If painting isn't time consuming I'll eat your hat. This is just to make painting much easier. The time savings is really worth it.
Is it costly? When you consider how little you use on ONE pair, then you realize how many projects you can use it on, and that $117 for the 2 cans and pumps goes a very long way. Compounded by the reduced amount of paint, primer, sand paper, and finishing materials; it actually can save money as well.
PVA or Elmer's glue can do a lot well. I used to do the same. However, nothing is better than epoxy at sealing MDF edge grain. PVA crums when sanded if too thick but i do not recommend dilluting it when water is MDF's enemy.
i'll add one more thing about epoxy, you really don't want to get it on your skin. it's a sensitizing irritant, you can have skin contact with it over a long period and it seems fine until one day you break out in hives and can't be anywhere near it - forever. not common but it does happen, boatbuilders will tell you. and who knows what else it's doing to your body?
what this means is that even if you are wearing gloves when you apply it, and somehow avoid the fumes, the uncured sanding dust will get on your skin and in your lungs when you sand it. even when it's hardened it's still uncured and still hazardous - unless you wait for it to fully cure, and that takes up to 72 hours.
Not to mention the problems associated with MDF dust and the usage of that medium. Not that i don't try to keep it at a minimum, but you can only do so much and go so far, and something will lead to death anyway. Yes, protect yourself as much as possible.
How wide?
You can get broad leaf veneer 305mm wide.
You can get "laserply" that's a 600mm wide. It comes with a furniture grade surface, multiple species available.
briggs.com.au and bord.com.au appear to sell veneer in 2.4 * 1.2 metre sheets, multiple species and types of grain matching available. The sample images seem pretty good.
For much less money / more DIY you can go hardware store or two, and look through their pile of hardwood braceply (4mm thick) to see if they have a colour / grain you like. Grab a few of the nicer sheets and cut your "veneer" sections out of the best bits - it is cheap enough that wasting part of a sheet isn't a big deal.
The species is a lucky dip, but other than that, there's not much wrong with braceply; you can use fine sandpaper to give it a very smooth, crisp surface, and the timber is slightly better than "premium" birch ply (better stress grade + surface hardness + waterproof glue).
If you try this, the worst case scenario is that you'll end up painting a cabinet with 19mm thick walls rather than 15mm thick walls 🙂
On a relatively high budget, you can get 5mm thick, single ply bamboo in full sheets - which you can order cut to size. Put in on with lots of polyurethane glue + weights + clamps, and it gives a crazy strong panel.
5mm is thick enough to be forgiving of sloppy workmanship. It is dense and strong and is dead (non resonant), so a skin layer of it improves a cabinet, without adding much extra bulk. It is also harder than almost all normal wood, and thus very scratch resistant.
The downsides are the price, and that, being a single thick layer, it is not strong (brittle in one dimension) until you laminate it onto a substrate.
Wide Veneers are hard to get in Oz land and like most specialist product's thats been imported very expensive, although a lot of Aussie wood is very spectacular in its grain and colour detail... but on a large floor standing speaker could easily look very gaudy.
I agree with wolf epoxy resin is the best sealer polyester resin next... a lot cheaper too. Superglue also works but gets real pricey real quick.
Another option is dewaxed shellac(blonde).
Someone was say MDF is bad to paint I'll digress and say its actually one of the best surfaces to paint for a nice finish, once you have dealt with the endgrain issue its a very nice super flat surface that needs little to no sanding if unblemished, primers are not really essential almost any type of paint adheres very well to it.
I agree with wolf epoxy resin is the best sealer polyester resin next... a lot cheaper too. Superglue also works but gets real pricey real quick.
Another option is dewaxed shellac(blonde).
Someone was say MDF is bad to paint I'll digress and say its actually one of the best surfaces to paint for a nice finish, once you have dealt with the endgrain issue its a very nice super flat surface that needs little to no sanding if unblemished, primers are not really essential almost any type of paint adheres very well to it.
If you want a flat surface, no matter if it's low gloss or high gloss, then you need to do the prep work.
As other have suggested, both epoxy and polyester work to stabilize the surface, and for some things it would make the most sense (yes they both have their own downsides for your health, but it's easy to protect yourself and your not doing it every day).
If you want to paint with automotive 2K then go to those products, use bondo and a 2K filler that you spray, that will also stabilize the surface and you can sand it really flat.
Even if you want to cover it with vinyl I would say that it's the way to go.
Just remember to let everything settle for a while, your glue joints will move for a while, potential swelling from products applied in the first stages might occur, so keep them in indoors for a week or so before sanding and painting.
My speakers, finished with automotive paint.
As other have suggested, both epoxy and polyester work to stabilize the surface, and for some things it would make the most sense (yes they both have their own downsides for your health, but it's easy to protect yourself and your not doing it every day).
