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andy_con
30-06-2016, 05:15 PM
when you go to shops etc... and they products have perfect finishes like this

https://www.clintonsretail.com/wedding/gifts/love-photo-frame-1

how is it achieved, powder coating?

magicniner
01-07-2016, 11:42 AM
For wood that has to look super-smooth you need a sealer coat to stop the thinner from subsequent coats deferentially soaking into the wood and creating "sink marks" which reveal the substrate texture.
Follow that with a self-levelling primer, then your finish coat. If the primer isn't 2-pack you may still get a slight matting/texture to the finish surface as thinner will leech out of the top coat into solvent evaporation drying primer giving a less than perfectly flat finish.

You also need a clean environment to spray in, ceiling and walls should be cleaned with clean wet cloth and the floor is best mopped and left wet to prevent any dust.
If you build a polythene sheet spray booth inside another structure a clean air flow with positive pressure is ideal, as is air-fed breathing apparatus.
For small items it's possible to build a spray booth like a blast cabinet with painter and the process air flow kept completely separate,

- Nick

andy_con
01-07-2016, 12:51 PM
so not powder coating then.

could you get this finish on mdf? once mdf has been machined it sides are very fibery


For wood that has to look super-smooth you need a sealer coat to stop the thinner from subsequent coats deferentially soaking into the wood and creating "sink marks" which reveal the substrate texture.
Follow that with a self-levelling primer, then your finish coat. If the primer isn't 2-pack you may still get a slight matting/texture to the finish surface as thinner will leech out of the top coat into solvent evaporation drying primer giving a less than perfectly flat finish.

You also need a clean environment to spray in, ceiling and walls should be cleaned with clean wet cloth and the floor is best mopped and left wet to prevent any dust.
If you build a polythene sheet spray booth inside another structure a clean air flow with positive pressure is ideal, as is air-fed breathing apparatus.
For small items it's possible to build a spray booth like a blast cabinet with painter and the process air flow kept completely separate,

- Nick

mekanik
01-07-2016, 01:59 PM
MDF isn't easy to get the sort of finish you require, as mentioned it first needs to be sealed, then rubbed down ect, very labour intensive. i have used a product called eposeal, it's a two part epoxy and very thin but when dry it can be rubbed down and should be sealed(used it to seal some Iroko windows that had water penetration)
Mike
http://www.ebay.co.uk/itm/Gurit-SP300-EPOSEAL-1-LITRE-PACK-UNIVERSAL-EPOXY-PRIMER-SYSTEM-F705-015-/301976589936?hash=item464f351670:g:hUEAAOSw~FNUaR5 p

andy_con
01-07-2016, 02:05 PM
many thanks

so whats a good wood to use then as im well aware mdf is poo. mdf just happens to be cheap and you can buy in large sheets


MDF isn't easy to get the sort of finish you require, as mentioned it first needs to be sealed, then rubbed down ect, very labour intensive. i have used a product called eposeal, it's a two part epoxy and very thin but when dry it can be rubbed down and should be sealed(used it to seal some Iroko windows that had water penetration)
Mike
http://www.ebay.co.uk/itm/Gurit-SP300-EPOSEAL-1-LITRE-PACK-UNIVERSAL-EPOXY-PRIMER-SYSTEM-F705-015-/301976589936?hash=item464f351670:g:hUEAAOSw~FNUaR5 p

mekanik
01-07-2016, 02:17 PM
Now that's the question?
I dont have a CNC so have to do my woodworking using router/spindle the advantage with CNC is you can take off very small cuts using high feed rates and i believe this vastly reduces breakout. If you don't want to make them out of acrylic i think i would try some quality beech ply, but that's only a guess.
Mike

Ger21
01-07-2016, 06:15 PM
the advantage with CNC is you can take off very small cuts using high feed rates and i believe this vastly reduces breakout.

Nope. Wood tears and chips just as easily on a CNC as it does with your hands. Sometimes even more.


so whats a good wood to use then as im well aware mdf is poo

The harder it is, the better the finish will probably be.

You can get a good finish on MDF, if you seal it with epoxy, and sand until glass smooth.

andy_con
01-07-2016, 07:16 PM
Link me to some suitable epoxy?

