dichromate

[Gene M.]

Re: dichromate

Jerry,
Your carb looks very nice and not over done. I have the caswell dichromate and never have been able to get any acceptable results with it. What ever did color wiped off. I gave up on it. I saw your write ups on your carb. I just figured the stuff from caswell is not always the same quality and that why it's not working for me. I can't even get it to color on fresh plated parts let alone cleaned carb zinc castings.

My only recourse on dichromate castings has been to ultra sonic clean then and use the resulting finish. It is never as dark as most on the flight judging field but it is more correct. More greenish than bronze gold. Yours looks that greenish hue (you must have a green thumb) and appears very correct.

I have caswell plating kit (copy cad) it worked poorly then and now 4 years later I tried it and parts came out gray. The parts originally done also rusted on a trailer queen in short order. The commercial plated parts held up nice.

I have a big power supply but the caswell kit nor dichromate just does not seem to perform acceptable for me.

[Gene M.]

Re: dichromate

Jerry,
Your carb looks very nice and not over done. I have the caswell dichromate and never have been able to get any acceptable results with it. What ever did color wiped off. I gave up on it. I saw your write ups on your carb. I just figured the stuff from caswell is not always the same quality and that why it's not working for me. I can't even get it to color on fresh plated parts let alone cleaned carb zinc castings.

My only recourse on dichromate castings has been to ultra sonic clean then and use the resulting finish. It is never as dark as most on the flight judging field but it is more correct. More greenish than bronze gold. Yours looks that greenish hue (you must have a green thumb) and appears very correct.

I have caswell plating kit (copy cad) it worked poorly then and now 4 years later I tried it and parts came out gray. The parts originally done also rusted on a trailer queen in short order. The commercial plated parts held up nice.

I have a big power supply but the caswell kit nor dichromate just does not seem to perform acceptable for me.

[Donald T.]

Re: dichromate

Gene,

Not sure why you've had trouble plating. I've used the Caswell system to plate many parts with good results. The dichromate solution provided by Caswell works very well. If your parts are rusting in short order, then you are not getting sufficient plating thickness on the part. I would review your plating procedures. Make sure the parts are perfectly clean. Also check the power to make sure it is sufficient for plating. The brightner is required to avoid parts coming out gray. Even if the parts do come out gray, then buffing with 000 steel wool should bring out the shine.

[Donald T.]

Re: dichromate

Gene,

Not sure why you've had trouble plating. I've used the Caswell system to plate many parts with good results. The dichromate solution provided by Caswell works very well. If your parts are rusting in short order, then you are not getting sufficient plating thickness on the part. I would review your plating procedures. Make sure the parts are perfectly clean. Also check the power to make sure it is sufficient for plating. The brightner is required to avoid parts coming out gray. Even if the parts do come out gray, then buffing with 000 steel wool should bring out the shine.

[Gerard F.]

Re: dichromate

Gene,

If you take a look at this post from the archives:

https://www.ncrs.org/forum/archive22.cgi?review=180225

You'll see that it was a real trial and error for me in coloring the potmetal on my carb with the Caswell stuff. My final solution was to beadblast the body, do a quick dip (5 seconds or less) in Pickle #2 (2 to 1 dilution of muriatic acid) flush the acid off, and then a quick dip in the dichromate (less than 30 seconds). Still it came out spotty in places.

I finally figured that there was some aluminum in the pot metal which would not take the yellow chromate. So I got some of the Caswell Zincate and tried brushing it on the spotty areas and the whole body. Zincate is a primer for aluminum plating which replaces the surface aluminum oxide with zinc. Then I started all over with the beadblasting, pickling, and dipping. I think I went through the process about 4 times until I got it right. The short pickling will take the dichromate off almost instantly and livens up the zinc.

On the dichromate mix you need to be concerned about the concentration of the solution as well as the temperature (exactly 80 degrees). For light yellow, the Caswell solution should no more than 1 oz per gallon. Higher concentrations will make the part come out darker or bronze. Also the length of the dip will make it come out darker, you need to trial and error this (30 seconds or less if you want it light). I usually dip the part, hang it up and let the dichromate take a set, then spray off any excess, and then hit it with a hair dryer (not too hot). No matter how light you think the part is, it will darken over a day.

On the zinc plated parts, I gave up on the brightener. I just plate it slow and give it plenty of time if it is going to be chromated, and plan on post plating shining with a nylon wheel. A fast dip in the pickle also helps.

I use a Kikusui 8-5 (0-8V, 0-5A) analog power supply. Seems to work fine on small parts in an 3 gallon tank. Actually when I did that carb, I used a battery charger plugged into a light dimmer switch with a light bulb in series to control the amps. Pretty crude arrangement but it worked.

Regards ,

Jerry Fuccillo
#42179

[Gerard F.]

Re: dichromate

Gene,

If you take a look at this post from the archives:

https://www.ncrs.org/forum/archive22.cgi?review=180225

You'll see that it was a real trial and error for me in coloring the potmetal on my carb with the Caswell stuff. My final solution was to beadblast the body, do a quick dip (5 seconds or less) in Pickle #2 (2 to 1 dilution of muriatic acid) flush the acid off, and then a quick dip in the dichromate (less than 30 seconds). Still it came out spotty in places.

I finally figured that there was some aluminum in the pot metal which would not take the yellow chromate. So I got some of the Caswell Zincate and tried brushing it on the spotty areas and the whole body. Zincate is a primer for aluminum plating which replaces the surface aluminum oxide with zinc. Then I started all over with the beadblasting, pickling, and dipping. I think I went through the process about 4 times until I got it right. The short pickling will take the dichromate off almost instantly and livens up the zinc.

On the dichromate mix you need to be concerned about the concentration of the solution as well as the temperature (exactly 80 degrees). For light yellow, the Caswell solution should no more than 1 oz per gallon. Higher concentrations will make the part come out darker or bronze. Also the length of the dip will make it come out darker, you need to trial and error this (30 seconds or less if you want it light). I usually dip the part, hang it up and let the dichromate take a set, then spray off any excess, and then hit it with a hair dryer (not too hot). No matter how light you think the part is, it will darken over a day.

On the zinc plated parts, I gave up on the brightener. I just plate it slow and give it plenty of time if it is going to be chromated, and plan on post plating shining with a nylon wheel. A fast dip in the pickle also helps.

I use a Kikusui 8-5 (0-8V, 0-5A) analog power supply. Seems to work fine on small parts in an 3 gallon tank. Actually when I did that carb, I used a battery charger plugged into a light dimmer switch with a light bulb in series to control the amps. Pretty crude arrangement but it worked.

Regards ,

Jerry Fuccillo
#42179