If you want to paint with automotive 2K then go to those products, use bondo and a 2K filler that you spray, that will also stabilize the surface and you can sand it really flat.
Even if you want to cover it with vinyl I would say that it's the way to go.
Just remember to let everything settle for a while, your glue joints will move for a while, potential swelling from products applied in the first stages might occur, so keep them in indoors for a week or so before sanding and painting.
My speakers, finished with automotive paint.
You are in Queensland so get some Boat Coat epoxy, that is where it is manufactured. It is a modern epoxy developed in Australia for wooden boats and is far less toxic than West Systems epoxy. I have used it on boats and also as a pore filler on guitars. As a pore filler there is nothing better. Highly recommended.
Boat Coat epoxy is a high quality product... Hard to get in the US, and more expensive than West systems. If I were down under, Boat Coat is what I would use.
I have found that (in North America), rotary cut birch veneer and soft maple veneer are a low cost way of covering an MDF cabinet prior to painting. Once covered in veneer, getting a high quality paint finish is much easier for me. I do not own any spray equipment, so all of my finish coatings are applied with a brush.
I have found that (in North America), rotary cut birch veneer and soft maple veneer are a low cost way of covering an MDF cabinet prior to painting. Once covered in veneer, getting a high quality paint finish is much easier for me. I do not own any spray equipment, so all of my finish coatings are applied with a brush.
Here's my 2 cents on the subject:
I have not done anything with oil / lacquer type high VOC paint. I just don't work with the stuff, as I don't want to deal with all the petroleum distillate cleanup chemicals.
I have done quite a bit of experimentation with other paints and here is the space I ended up in. Water based "oil modified" paint like Benjamin Moore Advance or Sherwin Williams Emerald Urethane was key for me. These were clearly the best paints I used when you consider durability / cured hardness, self leveling and sandability. These are expensive paints, but I didn't find anything else comparable, be it the trendy furniture paints you see on youtube / etsy DIY type areas of the web or lesser tier home trim paints. They're definitely on the expensive side, but the best of what I tried. As a bonus they can be mixed in any color or color matched, unlike the trendy furniture paints.
As far as prep, I've tried bondo, bondo glazing and spot putty, boat epoxy, wood filler, wood glue + sawdust, and drywall mud. Overall they are all about the same except the drywall mud / spackle wasn't good. I don't see a lot of advantage for epoxy (including bondo) over single part filler like the bondo glazing and spot putty. The epoxies are so much worse to work with, needing to mix and limited working time and toxicity, etc... I find the boat epoxy pretty wasteful with needing to toss the brush every time, and it bubbles if you're not careful.
So I do gross sand --> fill --> gross sand again --> usually need a 2nd round of fill in spots --> gross sand again --> fine sand step by step to 320 or 400 --> prime --> fine sand (evluate coverage and edges and prime / sand again if needed) --> paint --> fine sand --> paint.
If you do not sand enough grit by grit, these paints are revealing enough to show sanding scratches. FYI, I got some cheap sanding discs off Amazon, and they were inconsistent in grit size. A 220 grit disc would leave occasional stray deep marks that I didn't see from a better quality 180 grit disc, for example. You really cannot cheap out on any step here... I tried. It shows in the end product if you do.
As far as brush / rolling, the method I found best (and I tried over a dozen different brush and mini-roller types,) was to brush with almost any brush. Get a decently thick layer on there. not so thick it runs, but thick. Way thicker than I would have thought when I started. Then use a (dry-ish) velour / mohair roller to just go over the top and even out the brush strokes. This will leave you with a very minor amount of stippling, but otherwise smooth. This was the best I could get with a brush or roller, and it was easy to repeat. I have since gotten a fine finish airless sprayer, and that is smoother for sure, but the brush + velour roller method got a passing grade from my wife when literally zero other paints, rollers or brushes made that cut.
Hope all of that is helpful.
I have not done anything with oil / lacquer type high VOC paint. I just don't work with the stuff, as I don't want to deal with all the petroleum distillate cleanup chemicals.
I have done quite a bit of experimentation with other paints and here is the space I ended up in. Water based "oil modified" paint like Benjamin Moore Advance or Sherwin Williams Emerald Urethane was key for me. These were clearly the best paints I used when you consider durability / cured hardness, self leveling and sandability. These are expensive paints, but I didn't find anything else comparable, be it the trendy furniture paints you see on youtube / etsy DIY type areas of the web or lesser tier home trim paints. They're definitely on the expensive side, but the best of what I tried. As a bonus they can be mixed in any color or color matched, unlike the trendy furniture paints.
