I am modifying some extant chassis from old test equipment -- will probably be using 0.063. Which alloy will bend nicely -- and will lend itself to painting?
5052 is the alloy that is most often used for sheets. Paintable with the proper primer. Now even carried by Home Depot in a spray can.
my supplier always suggest me to use alum 6061 for bending, while 6063 for non-bending. but i've never found any good painting method on alum, paint just dont stick to alum well. anodise maybe the only choice
The secret to painting aluminum is to paint the aluminum itself, not the aluminum oxide (sapphire) coating that forms when aluminum is exposed to the air.
That requires either sanding or etching the aluminum immediatly before applying the special primer. The directions with the primer suggest using dish soap. I use a lye solution.
If the paint doesn't stick, the aluminum wasn't clean.
Recently I cleaned my circular saw blades. I tried lye, strong deterrents and solvents, including MEK. ( I have a fume hood.). Nothing really worked well until I tried spray on oven cleaner. Sprayed on wiped off and all the junk came right off. So next time I paint aluminum that will be on my list to try for cleaning it.
Now it used to be hard to find the special acid etching aluminum primer, so it was a surprise when Home Depot started selling it in a spray can. Even more surprising how well it worked.
Now as to alloys, 6061 is the most common alloy as it is okay go machine and is able to be welded with less fuss than most alloys. As a result it is the most common alloy. 6063 is the choice for extrusions and is not quite as strong as 6061. Very rarely available a sheet. 3003 is usually the cheapest and bends quite easily, however it has almost no strength. It is usually used for roof flashing. 5052 is the material sold in sheet form intended for things such as chassis.
Now all of the aluminums come in different tempers. Mostly an issue with 6061 as it is used for the most different uses. Never found 5052 stocked other than in the temper used for forming. Know the softer the temper the easier to bend and the weaker the finished product. So unless you have a tempering oven for after forming...
Now the largest aluminum order I ever did was just under 10,000 pounds. Normally it is a few hundred pounds at most. In small quantities depending on alloy the cost should be a bit more than $3 per pound. My local supplier charges $20 per cut to make pieces of sheet smaller than the stock 48" x 96". My usual is the 48" x 120" size. I get it in .062" thick with masking on one side to keep it pretty until finished forming.
As to bending, the small scale method is a folding style break. For large scale it is a press brake the pushes a ram into a die. The ram will have a radius to provide a nice corner without any tearing or fractures. A standard ram and die for .062 will bend a flange as tight as .625". I have some that are a bit more fragile and will do .5". These pieces are 8' long and the issue is when the ram is set too deep for the thickness of the material. Then when a small piece of say 4" is being bent all the ram pressure occurs in a small area of the die. Makes a nice bang when it splits the die. Now a cheap dies is a few hundred dollars delivered, if bought in modest quantity.
On occasion you may want a precision rounded edge to match another radius. This requires a precision ram and die. Last one I bought was $1,700.00 for a 2' piece!
Do let me know if you have any problems getting the metal in sizes you need.
That requires either sanding or etching the aluminum immediatly before applying the special primer. The directions with the primer suggest using dish soap. I use a lye solution.
If the paint doesn't stick, the aluminum wasn't clean.
Recently I cleaned my circular saw blades. I tried lye, strong deterrents and solvents, including MEK. ( I have a fume hood.). Nothing really worked well until I tried spray on oven cleaner. Sprayed on wiped off and all the junk came right off. So next time I paint aluminum that will be on my list to try for cleaning it.
Now it used to be hard to find the special acid etching aluminum primer, so it was a surprise when Home Depot started selling it in a spray can. Even more surprising how well it worked.
Now as to alloys, 6061 is the most common alloy as it is okay go machine and is able to be welded with less fuss than most alloys. As a result it is the most common alloy. 6063 is the choice for extrusions and is not quite as strong as 6061. Very rarely available a sheet. 3003 is usually the cheapest and bends quite easily, however it has almost no strength. It is usually used for roof flashing. 5052 is the material sold in sheet form intended for things such as chassis.
