Repairing major decoy damage

I had missed picking up a drake teal decoy one day and actally hit it with the motor as I went by.

Mmmmm....a small decoy vs. a propeller on a 60hp motor.....guess what got damaged the most? When I swung around to pick it up the decoy was listing badly to one side with its head in the water.  I thought I had lost a decoy for sure.

However, when I pick it up this is the damage that I found.  It doesn't look that serious, a hole in the bottom and a small crack in the seam where it was originally molded.  This is just a cheap Flambeau decoy and normally I would've just thrown it away, but I thought someone else might have a more expensive decoy with a similar problem that might want to repair it rather than throw it away.  I have the material and experience to do this repair so I thought I would do this page to show how I would repair this type of damage.  


Hopefully you will be able to do the same.





Follow along as I do the repair on this decoy.  You will see it is not difficult and will be able to see how I handle and unexpected problem.


The original plan was to clean and enlarge the damaged area, fill the body cavity with foam, cover the damaged area with new plastic and then give the repaired decoy a float test.  As you will see, there was a little extra work that needed to be done in order to complete the repair.





The first thing to do was to use a Dremel with a high speed cutter to cut the damaged area back to stable plastic.  You can see the the hole has been made considerably larger on the left side.  At this point I also made sure the decoy was dry on the inside in preparation for being filled with foam.



Now it is time to prepare to fill the body with expanding foam.  The first thing to do is coat the entire front half of the decoy with wax.  Wax will keep the foam from sticking to the plastic.  Don't be too light with the wax.  I also applied some wax to the work surface to make clean up easier.


Because the damaged area was in a location that was a little difficult to work with, I opted to build a little clay dam around the hole to help direct the excess foam.  Hopefully this will keep the foam from reaching areas that I do not want it.  This is an extra precaution that is not necessary, but I don't want to take any chances.  Also notice that I use scrap 2x4's to hold the decoy in the position that I want.  In this case there were times that I also put a 1x2 under the tail to help hold it as level as possible.
 


Now comes the fun part of the repair.  No matter how many times I use it, I always enjoy watching the foam expand.

It is now time to get ready to pour the foam.  Always wear latex or vinyl gloves when handling this material.  A well ventilated area is suggested along with goggles.  Try not to get the foam on your skin or clothing. In addition to latex gloves you will also need some dixie cups and something disposable to stir the liquid foam.  I use those craft sticks that can be purchased at many stores.  It is also a good idea to put some newspaper or something that can be thrown away over your work area.


I have always used Smooth-On's FOAM-iT 3 pound rigid foam to fill the body cavities of plastic decoys. This is a 2 part liquid foam, measured 1 to 1 by volume and expands 10 times in volume when cured. The foam is strong enough to prevent the plastic from being easily crushed, but not so dense that it adds a lot of weight to the decoy. I am sure there are other brands of foam that would work just as well.
In order to know how much liquid to use, the volume of the cavity needs to be determined.  I showed how to do this on the first page.  We know that it will take about 1.25 oz of Part A & Part B (2.5 total oz) to make enough foam to fill the cavity.

This picture shows the 2 parts measured out, ready to be mixed and poured.  I use the high tech method of measuring in dixie cups to get the correct amount of foam. This style of dixie cup works best because it is fairly transparent and has many markings on it that can be used for measuring.  Each cup is 3 oz and I filled each one slightly less than half full.  When it comes time to combine them to make foam, I pour the thinner clear liquid into the thicker dark liquid. Don't pour these until you are ready to use them as the dark liquid will begin to leak through the cup after sitting for several minutes.


When you are ready to fill the body with foam, you will need to have everthing set up so you can work quickly.  Mix the liquids together and stir them well for about 15 seconds.  Pour the liquid into the hole in the decoy using the stir stick to get as much as possible out of the container.  Now hold the decoy so the liquid goes to the lowest part of the body, in this case the tail.  It should take about 2 minutes for the foam to expand to the point it is visible through the hole.  At this point put the decoy back on the work surface so it is level and allows the foam to expand into the rest of the body cavity. As the foam expands to fill the cavity it will start to come out of the hole.  Hold the decoy in such a way the excess foam has as little contact with the outside of the decoy as possible.  Let the foam finish expanding, about 3-4 minutes and let it sit for at least an hour before handling it again.  Here is a series of pictures I took while the foam filling this decoy from pouring the foam, rotating the liquid to the tail, the expansion out of the hole and the adjustments I made to the positioning of the decoy to avoid too much contact with the foam and the final position where the foam was allowed to become solid.



   
  

One word of caution about using the foam.  If the weather is warm (over 80 degrees) the working time you have with the foam is substantially reduced.  At room temperatures the working time, the time before the liquid starts turning to foam, may be as long as 1.5 minutes but at 90 degrees or more the working time may be reduced to 45 seconds.  I have poured this foam in a building without air conditioning when it was 100 degrees outside and the total time from mixing the liquids to when the foam stopped expanding was 1 minute 20 seconds.  Believe me, I had to work very quickly to get the results I wanted.
Unexpected Problem !!!!


After the foam has quit expanding and become solid I carefully broke off the excess foam, leaving a small amount outside of the hole to be trimmed off.  When I turn the decoy over I was confronted with an unxpected problem: the crack in the molding line went further back than I had orginally thought and the pressure generated by the expanding foam bulged out the bottom of the decoy.