As far as prep, I've tried bondo, bondo glazing and spot putty, boat epoxy, wood filler, wood glue + sawdust, and drywall mud. Overall they are all about the same except the drywall mud / spackle wasn't good. I don't see a lot of advantage for epoxy (including bondo) over single part filler like the bondo glazing and spot putty. The epoxies are so much worse to work with, needing to mix and limited working time and toxicity, etc... I find the boat epoxy pretty wasteful with needing to toss the brush every time, and it bubbles if you're not careful.
So I do gross sand --> fill --> gross sand again --> usually need a 2nd round of fill in spots --> gross sand again --> fine sand step by step to 320 or 400 --> prime --> fine sand (evluate coverage and edges and prime / sand again if needed) --> paint --> fine sand --> paint.
If you do not sand enough grit by grit, these paints are revealing enough to show sanding scratches. FYI, I got some cheap sanding discs off Amazon, and they were inconsistent in grit size. A 220 grit disc would leave occasional stray deep marks that I didn't see from a better quality 180 grit disc, for example. You really cannot cheap out on any step here... I tried. It shows in the end product if you do.
As far as brush / rolling, the method I found best (and I tried over a dozen different brush and mini-roller types,) was to brush with almost any brush. Get a decently thick layer on there. not so thick it runs, but thick. Way thicker than I would have thought when I started. Then use a (dry-ish) velour / mohair roller to just go over the top and even out the brush strokes. This will leave you with a very minor amount of stippling, but otherwise smooth. This was the best I could get with a brush or roller, and it was easy to repeat. I have since gotten a fine finish airless sprayer, and that is smoother for sure, but the brush + velour roller method got a passing grade from my wife when literally zero other paints, rollers or brushes made that cut.
Hope all of that is helpful.
As far as paint is concerned, Norglass Paints is another Australian made product that is excellent. You can get it from most paint stores or from Bunnings. I used it on my boat and the finish is excellent. I brushed it on, but it looks like a sprayed finish, very happy with the results. However, it is a solvent based paint, and you need to be careful of the temperature. Around 24deg is about optimum, over 30deg forget it, below 20deg and it takes forever to dry. You can brush it on or spray. Boat Coat also make a paint that has had very good reviews but I have not used it.
Don't use a water based anything on MDF. It will swell. Use epoxy, as mentioned, but it's expensive and a pain in the ***. I'd suggest shellac, Kilz is readily available. Use a couple of coats with a light, 280 or 320 grit, sanding in between. Shellac will seal pitch pockets in pine, so it will seal MDF, and can be topped with anything.
Hi Prairieboy, when I wrote water based, I meant acrylic. I used acrylic wood varnish on MDF with no wrong behavior of its surface. It's easy to sand and a good sealer, I found. Maybe other water based coatings won't do, but this acrylic varnish I use has no odor to all, dries quickly and is a perfect undercoat for any painting. Found in France.
Easier to join the two pieces before glueing one down. Just make certain the two edges to join are straight - clamp between two straight boards and hand plane, use a router, or jointer - then use tape to hold the seam tight. Once taped, glue down.
This video gives an example.
https://www.google.com/url?sa=t&sou...wqsBegQIIxAE&usg=AOvVaw3mcEyPUfMLzIt4esn1iVZ8
I have done it, but not over the oil modified paints I mentioned, no. Those paints cure harder than a poly, and I like the satin finish they give. They have very good durability without a top coat.
For a glossy finish I have done multiple coats poly (5-6) with sanding grits to 600 then wet with "micromesh" all the grits to 12000, then cutting polish, then car finish polish... Talk about work... but the end result is super smooth. So smooth & flat you can get a coaster to stick on top of a speaker if you put your drink on it. With all the sanding you have to be SUPER careful about sanding through to the paint on the corners / edges.
I prefer the satin finish without, though. The polys I've tried have a pretty plasticky feel to them. They look okay, but just don't feel right to me. They also don't cure hard like the paints I mentioned. They're better than basic latex house paints, though.
There are similar clear products to the BM Advance / Sherwin Williams Emerald Urethane, and would like to try something like that for a clear at some point, though I'm more interested in something like that for a nice satin finish on something I make out of solid wood. Right now my wife isn't into wood finishes and is into painted finishes... Gotta find the right project to try it. I googled around at one point and came across EMtech 6000/7000/8000. I'm sure there are other similar products... I haven't managed to try any of them yet. I'm sure these would have a much harder surface than the polys I've tried, and I'd be looking into clears like that over the polys I've tried if I wanted a clear.
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What kind of sealing would you recommend on CNC machined MDF horn - whose surface is around 90 % machined/inside fluff? I tried to make a prototype cheaply, but even OSB was better than this (with a bit of bondo/putty). I am not after a super smooth finish inside the horn, I am looking for something to harden and seal the surface before applying the primer. Ideally not epoxy. Will acrylic lacquer do?