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Evanism
24th November 2014, 12:17 AM
I have a genuine conundrum.

I've been painting a lot of kids furniture recently. It's been ok, but I'm not entirely happy with the results. It very good, but the work involved is too much (time, effort, farting around...)

What vexxes me is the effort needed to sand primer and get a dead flat result on the final colours.

I was looking at some kids blocks in a recent postal spam and saw these at amazon: http://www.amazon.com/Melissa-Doug-100-Piece-Wood-Blocks/dp/B000068CKY .... Im very curious how these commercial places get everything so smooth.

Obviously they don't sand post priming. Also, I can't work out how they spray all sides so evenly. Top, bottom, sides, etc and not a mark to show how they were oriented or stood.

Also obviously, they mechanise the hell out of things, but the principals must be replicable with a decent home setup.

Anyone with any ideas?

ubeaut
24th November 2014, 01:39 AM
May well be electrostatic spray or powder coated.

About 17 years ago our club and students made a heap of rocking horses to give to a charity for Christmas. They were all powder coated and looked absolutely magnificent.

Some 35 odd years ago I helped out with finishing 3,000 wooden bunk beds, around 500 were electrostatically painted with Wagner equipment which from memory was on loan for trial as it was pretty new at the time.

That's a couple of ideas. Dipping would also work but you would need a way to hold them.

Spraying with HVLP spray equipment should work well but will have to be done twice to get all around.

Just my thoughts.

Cheers - Neil :U

Evanism
24th November 2014, 02:29 AM
Electrostatics. Even a simple google shows this is out of my financial depth.

I might give oils a crack.

soundman
24th November 2014, 10:30 AM
If you want fast smooth trouble free finising, this has to go right back to timber selection and design.

Timber selection alone can make or break some of these mechnised paint systems.....same with manual systems.

I ran into a guy at an auction and got talking.....he built high end office and entertainment units out of MDF and was running a european automated paint line......the boards went in one end of this box raw and came out the other end fully finished and dry on all faces.

His system revolved arround two things.....all the painted pieces being flat and the MDF having absolutely consistent density, absorbency and machining properties.....there was no sanding in his operation.
the boards came straight off the stack onto his CNC machine table and straight into the paint machine.


That level of mechanisation is beyond us, but the material selection and project design is not.



Different timbers behave differetly, some machine very crisply and have very dense end grain.

European burch and euro beach for example both machine very cleanly compared to most stuff we see in this country.


preparing and painting ( or at least partly painting) individual components prior to assembly is absolutely critical to most production line work.

it may even be that some parts are fully or partly painted prior to machining of joints.

If I am doing something in plywood that requires even a half decent finish, I at least prime and sand the whole board before if even goes over the saw bench.

some of the less well behaved timbers could be consolidated with a penetrating primer like shalac and sanded pretty early in the process.......

let me tell you prefinished timber cuts and machines very cleanly and crisply...so much so that some edges can be rasor sharp.

Look at the finish products you are using....pretty much all the common hardware shop and paint store products are crude, slow and inefficient compared to what is used in production.

Fast drying, free sanding, high build primers are the go...all the commercial finish supplier have them in all their finish types.

Then there are the top coats.
Ya looking for a fairly fast drying product that builds well and flows out to a smooth finish.


Another thing is tinting the undercoat or sealer to match the top coats....coverage or opacity become less of an issue in the top coat.


In the sanding department......knocking the nibs of the flat sections with flat sanding methods may still be the go, but for dealing with shapes or corners, think about the use of flutter disks or shredded drums.



In top coats I have had good sucess with Reseene lustacril ( satin) and enamacril ( gloss).....water borne enamel substitutes.

They are from the ground up formulations and nothing like most of the enamel substitutes from the major paint companies.

They are low odour, fast drying, pigment and resin dense paints.
The spray or brush well, build and flow out well.
Because they run a completly different tinting system, they can produce some very vivid colours.

OH... both low toxicity in the finished film.

cheers

Arron
24th November 2014, 06:44 PM
I have a genuine conundrum.

I've been painting a lot of kids furniture recently. It's been ok, but I'm not entirely happy with the results. It very good, but the work involved is too much (time, effort, farting around...)

What vexxes me is the effort needed to sand primer and get a dead flat result on the final colours.

I've been struggling with the same things.

I cant help much with the question about how to spray all sides at once of a small object. All the things I've been recommended like painter's pyramids and beds of nails and hanging from strings haven't come to much. You still get a little mark - tiny perhaps but still annoying. Why wouldn't you ?

