Here are my first 2 attempts, using Zombie green, the powder version, convection toaster oven, weigh and measured my coating and acetone so I should be spot on there, but I think my technique is off, the 9MM seems to get a good coverage, but very dark almost brown color, the 45's were more green, but pretty rough finish. Here are a couple pics, am I shaking too long or too much liquid with the bullets ? both sets got 2 coats.
Thanks, Fred
the 9MM (and a 45 after smash test)
the 45's
Two main things.Originally Posted by ffries61
Here are my first 2 attempts, using Zombie green, the powder version, convection toaster oven, weigh and measured my coating and acetone so I should be spot on there, but I think my technique is off, the 9MM seems to get a good coverage, but very dark almost brown color, the 45's were more green, but pretty rough finish. Here are a couple pics, am I shaking too long or too much liquid with the bullets ? both sets got 2 coats.
Thanks, Fred
the 9MM (and a 45 after smash test)
the 45's
1. If you look at pictures, you will see a different colour with same batch.
Some more Tan than others.
The 45's are more Green because the are heavier size. The 9mm are smaller in weight and heat up faster, and are more Tan.
Variations in colour are directly due to inadequate heat distribution. The tanned coloured finishes, may also be contributed to over heating or over cooking time.
2. Roughness, is normally due to tumble coating for too long.
After adding your 6mls of mixture to 250 bullets, mix shake coat for about 10 seconds, (just barely to coat all), then dump on drying mesh, and dry well and dont disturb.
2 coats done this way should be like glass finish, smooth and shiny.
Awesome, thanks !!
For those who might be interested in my efforts at insulating (with a fire blanket) my little oven.
Prior to insulating it took about 20 mins. to reach 200C.
After insulating, 5 mins!!!!!
I did this twice, to make sure it was right. I suspect that draping a piece across the inside of the glass door may have had the biggest single effect. The outside of the oven still gets hot, of course, as the blankets are woven so still let some heat through.
The biggest problem with the blanket is that although it's woven the individual strands are themselves made up of lots of finer strands, so when cut it starts unravelling and being so fine it's difficult to sew! I ended up sewing it and then working silicone sealant into the cut ends. It works, but even though the silicone had cured overnight lots of fumes came out on the initial heating up.
Now I just have to find some small mesh for the trays and I'm all set to go.
You can go to bunnings and get a roll of gutter gaurd mess then make to size i did that thanks to trevs advice works great
Just got back from Bunnings, and after walking up and down every aisle (!) to see what they had I came away with the same stuff. I've now got enough mesh to last me a lifetime (or two)!!
Ok, I started, and not surprisingly I've got some issues? Mixture is 20 gms. powder in 100 mls. acetone, tumbled in small bucket for 10 secs.
.44 cal, after initial coat, dried for 1/2 hour in hot sun.
.44, baked for 10 mins @ 200C on lower shelf
.357, initial coat, left in hot sun.
.357, baked at same time on top shelf.
Minimal temp variation in oven. Thoughts, anyone? I'll do a second coat once they've cooled to see what happens.
Later in the day:
I sized the boolits and re-coated them, but this time put them all on one shelf in the middle of the oven (near the temp. sensor). In thinking about it, I figured that the top shelf had probably overcooked, so by putting them on the middle shelf I could see what effect it would have. Cooked for 10 mins. @200C.
Both calibres passed the wipe test, but the .357 showed very small flakes when I hit it with a hammer on an anvil. The .44 passed ok. I'm guessing that the .357's were overcooked , which is why the flaking occurred?
These aren't pretty to look at, but that doesn't bother me as long as they work. I suspect my coating technique needs a bit of work (!), but I am wondering what colour these should be, as I expected gunmetal to be grey or bluish-grey? Maybe I need to cook them a little longer than 10 mins?
Last edited by dikman; 01-12-2016 at 01:00 AM.
Yep. Overbaked. use the middle shelf.
Bake a larger lot. Small lots tend to fail.
250 38 bullets, 200 44 bullets.
Use 6mls of coating per 2kg of bullets.
You will get it after awhile..
Hooroo.
Regards, Trevor.
Australia
I only did a small first lot mainly as a test, to see what would happen. Lower shelf and middle shelf produced the same result, so I now know not to use the top shelf. I'm curious about the colour, though, I didn't expect green ones! What effect would a slightly longer bake (12 mins instead of 10) have?
These are loaded with the Gunmetal. Kind of a dark grey-blue. Three coats 390 F to 400F for 12 min. I do three coats just for insurance against leading. It has worked for me. Because I just coat for myself it's not a lot of trouble to add the third coat.
Last edited by Avenger442; 01-12-2016 at 11:12 AM.
While I work at it, it is by God's grace that it happens. So it is best I ask him what, how and when before I start..
Dikbloke. What colour coating did you get?
Hooroo.
Regards, Trevor.
Australia
It's labelled Gunmetal (and comes out blue when it's mixed with acetone). The coating before baking is blue, as per the first photos. I'm perplexed as to why it turned green. Makes me wonder what my Zombie Green will turn out like.......
Have a look at avenger's photo. that is gunmetal. you have way way way overbaked yours. watch your temp readout.
prewarm oven. watch temp.
when at 200 deg, insert tray. watch temp
at 6 minute mark, watch temp. is it at 200 deg?
The coated bullets only need 2 minutes at the actual temp for the coating to "fix".
If you have improved the heat retaining ability of your oven, you may only need to bake for 8 minutes.
Trial and error.
Hooroo.
Regards, Trevor.
