Testing for Cracks at Home With DIY Dye Penetrants

Story and Photography by Kurt Schley

You are headed into a hard, fast, left turn with a descending radius, and your new suspension setup is undergoing incredible stress on the outboard side. Right now all of your attention should be focused solely on driving. 

Instead, there are several majo…

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Definitely not a bad way to avoid a costly mistake

Many years ago, a friend broke a brake rotor on a Civic–not a fast Civic, either, by modern standards. 

He was at Sebring.

IIRC, he wound up rolling the car. 

So, yeah, some inexpensive preventative maintenance. 

We dye pen check some welds at work.  Our certified weld inspector sprays the dye into a cup and uses a foam brush otherwise we spray it everywhere and it sucks to clean up.   

IIRC from my manufacturing days, dye pen only works on surface cracks, while mag particle (Magnaflux, which is a brand name) can find cracks or voids a little bit under the surface. 

Don't media blast the part before NDT.  Blasting can peen the lips of the crack closed, hiding the anomaly.  The Dye should be all but cleaned up before applying the white powder; red, dwell time, wipe profusely, then clean it again to almost bare looking, then the white to draw the dye out of the hiding spot.  (Certified Level III Mag, Level II Dye Pen and Zyglo, Level I  Eddy Current and X-Ray).

Another edifying article- thanks!  And as usual, much to my continued delight, the carefully copy edited use of the Kings English is punctuated by an oddball crack or two.

In reply to The Staff of Motorsport Marketing :

I'd sure like to know where one can buy a dye penetrant test kit for $30.  Can you give us some leads?  I've had no luck finding a kit for that little.

Thanks!

sakess said:

In reply to The Staff of Motorsport Marketing :

I'd sure like to know where one can buy a dye penetrant test kit for $30.  Can you give us some leads?  I've had no luck finding a kit for that little.

Thanks!

I bought a whole kit from mcmaster-carr for $200 (for work of course).  I see they also sell replacement material, the dye is PN 1383T4 for $24.27 and the developer is PN 1383T5 for $20.23.  A bit over $30 but with Mcmaster you're paying a little more for the convienience.

In reply to 914Driver :

If the part you want to test is painted, should the paint be removed before testing? If so what's the preferred method for pre-test paint removal?

I need  to check a set of Vortec heads that have been overheated. They're high risk for cracking, and $200 for a kit is way more than I can afford to spend. I sure haven't seen any $30 kits.

If anyone has any recommendations or previous experience with specific brands, please share.

Floating Doc (Forum Supporter) said:

I need  to check a set of Vortec heads that have been overheated. They're high risk for cracking, and $200 for a kit is way more than I can afford to spend. I sure haven't seen any $30 kits.

If anyone has any recommendations or previous experience with specific brands, please share.

Piece together a kit from here. It's about $15 a can for penetrant. Cleaner and developer. So about $45 all in. 

As cheap as you're going to get it.https://www.markingpendepot.com/browseproducts/SKC-HF-High-Flash-Cleaner-16-Oz-Aerosol.html

In reply to GaryC83 :

Thanks, that's definitely the cheapest I've seen for a full kit.

In reply to Autobreza :  

Anything but mechanical methods.

The stuff I see coming back from the NAPA shop is pink!  They spray penetrant on, no dwell time and shoot way too much developer on it without wiping.  Watch the video as see the last step, tiny thin coat.  I never use water, just very little alcohol on a paper towel, after all that work do you want to wash the results away?

 

Awesome article. You should setup an Amazon affiliate channel so we can buy this stuff and you get a kickback