However, I cant help thinking that though there are better high-build topcoats and topcoating systems available then those that are commonly deployed by us near-amateurs, if its a lack of surface flatness that is the problem then the place to fix that is at the primer level.

I also understand that you are not saying you cant get things flat - rather that you cant get things flat without a lot of work which is just out of proportion to the amount of money people will stump up for kids furniture.

So I'm thinking maybe the primer you are using is one that requires too much work. So what is the fastest-sanding, easiest working thing that you could use as a primer. Probably Spakfiller. Sands like a dream - almost vanishes the moment you hit it with an ROS. And it doesn't shrink, and it doesn't cut away below the surface. Its not anyones idea of a robust finishing product but what does it matter if its below the surface coat. So you have an object to finish, just slather on the spakfiller using your hands, rough as you like as long as all the surface is covered, once dry (10 minutes) hit it with an ROS attached to a dusty and its done in seconds.

I have tried this, and it works well. Maybe not suitable for all cases but just my 2c worth.

Reminds me once of when I took some kitchen cabinets to a spray painter to get them sprayed with 2 pack poly - he just filled the edges with plaster of paris. Looked good then and still looks good now 20 years later.



I was looking at some kids blocks in a recent postal spam and saw these at amazon: http://www.amazon.com/Melissa-Doug-100-Piece-Wood-Blocks/dp/B000068CKY .... Im very curious how these commercial places get everything so smooth.

I wasn't going to mention this because I know the blocks are just a 'for instance', but when I look closely at them they look pretty rough to me. See photo snippet attached with unfilled endgrain. I just mention this because its typical of me too - to imagine everyone else is doing things better then me - then to finally come face-to-face with other people's work and realise its not so.

332215

cheers
Arron

crowie
24th November 2014, 07:57 PM
I'm not sure this will help but it's a bit of history...
Back in 1978-1979 I worked in a factory in Brookvale, Sydney & the factory next door used to make children's wooden toy blocks.
The had a huge tumbler, like an industrial clothes dryer where they added the rough cut blocks of all shapes along with a ceramic abrasive block.
This machine was in operation for a set period of time which resulted in the blocks coming out ready for play.
The next process was in a similar machine except the ceramic abrasive blocks were replaced with about 1/3 full of powder dye with the same tumbling action.
The last process was the blocks were all forced dried in a warming kiln.
I scored a couple of buckets of the blocks which were over time given to friends with children.
The company I was working for moved to Vineyard near Windsor in mid-1979 so I can't give you any more info.
Cheers, crowie

Arron
24th November 2014, 08:14 PM
I'm not sure this will help but it's a bit of history...
Back in 1978-1979 I worked in a factory in Brookvale, Sydney & the factory next door used to make children's wooden toy blocks.
The had a huge tumbler, like an industrial clothes dryer where they added the rough cut blocks of all shapes along with a ceramic abrasive block.
This machine was in operation for a set period of time which resulted in the blocks coming out ready for play.
The next process was in a similar machine except the ceramic abrasive blocks were replaced with about 1/3 full of powder dye with the same tumbling action.
The last process was the blocks were all forced dried in a warming kiln.
I scored a couple of buckets of the blocks which were over time given to friends with children.
The company I was working for moved to Vineyard near Windsor in mid-1979 so I can't give you any more info.
Cheers, crowie

I don't get it. If you tumbled blocks with an abrasive, wouldn't you just end up with round blocks ?

crowie
24th November 2014, 08:44 PM
I don't get it. If you tumbled blocks with an abrasive, wouldn't you just end up with round blocks ?

Somehow Arron, All that happened was a rolled edge on each shaped block.... Sorry, can't tell you any more, too long ago....

Robson Valley
25th November 2014, 09:23 AM
Timing is everything for each wood = stop the thing and inspect the smoothing process.
Chunks of old grapevine root get polished as supports for started "air-plants" (bromeliads?).
On-site style mortar/concrete mixer and a shovel of coarse gravel (2 grit?).

For most of my wood carvings which will have smooth, featureless painted parts,
I rub the hard, set, first coat with extremely coarse steel wool. That stuff has flat strands
not round = works like a million chisels to actually cut off any raised grain.
Your fingertips will tell you when you're done.

Fine steel wool just snags and sandpaper shreds the paint.

soundman
25th November 2014, 11:33 AM
Like I said ealrier...everything about product and the process matters.