Australia
Temp drops about 20 degrees as soon as I open the oven to put in the tray, of course, can't avoid it. Takes about 2-3 mins to get back up and then stays within 3 degrees or so of 200C.
It did occur to me that maybe the oven is now working too well, but not knowing enough about the processes involved it was only speculation on my part. I'll try a few more and vary the procedure a bit, I figure it has to be something I'm doing because the stuff works for others.
A bit later...
I just did another batch of .357, first coat only and baked for 7-8 mins. They came out a lovely emerald green! (Like the others). I think I need to wait for Joe's input, as not knowing anything about the actual powder material makes it difficult to know what's going on. Without suitable test results, as in what happens to the coating at various temperatures and time frames I'm in the dark.
Last edited by dikman; 01-12-2016 at 07:14 PM.
My question/s at this stage are,
1. how do you measure your oven internal temperatures?
The Gunmetal, will turn a dark Emerald green when over cooked.
I did send you coated and baked Gunmetal picture, to show you what it should look like after two coats.
2. Is your oven fan forced air circulation?
With final colour and baking, did you test with smash test?
I have had a commercial manufacturer, cooked the Dark Green coating for 3 months at 8 hour shifts, 5 day week, at 200C.
It went Black, but worked extremely well when loaded and shot.
There are many contributing factors involved with colour chages. Much cannot be resolved as some of the colours are heat affected, chemical reactions take place with some colours and Resin, also,resin over cooked will turn from pale yellow to Tan.
If you just consider the Gunmetal colour, which is Dark Blue Greenish, when resin is over cooked and is tan, the effect is that the yellow colour in resin and Blue of product will end up a Green colour. (Essentially Blue plus Yellow make Green)
I hope I have offered adequate explanation.
Thanks Joe, I'm using a PID to control the oven and it's set to 200C, so it's probably about as good as I'm going to get at controlling the temp. The sensor is mounted in the back panel, sticking through at the halfway point, so a tray in the middle should be at that temp (unlike at the top, which I've proved can overheat). The oven isn't a convection type, but the boolits on the centre tray are showing even colouring.
The green ones passed the wipe and smash test.
What you seem to be saying is that my oven, set at 200C, is overcooking them, even at 8 mins?
I just started re-reading this thread (!!) and funnily enough it starts off showing some that are blue when first coated and then go green when baked, which is what I'm getting. I'm not complaining about the coating itself, as I'm sure that what I've done will work, I just can't figure out why I can't get that nice gunmetal look.
I guess I'll have to try one of the other colours that I've got to see what happens, that should prove if it's the oven causing the problem.
Oh, and I don't recall seeing any pictures of the colours I should expect.
OK< May be I was thinking of someone elses that asked for the Gunmetal colour.
I will try to post it here, but nor sure if I can.
[QUOTE=dikman;3503748]Thanks Joe, I'm using a PID to control the oven and it's set to 200C, so it's probably about as good as I'm going to get at controlling the temp.
It is as good as you can get, and at point of sampling it may be exactly 200C.
But where sensor is located, will tell you temperature at point of sampling, but from what I have seen, your oven has hot spots, and colder spots and is obvious from uneven baked colours being produced.
If you mount a small motor outside with shaft going through wall with a fan, you would get much more even all around heating, and your PID would measure moving air temperatures instead of static air at a fixed point.
Air circulation will also hugely increase temperature transfer and rise inside oven.
That will allow very good and even bake.
The coatings are not that upset with heating, but final colours can be affected and is not what was desired.
dikman
Do you have one of those cheap cooking thermometers?About $10 US.
When I first started baking the coating I didn't have a PID control. I used one of the thermometers in the tray of bullets and watched it as they cooked. Had to adjust the temp several times during the bake. The PID allowed me to walk away from the oven as they baked. I have put the thermometer in the tray of bullets with the PID controlling the temp and found that the bullets in the tray were 15-20 F hotter than the set temp on the PID. Which is what Joe is saying about the location of the sensor reading vs the actual temp of the bullets. Adjusted PID and all's good.
A fan will definitely even out the color in your tray.
If you have covered the glass with insulation you probably will have to move it to see the thermometer but it is a good check on the actual temp of the bullets.
While I work at it, it is by God's grace that it happens. So it is best I ask him what, how and when before I start..
I've toyed with the idea of fitting a fan, but because of the temp involved (200+C) it would have to be a fan designed for high temps. No point fitting it outside because it would be blowing in cold air.
Anyhow, I did some more experimenting and the results are......interesting.
I had a batch waiting to bake the second coat, so I got the oven up to temp, put them in and removed the covering over the glass. I had a stopwatch and sat in front and watched! At 2 1/2 mins the blue started turning green, no hint of any other colours, straight to green I think you'll have to admit that it's unlikely, at 2 1/2 mins @200C, that they've been overcooked. Yes, I could see that the heating was a little uneven in the oven, but it didn't take long for all of them to go green. I left them in for a total of 10 mins, let them cool then tried the smash test. No problems, other than a couple of tiny flakes where the lead had a sharp edge (flat round nose).
In the meantime, I mixed up a batch of Bronze and coated the remaining .357s. The first coat came out a lovely deep golden colour, the second coat a darker goldish-bronze. Smash test same as for the green.
As far as I'm concerned I've proven, to my satisfaction, that there's nothing wrong with my oven setup, my basic procedures (which will doubtless need refining a little) or the product. Which raises the question, Joe - although my jar is labelled Gunmetal, is there any chance it's actually got Green in it by mistake? Nothing else makes any sense to me.
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