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JOGARA
19-09-2017, 07:38 PM
Hi all.

Looking for guides on anodizing aluminum. I have seen a few online but looking for recommendations on ones other people have followed.
I don't really have time to experiment too much with this so rather just find a good guide and go from there instead of messing around.

Thanks
Jack,

Zeeflyboy
19-09-2017, 08:15 PM
http://www.caswellplating.com.au/LCD.pdf

pretty much all you need to know... easiest method for the DIYer i believe

m_c
19-09-2017, 10:13 PM
Caswell guide is probably the best one that's easily available.

The other guide if you can track down a copy, was the guide by Ron Newman. He used to have a section of his website dedicated to it, and supplied the stuff on the other side of the pond, but he stopped selling anodising stuff, and stopped selling his guide as well, so he could concentrate on his telescope parts.
I do have a PDF file which is just a screen grab from his website page covering anodising, which has a few hints/tips. If you want a copy, PM me your email and I'll send a copy across.

Nick952
20-09-2017, 12:49 PM
m-c, is this the Ron Newman guide that refer to? www.uponone.com/howtos/1.pdf

Nick.

Edit:- This looks like the information off his website, rather than the guide.

m_c
20-09-2017, 05:22 PM
Nick, that is similar to what I've already got, albeit cleaned up a bit, and the equipment sales bits removed.

I don't think Ron ever sold the guide digitally, as any reference I did find, was to a paper manual.

JOGARA
25-09-2017, 10:59 PM
Thanks for all the info guys!



Don't know if I replied to the email or not, but thanks for the PDF!

Finally get to start reading it tonight.



As for power supply. I already had the DPS5015 though never go around to building the whole thing with PSU. So grabbed a 48V 10A 480W cheapo from eBay and that should arrive next week.
I have had pretty good luck with these supplies so far. Have about five 12-24v ones but no 32-48v ones.

JOGARA
27-09-2017, 03:24 PM
What are you guys using for heating the baths?
And what material should the containers be? PP should be alright?

Thanks

[edit]
https://imgur.com/a/1kwXy
This guy does not use heat for the dye, I am guessing the heat helps?

m_c
28-09-2017, 12:20 AM
I've never got as far as setting up an anodising line, as I'm struggling for space, and never did find out the legalities of disposing of the waste.

When I looked into it, I was going to just buy one of the Caswell kits so I knew everything would work, however I see they only offer the one kit now, and is quite a bit more expensive than what I remember.

Zeeflyboy
28-09-2017, 10:32 AM
You don't need to heat the acid bath really, in fact in general the colder it is the better the result.

I often see other stages using an aquarium heater or other similar submersible heating element. This would certainly get things warmed up quickly enough!

http://www.ebay.co.uk/itm/like/261380651100?chn=ps&dispItem=1&adgroupid=43117927563&rlsatarget=pla-326054053624&abcId=1128936&adtype=pla&merchantid=113515306&poi=&googleloc=1006810&device=c&campaignid=856331929&crdt=0

JOGARA
01-10-2017, 08:14 PM
You don't need to heat the acid bath really, in fact in general the colder it is the better the result.

I often see other stages using an aquarium heater or other similar submersible heating element. This would certainly get things warmed up quickly enough!

http://www.ebay.co.uk/itm/like/261380651100?chn=ps&dispItem=1&adgroupid=43117927563&rlsatarget=pla-326054053624&abcId=1128936&adtype=pla&merchantid=113515306&poi=&googleloc=1006810&device=c&campaignid=856331929&crdt=0


From what I read you don't want the acid hot at all. Both the etch and/or the anodizing tanks should be room temp as those processes get hot when reacting/putting amps though them.
The Desmut, Colour and Seal should be heated though...


