I just can't unsee it !!!!!!!!!!!!!!!

[Qwkynuf]

Originally Posted by DouglasReid

This is precisely correct. By carefully drilling right at the end of the crack you take all the stress that was focused on that TINY point where both halves come together. Those stresses are what causes the crack to run.

By drilling the hole it spreads the stress out in the entire circle of the drilled hole and the crack stops "growing"



The fact you used the term "stop drill" told me you were in aviation in the US Military. Civilians don't seem to use that exact phrase. *S*

When I was an automotive machinist in the '80s, we used that term when doing crack repairs on blocks and cylinder heads. For low pressure, external cracks from the water jacket, we would stop drill both ends, grind out a "V" on the crack itself, and braze. For high pressure cracks - from combustion chamber to water jacket, stop drill both ends, and then "metal stitch" with cast iron or aluminum tapered plugs.

I was the specialist in our shop on this, and repaired *thousands* of cracks this way.

[Hatchee]

Originally Posted by Gmoney67

#3 instead caulk i would get clear epoxy.

^^^^THIS^^^^

[FordHauler]

We do not use silicone on our RV’s because it does not continue to bond due to movement caused by heat/cold, expansion/contraction, traveling, etc.
Tell me why epoxy, which hardens when cured, is a better choice than a clear caulk or Dicor. Will the epoxy hang on through the aforementioned stresses? Inquiring mind!
Travel safe

[mike.t]

How many people googled stop-drill?

[Grisham91402]

Another vote for drilling to stop the run. As for what to fill with that could be a whole topic of its own. Good luck. I certainly understand the anal attentive towards your equipment.

[Bhrava]

Assuming this is a fiberglass laminate skin. #3. Now here's a little trick to get the crack to seal permanently. With a sharp knife, make a very slight V along the entire crack. Wipe the area down good with Alcohol (IPA), run tape on either side of the crack, and get some 30 minute epoxy. Mix up a small batch and with a spreader, if you have an expired credit card or a gift card, perfect spreader. You want to force as much epoxy into the crack this way, then let it cure, and pull the tape off. This will bind both halves of the crack back together and seal it from the weather.

[DouglasReid]

Originally Posted by mike.t

How many people googled stop-drill?

Only those who had NO idea what we were talking about.

[mike.t]

Thanks for your input Douglas.

[hobienick]

Originally Posted by Bhrava

Assuming this is a fiberglass laminate skin. #3. Now here's a little trick to get the crack to seal permanently. With a sharp knife, make a very slight V along the entire crack. Wipe the area down good with Alcohol (IPA), run tape on either side of the crack, and get some 30 minute epoxy. Mix up a small batch and with a spreader, if you have an expired credit card or a gift card, perfect spreader. You want to force as much epoxy into the crack this way, then let it cure, and pull the tape off. This will bind both halves of the crack back together and seal it from the weather.

This, then cover the epoxy with something that blocks UV. Epoxy and UV do not play well together. The epoxy will yellow then break down in a few years opening up the crack again.