Finish cleaning, filling, painting, powder coating, etc.

[ldorta]

Friends, looking into my Y car, I found some rust on it, so I'll need to paint it as soon as possible. What do you use to prepare the surface (before the paint)?
Gerald, in a previous post I read (don't remember where) that you use kind a filler on the corners, is that right? Which filler is this?

Thanks
Leandro

[Gerald D]

Leandro, you have not got enough rust yet! Seriously . . . . . :)

There are two secrets for getting paint to grip to steel:
- there must be no grease or oil
- the surface must be slightly rough

A little bit of rust proves that there is no oil . . . . and it makes the surface rough. You do not want too much rust - the paint must get through to the steel at the bottom.

The filler is acrylic based (definitely not silicon). It cleans and shapes with water or a wet sponge/finger. You put this on after the first coat of paint.

Our paint process is:
1. Remove all loose rust
2. Remove all sharp edges & points. (paint does not stick to a sharp edge - its surface tension pulls it away)
3. Degrease - we use a water-soluble kerosene, rinsed with water
4. Apply primer paint - we use a slightly acid paint that roughens/etches the metal.
5. Do the acrylic filler work
6. Apply second coat of primer over the filled areas.
7. Finish paint - two coats

[Marc Shlaes]

Gerald,

I am not familiar with the term "acrylic filler". Is there a brand name that I might be able to find on the internet so that I might be able to find something equal to that here in the US.

Thanks.

[Gerald D]

I saw them at your Home Depot, but none of your brand names were familiar to me. All in tubes that fit into caulking guns - the word "acrylic" is prominent and the word "silicon" is absent, with other words containing "paint". Our popular brand is PaintersMate, similar to this:
http://www.countyconchem.co.uk/docs/products/sealants/onepart/dow&geo/pages/paintersmate.htm
but doesn't carry the Dow Corning logo any more.

[Marc Shlaes]

Oh, that is what we call "painter's caulk". I never used that on anything metal before. I typically use that for caulking seams prior to house painting. For metal work, I have always used polyester or epoxy fillers.

I never would have thought. :rolleyes:

[domino11]

Gerald,
Is the application of the filler just for looks, or is it for eliminating dust accumulation etc? Would Marc's polyester or epoxy type fillers be a better choice? Maybe add a little strength as well to the assemblies in question?

[Gerald D]

It is mainly for paintability which firstly is for corrosion protection and secondly for looks. . . . . .

Spray paint does not blow into the corners or around the tips of butt joints. But moisture loves those crevices and that's where the serious corrosion starts - you can't get in there to fix the corrosion either. The old way of stopping corrosion on dump and garbage trucks (as examples) was to weld along the full length of the joint; which caused massive distortion but longer life due to less corrosion. The popular way these days is to use space welds and filler in between. Polyester or epoxy is not necessary - we don't want any strength from the filler, other than to support a coat of paint that flows smoothly from one surface to the next.

You guys have access to Sika over there. It was mainly Sika that came and taught us to use fillers instead of full welds - and tried to sell us all their fancy fillers: http://www.sikaindustry.com/ind/ipd-transoem.htm But we discovered that the cheap acrylic stuff from the local hardware store does as good a job of filling.

[smreish]

...and Gerald knows dump trucks! Great point.

[Leko]

Hello all, I'm Leko, and you'll soon find out who I am, but I thought I'd jump in here...

I haven't seen anybody talking about powder coating their MM's but I'm sure the day will come (nudge, nudge SMR.)

I asked my powdercoater if there was any filler that could handle being coated, and he said that JB Weld holds up to the the oven temps fine and coats well, also this stuff called Lab Metal which works just like body filler comes in a high temp version that can be powder coated.

Even if you're just going to paint and want to make your machine look more polished (or if you're welding isn't as pretty as could be) you can always fill fillets or seams with Bondo and sand.

[smreish]

Leko,
Good to see you chimed in. I have called Powder Tech here in Orlando and they are putting together pricing at this time. They have an oven 10 x 10 x 20, so I can take the machine to them assembled if I wanted. Who knows, it's stiff enough to be forklifted - moving would not be a problem.
...and I really like the lab metal stuff. Mmmmm...good ideas. Thanks

[Gerald D]

The filler is optional - it adds nothing to performance.