Going off the Ron Newman guide that m_c sent be lists this;

Polish part using fine sand paper for shiny finish, or wire wool for matte (can also etch for a little longer for matte finish/hide imperfections)
Cleaner @ 140F 5 mins
Rinse (de-ionized water)
Etch in Lye for 10-30 seconds @ room temp
Rinse (de-ionized water)
Desmut @ room temp 1-3mins
Rinse (de-ionized water)
Anodize at room temp based off 720 rule
Rinse (de-ionized water)
Dye @ 140F for 15s-15m
Rinse (de-ionized water)
Seal @ 180F
Rinse (de-ionized water)
Hang to dry for 24 hours



Other guides I have seen do mostly the same procedure, though one suggested using "Sodium Bisulfate/Sodium Hydrogen Sulfate" instead of Sulfuric which I guess is safer?

As for heating the buckets, I like the one you linked, but I am limited on power in my current workshop. Wont be in my new one till end of November.
Pretty much can't draw more than 3000w in total.

Thinking of getting a couple 12v ones that I can then use one of these cheap controller boxes with. Safer too as those immersion ones don't always have earth on the metal case.
https://www.ebay.co.uk/itm/172822446960?var=471604592191 (This is 220v ones yes, they do 12v too)

JOGARA
02-10-2017, 04:03 PM
Just tried one of these in a 500ml glass jar and it worked pretty well.
22911

Took a good 10-15 mins to get up to temperature so would expect a lot longer with 5l tubs.
Runs at 12v and draws pretty much bang on 10A so 120watts.

Going to test wit 5L now!

https://s1.postimg.org/1kwvscfnsf/IMG_20171002_133301345.jpg

m_c
02-10-2017, 07:12 PM
The specific heat capacity of water is 4.184 joules/gram/deg, so to raise 5 litres of water from 20 to 80 degC, would take 1255200 joules (4.184 * 5000 * (80-20)), or 0.349 KWh. Now if you've only got 120W, that means it would take 2.91 hours (0.349 / 0.12) assuming you have zero heat loss.

However, unless you've got insulated containers, I'd doubt you'd ever get to 80degC.

JOGARA
02-10-2017, 11:23 PM
The specific heat capacity of water is 4.184 joules/gram/deg, so to raise 5 litres of water from 20 to 80 degC, would take 1255200 joules (4.184 * 5000 * (80-20)), or 0.349 KWh. Now if you've only got 120W, that means it would take 2.91 hours (0.349 / 0.12) assuming you have zero heat loss.

However, unless you've got insulated containers, I'd doubt you'd ever get to 80degC.


Pretty much spot on. Tried it for the hell of it and got the top third of the water to 50c/
The rest stayed at 16c (workshop room temp). That was nearly 1 hour.

I am thinking 1000w min really as I don't want to wait too long for it and once one puts the part into the bucket the temp will go down quite a bit. So need it to be fast enough to recover from that.

Wondering if something like this would work?
https://www.aliexpress.com/item/900W-1000W-1200W-Cartridge-Heater-Element-12x180mm-12x200mm-12x250mm-AC-110V-220V-380V/32809794841.html
Keeping in mind a 5L bucket is around 200-220mm tall?
Not sure if these are designed for water but should be okay as long as the top is kept above water line I believe.

m_c
02-10-2017, 11:46 PM
With something like that, I'd be making sure they were well earthed, and powered via a good RCD.

Have you had a look at any of the youtube videos for ideas?
I've got these saved in my watch later list
https://www.youtube.com/watch?v=BtYHcsq7s5A
https://www.youtube.com/watch?v=GccTVfMiIIo
https://www.youtube.com/watch?v=TGi-nqNnENE


It's been a while since I watched them, so can't remember exactly what they covered, but they must of contained something worthwhile that I never deleted them after watching them..

JOGARA
03-10-2017, 03:25 PM
Thinking about it.
Cleaner, Dye and Sealer don't care if they are in a metal container?
Why not just use stainless cooking pots and put them on those cheap hot plates?
http://www.ebay.co.uk/itm/Single-Electric-Cooking-Hob-1000w-Hot-Plate-Camping-Caravan-Motorhome-/152557607465?epid=1273043865&hash=item2385245a29:g:dGEAAOSw-K9ZIxN4

As variable knob too so could potentially not even need thermostat controller?

Obviously not put the acid/lye in these, they still need plastic containers.

