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View Full Version : Dip or not to Dip



cybor462
07-10-2007, 06:46 PM
I am working on my Blade Gauges. I was hoping to keep them in their original aluminum finish. The one I prototyped had a very nice finish overall. I was hoping to have them all that way.
What I got back from the cnc shop were with a very poor finish. Tin Falcon saw them and agreed.
Now I need to blast them and paint or powder coat them. My powder coat booth (shed) has been demolished. I will put up another someday. So this leaves me with painting them.
Have any of you guys dip painted aluminum? I do not have a booth so spray bombing them is not a good way. The humidity is so high now spraying them is very difficult anyway.
I was wondering if I dipped them how they might come out. I do not want to buy a gallon of metal paint like rustoleum if it will not work.
Any suggestions?

japcas
07-10-2007, 06:56 PM
A picture of the part might help but I doubt you could dip anything and get it to look decent with out it having lumps or runs in it but I don't claim to know much in that area. Why not set up an anodizing station. Lot's of people do that at home now with a little know how and get good results affordably.

cybor462
07-10-2007, 07:02 PM
I looked into that but it is not as easy as you may think. Not only are you dealing with nasty stuff (acid) but it takes a bit of room.
I read some advertising from the places that sell the kits and many make it look easy.
If your interested I would check out Caswell Plating. They have much good info and they do not candy coat it.
I decided not to do it for many reasons. Acid was one. And room was another. Cost was another as the real deal systems are expensive.

japcas
07-10-2007, 07:16 PM
I believe Evan has done some anodizing at home. I'm not sure what process he uses. Might check the search feature and see if you can find the thread about it.

One other method I've heard about it RIT dye and diluted battery acid. But I don't know all the particulars but there seems to be a lot of people using that method at home. The aluminum needs to be a 2000 or 6000 series to work though. Check out the link below for a little more info on this method.

http://www.mini-lathe.com/Anodizing/anodizing_aluminum.htm

cybor462
07-10-2007, 07:54 PM
The key is battery acid. Most all methods use acid. Dont like it dont use it, dont drink it...oppps ;)
I decided not to go that route. Today with EPA out for everyone I rather not get into that stuff. Many guys are worried about machine coolant as far as how to get rid of it. Battery acid is a whole other ball game.
Evan is in the Great White North where you can dump anything and never be found out. Of course Evan drinks his.. Just kidding Evan..
But where I am there is such a push for controls on this stuff I just dont want any part of it.

japcas
07-10-2007, 08:24 PM
If you were willing to leave them natural then sounds like you are willing to live with the standard oxidation that comes with aluminum. Why not just blast them with glass beads and be done with it. That leaves a nice matte finish and doesn't cost much to do and only takes a second for small parts.

cybor462
07-10-2007, 10:39 PM
I have been blasting them but with Black Beauty. It leaves a nice matte grayish finish. I thought by leaving it that way it would quicken the oxidation. Am I wrong? If so maybe I found the answer.

japcas
07-10-2007, 10:43 PM
I have blasted a bunch of aluminum with glass beads just to "even" the finish and I can't tell much difference between blasted or as machined concerning oxidation. I like it because it hides tool marks with little effort. Compared to some of the other ideas you listed it may not look as good but for the amount of work involved I think it looks great.

Evan
07-11-2007, 07:39 AM
Many guys are worried about machine coolant as far as how to get rid of it. Battery acid is a whole other ball game.

The acid used in anodizing is indeed battery acid, a weak solution of sulphuric acid and water about the same strength as the acid in a completely flat car battery or even less. It shouldn't be used anywhere near machines as it will cause extensive rusting on any metal nearby. I do my anodizing outside to avoid problems. I haven't set up my system as yet this year and may not as I am currently working mainly in steel.

The only semi hazardous part of the process is the weak acid bath and, if used for the cleaning bath, a weak lye solution. These can indeed be poured on the ground especially if mixed together when done using them. There are no environmentally toxic materials involved. If the weak acid bath is neutralized with baking soda or the lye solution then the resulting liquid contains water, aluminum sulphate and sodium sulphate. Aluminum sulphate is used as a minor ingredient in fertilizer. Sodium sulphate is a laxative and is also used in animal feed and laundry detergent. The mixture is non toxic and environmentally safe.

In general sulphuric acid is no more dangerous to handle in low concentrations than many other chemicals routinely used around the home. The worst hazard it presents is splashing in the eyes but then you wouldn't want to splash bleach or gasoline in your eyes either.

Evan
07-11-2007, 07:45 AM
I thought by leaving it that way it would quicken the oxidation
Raw aluminum exposed to air develops a layer of aluminum oxide a few molecules thick in just a few seconds. After that very little else happens unless the surface is disturbed because the oxide layer protects it from further oxidation. This layer is entirely invisible and transparent and doesn't change the appearance of the metal.