If done neatly, it adds a lot to re-sale value :)

[WTI]

We have a powder coat system, but our oven is way too small for how large most of the MM parts are!

I guess we would have to weigh the cost of having it done by an outside shop vs. the few hundred dollars in buying a heat lamp:

http://www.caswellplating.com/powder/caswell_lamp.html

If I thought we would ever use the heat lamp again, I would get it in a heartbeat. But in 8 years of our shop running, this is the first time our parts were larger than our oven.

Another idea was to just melt the powder with a regular heat gun. It is not like we are going to enter the MM in a show, so if we overheat a few spots and the finish runs, who cares? All we want is the great protection powder coating provides.

[Gerald D]

Why not regular automotive spray paint as opposed to powder coat?

[smreish]

Oh, I love paint. Most likely this will be painted. I just thought I would check into pricing for giggles.

[domino11]

Gerald,
I remember that someone posted links to some Farm implement paint. This comes in Mechmate blue (sometimes called Ford Blue I think :) ) This is cheaper than automotive paint but still very durable and more easily obtained. This is what I will be using. This can be sprayed or brushed with equally good results.

[Marc Shlaes]

It was J.R.

I cut and pasted his post: (below)
================================================== ====
I think this might help others. I used paint from Carquest, it was $30 per gal. It takes forever to dry, to touch 3 hrs. Completely I don't know yet it's only been 3 days. I found a better paint, I wish I had found it a week ago.

Paint http://www.agrisupplyco.com/cgi-bin/...0000&l=1#Order (http://www.agrisupplyco.com/cgi-bin/cgiitmls?m=ThisP&p=20088.000000&l=1#Order)

Reducer http://www.agrisupplyco.com/cgi-bin/...0000&l=1#Order (http://www.agrisupplyco.com/cgi-bin/cgiitmls?m=ThisP&p=57796.000000&l=1#Order)

Hardner http://www.agrisupplyco.com/cgi-bin/...0000&l=1#Order (http://www.agrisupplyco.com/cgi-bin/cgiitmls?m=ThisP&p=34536.000000&l=1#Order)

[WTI]

Why not regular automotive spray paint as opposed to powder coat?


Powder coat is extremely thick and durable paint. Boat trailers that spend much of their time submerged in water are always coated with it around here to prevent rust. It melts into a plastic coating and completely covers the surface without runs or drips. Because it clings electrostaticly, it coats the inside of parts that might otherwise be un-sprayable. Usually no primer is required and there are no VOCs.

You can reuse what little "over spray" there is, so it is almost 100% usable.

And maybe the best part, it is rock hard dry as soon as it cools.

[Gerald D]

Yes, I know all the salestalk of powder coat (we have it here too), but why aren't any cars finished in powder coat? :)

(PS. I don't know of any powder coated boat trailers here - the decent ones are either hot-dipped galvanised or painted. We have a popular trailer range over here (http://www.ventertrailers.co.za/trailers.htm) that is notorious for rust - I think it is (badly) powder coated)

[tpworks]

Hey Guys in the US,
For filling in minor imperfections this works great on wood or metal.
Can be wet sanded and dries virtually in minutes in thin applications.
http://www.bondo.com/catalog_item.asp?itemNbr=736

Tom

P.S.
Another great but expensive product is POR-15 it loves rusty metal www.por-15.com

[smreish]

Oh my, look what Leko and I started! Bondo (or my favorite) Everclear polyester which is used in boat hull mold final finish is my favorite choice It's lighter weight (easier to sand) than bondo, and it's grey! Not that darn orange color...makes it easier to paint over without to much extra paint/primer. Now, it's time to go to the shop and start working on those rails!

[cbboatworks]

Hello Guys

I am a Boat builder and a painter,My choice of paint would be Imron 3.5 HG. I paint all of the boats that come through my shop with it. you can get a spay-able gallon for around $60.00 just remember that this is one of the most toxic paints known to man so if you use it use a good respirator. I will post a picture of the finish product that was sprayed with it. Gerald if the picture is taking up to much space please remove it. if anyone is interested in more info on this paint please PM me and i will help all that i can. Thanks

cbboatworks@aol.com

http://i36.photobucket.com/albums/e39/cbboatworks/P1010001-6.jpg

[Marc Shlaes]

Gene,

That looks beautiful! Does it come in MechMate / Ford Blue?

[tpworks]

Oh my, look what Leko and I started! Bondo (or my favorite) Everclear polyester which is used in boat hull mold final finish is my favorite choice It's lighter weight (easier to sand) than bondo, and it's grey! Not that darn orange color...makes it easier to paint over without to much extra paint/primer. Now, it's time to go to the shop and start working on those rails!

Go ahead, knock bondo, but you can't beat POR-15 it covers all the bases, even fillers that withstand 2000 degrees. I didn't think we were trying to float a boat. I thought heavier was better for this project? But maybe that's just me.

Tom

[Gerald D]

Okay, let's get back to basics. The MechMate is not meant to be used by dipping into lakes or the sea. :) It is a piece of workshop woodworking machinery like your table saw. The accurate rail (and gear) surfaces are not going to get any paint or powder so we are going to keep the machine indoors where it will stay dry. We do not have to discuss the most corrosion-resistant paint systems - the demands on the paint are very low.

Powder coating is not for the average DIY guy. I think the main reason I dislike powder coating for this project is because it only gives you one chance at welding. After it is powder coated you are locked out from welding again. I like to be able to weld a bracket a month later without worrying how to touch up the finish. A basic paint system gives me the most freedom to modify to taste.

For those that don't know it yet, the "Ford Blue" was chosen because our local hardware shop stocks it in aerosol cans. (rattle cans) On our machine, only the base table was painted by spray-gun. Everything else (gantry,y-car,z-slide,motor-plates,etc.) was done with caulk and rattle cans from the corner hardware shop. I can decide now to move a bracket and within an hour it will look brand new again.

[Marc Shlaes]

I do intend to paint, not powdercoat for the exact reason Gerald stated. I can assume that since I will have built it myself, I will probably want to modify something later on.

But my shop is in a coastal area - fresh water - not even salt water - and I have a VERY REAL problem with rust. That is why I posted my secret sauce T-8 from Boeshield in a post a few months ago. I will probably use the very best primer I can find for rusty environments. I didn't know about the POR-15 products. I appreciate that link and endorsement very much.

For paint, I will stick to Ford blue because "Gerald says so" and frankly that is quite enough for me! I might, however, buy marine paint if it comes in the right color. I certainly don't want to be sandblasting my machine in three years. If good paint keeps it making money, then the price is nothing in my book.

Just my two Cents / Rand / Rupee, etc.

[cbboatworks]

Go ahead, knock bondo, but you can't beat POR-15 it covers all the bases, even fillers that withstand 2000 degrees. I didn't think we were trying to float a boat. I thought heavier was better for this project? But maybe that's just me.

Tom

The paint that I reccommended is an industrial paint, used in theme parks and industrial machines. I use it on boats b/c it is such a hard and durable paint. It is not really intended for boats.

[cbboatworks]

Gene,

That looks beautiful! Does it come in MechMate / Ford Blue?


Hello Marc

You can get it mixed in any color.

[Gerald D]

Marc, I live near the sea, where the salty spray of the jumping sharks (http://images.google.com/images?sourceid=navclient&ie=UTF-8&rls=GGLD,GGLD:2005-07,GGLD:en&q=shark+breach&um=1&sa=N&tab=wi) blows over us. :) Also, I build equipment that gets dunked with corrosive sauces - ketchup being one of the worst. And the biggest lesson I have learnt for anti-corrosive painting is that the quality of the final paint has nearly nothing to do about the anti-corrosion. Steps 1-6 in post number 2 is what counts.

[Marc Shlaes]

Agreed. For me, it seems that the very hardest thing is the degreasing step for steel that still has mill scale. Removing all mill scale is just not practical. Therefore there are billions of places for the oil to hide. I am not looking for magic but a little help from the primer and paint doesn't seem to hurt.

[gmessler]

Hi Marc,

To help you out about the grease thing. When was trying to get tape to stick to the parts for marking purposes I found that a cheap quick fix was to spray brakleen on the metal and the tape stuck very well. The brakleen doesn't leave any residue and dries fast so I would imagine that primer/paint would stick well after cleaning. I also gave a quick shot of it to the inside of my x channel to clean off the gobs of threading oil/metal chips. It worked exceptionally well. It even cleaned out the tight inside corners at the ends.

[smreish]

In our shop...the environmental way for us is to use simple green in a pressure washer to degrease. Scale - vinegar does work well, but takes a while. Sean

[Gerald D]

There is an easy way to get rid of mill-scale . . . . . . buy steel that is clean. Shop around and be fussy with the suppliers. The dirty steel is kept for the guys who aren't fussy.

Another beauty of laser cut steel is that the stuff is absolutely clean - the laser doesn't like the mill scale either.

For degreasing we use an emulsified kerosene. In the can it looks and smells like kerosene, but it is totally water soluble. Turns white when water mixes with it. Apply it all over by brush, spray or dip and it dissolves the oil. Then rinse off with liberal quantities of water until the whiteness is gone. (Similar products sold here as engine cleaner or paint brush cleaner - ours is called Tekprol 131 (http://www.engen.co.za/home/server/products_and_services/safety_data/FileDownload.aspx?lineitemid=612)). The key is to rinse the dissolved grease away before the kerosene dries. After degreasing with this system, light red/brown rust is seen within 30 minutes!

[Belli]

Hi All,

If it is your intention to paint the steel, specify hot rolled steel versus cold rolled, cold rolled is done under a flood of oil to lubricate the rollers, this oil becomes inbedded in the surface making painting very difficult.

Regards,
Greg

[Alan_c]

Bear in mind though that the cold rolled is usually more accurate and consistent in size - this usually only applies to round, square and rectangular tubing, lipped purlins, lipped channels, zed sections and top hat sections (max wall thickness 3mm) - the channels and angles are almost always hot rolled.

[Gerald D]

Greg, do your suppliers offer you a choice between hot or cold rolled for:
- angle iron
- channel iron
- round pipe
- flat bar
- square/rectangular tubes
- laser cut plate?

[tpworks]

For cleaning rust, paint, oil and even powdercoat a method soda blasting is very effective without wearing on the base metal unlike sand which wears away the metal along with everything else.
http://www.ace-sandblasting.com/soda-blasting-article.html
http://www.mikesmediablasting.com/

[Gerald D]

I have to laugh when I read these statements:

". . . . . uses safe, edible baking soda instead of sand. . . . . Unlike sand, which must be swept up, and whose dust is dangerous, baking soda is harmless"

Sand dangerous? We live and play on it and clean sand (silica) can be eaten - it is inert and indigestable. The baking soda/old paint doesn't have to be swept up? Oh yes, sand is not good when you get it in the lungs, but who has said that it is safe to breathe baking soda....mixed with old paint?

I am going to have to close this topic soon - it is getting too exotic :)

[tpworks]

Gerald,
Now now, you know you can't believe everything you read, and that is not the point I was trying to make. Mainly avoiding eating up the metal along with the abscence of chemical pollutants.

[Gerald D]

Couldn't resist Tom :)

There are zillions of ways to clean and colour steel. Everyone has an opinion on it. There must be other forums that do this subject more justice. Don't want everyone slowed down in their builds by procrastinating on how they are going to paint it.

[cobra427mnsi]

A question for you guys that have painted already. Do you remove that grey/bluish scale that is on new steel before painting ? The only way that I can see to get down to clean bare metal is sand blasting and that will be a lot of messy dirty work. I would prefer not to do that but I will do anything I have to do to do a good job. I have a HVLP sprayer for painting an automotive urethane paint but preparing the surface properly is important. What did you guys do? Please describe the steps you took to prepare and paint the beast.

Thanks
Paul

[Greg J]

Paul,

I just started painting and here's what I do. Let's see if it's correct with the crowd. :)

1. Remove all weld slag and splatter with wire wheel (also use some new synthetic wheel, don't know what's it called) and scraping with chisel.

2. Remove all rust with wire wheel.

3. Remove all grease. I'm using "Acid-tone" (not spelled correctly).

4. Apply 2 thin coats of primer.

5. Apply 2 thin coats of MechMate blue.

I don't remove the "blue" coating to bare steel. I have a small sand blaster, and if my procedure is not proper, then I'll do it again the correct way. I should note, on the skate, I did sand blast to bare metal.