Zeeflyboy
03-10-2017, 03:42 PM
that's probably the way i'd do it personally yeah

JOGARA
03-10-2017, 04:15 PM
that's probably the way i'd do it personally yeah

£11 for the hotplate, £8 for the 5L stainless pot. Total price is much better than Plastic tub plus heat element and controller...

JOGARA
03-10-2017, 05:27 PM
Okay so here is my shopping list for each step.

Washing between steps
1 PP tub http://www.ebay.co.uk/itm/Plastic-Buckets-Tubs-Containers-with-Tamper-Evident-Lids-0-5L-1L-3L-5L-10L-25L/381353422181?ssPageName=STRK%3AMEBIDX%3AIT&var=650547896358&_trksid=p2057872.m2749.l2649
Deionised water (got loads of but will be buying more)
1 spray bottle

Cleaner
Stainless steel pot 5L http://www.ikea.com/gb/en/products/cookware/pots-pans/snitsig-pot-with-lid-stainless-steel-art-80129725/
1000w Stove http://www.ebay.co.uk/itm/Streetwize-Camping-Portable-Single-Hob-Cooking-Stove-Hot-Plate-1000W/202025024429?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Cleaner poweder https://www.ebay.co.uk/itm/381987813243


Etch
1 PP tub http://www.ebay.co.uk/itm/Plastic-Buckets-Tubs-Containers-with-Tamper-Evident-Lids-0-5L-1L-3L-5L-10L-25L/381353422181?ssPageName=STRK%3AMEBIDX%3AIT&var=650547896358&_trksid=p2057872.m2749.l2649
Lye https://www.ebay.co.uk/itm/231690311428


Desmut
Stainless steel pot 5L http://www.ikea.com/gb/en/products/cookware/pots-pans/snitsig-pot-with-lid-stainless-steel-art-80129725/
Desmut https://www.ebay.co.uk/itm/352012108749
1000w Stove http://www.ebay.co.uk/itm/Streetwize-Camping-Portable-Single-Hob-Cooking-Stove-Hot-Plate-1000W/202025024429?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649


Anodize
1 PP tub http://www.ebay.co.uk/itm/Plastic-Buckets-Tubs-Containers-with-Tamper-Evident-Lids-0-5L-1L-3L-5L-10L-25L/381353422181?ssPageName=STRK%3AMEBIDX%3AIT&var=650547896358&_trksid=p2057872.m2749.l2649
1L sulfuric acid https://www.ebay.co.uk/itm/141920434018
Titanium wire for holding work piece https://www.ebay.co.uk/itm/221839543727?var=520722722260
Not sure if to go lead or aluminum cathodes?
Already got my DPS5015 with 480w 48v PSU and some 18awg silicone wire.
Not forgotten about air agitation, just testing my old air pump first.


Dye
Black Dye https://www.ebay.co.uk/itm/253186569978
Stainless steel pot 5L http://www.ikea.com/gb/en/products/cookware/pots-pans/snitsig-pot-with-lid-stainless-steel-art-80129725/
1000w Stove http://www.ebay.co.uk/itm/Streetwize-Camping-Portable-Single-Hob-Cooking-Stove-Hot-Plate-1000W/202025024429?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649


Seal
Stainless steel pot 5L http://www.ikea.com/gb/en/products/cookware/pots-pans/snitsig-pot-with-lid-stainless-steel-art-80129725/
1000w Stove http://www.ebay.co.uk/itm/Streetwize-Camping-Portable-Single-Hob-Cooking-Stove-Hot-Plate-1000W/202025024429?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Sealer https://www.ebay.co.uk/itm/382075702419


Looking good? Already bought some stuff like the stoves, PP buckets. Not got any of the materials like acid, dye etc yet.

Desertboy
03-10-2017, 06:32 PM
From what I read you don't want the acid hot at all. Both the etch and/or the anodizing tanks should be room temp as those processes get hot when reacting/putting amps though them.
The Desmut, Colour and Seal should be heated though...


