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-   -   DIY Fiberglass PCB Strata Construction (http://www.diyaudio.com/forums/parts/240384-diy-fiberglass-pcb-strata-construction.html)

bcmbob 6th August 2013 11:41 AM

DIY Fiberglass PCB Strata Construction
 
****WARNING !!! This process uses strong chemicals that can produce health and safety hazards. The items used are neither fireproof nor flame retardant. The user must consider and assume all risks involved.

As with all DIY projects - SAFETY MUST BE THE FIRST CONSIDERATION.
****


Here is a quick pictorial on DIY PCBs. Once the materials are collected the laminating and clamping process takes less than twenty minutes.

Double waxed paper on flat surface. Some coat it with cooking spray but I haven't found it necessary.

http://origin.dastatic.com/forums/ga..._123230_2_.jpg


For this project I used both woven and bulk pad fabric.

http://origin.dastatic.com/forums/ga..._123246_2_.jpg

http://origin.dastatic.com/forums/ga...804_123627.jpg


Flow an spread some of the resin/hardener mixture on the core. Don't try to make it too uniform on this step as the mat will pull apart and make uneven clogs.

http://origin.dastatic.com/forums/ga...804_124232.jpg

Cover that with a second layer of the woven fabric. Distribute the remainder on the mixture and smooth out with a flat tool. Try to get an even amount on the entire sandwich.

http://origin.dastatic.com/forums/ga...804_124458.jpg


You don't have to be perfect as the next step helps the distribution.

http://origin.dastatic.com/forums/ga...804_124747.jpg


Cover the entire sandwich with another piece of waxed paper and then the top clamping plate.

http://origin.dastatic.com/forums/ga...804_125153.jpg


If you have long reach clamps, start in the middle and work out. If you don't own clamps just place something very heavy on the top - apiece of plywood or metal, a ceramic tile or for perfectionists - a square of marble/granite flooring from your local home improvement store.



After 2 -6 hours, depending how you mixed the resin and hardner - and the thickness - this is what you get.

http://origin.dastatic.com/forums/ga...m/DSC00978.JPG

A little trimming (did mine on an old tile saw) and a uniform, strong product is ready for final smoothing (optional) and sizing. These are 7.5" X 7" and 1.75" X 10".

http://origin.dastatic.com/forums/ga...806_064120.jpg


The thickness can be adjusted by using the desired amount of the matt fabric if you have it. The auto parts stores carry a variety of kits that may or may not include the matting. Several layers of the woven stuff also works well .

http://origin.dastatic.com/forums/ga.../DSC009801.JPG



In the next days I'll continue with the sizing, drilling and finishing of an example PS project,

marce 6th August 2013 12:31 PM

Is it flame retardant? quite important for electrical safety....
I do have to ask whether it is worth the effort, PCB material is not that expensive and the quality is a zillion times better than what you can make at home.

bcmbob 6th August 2013 02:07 PM

It's worth it to someone like me who already has the materials on hand, likes to tinker and is sometimes needing (impatient) a solution sooner than ordering and shipping can provide. Unfortunately it is not flame retardant so it's use is at the risk of the user. I suspect if temps high enough to ignite the fiberglass are present, other components will have failed before that happens. The user/builder must make the proper considerations. Mine have worked well over a long period.

As for cost, half of the $17 kit I bought many years ago was used for auto body patching. With what's left I could make 10 -12 more slabs about the size of those shown above. I'm not claiming this method to be a full on substitute for what is commonly used for PCBs. It's simply info on something that has worked for me when needed.:happy1:

Thanks for pointing out the potential fire hazard. I'll put a disclaimer at the top of the thread. :yes:

debk 6th August 2013 02:36 PM

Have you tried to vacuum bag it, instead of pressing it

debk 6th August 2013 02:38 PM

Did you use regular epoxy of something like West Systems?

bcmbob 6th August 2013 02:54 PM

Vacuum bagging is something I have always been interested in for building speaker cabinets. I haven't tried it yet but it's on my list.

The exact kit I bought is no longer available but this is the base product. Bondo has similar items. I'll take a look at West Systems, but what I have will probably fill my needs for years.

debk 6th August 2013 03:04 PM

for small items like the boards you may be able to use a food saver to do the vacuum bagging. Though you will still need a release film and bleeder layer

bcmbob 6th August 2013 03:06 PM

I have one of those - I'll give it a try.

marce 6th August 2013 04:06 PM

Some more info you may find interesting.
http://www.ieca-inc.com/images/Laminate_Materials.pdf

FR4 is the same as standard GR4 just has flame retardant added, cos some electronics get hot, when they go wrong.
Still think its crazy though:) making your own PCB material. Its pretty much how its made anyway, so a good insight into the real basics of PCB material (car repair kit and copper).:D:D
Now to be really clever you need to do a 3D PCB, shaped to perfectly fit a case, with different levels for the connectors and other bits. Many years ago, they did raise there heads (1990 ish) but never caught on due to the problems of handling and component stuffing for volume. Hand done though would not be a problem.

bcmbob 6th August 2013 04:51 PM

1 Attachment(s)
I actually was considering a multi-layer PS board for my current project yesterday. I needed to elevate the rectifiers to keep their heat snks in the air flow of a cooling fan. But I figured out a way to avoid that. Might try something fancy next time.


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