[gmessler]

Not sure where it is without looking, but there is a whole thread on metal prep.

[Greg J]

How right you are Greg,

And it's right below this thread.

http://www.mechmate.com/forums/showthread.php?t=484

[BernardR]

I'm a late comer to this thread, but having done a lot of home machine rebuilding over the years I have found that not all paints are created equal. One of the best paints I have found for painting machinery is Hammerite, it can be applied to rusty surfaces after loose rust is removed. It comes in two different finishes, the original was a hammered finish, ideal if the surface isn't perfect, and more recently in smooth. It is thicker than normal paints and can be either brushed or sprayed, it is fairly fast drying. It is highly popular in the UK and Europe, more difficult, but not impossible, to get in the US.
If you do use it be sure to buy plenty of thinners, it is not compatible with white spirit or lacquer thinner.
Rust-Oleum is a similar US product, but IMHO not as good as Hammerite.

[cbboatworks]

Copied from another thread

It is a great feeling to see some MM blue of my own.

http://i36.photobucket.com/albums/e39/cbboatworks/P1010012-5.jpg


http://i36.photobucket.com/albums/e39/cbboatworks/P1010008-4.jpg


http://i36.photobucket.com/albums/e39/cbboatworks/P1010006-7.jpg
http://i36.photobucket.com/albums/e39/cbboatworks/P1010004-11.jpg

[smreish]

mmmm. automotive paint. nice :)

[domino11]

Ouch,
My eyes, my eyes. :)

[cbboatworks]

mmmm. automotive paint. nice :)

Sean

The paint is Imron 3.5 HG Industrial. It is used on park rides, industrial machines etc. It is a single stage two part paint great stuff... It is the same as the automotive Imron 5000 but much cheaper. I have been using it for sometime now and love it. Thanks for posting

[domino11]

Gene,
Is that paint hard to find? I really like the finish. What kind of thinner does it require?

[cbboatworks]

Gene,
Is that paint hard to find? I really like the finish. What kind of thinner does it require?


The paint can be bought a most auto paint stores that sell Dupont products. it is a two part paint so you will need to buy the paint,activator and urethane reducer.also if it is cold when you paint you will need a accelerator.

Paint is Imron 3.5 HG
Activator part# VGM-6005
you need to ask the person at the paint store to give you the same brand of accelerator.

(NOTE This is very Toxic paint so Please use a NIOSH Respirator)

http://www.bennette.com/pdf/Imron3-5HG.pdf

[cbboatworks]

For the folks that will ask what gun do you use. I have a $550.00 Sata jet Digital 2000...But get this my $14.99 Harbor freight gun puts down a better finish. so if any of you have ?s on what gun to buy. Dig deep into your pockets at get out that $14.99. I use the harbor freight gun on everthing I paint.

47016-4VGA
Central Pneumatic Professional 20 OZ. GRAVITY FEED SPRAY GUN.
Online the gun is listed for $24.99 in the store it is $14.99

[smreish]

Gene,
Interestingly you mention the HF gun at 15 dollars. At my shop, where labor cost more per hour than the cost of 3 guns....I buy these by the case. It's easier to toss-the-gun after spraying some materials than actually cleaning it and paying the guy to sit on the clock and "clean up everything 3 times".
...just the penny pinching boss man talking :)

[Greg J]

Gene,

Nice paint job. But I'm going the South African rattle can method.

Well, wait a second, $15 for a spray gun, ... hmmmm ... the rattle can's I'm buying now are $5/ea ... let me price a gal of Imron 3.5 HG and activator and rethink this paint job. :)

[Gerald D]

Gene warned us about his paint - see post #24 in this thread :)

[Greg J]

I have a hypothetical question. Suppose my "friend" was painting and had a couple of runs in his paint job. Not bad for a beginner.

I'm assuming that one just wet sands with fine (440 or greater) sandpaper and re-paints. After its had plenty of time to dry. Is that all one does?

Amazing, my "friend" is using a high gloss MechMate blue. Aside from the couple of runs / errors, the first topcoat looks pretty good. ;)

[Doug_Ford]

Greg,

Tell your "friend" this he has completely ruined his whole machine and it isn't salvagable. However, if you will give me his address, I will haul it off immediately, free of charge.:D

[Greg J]

Doug,

Well ... uh .... OK, it's me. I wouldn't give up / sell / barter my "number 1" MM for all the gold in the world.