Going off the Ron Newman guide that m_c sent be lists this;

Polish part using fine sand paper for shiny finish, or wire wool for matte (can also etch for a little longer for matte finish/hide imperfections)
Cleaner @ 140F 5 mins
Rinse (de-ionized water)
Etch in Lye for 10-30 seconds @ room temp
Rinse (de-ionized water)
Desmut @ room temp 1-3mins
Rinse (de-ionized water)
Anodize at room temp based off 720 rule
Rinse (de-ionized water)
Dye @ 140F for 15s-15m
Rinse (de-ionized water)
Seal @ 180F
Rinse (de-ionized water)
Hang to dry for 24 hours



Other guides I have seen do mostly the same procedure, though one suggested using "Sodium Bisulfate/Sodium Hydrogen Sulfate" instead of Sulfuric which I guess is safer?

As for heating the buckets, I like the one you linked, but I am limited on power in my current workshop. Wont be in my new one till end of November.
Pretty much can't draw more than 3000w in total.

Thinking of getting a couple 12v ones that I can then use one of these cheap controller boxes with. Safer too as those immersion ones don't always have earth on the metal case.
https://www.ebay.co.uk/itm/172822446960?var=471604592191 (This is 220v ones yes, they do 12v too)

If you have a mains thermostat just tape the probe to the outside of the bucket accuracy will be good enough.

I use these
http://www.ebay.co.uk/itm/220V-10A-Mini-Digital-STC-1000-All-purpose-Temperature-Controller-Sensor-TE54/142426824134?

daily very reliable never had one fail over 5 years.

JOGARA
03-10-2017, 11:11 PM
If you have a mains thermostat just tape the probe to the outside of the bucket accuracy will be good enough.

I use these
http://www.ebay.co.uk/itm/220V-10A-Mini-Digital-STC-1000-All-purpose-Temperature-Controller-Sensor-TE54/142426824134?

daily very reliable never had one fail over 5 years.

I presume that as long as the temps are in the ballpark around 120-140F then it is okay? Don't have to be so bang on?

[edit]
Multi buy, 3 for 2 https://www.ebay.co.uk/itm/292039778779?var=591027809178

Desertboy
04-10-2017, 06:09 AM
What are you using for a heater?

I would think something like this would be good http://www.thermosensedirect.com/acatalog/lm_silicone_rubber_mat_heater_240v.html?gclid=EAIa IQobChMIp-Ch0orW1gIVRTobCh30DgrrEAQYAiABEgLg2PD_BwE

I'm also thinking a bucket in a bucket, the outer container galvanised steel the inner one plastic. Water is the outer container with heater it the bucket and the inner plastic bucket sat on bricks inside the outer container. You control the temperature in the outer bucket the water acts like a heat sink and evens out the temperature spikes. You would have to leave a water pump circulating the warm water 50-60c you could use a hot water pump from a caravan cheap as chips.

Why Galvanised? Because it conducts heat better without the danger of melting, stainless steel is a crap conductor and expensive. I would worry the heater I linked to could melt the plastic if the conduction rate is too slow. If you used an arduino and PWM this would be a non issue and you could use plastic all round, think of it as a heated bed on a 3d printer.

No reason you couldn't use am immersion heater element if you did a bucket in a bucket setup.

JOGARA
04-10-2017, 08:16 AM
Thinking of using a £10 1000w hotplate http://www.ebay.co.uk/itm/202025024429
I actually already ordered these for some reason xD

So that plus a 5L stainless pot http://www.ikea.com/gb/en/products/cookware/pots-pans/snitsig-pot-with-lid-stainless-steel-art-80129725/

Desertboy
04-10-2017, 08:41 AM
Thinking of using a £10 1000w hotplate http://www.ebay.co.uk/itm/202025024429
I actually already ordered these for some reason xD

So that plus a 5L stainless pot http://www.ikea.com/gb/en/products/cookware/pots-pans/snitsig-pot-with-lid-stainless-steel-art-80129725/

That would work fine, stainless is fine I bought a stainless steel still from America may years ago that I have never used and never will probably lol but I love because it's work of art.

Stainless is a poor conductor but when you have 1kw hot plate that's not really at issue lol.

