[Otto Nobedder]

Jeff,

I'd love to hear your thoughts on the homemade dye-penetrant. While Jody talked about it, he didn't demonstrate it.

Steve

[olek]

Hello,

I missed that one, but before finally buying 2 spray for about 25 USD, (and no regrets) , I did have a thread on that subject of "old times crack control "

essentially the penetrant can be red gasoil as we use here for trucks, then 30 minutes later cleaning , and using talcum or any thin white powder with a good absorbtion capacity.

others use oil (for etancheity testing) dripping for 24 hours and using "silk paper" on the other side of the part"s wall .

I do not regret the specific products, they are very precise and allow to see bad "glued" weld ( no penetration)

as I had to file and get rid of all the bad weld until the white spray gives a white surface everywhere (if you leave it for long it
will detect finest cracks or spaces, it really seem to be a very thin powder that is very efficient to attract the dye.)

it should be easy to clean afterthat, due to multiple testing.

the less dye and the less revelation spray are used, the better the results (cleaner reading, easier cleaning)

worth the small price if you want my advice.

best regards

[Otto Nobedder]

Olek,

I use the professional products, specifically the MagnaFlux brand, very often. I'm interested in how the "home-brew" version works, and from what you said, and what Jeff did, it seems quite successful.

Steve

[olek]

it works certainly at an accepteable quality level, (some said they never used the commercial products, but other answered that they are available since 40 years at least

I suspect the size of the particle of the white "reader" spray is what ameliorate the precision.

I use different very thin powders as microfine Teflon, talcum, "diatomite (silicium dioxyde), and the powder of the white spray is really thinner when rubbed between fingers it is surprising (try it if you did not

so better readings probably with the specific products. I am no welder but did discover bad weld on weld joints that I did not see even with a magnifier.
The easy cleaning is probably also an advantage

btw a method was given where a white powder (calcium carbonate) is delayed in water , brushed, let dry. It makes a very thin coating as a "silk paper"

when dry , petroleum is brushed on the other face of the part. if it goes thru it makes very visible stain on the white coat



regards

[Jakedaawg]

exnailpounder Please forgive the stupid question I am about to ask.

Why, in the first place, would someone want to try to repair a merc manifold? They are ~$250 brand new and you dont need to worry about any internal cracks that you can not see? I can understand trying if it was your own time or you are doing it for free. These things only crack for two reasons...serious overheat, or freeze damage. Usually they go bad from sediment build up in the internal space.

[Fly]

I have done many cast iron cracked jobs. I always drill a hole at each end of crack to prevent the crack
from going any farther. I almost always braze them. For cracks in cylinder heads I plug weld them. Never
had a come back in 45 years.

Fly

[olek]

I have done many cast iron cracked jobs. I always drill a hole at each end of crack to prevent the crack
from going any farther. I almost always braze them. For cracks in cylinder heads I plug weld them. Never
had a come back in 45 years.

Fly

Hello do you left open the holes when possible ? It is considered good practice as it release the stress of fatigue crack ? (Grey iron)

When talking PITA is it only aluminium ?