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Author Topic:   Oil seeping from holes
jking posted 07-07-2002 11:27 PM ET (US)   Profile for jking   Send Email to jking  
While reading about filling screw holes in figreglass I thought of a question no seems to know a answer. In my splash well the owner before me had a oil tank for his outboard mounted with screws. I took the tank out and repaired the screw holes with gel coat and it looked great. Later the patched screw holes started seeping some oil. Before I patched the screw holes I cleaned the holes good but I guess there is still some oil left inside. Any ideas how to get the oil out?
jimh posted 07-08-2002 07:15 AM ET (US)     Profile for jimh  Send Email to jimh     
Are you sure it is oil coming out?

Some people have described the water coming out of their boats as having been dark and stained.

jking posted 07-08-2002 12:27 PM ET (US)     Profile for jking  Send Email to jking     
It did have the appearance of oil. I assumed it was oil because there was some oil under the tank and assumed some made its way in the hull. On one of the holes I used marine tex and then gel coat over that and it still seeped through.
Bigshot posted 07-08-2002 02:16 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
The water can weep red, brown, clear, etc. I have seen some weird stuff weep out of pinholes on Whalers.
jking posted 07-08-2002 11:54 PM ET (US)     Profile for jking  Send Email to jking     
If it is oil can it damage the foam? This is on a 1989 18' Outrage.
Bigshot posted 07-09-2002 10:43 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
I doubt that much oil could do much. Plus how are you gonna do anything about it anyway?
jking posted 07-09-2002 11:04 PM ET (US)     Profile for jking  Send Email to jking     
Thanks for the info!!... I guess I will try to clean them better and try again to gel coat over them.


Cpt Quint posted 07-10-2002 09:45 AM ET (US)     Profile for Cpt Quint  Send Email to Cpt Quint     
Jking, wait a minute. If the holes in question are truely above the waterline/and above the deck where water may normally sits up, I would suggest a patch or tape over when in use but not a permenant repair just yet. If moisture is trying to get out, let it. I would wipe and watch for a couple months and wait for it to dry out before making the final repair/ If you gelcoat over the moisture will only push through.
jking posted 07-10-2002 11:04 PM ET (US)     Profile for jking  Send Email to jking     
Thanks Cpt Q!
That sounds like a good idea. I think that is what I will do.
Plus it's time to go fishing.......


Tom W Clark posted 07-11-2002 10:02 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

I also doubt there is oil coming out of those holes. Just because they are where the oil tank was doesn't haven't anything to do with oil getting in there.

The splashwell in an Outrage 18 is very wet. If those holes were not well sealed originally then water has probably gotten into the hull.

The repairs might not be holding up to well because of oily films being on the surrounding fiberglass. The splashwell typically gets a lot of backwash from the motors exhaust and drippings from the motor itself when it's tilted up. If water with a little oil on it were soaking the holes for a long time then it could be the foam and glass is a little oily.

When you patched the holes did you drill them out over size to get to clean 'glass? You might try doing this now.

You could also try sucking any water out of the immediate area of the repair with a vacuum before repairing again.

Another technique suggested by DIVE 1 is to use some calcium chloride to draw out the water. Calcium chloride is sold as "No Damp" or "Dri-Z-Air" dehumidifiers as well as as a concrete additive. A small pack costs a couple of bucks.

Tape plastic over the calcium chloride that you put on top of the repair area and let the calcium chloride draw the water/oil out of the holes/foam.

DIVE 1 claims that he did an experiment that demonstrated calcium chloride could pull oil through the hull of a fiberglass boat. I find this a bit hard to believe but his posts are in the CSW thread. Wouldn't cost much to try at any rate.

Tom W Clark posted 07-11-2002 10:13 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Here's the pertinent quote from DIVE 1:


I usually get calcium chloride from the local marinas. It looks like crushed rock salt. When you are finished with it you throw it away. A lot of the marinas use it to help dry balsa cored boats prior to patching repairs. We tried an experiment with oil and calcium chloride. Taking a piece of a fiberglass hull that was shaped like a bowl(chine and transom corner), we ground the inside with a 24-grit disc making it very rough. After cleaning we rubbed 2-cycle oil in the bottom of the bowl. We then added acetone to cover the oil and quickly covered the top of the bowl with Saran wrap and taped the edges airtight. On the bottom of the bowl we made the calcium chloride tent and let it set for several days. The oil was drawn through the fiberglass and gel coat by the calcium chloride. This experiment was tried to determine if we could remove oil that was impregnated into fiberglass so that a decent repair could be accomplished. How do you effectively repair the bottom of a conventional fiberglass hull(non-cored hull) that has had engine oil absorbed into the fiberglass? If the oil is not removed the patch will not adhere very well to the original fiberglass.


DIVE 1 posted 07-11-2002 09:39 PM ET (US)     Profile for DIVE 1    
I think the success of the test was due to adding acetone to the inside of the bowl. The calcium chloride drew the acetone through the glass and as it diluted the oil, it came along for the ride.
blackdog posted 07-12-2002 11:24 AM ET (US)     Profile for blackdog  Send Email to blackdog     
I am probaly wrong but is that the same as Ice melt?
ShrimpBurrito posted 07-13-2002 08:43 PM ET (US)     Profile for ShrimpBurrito  Send Email to ShrimpBurrito     
Not sure if the "ice melt" you are referring to is a trade name, but generally, the stuff that you buy at the store to melt the ice on your sidewalks is calcium chloride. Comes as small white pellets.
blackdog posted 07-15-2002 08:17 AM ET (US)     Profile for blackdog  Send Email to blackdog     
Yes, same stuff

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