Ger21
01-07-2016, 07:36 PM
West System or similar.

magicniner
01-07-2016, 07:36 PM
Commercial finishing processes rarely involve much manual work, if you use a self levelling primer after sealing you will have to sand rough areas after sealing but you won't need them perfectly smooth, experimentation will determine how smooth you need to go to achieve what you need ;-)

I've achieved good finishes on wood sealed with an alcohol based automotive sealer, U-Pol's version of this is Barcoat, others are available. Snother option if you want to do more sanding is to use a Polyester based spray filler, U-Pol's version of this is Reface, it sands very easily and doesn't clog paper like hand mixed polyester fillers,

- Nick

cropwell
01-07-2016, 07:45 PM
You could try a shellac based sealer like Rustins Sanding Sealer. At least it dries quickly.

andy_con
01-07-2016, 08:06 PM
ok lots of suggestions thanks.

just to give a bit of context, I want to get a really good finish on this like this. its machines from mdf, due to the complex nature sanding is not welcome

http://i187.photobucket.com/albums/x202/magicmushrooms1/cnc/DSC_2165_zpsi1yvenbz.jpg

so with this stuff, put it first? then spray what ever colour over the top?

http://www.ebay.co.uk/itm/U-pol-Barcoat-Quick-Drying-Isolator-1Ltr-Upol-/301520081268?hash=item4633ff5174:g:3PAAAOSwBLlU1gc f


this suggests lots of sanding

http://www.ebay.co.uk/itm/Rustins-SANS500-Sanding-Sealer-500ml-/252437619330?hash=item3ac6746282:g:~iIAAOSw3YNXbkc a

magicniner
01-07-2016, 09:17 PM
The reasonably fine "engraved" features will tend to fill up with anything that might help cover rough surfaces.
The example you asked about has no fine surface detail, most likely for this reason.

You could cut the part leaving material for a fine finish path with a ball nose cutter on the detail and seal it with cyanoacrylate before the finishing cut,

- Nick

Lee Roberts
01-07-2016, 09:57 PM
If it was me I would spray the finish, dulux undercoat with dulux liquid gloss for the top coat. Thin them both down enough that they pass well through your spray system but also coat the job well, light sand in between coats and the job should turn out very nice.

With any paint job, the finish is a result of the prep, so on this, only you can decide what level of prep your willing to go to.

Edit/tip: Warm the paint up in the tin first as it makes it much easier to apply and with good spray gear you may not need any thinning.

.Me

andy_con
01-07-2016, 10:25 PM
the engraving was a bit of a one off, but point taken


The reasonably fine "engraved" features will tend to fill up with anything that might help cover rough surfaces.
The example you asked about has no fine surface detail, most likely for this reason.

You could cut the part leaving material for a fine finish path with a ball nose cutter on the detail and seal it with cyanoacrylate before the finishing cut,

- Nick

andy_con
01-07-2016, 10:39 PM
not sure dulux would cut it, especially watered down. ive got some mdf primer from wickes and its ok but not great


If it was me I would spray the finish, dulux undercoat with dulux liquid gloss for the top coat. Thin them both down enough that they pass well through your spray system but also coat the job well, light sand in between coats and the job should turn out very nice.

With any paint job, the finish is a result of the prep, so on this, only you can decide what level of prep your willing to go to.

Edit/tip: Warm the paint up in the tin first as it makes it much easier to apply and with good spray gear you may not need any thinning.

.Me

alboy
01-07-2016, 11:21 PM
The type of finish you are after is attainable but only with considerable time and money. Normal household paints or automotive rattle cans just do not cut it. Only one way I have found to get a decent finish on MDF.

Sand well with fine grit sanding wheel.
Apply MDF sealer,
Sand lightly again.
Use a 2 pack Hi-build primer.
Light sand with 600 grit paper.
2 or 3 coats of 2 pack finish colour,
2 or more coats of clear coat.

If you want to go this route you will need a good quality air fed spray gun, a spray booth and good PPE because the 2 pack is nasty stuff if you inhale it.

Commercial furniture spray paints are available that can do the job much easier but are expensive and you have to buy at least 100 litres at a time.

Good luck

andy_con
01-07-2016, 11:25 PM
Im not after perfect juaf after a good finish

Thanks for all thd advice

Lee Roberts
02-07-2016, 12:52 PM
not sure dulux would cut it, especially watered down. ive got some mdf primer from wickes and its ok but not great

I am, o it's oil based by the way, good luck.

.Me

Fred
02-07-2016, 02:53 PM
If you're planning to paint it and not have any wood grain visible, maybe don't use wood. Is there another material that suits your requirements better?

andy_con
03-07-2016, 09:50 AM
Like what?

Fred
03-07-2016, 10:08 AM
I was thinking of things like Delrin, acrylic, nylon. There are a few different engineering plastics that might fit the bill. I didn't really specify one as I don't know your other criteria like weight, cost, durability, etc.

m_c
03-07-2016, 11:45 AM
You'll probably find the item you linked to has been laser cut, which will avoid any MDF furring issues, then given a coat of some form of fast drying paint to minimise absorption. It will also likely of been baked very quickly, so the paint is most likely set within minutes of being applied, and if needed a second coat applied to give a better finish.

Boyan Silyavski
04-07-2016, 11:46 PM
MDF looks nice when sealed with Acrylic Primer , used in cars and then finished at least with 2 component Polyurethane Paint. Or car paint.

If perfect finish is desired, it should be treated exactly like painting an expensive car. Thick primer, Thin Primer, etc...

Having said that the typical industrial finish is Polyurethane.

andy_con
04-07-2016, 11:58 PM
name or link me up with some products ;)


MDF looks nice when sealed with Acrylic Primer , used in cars and then finished at least with 2 component Polyurethane Paint. Or car paint.

If perfect finish is desired, it should be treated exactly like painting an expensive car. Thick primer, Thin Primer, etc...

Having said that the typical industrial finish is Polyurethane.

Boyan Silyavski
05-07-2016, 12:24 AM
name or link me up with some products ;)

Don't you have a local professional paint shop or a place where they sell car parts to mechanics? These are the right places to find all cheap and compatible.

I did not get if you would be painting professionally or not, but i assume yes.


1. You need a proper Gun/s . Saving money here will make you sorry later. These are the guns i made a present to my wife's father. he is a carpenter and uses them exactly for the same purpose like you. This is just basic setup. Just to compare i am using a cheapo chinese gun for crap and 400euro 3m gun for important stuff.

You will need that sizes nozzles for the primers and the other for the actual painting

2 x Devilbiss SLG-620 Compliant Spray Gun Gravity Feed 1.3mm/1.8mm Paint/Primers (http://www.ebay.co.uk/itm/2-x-Devilbiss-SLG-620-Compliant-Spray-Gun-Gravity-Feed-1-3mm-1-8mm-Paint-Primers-/111592767872?hash=item19fb728180:g:sOUAAOSwBahU2eA S)



2. Any normal car primer will do / not if you use epoxy, you will need a better one (http://www.autopaintsbrighton.co.uk/primers-sealers--adhesives-8-c.asp).

Synthetic High Build Primer Grey Fast Drying 1L/5L (http://www.autopaintsbrighton.co.uk/synthetic-high-build-primer-grey-fast-drying-1l5l-881-p.asp)


3. Hempel (http://www.hempel.co.uk/en-GB/product-list) is a good quality polyurethane paint. Though as i said your local paint shop is your best bet, as there paint will be around 18GBP, and they will have the proper thinner and base. hempel for example is double the price.

In short, locally=cheaper, better

Boyan Silyavski
05-07-2016, 12:31 AM
PS. Without air drier =Mission Impossible. DIY one from water filter vase filled with reusable silica (http://www.ebay.co.uk/sch/i.html?_odkw=polyurethane+2+component&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.X1kg+silic a.TRS0&_nkw=1kg+silica&_sacat=0)

18856


PS2. Even if you are tempted to use cans, dont do it. You will never even get close to the desired result, whatever sb would advise you. There is no free lunch.

Ger21
05-07-2016, 12:47 AM
There are no short cuts to a really good finish. And it all starts with the material, and preparation.
MDF is probably not the right material for a high quality paint finish. High density fiberboard is a better choice, as it's less porous.