Clive S
04-10-2017, 11:27 AM
I'm also thinking a bucket in a bucket,Do you not think the inner bucket would float like a ship:whistle:

Desertboy
04-10-2017, 11:44 AM
I thought the solution was mostly acid, sulphuric has an SG of 1.85! It's 85% heavier!

But is floating even an issue? and I'm sure a clamp can by rigged up rather quickly if this was an issue.

JOGARA
04-10-2017, 12:00 PM
The acid baths are not heated so no need to bucket within a bucket to heat?

Zeeflyboy
05-10-2017, 10:57 PM
I thought the solution was mostly acid, sulphuric has an SG of 1.85! It's 85% heavier!

But is floating even an issue? and I'm sure a clamp can by rigged up rather quickly if this was an issue.

Not that it changes your point, but most definitely not "mostly" sulphuric acid... in fact it's pretty dilute using the LCD process. Somewhere around 1 part acid to 15 parts water by volume for 6 asf.

JOGARA
12-10-2017, 07:08 PM
Not sure what I am doing wrong...

But the dye is not sticking, and from the looks of it not absorbing into the part much if at all.

https://preview.ibb.co/kNHTrG/IMG_20171012_173226910.jpg

When I spray with water it just all falls off.
https://preview.ibb.co/dGWA5b/IMG_20171012_173334817.jpg


I know black can he hard to work with as the ink bits are quite large.
Not sure what to do...


Here is a part that is not been tumbled. It has been through the system before the dye bath.
As you can see, I hope, it does look like it is anodizing. This part was shiny on the flats before starting the process.

https://www.youtube.com/watch?v=HcqPXJLJRww

m_c
13-10-2017, 12:28 AM
Is the part actually being anodised?
Enough current flowing for the duration, with a good contact to the work piece?
Using a grade of aluminium that can be anodised?

JOGARA
13-10-2017, 12:44 AM
Is the part actually being anodised?
Enough current flowing for the duration, with a good contact to the work piece?
Using a grade of aluminium that can be anodised?

I believe so.
Using eco cast from aluminium warehouse

JOGARA
14-10-2017, 05:36 PM
https://youtu.be/6zoH5OUDsAo

Not sure what is wrong. It looks like it is anodising but just doesn't want to take the ink.


https://s1.postimg.org/1crcg33rof/IMG_20171014_161836894.jpg (http://postimg.org/image/2c7ft96iu3/)

https://s1.postimg.org/1cel1xac33/IMG_20171014_161845082.jpg (http://postimg.org/image/5ha6e17i5n/)

Zeeflyboy
14-10-2017, 06:47 PM
How long are you actually leaving it in the dye for? In the videos it seems you are just doing a very quick dip, I was of the understanding that itís more like 15mins.

Are you going straight from anodising to dying after a rinse with distilled water?

If it isnít accepting the dye, in my very limited knowledge I would say it can only be a few things - either the anodised layer isnít sufficient (poor connection/insuffficient power supply/not long enough in the run), or the pores are too small


The size of the pore will depend on:
Solution Concentration
Solution Temperature
Current Density
Higher solution concentrations and temperatures give higher pore sizes, which are good for dyes
Lower concentrations and temperatures give smaller pore sizes and thicker harder coatings. Higher current densities give thicker films and cooling is necessary to keep the temperature constant..

What solution strength have you got and at what current per square foot are you doing it?

chas-SX3
15-10-2017, 06:55 AM
I did a lot of home anodising a few years ago but now get my parts done at a local shop.

To get expected,repeatable & consistent results you need to follow a system using proven techniques. By far the easiest & cheapest is Caswell's LCD method & the 720 rule, you need to have a constant current power source where you control the amps going in. Don't buy anything/everything from Caswell, it can all be sourced cheaper if you look.

I used to get excellent results but you MUST stick to the method or diagnosis of any problems is very difficult. Caswell's anodizing forum is very helpful & can sort out any problems as long as you are following a proven method & not just 'experimenting'.

For dyeing you need to dip the parts for at least 10mins, I used to dip black for 15mins for repeatable results. If the dye isn't taking then either the part is not anodised or the anodised layer hasn't 'grown' the correct pore size.

Unless you follow a method & unless you can control the amps entering the bath then every attempt is going to be an experiment with variable results which often means failure.