Now all of the aluminums come in different tempers. Mostly an issue with 6061 as it is used for the most different uses. Never found 5052 stocked other than in the temper used for forming. Know the softer the temper the easier to bend and the weaker the finished product. So unless you have a tempering oven for after forming...
Now the largest aluminum order I ever did was just under 10,000 pounds. Normally it is a few hundred pounds at most. In small quantities depending on alloy the cost should be a bit more than $3 per pound. My local supplier charges $20 per cut to make pieces of sheet smaller than the stock 48" x 96". My usual is the 48" x 120" size. I get it in .062" thick with masking on one side to keep it pretty until finished forming.
As to bending, the small scale method is a folding style break. For large scale it is a press brake the pushes a ram into a die. The ram will have a radius to provide a nice corner without any tearing or fractures. A standard ram and die for .062 will bend a flange as tight as .625". I have some that are a bit more fragile and will do .5". These pieces are 8' long and the issue is when the ram is set too deep for the thickness of the material. Then when a small piece of say 4" is being bent all the ram pressure occurs in a small area of the die. Makes a nice bang when it splits the die. Now a cheap dies is a few hundred dollars delivered, if bought in modest quantity.
On occasion you may want a precision rounded edge to match another radius. This requires a precision ram and die. Last one I bought was $1,700.00 for a 2' piece!
Do let me know if you have any problems getting the metal in sizes you need.
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Remember that scene from "The Blues Brothers" -- when Elwood applies spray cement to the accelerator pedal of "The Good Old Boys" RV: "It's glue, strong stuff..."
Oven cleaner is mostly sodium hydroxide and some version of an ethanolamine, isn't it?
Yes that is why I'll try it on the aluminum. No mixing, easy to apply and for reasons I don't understand worked much better on the saw blade than hot lye in water solution. The other issue is that small packages of lye are off the market as many purchasers were using it to make methamphetamines.
I recently built my F5TV3 and used the following method for painting which has worked very well.
1) Wash panel with dish washing detergent and hot water.
2)Sand surfaces with 320 grit emery paper.
3)Wash again with detergent and hot water.
4)Immerse entire panel in a mixture of 50/50 white vinegar and water for about 30 minutes. If the panel is very large then wet it continually with the mixture.
5)Wash again with detergent and hot water. Dry.
6)Coat the panel with self etching primer.
Rust-Oleum Automotive 12 oz. Self Etching Primer Spray Paint-249322 - The Home Depot
7)Sand lightly with 400 grit paper
8)Paint and let dry.
9)Let it sit in the hot sun for a few hours to cure.
Nash
1) Wash panel with dish washing detergent and hot water.
2)Sand surfaces with 320 grit emery paper.
3)Wash again with detergent and hot water.
4)Immerse entire panel in a mixture of 50/50 white vinegar and water for about 30 minutes. If the panel is very large then wet it continually with the mixture.
5)Wash again with detergent and hot water. Dry.
6)Coat the panel with self etching primer.
Rust-Oleum Automotive 12 oz. Self Etching Primer Spray Paint-249322 - The Home Depot
7)Sand lightly with 400 grit paper
8)Paint and let dry.
9)Let it sit in the hot sun for a few hours to cure.
Nash
@nashbab
nice tips, just saved these steps and would try someday. no wonder my paint never worked, after sanding and washing, i directly paint the aluminum 😀
nice tips, just saved these steps and would try someday. no wonder my paint never worked, after sanding and washing, i directly paint the aluminum 😀
I'm glad you read the label.I used to do chem cleaning in refineries.Sodium Hydroxide can and will leave your aluminum looking like the termites ate it.I have afriend that tried it on polished aluminum(his Harley) and was depressed for a long time.I like the vinagar & water idea better,and lots of sun before & after.
Try Alminium prep acid etch and Alodine before painting over the surface
I typically use the acid without the Alodine if clear coating since it sometimes leaves a slightly yellow tint
Regards
David
I typically use the acid without the Alodine if clear coating since it sometimes leaves a slightly yellow tint
Regards
David
Alodine is chromenickle.Please do not mix any chemicals without knowing the reactions.This is a pioson and I asume it is not available to the general public.The places I used to work at banned this many years ago,for good reasons I'm sure.
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