I forgot to mention that if you are going to dip paint use an epoxy paint. Epoxy paint flows out better than most any other kind and won't leave run marks. It does of course have a limited pot life after mixing.

cybor462
07-11-2007, 08:34 AM
Raw aluminum exposed to air develops a layer of aluminum oxide a few molecules thick in just a few seconds. After that very little else happens unless the surface is disturbed because the oxide layer protects it from further oxidation. This layer is entirely invisible and transparent and doesn't change the appearance of the metal

Evan... what do you think about blasting the aluminum to the point of that grayish very rough texture? Will that show any oxidation? I kinda like that finish but was afraid it would turn much darker and look lousy after a bit.

Back to the dipping thing. Regular enamel or shall I say a good rustoleum maybe lightly thinned would leave drip and other marks? I thought that may work. Epoxy paint is very smelly (good way to get high) and somewhat expensive. Not sure if that would work in my situation. I do not have any brain cells to give up anymore.
And like you said once you mix it you have to use or lose it!

Evan
07-11-2007, 10:00 AM
Sand blasted aluminum looks nice until you handle it. Then it will become damaged and/or pick up any and everything and look like crap. It is a very fragile finish by itself. I use sandblasting and then anodizing black to produce a matte black finish and that works really well as the anodizing protects the finish. Anodizing is extremely hard, the same as sapphire which is really just aluminum oxide, also known as corundum and ruby.

What makes epoxy paint different is that it doesn't dry, it sets. That prevents it from skinning over and preserving marks before they can level. If you want to try another paint pick the slowest drying paint you can find. Epoxy paint can be kept overnight by putting the mixed batch in the freezer.

BigBoy1
07-11-2007, 10:09 AM
I have been experimenting with a paint that is baked after it is sprayed. I'm looking to use it on some aluminun gun parts I have made. I have tried it on both bead blasted and machined surface of aluminum and it seems to work slighly better on the bead blasted surfaces. It seems to be a rather hard finish but don't know how it will stand up to wear.

I got the paint from Brownell's in Montezuma, Iowa. They have several that you can chose from. I tried the "Aluma-Hyde II" becasue it came in different colors and I wanted a grey color. They have others types of paint that give a clear finish, which is maybe what you are looking for. There website is: www.brownells.com

Bill

Evan
07-11-2007, 10:32 AM
Actually, it sounds like a job for powder coating. I haven't tried that but it's on the list.

cybor462
07-11-2007, 12:02 PM
I have been experimenting with a paint that is baked after it is sprayed. I'm looking to use it on some aluminun gun parts I have made. I have tried it on both bead blasted and machined surface of aluminum and it seems to work slighly better on the bead blasted surfaces. It seems to be a rather hard finish but don't know how it will stand up to wear.

I got the paint from Brownell's in Montezuma, Iowa. They have several that you can chose from. I tried the "Aluma-Hyde II" becasue it came in different colors and I wanted a grey color. They have others types of paint that give a clear finish, which is maybe what you are looking for. There website is: www.brownells.com

Bill
Does it have to be sprayed or dipped?
I justed looked at their website, thanks for the link. It is very expensive at 30 bucks a can. It looks like the part needs to be pre heated and sprayed and then baked. Ok for a one and done item but too involved if you have a number of items to do.

cybor462
07-11-2007, 12:05 PM
Actually, it sounds like a job for powder coating. I haven't tried that but it's on the list.

Evan.. I have powder coated and it works rather well. My problem is I used to spray it in an old shed that I tore down before it fell down. I have no place to spray it right now or I would do it that way. As I need to get these finished I am forced to paint them.

I think I may try to dip and see how it works. I will get a Qt can so I will not waste much if it does not work.

Swarf&Sparks
07-11-2007, 12:51 PM
Pardon my ignorance, but what is a blade guage?

cybor462
07-11-2007, 02:38 PM
The BG was a topic brought up here quite a few times. It is a tool that allows you to check the tension of your saw blade for maximum blade life. The one I make shows the amount of stretch that is on the blade so you can properly tighten it.
The initial design was by another HSM member which I made a number of changes to, that suit my needs and make what I felt is a marketable item. I made 5 different versions the last one a collection of trial and error corrections. The original method of detection is still the same as the first but there have been many mods since that to correct and better the original design.

After completing the final prototype I sent them out to have a run made at a local cnc shop. I am now in the final stages of prep work to get them online for sale.

As soon as I have them finished (should be tomorrow) I will get a pic and post it for you.