Tip No'1. Use as big an acid bath as you can, helps massively with keeping the temp stable.

Tip No'2. Use titanium to connect the part. Using ally wires was always hit n miss, I ended up screwing in titanium bolts to the part & connecting with titanium wire . . . never had a failed connection.

JOGARA
15-10-2017, 10:34 AM
How long are you actually leaving it in the dye for? In the videos it seems you are just doing a very quick dip, I was of the understanding that it’s more like 15mins.

Are you going straight from anodising to dying after a rinse with distilled water?

If it isn’t accepting the dye, in my very limited knowledge I would say it can only be a few things - either the anodised layer isn’t sufficient (poor connection/insuffficient power supply/not long enough in the run), or the pores are too small

.

What solution strength have you got and at what current per square foot are you doing it?

I have left it in for 20-30 mins and even an hour. Same result as putting it in for 20 seconds.
Yep Anodizing > Rinse > Dye > Seal
Have not got to seal yet though...

I have directly connected my alligator clips to the part and it still didn't accept the dye. The power supply is 48V 5A so plenty and I have left it in for 2+ hours yesterday.

I believe my solution is around 20-25% acid to water.
My acid was only 85% though so I might add some more.

Calculated for my part 25V max, 2.7A for 72 mins.

chas-SX3
15-10-2017, 10:42 AM
I have left it in for 20-30 mins and even an hour. Same result as putting it in for 20 seconds.
Yep Anodizing > Rinse > Dye > Seal
Have not got to seal yet though...

I have directly connected my alligator clips to the part and it still didn't accept the dye. The power supply is 48V 5A so plenty and I have left it in for 2+ hours yesterday.

I believe my solution is around 20-25% acid to water.
My acid was only 85% though so I might add some more.

Calculated for my part 25V max, 2.7A for 72 mins.

Is your part electrically conductive across its surface after anodising?

chas-SX3
15-10-2017, 10:45 AM
When you say your power supply is 48v 5a . . . . Exactly what power supply is it?

You MUST use a power supply where YOU set the amps it's putting out.

Zeeflyboy
15-10-2017, 10:54 AM
Calculated for my part 25V max, 2.7A for 72 mins.


Sounds like he is using a constant current supply if he is able to set 2.7 amps... I assume you are using 6 asf and then using your cad program to determine surface area of the part multiplied by the number of parts being done at once to arrive at the result?

From my research I've seen suggested that for 6 ASF you are looking at something around 1:15 acid to water ratio (6.7%), so actually if anything yours sounds significantly too strong. Caswell only mention battery acid (usually around 32%) at 3:1 with their 4.5 ASF, so unless my maths fails me that would be an actual acid/water ratio of around 1:11 or roughly 9%, again making your mixture far too strong if using their 4.5asf method. Oddly enough that should result in a larger pore size however... perhaps you actually end up with pores too large to hold on to the dye? Conversely the excess acid concentration may mean that it is breaking down as fast as it builds up, leaving you with an insufficient anodised layer.

I would suggest you adjust your solution to the correct strength and see how it goes.

Also don't submerge crocodile clips into the bath, no metals other than the lead/alu cathodes and alu/titanium wires/rods should be in contact with the acid solution. Other than potentially contaminating the bath, the current will try to flow through the steel clips instead of the aluminium and your anodising will stop.

JOGARA
15-10-2017, 03:22 PM
I have a DPS5015 so yes can set max current and voltage.

I had use use STL to surface area calculator http://preview.codecanyon.net/item/3d-surface-area-calculator/full_screen_preview/10457510?_ga=2.215453655.1106369714.1508073459-170998762.1508073459
Then metric to imperial and used this 720 calculator http://www.ndhsubmersiblescience.com/ano/720rule.html

Worked out to the 25V max, 2.7A at 72 mins for my parts.

My clips are not in the bath, I read about the problems with contamination.

I think ill split my tank in 2. Then add 1L to one of them and see if that is okay.

Zeeflyboy
15-10-2017, 03:24 PM
What cad program are you designing in? I can't imagine you need to use an STL to surface area calculator, should be able to pull that info straight from the CAD program.