If you have the right timber, the tumbling will work...if the timber is prone to one sort of damage or another or if all the timber in the tumbler is not of the same hardness and of similar size and weight the blocks will end up beat to hell.

Tumbling is a far from uncommon industrial process, its used for all sorts of things
cleaning and polishing gravel for decorative uses.
Polishing gem stones
Cleaning and de-stressing metal parts
Artificially ageing clothing
Peeling potatoes
plucking chickens
dehairing piglets

Its all a case of what is in the barrel with the product, the size and shape of the drum and how fast it rotates.

For a small shed operation with limited thru-put I doubt that it is viable

For a small operation I think ya better off looking at some more conventional processs

look at how the product is designed.

prefinish as many of the parts as far as possible before assembly.
I can not emphasise how much time effort and fiddle can be saved by prefinishing.....but many are completly focused on the building and assembly they cant bring themselves to prefinish becase it seems to slow the process of building....nothing could be further from the truth

use machining methods that provide the best possible finish off the tool.

Investigate more efficient finish products

Look at the various sanding machines...stationary belt and disk sanders are very good for finshing parts

Look at some of the less conventional abrasives....I know the traditionlists are into steel wool......but for a lot of stuff particularly painted product the commercial grades of scotchbrite (or similar) are great stuff....domesticly we see one grade green....commercially there are 5 grades from coarse to fine Black, Green, Maroon, grey and white.
It comes in bigger sheets than domestic scourers too.
I mostly use maroon with a little green and grey.

Flutter sheets, flap wheels and disks, shredded sand paper drums and sanding brushes can be just fabuous for finsihing shapes.

There is no one single solution and nearly always it will mean changing priorities about how you work.

cheers

soundman
25th November 2014, 11:58 AM
Another thaught if I may.

If you are spraying clear finishes.

the change from hardware shop polyeurathane to either nitrocelulose or acrillic laquer will be a quantum leap.

Hardware shop poly is only a fair spraying product for starters, nothing about it is as good as the laquers.

If you spray one side of something in pollyU its going to be a coulpe of hours before you can handle it without risk of marking it..even in warm weather, its going to be 24 hours before you can sand it reliably.
It will still be wet and tacky 5 or 10 minutes after its been sprayed and for some reason it is particularly attractive to moths and beetles

If you spray a light coat of nitro it will have started to go off before you have even hung the gun up, in 5 minutes it will be touch dry and in 15 minutes to half an hour you can handle it without any concern.

When you turn over to spray the other side, as long as your overspray is not pissing every where and your are spraying fairly wet, the overspray will melt into the existing finish

Half an hour later the whole thing can be handled.....if you must you will get away with a light sand at this point, but better leaving it 45 minutes to an hour.

It is well within reality to get 3 good coats of nitro on a job in a day.
That would take nearly a week in pollyU to the same standard.

A mate of mine trained as a piano restorer.....at the colledge in melbourne in winter on a fine sunny day (they come every third Tuesday, I believe).....they reconed to get at least 5 full coats on a piano in a day by warming the pieces in the sun.

cheers

Robson Valley
25th November 2014, 01:34 PM
soundman: there are numerous large colonies of Hutterites, a religous sect, in western Canada.
It is common for them to grow large crops of everyday foods for their members.
They build home-made tumblers for birds.
They build home-made tumblers which will do a perfect job of shelling peas!
It is a sight to behold to see sacks of fresh-picked pea pods go in the top
and the results separated in a continous operation.

Evanism
26th November 2014, 02:09 AM
Not sure how we progressed to Hutterite Pea Shelling machinery, but bringing it back a bit, I thought the idea of steel wool or scourers is a good one.

A lot of the work is mdf and getting the painted edges clean on round overs is very un-fun.

I'll give these a crack.

soundman
26th November 2014, 11:11 AM
Yeh great deal of what I have done is edge rounded and either on ply or MDF

To get a good clean durable edge you must consolidate that end grain.

The flat surface of MDF is already bound and consolidated with a wax like substance from the factory and prticularly on lesser brands of MDF the surface layers are way more dennse than the core.

Some sort of crisp penetrating sealer is required to harden up the fluffy edge grain of MDF.

My go to opaque primer is Wattyl Superetch, it is a thinners bassed self etching metal primer, but it works pretty damn fine on just about anything.