Painted everything today and went pretty good. Had a "paint run" on the control box front cover, of all places. I'll give it a couple of days to dry and touch up that spot.

[Gerald D]

I don't wait for runs to dry - that takes too long, because the paint is thick. I wipe them them off ASAP and let the thin paint dry quicker before the repair.

[Greg J]

Aaaah, that make sense. Thanks.

I only have that one run on the control box door. :mad: It'll be a couple of days before I need it.

[TheDave]

What, nobody is going with the $7000 holographic paint that changes colors when you look at it from different angles? :)

[TheDave]

I'm no professional, but I use my trusty DA sander to smooth sharp edges and remove rust at the same time. I only worry about degreasing if there is a noticable spot after I'm done sanding.

Greg, just my 2 cents, but I would just sand the control box door down and start over. I suck at painting, so matching the spot where I clean off drips is usually harder than repainting.

[Kobus_Joubert]

Moved from another thread:

Thanks, this will be the last drilling on the gantry. At the moment it is outside...to collect some rust before painting. On that note...is painting done with the rails in place or is it better to paint the loose parts by themselves and then assemble it.

[Gerald D]

I did loose parts first and then touched up paint after shimmimg and alignment.

[J.R. Hatcher]

I also did loose parts. It works better for me.

[Kobus_Joubert]

come on rust :D
On some of the lasercut parts it looks like the laser process BURN't the oil onto the metal...Hard shiny black surface. Suppose the best is to sand it down with a flapper disk.

[DMS]

I am not very much experienced with paints,
Should I us 'Red Oxide' primer paint, which is commonly used here or should I use other specilised primer ?
Also should I apply putty after primer or before primer??

Thanks

[javeria]

Hi Sharma,

get it all sand blasted and powder coated.

RGDS
irfan

[Doug_Ford]

I'm no expert on paint but I will tell you that I used red oxide primer and I applied the putty after the primer.

[DMS]

Thanks Doug,
Did you apply another coat of red oxide over putty ?

[Doug_Ford]

Sharma,

No. I probably should have but I was ready to cut so I just painted over the putty. I'm happy with it.

I've been out of town for the past few days and while I was away, I remembered that Gerald recommended against powder coating because he said that it makes it difficult to make changes later. I agree with him. I've made a couple of changes and additions later and it was simple to touch them up with a spray can.

[DMS]

Thanks Doug,
I am painting it myself with spray gun I have. Later after shifting and adjustments, retouching will be necessary, then with same remaining paint it will be uniform. So what Gerald suggested is well thought of.

[KenC]

If sand blasting is not a piratical implementation, buy rust covered steel; With a thorough wire brush, the mill scale will come off with the rust.

Apply diluted salt solution helps accelerate the rust formation as well. I never tried vinegar, but salt solution is so much cheaper.

This is a common practice in my trade.

Hope this helps.

[Claudiu]

If you do not have sandblaster by the hand...
We use acid for removing oxides from metal surfaces.
Ex. Use citrus acid diluted for copper.
Ex. Use HCL or Phosphorous acid for steel.

Of course you first remove mechanically all the big stuff.

[Jan de Ruyter]

Phosphoric acid (read the label on your favourite soft drink) leaves a coat of phosphate on the steel. Also removes the mill scale, but takes a while. It is better to remove all the big blotches of rust with a wire brush/flap disk. Phosphoric acid doesn't prevent rust from forming but it makes the paint stick better to the steel. Dip/wash steel in acid, wipe with a cloth to remove nibs, paint as soon as dry, otherwise rust will form very quickly. Blemishes can be filled with body putty (raid your wife's vanity cupboard, no just joking!) Lightly sand with 220 water paper between coats to get a good finish.

[Jan de Ruyter]

http://en.wikipedia.org/wiki/Phosphoric_acid

[chris saintdenis]

I am very impressed with how well this item removes heavy rust. I know most of you have seen these in action but this was my first time using one. Screw it on to an angle grinder and go.

On the Harbor Freight website it shows one mounted onto an angle grinder with no guard. It is typical to not use the guard for this type of brush? No guard, safety glasses, and gloves, is that safe enough? I left my guard "better safe than sorry" but it seems the tool would be more effective with out a guard.

[domino11]

Chris, It may be more effective at removing skin without the guard. :) I think they left it off for the pictures so you could see the product. I always use a guard with mine. I like the skin on my fingers.

[ifffff]

Safety glasses are most important with that tool. Skin grows back but eyes dont. I personally know two who had little piece of wire on eye. One hasnt luck and is on one eye blind.

[BartDeckers]

I would like to share how i will paint my MM.

I used to work as a painting inspector for Hempel Coatings. My job was to visit the shipyards, steel construction and container manufacturers and advise on the correct use of the Hempel paints.

In my opinion Geralds advise in post 2 is right on the spot.

A cheap but good quality and easy way to paint is to use an alkyd paint system and apply the paint with a brush and a paint roller. http://en.wikipedia.org/wiki/Alkyd

It will not give you the smooth finish of spray coated paint or the durability of a gritblasted and powder coated system but it will be more than sufficient to protect your MM from corrosion and it will look good.

Use a brush first to apply the paint in all the difficult to reach areas like corners and recesses, then use the roller to apply the paint on the flat surfaces. Use a round brush and a lacker roller.

Alkyds can have different names like "phtalic ..." and other exotic descriptions but if it says on the can to use white spirit to thin the paint or to clean the brushes than it very likely is an alkyd based paint.

I will use two coats of primer then apply the caulk and then apply one or two coats of topcoat. Each coat not more than about 50 microns in thickness. More paint is not allways better!

Alkyds actually are two component paints, the "curing agent" being oxygen from the air. They will crosslink and form a tough coating. Because alkyds are "oil" based alkyd primers will adhere well to a properly prepared surface.

Don't use alkyds over galvanised surfaces. The paint will turn into a form of "soap" at the contact surface with the metal and will peel off.

Happy building,

Bart

[KenC]

We have a paint guru in the house!

Alkyd paint, I think they are commonly known as glossy paint. A good option for those (me included) whom doesn't have spray paint facilities. I always has that impression of high paint losses when spraying skeleton structure, and require great length site preparation if one don't wish to see patches of paint all over the place. These are the excuses I can come up with for the moment to delay buying that air compressor in the hardware store 2 blocks away...

It does take lots of patient & skill to produce good hand brush job.

If I remember correctly, except epoxy & Zinc Chromate nothing goes well on galvernised surfaces.

[Claudiu]

Hey Ken,

I`ve used 2 liters of blue paint and 10% thinner for the whole table. I don`t know if it`s too much or not, I`m not a pro painter. I had also some paint noses hanging from the table due to the fact that light conditions were not so good.
But in the end everything looks fine.

Greetings
Claus

[BartDeckers]

Hi Ken,

I would not call myself a guru but i have looked at so many square meters of steel being painted that i got a good knowledge what it takes to get a good paint system.

Like you point out the advantage of using alkyd paint and applying it with a brush and a roller is that you don't need any special equipment or special skills. Spray painting takes some exercise en training, just like welding :)

Anybody (well you know what i mean) can get a feeling of how to use a brush and a roller.

[KenC]

Hi Claus, I am trying hard to refrain from adding more toys in my shop... :o

[Robert M]

Hi all,
To those who knows a thing or two about powder coating, I need some advice sound, experienced please !
Looking at getting some powder coating done for the beast, I know a lot about finishing, preparing & protecting wood, but NADA about steel, worst…. about powder coats.
I read & understand how & with what it’s done, but not enough info to please my doubts & curiosity!

What type of powder should I request for structural steel ; Epoxy, polyester or hybrid of those two ??? ( see this )
Also, for prep the steel, one tells me sand blast is the only way to go, another tell me phosphate cleaning is well enough for steel ( structure or not) indoor usage ( Ie ; our beast ) !
Phosphate cleaning is considerable less expensive, but is it good enough to prep surface ???
I’m concern about some resilient scaling not being removed by this method ( where a light sand blast will ) and only to later increase the chance to loosen the top coat by lack of adhesion !!