How big is your bath? Will splitting in two and diluting with 1L bring you to something under 10%?

JOGARA
15-10-2017, 03:35 PM
What cad program are you designing in? I can't imagine you need to use an STL to surface area calculator, should be able to pull that info straight from the CAD program.

How big is your bath? Will splitting in two and diluting with 1L bring you to something under 10%?


Fusion 360 but can't work out surface area for some reason.

I have 5L tubs. Only 3L of water plus added ingredients.
By weight I have 3000g of water and 400g of 85% acid. So that is 7.5% of 85% acid?

JOGARA
15-10-2017, 03:45 PM
Forgot camera was in JPEG >.<
Should be able to see well enough though. This is the part I had in for a tad over 72 mins (by accident).

https://s1.postimg.org/6bqlyac4kv/IMG_1350_1.jpg

Zeeflyboy
15-10-2017, 04:46 PM
Fusion 360 but can't work out surface area for some reason.

I have 5L tubs. Only 3L of water plus added ingredients.
By weight I have 3000g of water and 400g of 85% acid. So that is 7.5% of 85% acid?

Rarely see suggested ratio by weight, usually by volume.

However, simple enough to figure out an approximation I guess. 3kg of water is 3L, for the sake of simplicity we'll say your 400g of 85% acid is actually 340g (400 * 0.85) and ignore the extra 60g of water, which when considering the specific gravity of sulphuric acid is 1.85 should mean it was about 184ml.

So you have actually got 0.184L acid to 3L water, or roughly a 1:16 ratio which is not too far off what I've seen recommended for 6asf (slightly low perhaps), but more than a little on the low side if using 4.5asf (caswell recommend 1:3 battery acid/water, or around 1:11 acid/water if my maths holds up).

That jives more with what you would expect - too low a concentration will give a smaller pore size which is bad for dying. Were you calculating with 4.5asf or 6asf out of interest?

Zeeflyboy
15-10-2017, 04:51 PM
Oh and fusion will give you surface area very simply - just use the menu on the left, select the body in question and right click - properties. First property is area.

JOGARA
15-10-2017, 04:52 PM
Rarely see suggested ratio by weight, usually by volume.

However, simple enough to figure out an approximation I guess. 3kg of water is 3L, for the sake of simplicity we'll say your 400g of 85% acid is actually 340g (400 * 0.85) and ignore the extra 60g of water, which when considering the specific gravity of sulphuric acid is 1.85 should mean it was about 184ml.

So you have actually got 0.184L acid to 3L water, or roughly a 1:16 ratio which is not too far off what I've seen recommended for 6asf (slightly low perhaps), but more than a little on the low side if using 4.5asf (caswell recommend 1:3 battery acid/water, or around 1:11 acid/water if my maths holds up).

That jives more with what you would expect - too low a concentration will give a smaller pore size which is bad for dying. Were you calculating with 4.5asf or 6asf out of interest?

So I had too little?
Dam it I already diluted half my mix. I got loads of everything so can make a proper batch using fluid measuring.
I didn't account for the acid being heavier than the water. I thought it was near enough and it being 85% I could within range say that it is 100% and the extra weight would offset that xD

I guess this is why I am having problems then...

Zeeflyboy
15-10-2017, 05:00 PM
Yeah sulphuric acid is nearly twice as dense as water (1.85g/ml vs 1g/ml)... easy mistake to make.

From what you've said, you definitely seem to have far less than recommended for 4.5asf by cadwell's guide. You aren't that far off what I've seen recommended elsewhere for 6asf though.

It is certainly a potential explanation, one of the side effects of too low a concentration is small pore size which then can give issues taking a dye.

Did you see my second post about fusion btw? Few clicks to get area of a body... copy to clipboard and ask google to convert the area value to square feet, multiply by number of the parts you are doing at once and then desired amps per square foot.

JOGARA
15-10-2017, 05:16 PM
I think I need to start from the beginning. I have read through a few of the guilds and have gotten mixed up a bit with everything.