The big thing is you can put just about anything over it.
It comes in black and grey....it no longer comes in white ( wattyl industrial etch, white) since the solver / valspa buy out.

If I'm working in pollyU either clear or in paving paint ( as an opaque), I'll use estipol sanding sealer ( a turps bassed, clear polyU sanding sealer).

Shelac would work well...anything that will absorb into the edge grain..and the harder and crisper the better.

There are better high build, free sanding sealers around, but I use what I use because I keep it in quantity.

Forget PVA glue....tried it...a lot of people try to do things that worked realy well with hide glue with PVA...mostly they dont.
Modern PVA is a great glue...it makes a lousy filler and sealer.

Some will go for "build" rather than "consolidation"....but mostly I am looking for durability

Whatever you use, apply it with a brush to your edge grain...and rub it in...if its a big piece go round once, by the time you get all the way round it will be ready for a second drink.....on small pieces go once and go a second time about 5 minutes later.

Depending on your aim.

If you want as hard and durable an edge as you can, do not sand before your first edge prime.....it will drink more product

If you want an easy life and a faster job, sand your edge grain first, it will reduce you sanding effort after the first prime.

I will generally do my first edge prime before I do anything about the faces.
I will do my first edge sand before my first face sand.
I will then do my second edge prime with my face prime, be that brushed or sprayed.

If I'm being fussy I will do a second over all prime and sand before I start top coating.

Remember the prime coats are more important than the top coats.

If I am working in clear I may only lay up 1 or 2 top coats and do all the hard work with the sanding sealer which sands a hell of a lot more freely.

I have not done it but I know others...use a primer/ undercoat that chemically matches their top coat and have it tinted to match the top coat...they may do several undercoats....and they only shoot a single top coat.

In economic production it may be 1 edge prime, 1 overall prime and one top coat...IF the primers colour match the top coat.


cheers

Arron
26th November 2014, 12:03 PM
Soundman what is your reference to paving paint in your last post all about?

I'm suspecting some type of unconventional use here and would like to know more about it.

Cheers
Arron

soundman
26th November 2014, 01:27 PM
I've been using paving paint for years as a hard wearing timber finish.

I've been using berger jet dry, but any of the other paving paints will work well.

In general they are opaque pollyeurthanes.

Treat em more or less like you would clear pollyeurthanes.

As you may gather there are intended to be walked on thus are hard wearing.
Jet dry in particular is fast drying.

You will never get a supper high quality finish out of it but as a pretty fair, hard wearing utility finish that can be applied by any mug its great.

I find I cant get a good flat finish out of it off the gun, but rub it out with a bit of 1200W&D or a fine scotch brite and a coat of wax and it can look bretty damn fair.

Another one to consider is Killrust.....it is a single pack epoxy enamel....I've not played with it but I know someone who does.

Both harder wearing than normal household enamel and many of the automotive paints.


cheers

Arron
26th November 2014, 06:19 PM
Ok, i thought it was something like that.

I do use Killrust. A very good utility paint. Needs disposable brushes.

Cheers
Arron

Robson Valley
27th November 2014, 04:53 AM
Evanism: the pea shelling was just to illustrate the diversity of tumblers as soundman listed.

But back to the paint: The air temperature at the time of application might be a consideration.

I bought a set of extra steel wheels for my car at the wreckers. They spin them all so you get good ones.
I bought some sort of dark blue rust(?) paint so they would all look the same.
The can said to apply above 20C. Well, it wasn't more than 15C and winter was tuning up.
The law here reads that you must drive with genuine winter/snow tread pattern Oct 15 - Apr 15.
So two sets of tires is the go.

What I saw was the very slow evaporation of the solvent in the paint. So slow in fact
that I could watch the brush marks flow together! What I got was a smooth finish
which appeared to have been sprayed.

soundman
27th November 2014, 08:57 AM
Good flow out is a favorable atribute of a modern finish.

It takes some pretty clever stuff the get, fast dry, good hold up ( not running) and good flow out all together in the same paint.

There is a lot more than viscosity and drying time involved.

A finish that in intended for brush or roller application may not behave very well at all when sprayed

Some paints you will see the brush marks melt away right in front of your face.
The same paint when sprayed will look fantastic as it goes on....will look great a minute or two after application.....but can have a sneaky run 10 or 15 minutes after you walk away.....particulrly if it has been thinned and laid on a bit thick.


For most paints & finishes temperature and humidity are critical if a perfect finish is to be achieved.

cheers