Any wood type product is going to need all of the pores sealed, followed by a heavy coat of primer, sanding, filling, more primer, and more sanding before it's ready for a top coat.

As I mentioned earlier, I seal my MDF with epoxy.
My method will eliminate most priming and sanding, but it's time intensive.
Cut your part about .1mm oversize, and leave an onion skin of about .25-.5mm thick. Do not remove it from your machine!!
Brush a heavy coat of epoxy over all surfaces, especially cut edges. Wait a few minutes, and do it again, so it soaks in thoroughly.
Wipe off any excess from the top surface, as you don't want to have to sand or machine it away.
Let cure.
Cut your part to the finished side.
The edges should be smooth, like a hard plastic, right off the machine. Prime and paint.

JAZZCNC
05-07-2016, 02:34 AM
Cut your part about .1mm oversize

Gerry you do realise this is UK.?. . . . We have moisture on top of moisture here.! 0.1mm in MDF will last about 30's before it's changed shape again. . .Lol

Also got to realise we are still 20yr behind USA and we don't have such places like Wall mart so materials you take for granted like HDFB are like rocking horse droppings around here and cost twice as much every where else in world if find supplier and then they will be to order only.!! . . . . And you'll have to order 100sht's. . .:hysterical:

Ger21
05-07-2016, 03:25 AM
Gerry you do realise this is UK

Not for much longer, according to the news here. :joker:

JAZZCNC
05-07-2016, 11:43 PM
Not for much longer, according to the news here. :joker:

Don't want to distract OP thread but got to answer this.!

Don't believe everything your told Gerry. The UK has whole is taking a Hit yes but we are also known by another name GREAT BRITAIN and this is for good reason.

The GREAT comes from the fact we don't lie down roll over or shy away from what needs to be done. No matter how hard or at what initial cost to our self's.
The EU is dying and the sooner it's realised by the rest the better and stronger the whole of Europe will become.

Our country, The UK, is one of the most tolerant and multi cultural country’s in the world but the simple fact is that we are FULL. The people have being crying this for long time and finally had enough of being ignored by the low life spineless politicians who supposedly run our Country and the whole EU bureaucracy so have spoken out.!! . . . . In your country this would be known as patriotism or being a patriot.

In UK/EU we are called racists.!! . . . . Yes unfortunately it released or gave voice to few true vial racists but we have or will stuff them back in the box as they pop up.

We are not racists, very far from it. Lots of our friends or mine at least are either from EU, Asia or some other far flung place. We embrace and tolerate cultures others won’t.
We are also not Anti Immigration. We just want sensible immigration but the Open border policy just isn’t working here. It’s strangling our country and changing it in ways which are not British. We are and should always be BRITISH First fore most while all the rest that makes us GREAT coming close second.

We are not even Anti EU in many ways. We signed up all those years ago to European union for Trade but it’s become monster that is something far more than that and not what we signed up for.
It’s out of balance and with power resting in the hands of too few (or the One strong lady and her muppets) who have no interests but there own rather than for the union has whole. But they are Politicians so shouldn’t expect any less.!!

We don’t want our country run from Brussels by people we didn’t elect or Faceless politicians we’ve never heard of. We have enough trouble getting our own spineless shower of shit politicians of all side to listen so what chance have we when Brussels is selectively deaf.!

At the moment Our current Prime minister hasn’t got the balls to stand up and make happen what the people voted to happen, despite the fact he was the one who started all this.! The result didn’t go his way so he’s not playing anymore which is typical of upper class spoilt child and in line with Yellow belly coward.!

BUT the WHOLE world and The REST of the EU please take note We are GREAT BRITAIN and sooner or later some one with the moral fibre and guts will step up to the plate and we will come back Stronger, leaner and meaner.
You can count on the fact we won’t run away, lie down or Give up. . . . . So Gerry have no fear and tell your friends and the news the UK will still be here long after the EU has broken up.!

Now back to making chips.!! . .:beer:

andy_con
05-07-2016, 11:53 PM
some very useful information has been posted many thanks.

many options and not sure which one to take yet lol