For those that may ask if this is a stolen design, it is not as I kept in touch with the original maker (he borrowed it from another tool he saw) and offered to compensate him for each I sell as it was he that embedded the idea for me to try. The design now is much different although their are still some similarities to the original. The actual overall tool itself is no longer anywhere close to the original except for a few aesthetic features.

Swarf&Sparks
07-11-2007, 02:42 PM
Thanks Cybor, I remember the thread now
(CRAFT syndrome)

cybor462
07-12-2007, 10:53 AM
This is a finished part....
http://mywebpages.comcast.net/cybor462/bg2.jpg

This poses a new problem. I designed all specs. based on leaving these raw aluminum and now I have to paint them poses a new issue. Clearance....I had a fairly tight pivot leg to body at .001 This was done to keep cocking, due to slop in pin, pin bore, total of all added tolerances. With a fairly close tolerance it would assure the least amount of unwanted deflection in the pivot leg.

As we all know paint adds a layer which now puts my specs. in the dumper. At this point I will tape off the inside area where the leg swings and also the two surfaces on the leg to prevent painting those areas but I do not like what it will look like.
I know anodizing may be the only answer outside of machining the leg to take off a few thousands to add room. The other problem with that is paint will get soft in heat and would probably stick.
I do not have a lot of choices at this point or do I?

Swarf&Sparks
07-12-2007, 10:56 AM
The old hammer-tone enamel covers a multitude of sins.
Or crackle finish?
edit to say, sorry, that should have been wrinkle finish.

japcas
07-12-2007, 12:17 PM
Cybor, I think you are fretting over nothing. For a tool like that I don't believe your intended customers are really going to care if it is gold plated, chrome plated, painted or just left natural. It is designed to do a specific function and looking good really isn't one of them. You are obviously trying to make some money from the sales of these. Why not leave them natural or just blast them as we talked about earlier and sell the unit for a couple of dollars less. This way you may sell more units by making them more affordable.

This is just my opinion but I've seen a lot of neat little gadgets that are very handy once you get used to them but not necessarily needed to get the job done. Some of them would be nice to have but are priced to high when you think "well I've been getting by this long with out one" that if it was sold more affordably more people might be willing to try it. Why not try to sell the first batch with a natural finish and if things go well then make more. If they don't seem to be selling try putting some fancy finish on it and see what happens. I know this gets more into marketing strategy and I don't claim to know much about that. That's a nice looking part by the way and I'm not trying to tell you what to do, just offer up some other opinions to think about.

cybor462
07-12-2007, 02:53 PM
jacpas... I sure hope the majority of potential customers are like you. I feel in todays market the better it looks the easier it is to sell. I guess I have the used car mentality. The car can be the biggest pc. of junk but if it looks new it will sell. If it is the best mechanical car but looks like junk you could not give it away.

I asked the cnc guy what he felt about finish and he said nice looking is a plus. Many people feel if your fit and finish are poor than you probably have a poor product.

I did plan on selling these in the raw state but these I have now are just too messy looking, full of tool marks, pitting, and what appears to be file marks from breaking edges maybe.

My test of what is the right finish is would I buy that tool looking like that? My answer to these are hell no. Maybe for $5 but not for what I need to sell them for. The charge just for cnc each is $20 just for the machine work. Now add in cost to sell them, raw materials, hardware,ind., and the machine work I need to do to them after I get them back and I have to sell them for min. $90 bucks each to turn a profit.
Granted the only other tools like this sell for $200+ so a decent looking tool should easily sell for $90+ I was hoping to see it sell for $150 if marketed correctly.

The next batch I will try to get them to have a better finish so I can leave them as is.

Thanks for you suggestions and compliment. Do not stop giving your opinions. That is mostly why I like this board. A person can learn so much from others. To you it just may be your opinion, but to others it just might be their tip of the day.;) Thanks

jkeyser14
07-12-2007, 08:16 PM
If you talk to a professional anodizing place, they should be able to maintain a reasonable thickness for you, adding anything you spec from .0005-.003".

If you aren't too afraid of trying it yourself (it's really not very hard), check out my website:

http://engineeringhobbyist.com/projects/completed/anodizing/

I use a computer power supply, but a lot of people also use battery chargers.

cybor462
07-13-2007, 12:12 AM
I called Caswell as I have used their products before and have been pleased. I researched this some time ago and found many how to's on it. What I have heard all is the time that the power needs to be regulated properly. Caswell has a system for 500 bucks that includes everything you need with regulated/adjustable PS. Can't spend that right now so I guess I will find another way. I was told by others that the home brew method is hit or miss something I can't afford to deal with since I am doing these for profit.