Any experienced advice would be well appreciated !
Thanks in advance, Amicalement Robert ;)

[Robert M]

Sorry, forgot this link : See this (http://oem.sherwin-williams.com/us/eng/services/color/color-selectors/powdura-powder-coatings/standard/)
:o

[domino11]

I believe the worst thing about powder coating is that it is hard to touch up when you get the inevitable garage rash, ding etc. With paint it is easy to touch up and or grind some off, make a mod and then touch up again. I would stick to paint. Cheaper too. :)

[midmod]

I'm new to this and wanted to know the correct order of events between attaching the rack to the rails and painting and shimming of the rails.
Are the racks painted too?
And do you guys paint the v-rails separate and tape off the area where the racks attach?

[Gerald D]

Racks are greased, they don't get painted. The rails are fully painted and the tape attaches to the paint. We first paint the rails, then do shimming/tightentening down then attach racks.

[Jan de Ruyter]

Hi Robert,

Sandblasting is one way to go. The problem I found was that it does not reach those hidden places and it is very operator dependent. If the parts are thin and you are using the wrong media, they tend to distort. Pick the media carefully, shot blast is little iron slugs that beat the living daylights out of the steel. We used the stuff to harden torsion bars for some heavy equipment. Sand (carborundum) is very abrasive and can be found in different grades. Soft blasting can be achieved by using nut shells and is typically used on aluminium or soft body panels.

Hydrochloric acid (swimming pool stuff) can be used to strip rust and scale. Simply immerse in the stuff in a diluted form. Always add acid to water and not the other way round. It does not do anything but to remove rust and steel. The item must be rinsed properly to neutralise the acid immediately as it will start to rust in 10 min.

The problem with this acid is that it is highly corrosive and will attack anything near it. So don't use or store it in your garage, everything will have a nice, antique, rusty look.

Sulphuric acid actually penetrates the cracks in the scale and forms little hydrogen bubbles which pops off the scale in the first phase. That is the black stuff you will find at the bottom of your vessel. It then attacks the steel to form a nice clean surface. The longer you leave it, the more it will eat into the steel, forming a nice rough surface for the paint.

Seeing that it is Christmas, you can make your own snow using this method. The by-product of the process is iron sulphate, a nice, flaky, blue, white powder. Just create a saturated solution and put it in the fridge.

Phosphoric acid removes the scale as well, but additionally, it leaves a phosphate layer on top of the steel, which makes the paint stick better, but in itself it gives no protection to the steel. Phosphoric acid is also less aggressive than hydrochloric and sulphuric acid.

My recommendation is to use mechanical means to remove the worst of the scale. A rough steel brush or a flap disk in a grinder provides good results. After that I would use phosphoric acid to prep the steel before painting. Use an etch primer, touch the flaws up with body putty and give a coat of epoxy paint. Hammerite is also a good paint but it is very expensive.

The ultimate test for your paint project is to throw it down a mine shaft.

[Robert M]

Jan….This is GOOD…I like reading this type of info…. I’m drooling….:D
Thanks a lot for your answer.
Amicalement, Robert ;)

[Immy000]

We are currently powdercoating some parts for a company who is experiencing problems with pinholes in the welds and with lines and marks on the steel of the product. Our process is to sandblast the parts to remove the metal scale before powdercoating, but this is not removing these marks . This customer is very concerned about the smoothness of the finish and is wondering if there is anyway that we can fill these pinholes and smooth out the metal. We have not successfully found any type of metal filler that will withstand the temperatures needed to cure powdercoat and be unnoticeable after curing.

Does anyone know of such a product...

... or have any other suggestions? We have already suggested that they check with the welder to see if any of these problems can be eliminated before the parts ship to us, but they are still asking us to check in to using a filler of some sort.

[Robert M]

Have a look at this (http://www.uschem.com/index.cfm?page=productDetail&id=54&pid=1). It has done miricle for me, many times.
Robert

[wintersgillg]

But I found this:

http://www.thermobond3.com/index.cfm/HOME_PAGE

Regards

[melissa]

I'm wondering what other builders have done for painting the rails. I understand that the V profile is left unpainted.

What's the best approach to do that -- apply a strip of masking tape and use a knife to cut off the excess that's wider than the V?

[Alan_c]

Michel - Yep thats about as simple as it gets, maybe use a small fine file to trim the masking tape - works better than a knife blade.