From what I have gathered, 6asf is only really for dark colours with large dye molecules, 4.5asf works for pretty much everything?
I should have for 4.5asf a 20-25% acid concentration?


What am I better off doing for my process? I am dyeing black and need it to be a tough enough for a product case that might be battered a bit.
Ill mix up a new batch, using scales but account for the higher weight and concentration.

JOGARA
15-10-2017, 05:38 PM
Hang on. I am using Phosphoric not Sulphuric.

Did I mess up?

Zeeflyboy
15-10-2017, 05:49 PM
Well you can anodise using phosphoric, but all these guides are based around the use of sulphuric acid. I don't really know much about phosphoric acid anodising but I certainly wouldn't assume the processes are the same regarding concentrations/time/current etc, nor in it's ability to take dyes afterwards.

And no, 20-25% is far too high (for sulphuric, no idea about phosphoric). The caswell guide says 3 gallons water to 1 gallon battery acid, but battery acid is typically only around 32% - when you run the maths that works out to around 1:11 or approximately 9% by volume.

I don't think there is any problem using 6 asf as long as the concentration is appropriate. I have never seen any suggestion that it will struggle to take dye. If you ran 6asf using the same concentration as for 4.5asf then you would potentially end up with a smaller pore size... if you use a lower concentration of 1:15 then you should end up with similar pore size to the 4.5asf at the higher concentration.

edit, out of interest:


Phosphoric acid anodizing is basically used for structural adhesive bonding in high-humidity environments. This process is known as the Boeing Process and is carried out at 10-15 V. The formed oxide film has a greater durability under adverse conditions than film formed in chromic acid and sulfuric acid. One of the reasons for the great adhesive property is said to be due to the morphology of the oxide film, which should be a film of pores with whiskers or protrusions on the top surface of the formed film.

Sounds like the morphology of the surface is different which makes it particularly suitable for adhesives... if the morphology is that significantly different then it could certainly prevent the acceptance of dyes.

JOGARA
15-10-2017, 07:02 PM
Off to go buy some battery acid then :p

Thanks

[edit]
Looks about right this stuff
http://www.ebay.co.uk/itm/161904105341

Used these guys last time for my other acid.

Zeeflyboy
15-10-2017, 09:12 PM
Yeah so with that, to do 4.5asf as per caswell guide you would mix 1L of that to 3L distilled water.

You can get 1L of 98% sulphuric acid on amazon for that price, but there is an argument to be made that buying battery acid is safer. Sulphuric Acid Pure (H2SO4) Min. 98% 1*Litre https://www.amazon.co.uk/dp/B013T3EON8/ref=cm_sw_r_cp_api_Nk74zbXPCQA3M

If you go the 98% route needless to say you need to be effing careful with it, especially when mixing with water.

JOGARA
15-10-2017, 09:17 PM
Yeah so with that, to do 4.5asf as per caswell guide you would mix 1L of that to 3L distilled water.

You can get 1L of 98% sulphuric acid on amazon for that price, but there is an argument to be made that buying battery acid is safer. Sulphuric Acid Pure (H2SO4) Min. 98% 1*Litre https://www.amazon.co.uk/dp/B013T3EON8/ref=cm_sw_r_cp_api_Nk74zbXPCQA3M

If you go the 98% route needless to say you need to be effing careful with it, especially when mixing with water.

Yea I only got chemical gloves and glasses. No HEV suit...

Happy to just get the 33%.

JOGARA
17-10-2017, 04:58 PM
Hmmmm Not looking great...

https://s1.postimg.org/7wz5o4ht1b/IMG_20171017_155340523.jpg

Ill leave it in the dye for 15 mins and come back.

JOGARA
17-10-2017, 05:25 PM
Ohhhhhhhhh


https://s1.postimg.org/5h54ikq3pr/IMG_20171017_161040216_HDR.jpg (https://postimg.org/image/5h54ikq3pn/)

https://s1.postimg.org/4alt9z0rov/IMG_20171017_161921893.jpg (https://postimg.org/image/8bxsod4v1n/)

Zeeflyboy
18-10-2017, 08:34 PM
Great - glad we managed to dig to the bottom of the problem!

good job :)