Crack check parts

I dont mean look for drugs or bending over to kiss yourown butt. this is a way to check brackets, heads and castings for cracks before you sink money into it or have a failure while enjoying your ride.

All you need is a yellow fluorescent markers [hiliters, the cheaper the better, dollar store ones with the clear reservoir are perfect], a CFL Blacklight bulb, brake cleaner spray or alcohol [rubbing NOT vodka or rum] and a black permanent marker. Also somewhere that you can make dark to see the results under the blacklight. You have to bust open the highliter so get a couple and a shot glass or something to pour the dye into from the opened highliter.

If the dye is thicker then water then you need to thin out the dye a little unless it is a really really cheap hilighter

First you need to check if the hilighter is water or oil base dye wet a spot on the back of your hand with water and dab it with the highlighter water base will just colour the wet spot, oil base will mark your hand without colouring the water

Thin water base hilighter with a little water, oil base can be thinned with a little clear varsol or kerosene the really really cheap ones at the dollar store are 3 or 4 for a buck, water base and thin dye - perfect!

Remove the part or casting that needs checking.

Clean the heck out of it with brake cleaner spray or alcohol so there is zero oil on it.

Let the part dry well.

Place it so the surface to be checked is horizontal.

Pour the hilighter dye onto the surface to be checked.

Wait a couple of minutes.

Turn on the blacklight and turn off the regular lights.

If there are any cracks the thin dye would have found them and will hilight the cracks because it will seep into the cracks.

If it is a casting or bracket that you intend to repair then you can trace over the crack with the black permanent marker so you can see it in normal light.

Hope that helps some of you making viscious mods to mopeds. specially sexy mobys!

Re: Crack check parts

Thanks WariSesi. Very useful information for anyone wanted to know. This is a pretty standard technique in engine rebuilding but one of those secret things that they won't tell you about. There are other ways to check for cracks: magnafluxing (which really only works for cast iron and steel parts), pressure testing (for inside passages that cannot be looked at directly), and x-ray (very expensive but used regularly in manufacturing when welding structural parts)

Re: Crack check parts

el-cheapo magnafluxing, totally bitchin', never heard of that technique before.

Re: Crack check parts

I've done it with the professional dye, but with what they charge for the can of flouresent spray, I'm going the highlighter route.

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