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Dry film woes, maybe the developer is at fault

Dry film woes, maybe the developer is at fault

2008-10-11 by David Hopkins

I wonder if the resist is anything like the Riston blue -Ve acting 
dry film. This film is the main one used by the manufactures here.
It sounds a lot like it.

I have used this resist for many years.

The exposure for this film requires a strong UV light source. A 
standard light would do little in the way of exposing it.

I use a 300W mercury vapor street light at about 300mm. This gives an 
exposure of two minutes. The mercury vapor light produces a fair bit 
of UV light.

With this light source I never have a failure.

I notice you use Calcium carbonate to develop. The Riston uses Sodium 
Carbonate. I wonder If this would work on your resist. Sodium 
Carbonate is also known as washing soda and is very cheap. I think I 
paid about $25 for 25 Kilos. The mixture ratio is about 8 teaspoons 
to 4 liters of water (not the least bit critical). 25KG will last 
longer than I will.

Could be worth a try.

David

David G. Hopkins (Vk4ZF)
CAPALABA QLD.
AUSTRALIA
S27 32.191 E153 11.867

Re: [Homebrew_PCBs] Dry film woes, maybe the developer is at fault

2008-10-11 by leon Heller

----- Original Message -----
Show quoted textHide quoted text
From: "David Hopkins" <davhop@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, October 11, 2008 3:49 AM
Subject: [Homebrew_PCBs] Dry film woes, maybe the developer is at fault


>I wonder if the resist is anything like the Riston blue -Ve acting
> dry film. This film is the main one used by the manufactures here.
> It sounds a lot like it.
>
> I have used this resist for many years.
>
> The exposure for this film requires a strong UV light source. A
> standard light would do little in the way of exposing it.
>
> I use a 300W mercury vapor street light at about 300mm. This gives an
> exposure of two minutes. The mercury vapor light produces a fair bit
> of UV light.
>
> With this light source I never have a failure.
>
> I notice you use Calcium carbonate to develop. The Riston uses Sodium
> Carbonate. I wonder If this would work on your resist. Sodium
> Carbonate is also known as washing soda and is very cheap. I think I
> paid about $25 for 25 Kilos. The mixture ratio is about 8 teaspoons
> to 4 liters of water (not the least bit critical). 25KG will last
> longer than I will.

The OP must have been wrong about calcium carbonate haveing been supplied. 
It's chalk, and won't dissolve in water. It musr have been sodium carbonate.

Leon

Re: [Homebrew_PCBs] Dry film woes, maybe the developer is at fault

2008-10-11 by VK3YV

Sodium Carbonate also known as Soda Ash used for adjusting swiming pool PH.
Don VK3YV....
Show quoted textHide quoted text
----- Original Message ----- 
From: "leon Heller" <leon355@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, October 11, 2008 8:34 PM
Subject: Re: [Homebrew_PCBs] Dry film woes, maybe the developer is at fault


> ----- Original Message ----- 
> From: "David Hopkins" <davhop@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Saturday, October 11, 2008 3:49 AM
> Subject: [Homebrew_PCBs] Dry film woes, maybe the developer is at fault
>
>
>>I wonder if the resist is anything like the Riston blue -Ve acting
>> dry film. This film is the main one used by the manufactures here.
>> It sounds a lot like it.
>>
>> I have used this resist for many years.
>>
>> The exposure for this film requires a strong UV light source. A
>> standard light would do little in the way of exposing it.
>>
>> I use a 300W mercury vapor street light at about 300mm. This gives an
>> exposure of two minutes. The mercury vapor light produces a fair bit
>> of UV light.
>>
>> With this light source I never have a failure.
>>
>> I notice you use Calcium carbonate to develop. The Riston uses Sodium
>> Carbonate. I wonder If this would work on your resist. Sodium
>> Carbonate is also known as washing soda and is very cheap. I think I
>> paid about $25 for 25 Kilos. The mixture ratio is about 8 teaspoons
>> to 4 liters of water (not the least bit critical). 25KG will last
>> longer than I will.
>
> The OP must have been wrong about calcium carbonate haveing been supplied.
> It's chalk, and won't dissolve in water. It musr have been sodium 
> carbonate.
>
> Leon
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
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>
>
>


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