I was wondering if there is some type of clear that I can dip them in after sandblasting to protect them from oxidation. I will see if the cnc shop can give me a better finish next time but this time I need to fix this small batch and paint is not the answer.

mochinist
07-13-2007, 12:41 AM
Anodizing them would be best in my opinion and around here those wouldnt cost very much if done in bulk, like say 30 or more. I would check around your area.

Evan
07-13-2007, 01:42 AM
Oxidation after sand blasting isn't an issue. As I said earlier raw aluminum oxidizes almost instantly and then stops. The biggest problem with a sand blast finish is that it is fragile. You can damage it with a fingernail. Aluminum is easy to push around when it is in the form of millions of tiny aluminum molehills. Any contact of the sandblasted surface with almost anything else will leave a mark.

Anodizing fixes that problem on nearly any type of aluminum mechanical finish. While home anodizing can be variable due to poor process control this isn't much of an issue until the dye stage. The parts can be clear anodized and it is just as effective at protecting the surface as colored anodizing. It is also a simpler process since no dye is involved. It's just as hard but invisible.

You don't need a regulated power supply. You do need to adjust the current and a resistor will do, variable is best. A resistor can be made from several brake light bulbs that can be switched in parallel to vary the current. It doesn't need to be exact.

This is my anodizing line from last year. I use a battery charger with filter capacitors. I was experimenting with hard anodizing so I also had a little 110AC stick welder and my AC/DC adapter for the high current density required.

http://vts.bc.ca/pics/ano1.jpg

This is the sort of result it produces:

http://vts.bc.ca/pics/anomt2.jpg

Joel
07-13-2007, 01:55 AM
Without a doubt, I would anodize these parts. With equal certainty, I would sub the job out - my local shop would charge very little to run a batch of parts such as these.

Oldguy
07-13-2007, 05:28 AM
How about running them through a vibrator/tumbler as a finishing step? I don't think that an anodized finish would hide the defects and it does increase your costs and adds another level of complexity to the process.

Evan
07-13-2007, 07:21 AM
Oldguy has a good idea. Anodizing won't hide a thing but is used in conjunction with whatever mechanical finishing you use on the part (sandblasting etc). Tumbling makes a pretty nice looking finish and isn't hard or expensive to do if you make your own machine. It's expecially good at hiding tooling marks and burr removal. The resulting finish isn't fragile like a sandblasted finish.

Lurkerjo
07-13-2007, 07:43 AM
On the subject of the hardness of anodising, has anyone seen it strip the black oxide layer off the surface of a HSS drill bit? - after just one hole through an anodised part. It takes a long time to do this drilling steel parts.

Jozef

Evan
07-13-2007, 08:03 AM
It will also strip the edge from the tool, including carbide. I use diamond tooling to machine through thicker hard anodizing.

cybor462
07-13-2007, 12:37 PM
Oxidation after sand blasting isn't an issue. As I said earlier raw aluminum oxidizes almost instantly and then stops. The biggest problem with a sand blast finish is that it is fragile. You can damage it with a fingernail. Aluminum is easy to push around when it is in the form of millions of tiny aluminum molehills. Any contact of the sandblasted surface with almost anything else will leave a mark.

Anodizing fixes that problem on nearly any type of aluminum mechanical finish. While home anodizing can be variable due to poor process control this isn't much of an issue until the dye stage. The parts can be clear anodized and it is just as effective at protecting the surface as colored anodizing. It is also a simpler process since no dye is involved. It's just as hard but invisible.

You don't need a regulated power supply. You do need to adjust the current and a resistor will do, variable is best. A resistor can be made from several brake light bulbs that can be switched in parallel to vary the current. It doesn't need to be exact.
Evan that is very nice looking. I understand your point. Your line is interesting but all in all there is just too much involved for me. I do not have the room. I would not dare do it outdoors as the neighbors would have the white suits out in no time. Do not need that type of advertising.
I checked locally last year for a project I was running and unless I was willing to wait to sneak it in on a large scheduled batch the cost was too high for a small run of under 100.

cybor462
07-14-2007, 12:37 AM
You don't need a regulated power supply. You do need to adjust the current and a resistor will do, variable is best. A resistor can be made from several brake light bulbs that can be switched in parallel to vary the current. It doesn't need to be exact.
Evan I meant regulate the output. I am again looking at doing it myself. Do you have a favorite (how to site)? I would like to try to build something myself. A best do site would be better. Not into too much trial and error as I am short on time.

cybor462
07-16-2007, 12:01 AM
Pulled out my old research on anodizing I amassed last year. Seems it is based on an all do-it-yourself brew. I will read it again and post a few questions for you finish buffs.

Looks like I am getting into the anodizing spirit!:eek: