another one just like it, with 1.7cm thick MDF, and stick it right below the existing piece.
So 5.2 - 1.7 = 3.5. I'll lose some internal volume for the piece that was placed at the wrong height, but it shouldn't be too bad.
Your thoughts? 🙂
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I'd write it off as a learning exercise, and find another craftsperson - at the risk of a bad joke, not all carpenters are created equal - what you want is a furniture / cabinetmaker.
I didn't say this before, but $50 was far too cheap for a properly made sub enclosure of the design details given. I personally avoid MDF for all speaker cabinet including subs, but the labour on that enclosure should have been at least 4 hrs.
I didn't say this before, but $50 was far too cheap for a properly made sub enclosure of the design details given. I personally avoid MDF for all speaker cabinet including subs, but the labour on that enclosure should have been at least 4 hrs.
I actually paid $160 for it. Double front baffle and stuff.
I don't understand why a carpenter would miss by 2 cm. You don't need any skills to use a ruler. I think he just got confused or misread my sketch or something.
A small fix, it's actually 5.5cm for the upper part of the port, so I need a 2cm thich piece of MDF beneath the existing one. The support is there so gluing it should be enough, maybe I'll add nails from the rear side of the cabinet.
He better have 2cm MDF, though. It's like he used remnants for my project, one of the sides has a white formica coating. I mean what the hell...
Oh and he also seems to have used an angle grinder to cut the rear rectangle for the amp, because the cut isn't like 1.7cm thick and then no wood, you can see some of the wood is like 0.4mm thick near the edges of the rectangle cut. Did I say amateur?
I don't understand why a carpenter would miss by 2 cm. You don't need any skills to use a ruler. I think he just got confused or misread my sketch or something.
A small fix, it's actually 5.5cm for the upper part of the port, so I need a 2cm thich piece of MDF beneath the existing one. The support is there so gluing it should be enough, maybe I'll add nails from the rear side of the cabinet.
He better have 2cm MDF, though. It's like he used remnants for my project, one of the sides has a white formica coating. I mean what the hell...
Oh and he also seems to have used an angle grinder to cut the rear rectangle for the amp, because the cut isn't like 1.7cm thick and then no wood, you can see some of the wood is like 0.4mm thick near the edges of the rectangle cut. Did I say amateur?
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Is there a way to move the misplaced MDF panel 2 cm lower? Or should I just cut as much as I can of it and place another one beneath it?
Guys, I bought a primer and apparently it's based on turpentine (thinner). Is this safe for use with MDF?
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Right, anything but water based for the primer. Use oil, etc., based putty to seal any raw edges, then apply sufficient primer both inside and out to seal it from moisture.
Google is your friend here as anything MDF related is a popular subject.
GM
Google is your friend here as anything MDF related is a popular subject.
GM
I actually Googled "turpentine MDF" and found nothing relevant so I went to toe trouble of opening an account on a wood working forum just to ask this question. 🙂
The putty I used is based on "acrylic latex glue" so I guess it's OK.
Are you saying that I need to apply the primer to the interior of the enclosure, not only to where I'll be painting?
Edit: Also, suggestions for T-nuts and screw size (for both the speaker and amp).
Thanks.
The putty I used is based on "acrylic latex glue" so I guess it's OK.
Are you saying that I need to apply the primer to the interior of the enclosure, not only to where I'll be painting?
Edit: Also, suggestions for T-nuts and screw size (for both the speaker and amp).
Thanks.
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You're welcome!
https://www.google.com/search?q=How...DF&aqs=chrome..69i57&sourceid=chrome&ie=UTF-8
Hmm, to me, 'latex' means water based, but never tried it on MDF, so will leave this to others or Google it.
Well, since it's a vented alignment, not a bad plan unless the humidity will always be low wherever it may be. Around here, a lot of cheap MDF consumer cabs have littered the weekly trash piles for decades due primarily to moisture attacking from within, especially after someone spilled/squirted some liquid in them.
While one can make T-nuts work well in MDF, most folks fail or at least wish they hadn't used them, so best to use threaded inserts: https://www.google.com/webhp?source...1&espv=2&ie=UTF-8#q=threaded inserts for wood
Choose a thread size that's a little smaller than the mounting holes to allow for installation error and assuming there's room enough to use them, washer head machine screws [or similar bolt head] is a good plan: https://www.google.com/webhp?source...2&ie=UTF-8#q=round washer head machine screws
Whatever hardware you use, don't over tighten them. I have various calibrated torque wrenches, but few folks do, so recommend starting them loose and tighten [do them a little at a time in a pattern like one does with vehicle wheels] while feeding the speaker some pink noise or at least some bass heavy music at low SPL and once there's no leaks, you're done and with good gaskets, don't be surprised if they only feel barely finger tight.
GM
https://www.google.com/search?q=How...DF&aqs=chrome..69i57&sourceid=chrome&ie=UTF-8
Hmm, to me, 'latex' means water based, but never tried it on MDF, so will leave this to others or Google it.
Well, since it's a vented alignment, not a bad plan unless the humidity will always be low wherever it may be. Around here, a lot of cheap MDF consumer cabs have littered the weekly trash piles for decades due primarily to moisture attacking from within, especially after someone spilled/squirted some liquid in them.
While one can make T-nuts work well in MDF, most folks fail or at least wish they hadn't used them, so best to use threaded inserts: https://www.google.com/webhp?source...1&espv=2&ie=UTF-8#q=threaded inserts for wood
Choose a thread size that's a little smaller than the mounting holes to allow for installation error and assuming there's room enough to use them, washer head machine screws [or similar bolt head] is a good plan: https://www.google.com/webhp?source...2&ie=UTF-8#q=round washer head machine screws
Whatever hardware you use, don't over tighten them. I have various calibrated torque wrenches, but few folks do, so recommend starting them loose and tighten [do them a little at a time in a pattern like one does with vehicle wheels] while feeding the speaker some pink noise or at least some bass heavy music at low SPL and once there's no leaks, you're done and with good gaskets, don't be surprised if they only feel barely finger tight.
GM
I just came back from the two biggest hardware stores in the country (before I saw this post of yours), and neither have T-nuts, countersink bits or threaded inserts.
What are my options, other than buying these from eBay and waiting probably a month for them to arrive?
As for covering the interior with a primer, some areas are accessible, but the entire port (80 cm in length) is not, it's only 3.5cm high and I just cannot get a brush inside to paint.
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Bummer! 😡
Well, in my youth I was in the same 'boat', so glued scrap pieces of hardwood to the backside of the plywood or pine board baffle [no MDF back then] and used wood screws, which held even heavy 15" woofers just fine. The only downside being that after awhile, swapping out drivers required shifting to larger screws.
I've also mounted carriage or hex head bolts from the backside to create mounting studs for nuts/washers, just make the hole for the 'stud' and use a large 'fender' washer [auto parts] or similar + nut to tighten down, 'sink' it flush/perpendicular. Preferably use Nylock or similar nuts to hold down the driver if there's not enough room for flat, lock washers: https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=nyloc nut vs lock nut
Later, I learned that fiberglass epoxy resin could be used to fill [and tap] for machine screws or bolts, then almost immediately afterwards bought my first 15" Altec woofers [26 lbs/ea.!], which came with T-nuts, machine screws, washers, using them even today.
Anyway, I assume Israel is still in the boat and furniture building business and if so, I imagine they have everything you want/need in stock or can tell you where to quickly get it, not to mention several thousand years worth of know how to do it every way mankind has thought up, so kind of surprised you're relying on us 'newcomers' to help with woodworking of any type.
If no access to a sprayer, then thin some as required to get it to soak in a bit and pour it in, 'roll' it around to at least get good coverage on as many seams as you can since this is the 'weakest' spots, let it sink in a bit and pour it back out.
GM
Well, in my youth I was in the same 'boat', so glued scrap pieces of hardwood to the backside of the plywood or pine board baffle [no MDF back then] and used wood screws, which held even heavy 15" woofers just fine. The only downside being that after awhile, swapping out drivers required shifting to larger screws.
I've also mounted carriage or hex head bolts from the backside to create mounting studs for nuts/washers, just make the hole for the 'stud' and use a large 'fender' washer [auto parts] or similar + nut to tighten down, 'sink' it flush/perpendicular. Preferably use Nylock or similar nuts to hold down the driver if there's not enough room for flat, lock washers: https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=nyloc nut vs lock nut
Later, I learned that fiberglass epoxy resin could be used to fill [and tap] for machine screws or bolts, then almost immediately afterwards bought my first 15" Altec woofers [26 lbs/ea.!], which came with T-nuts, machine screws, washers, using them even today.
Anyway, I assume Israel is still in the boat and furniture building business and if so, I imagine they have everything you want/need in stock or can tell you where to quickly get it, not to mention several thousand years worth of know how to do it every way mankind has thought up, so kind of surprised you're relying on us 'newcomers' to help with woodworking of any type.
If no access to a sprayer, then thin some as required to get it to soak in a bit and pour it in, 'roll' it around to at least get good coverage on as many seams as you can since this is the 'weakest' spots, let it sink in a bit and pour it back out.
GM
What if my sub box is not 100% airtight? I mean the edges of the box, not the woofer cutout (where I'll use the tape that came with the woofer). Some of the inaccessible edges have gaps that I measured at roughly 1/6 of a mm. I got my smartphone's flashlight very close to them and the light wasn't visible on the other side, but still... I've already used caulk wherever accessible. It's the 3.5 cm height of the port that prevents me from being able to seal it with caulk too.
Also, good news - I have found an Israel online store that has 1/4" T-nuts. So I wonder if the size refers to the diameter of the part that has the sharp bits, or is it the diameter of the round and long bit that goes into the wood. I simply need to know what size drill bit and screws I'll need... And will I need washers as well?
Also, good news - I have found an Israel online store that has 1/4" T-nuts. So I wonder if the size refers to the diameter of the part that has the sharp bits, or is it the diameter of the round and long bit that goes into the wood. I simply need to know what size drill bit and screws I'll need... And will I need washers as well?
ANY air leak [even as small as around mounting hardware or through a seemingly dense gasket in some cases!] causes the tuning to be higher, so doesn't take much of a leak to completely ruin a speaker's bass and up through the mid-bass frequency/power response BW.
If there's leaks in the vent's path, it will effectively shorten it, so again, tuning will be higher, though not as high as a box leak. The poured in primer/sealer will seal it and one reason why I suggested sloshing it around, concentrating on joint seams both in the box and through the vent opening.
Again, Google and your local supplier are your friend: https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=t nut sizing
https://www.google.com/webhp?source...2&ie=UTF-8#q=proper+t+nut+installation+in+mdf
GM
If there's leaks in the vent's path, it will effectively shorten it, so again, tuning will be higher, though not as high as a box leak. The poured in primer/sealer will seal it and one reason why I suggested sloshing it around, concentrating on joint seams both in the box and through the vent opening.
Again, Google and your local supplier
https://www.google.com/webhp?source...2&ie=UTF-8#q=proper+t+nut+installation+in+mdf
GM
Thanks, I need to get another (small) can of primer to fix some painting errors so I'll follow your suggestion and use it for sealing as well.
A question regarding the port: It is comprised of two pieces, and the first (long) piece is 3.5 cm above the bottom panel, but the second (short) piece is actually 5.5 cm above the first piece. So the carpenter cut a new short piece for me but it's made of 1.7 cm thick MDF (he doesn't have a 2 cm one), so the opening of the upper part of the port would be 3.8 cm instead of 3.5 cm. Is this OK? Should I attempt to glue it somewhat lower (then I won't be able to use the mis-placed short piece as the base, so I'll have to rely on steady hands and insert it properly.
Also, its width is 2 mm shorter than needed (lost in cutting it in half in order to be able to insert it into the box through the woofer cutout), so I figured I could use a combination of carpenter's glue (lots of it), then wood filler, than the primer for the really tiny gaps that might be left and finally silicone caulk. Will this work?
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Hi,
I was going to connect the amp to the sub for testing inside the cabinet, but the wires supplied with the plate amp are roughly 10cm too short. I am OK with soldering, but what kind of wires are these? Are they like RCA so each color (black and red) have two wires inside, or is it just one in each color? And what are they called so I could find where to buy them? Also, what about thickness? I have no idea what "gauge" they are.
I was going to connect the amp to the sub for testing inside the cabinet, but the wires supplied with the plate amp are roughly 10cm too short. I am OK with soldering, but what kind of wires are these? Are they like RCA so each color (black and red) have two wires inside, or is it just one in each color? And what are they called so I could find where to buy them? Also, what about thickness? I have no idea what "gauge" they are.
You're welcome!
Hmm, please post a sketch with dimensions to make sure we're all on the same 'page'.
GM
Please post all amp info as the few plate amps I've seen [don't use them] all had power cords either attached or to plug one in like a computer.
GM
GM
OK, let's start with the sketch. Here it is:
Explanation:
1 - this is the misplaced upper port piece (thanks mr. carpenter). It sits 2cm too high.
2 - this is a piece I added, it's like the one above it, except it's 2mm less wide (the depth is identical). It's actually 1.7cm thick, despite the fact that I needed it to be 2cm to precisely correct the carpenter's mistake, but it's all I was able to get.
So the fact that it's 2mm less wide (where the arrow points) means it doesn't touch the side panel, however, there's the piece above it (1), which means air won't escape from there, it will only go 1.7cm higher at this very edge (which is only 2mm wide).
The second thing is regarding the fact that piece number 2 is 1.7cm thick instead of 2cm. This means that the upper part of the port is not 3.5cm, but 3.8cm high.
And regarding these two points, I ask - does it really matter?
Now regarding the amp, its wires are connected with a clip of some sort to the amp, and I intend to cut them near the other end, so the clips will remain. At that point of cutting I'll add more wire. I just don't know what exactly I'm looking for and I don't wanna carry this amp with me to stores. It's a BASH 300s, by the way.
Edit: Another question. I ordered 4mm T nuts and screws for the speaker, do I also need these for the plate amp or will simple wood screws do the trick?
An externally hosted image should be here but it was not working when we last tested it.
Explanation:
1 - this is the misplaced upper port piece (thanks mr. carpenter). It sits 2cm too high.
2 - this is a piece I added, it's like the one above it, except it's 2mm less wide (the depth is identical). It's actually 1.7cm thick, despite the fact that I needed it to be 2cm to precisely correct the carpenter's mistake, but it's all I was able to get.
So the fact that it's 2mm less wide (where the arrow points) means it doesn't touch the side panel, however, there's the piece above it (1), which means air won't escape from there, it will only go 1.7cm higher at this very edge (which is only 2mm wide).
The second thing is regarding the fact that piece number 2 is 1.7cm thick instead of 2cm. This means that the upper part of the port is not 3.5cm, but 3.8cm high.
And regarding these two points, I ask - does it really matter?
Now regarding the amp, its wires are connected with a clip of some sort to the amp, and I intend to cut them near the other end, so the clips will remain. At that point of cutting I'll add more wire. I just don't know what exactly I'm looking for and I don't wanna carry this amp with me to stores. It's a BASH 300s, by the way.
Edit: Another question. I ordered 4mm T nuts and screws for the speaker, do I also need these for the plate amp or will simple wood screws do the trick?
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