My first reaction was to throw it away and not worry about it, but then the challenge of fixing this problem too got to me.  So now I have to fix this and complete the original repair.  I decided the best thing to do was proceed with the repair as if there was no problem and see what else is needed to fix the "extra" problem.






With or without the extra problem, the next step is to trim the excess foam.  I used a Dremel and a cutoff wheel to trim it flush with the bottom of the decoy.








Again, with or without the extra problem, the foam needs to be cut back to make room for the hard plastic, Using the same attachment, I made an indentation in the foam to give sufficient thickness to the plastic.  No more than 1/4" is needed for the plastic.







This is the first step I had to take to fix the extra unexpected problem.  The bottom had pushed out beyond what I felt was a reasonable joint for the new and old plastics.  The best thing I could think of to do was to try and lower the existing bottom to flatten the joint area.  Using a high speed cutter on my Dremel, I cut enough foam out from under the bottom that it could be forced down.  I then took an elastic ankle support with a velcro closure and wrapped it around the decoy to hold the bottom in.







This step applies with or without the extra problem.  It is now time to get ready to pour the liquid plastic.  I use a clay dam to give the extra height necessary to get the new plastic above the old.  It can then be filed down to make a smooth joint.







For deep or large repairs in plastic, I like to use a 2 part liquid plastic that will meld with the old to make a water tight repair.  The plastic I use is Smooth-On's Smooth Cast 320 plastic.  It is mixed 1 to 1 by volume and does not expand as it cures.  Once again, I use the high tech dixie cup method for measuring out equal parts of Part A and Part B.  In this case I put about 1/4" in the bottom of each cup.  

When you are ready to pour the plastic, mix the thinner clear liquid into the thicker dark liquid.  Mix them together with a stir stick for about 30 seconds.  Now hold the decoy with one hand and pour the liquid with the other.  Move the decoy as necessary in order to keep the liquid as level as possible and also to fill the area as deep as possible.  You will have to hold the decoy in this position until the plastic has set.  This particular plastic takes approximately 5 minutes for the reaction to start and the liquid begins to change to a solid.  This is something else that I like to watch.  At first the liquid is amber colored, then it begins turn slightly foggy and then it suddenly changes to a white solid.  Very interesting to watch.  The liquid should be solid in about 7 minutes and totally cured in about 10 minutes.  I do like to let it sit for at least an hour before I begin to work with it.

The same precautions regarding heat apply to this 2 part plastic as it does to the 2 part foam.  The hotter the temperature, the shorter the cure time.  I have had this plastic set up hard enough to demold in as little as 5-6 minutes in the middle of a Houston summer.



This is what the decoy looked like after the first layer of plastic was poured.  If the elastic bandage was removed, the bottom would most likely remain in place but I don't want to take any chances so I am going to leave it in place.  Notice how the left side of the bottom is higher than the right and there is still a large drop from the existing bottom to the new plastic.  The only way to fix this is to build a dam high enough that the plastic will fill in the low area and transition smoothly with the existing  plastic.









Here is my solution to this problem.  Using acrylic latex caulk, I built up an area that will hold the liquid plastic high enough to make a level that will make the repair work.  I let this cure for a full day before pouring the plastic.








Here is what it looked like after the second pour of plastic and the caulk has been removed. I used considerably more plastic for the second pour than the first. The heat generated by the chemical reaction when the plastic cured soften the caulk enough that it did not come off in hard pieces.  Instead it was hard on the outside and soft on the inside.  That meant I had to use a cloth and a screwdriver to remove most of the caulk from the edges of the plastic.  Rather than work with a soft caulk possibly still on the plastic, I opted to let it sit overnight and hope it cured again.  Luckily the remaining caulk cured enough that I could file the plastic without any problems from a gummy caulk.






I first used a large wood rasp (actually I used the rasp I use on my horses hooves) to rough shape the plastic as closely as possible to it original configuration.  Then I used a smaller flat file to do the finish filing.  This is how I will leave the bottom of the decoy.  The left side is slightly higher than the right, but it is water tight and will float.








This is another picture of the finished repair of the bottom.













This picture is from further back and from the side of the decoy.  It should be noted that during the course of the repair, the use of the front hole in the keel was lost.  This decoy will always have to be tied using the back hole.  Nothing serious in my opinion.








Here is the repaired decoy in my combination dog bath/decoy test tank/outdoor sink with a drake that has not had any repairs done to it.  The repaired decoy is the one on the left and it floats the same and looks the same as before it needed repairing.  I will dunk the repaired decoy under water several times and look for air bubbles escaping at the place the repair was done.  If there are air bubbles, the plastic did not completely seal to the plastic, water is getting inside and I would have to re-work the repair.

This drake is going to get a new paint job as it is looking a little worse for wear, but that is another subject.
The decoy is repaired!!!!!
The total time it took to repair this decoy, not including the time it takes for the foam, plastic or caulk to cure was about an hour and a half. This includes repairing the unexpected problem.  My estimated cost of the repair was less than $4.00. This type of repair is very a little more difficult to do, but can be done.  The cost of the foam and the plastic in the smallest quantity is about $50.00 so you should have enough damaged decoys to justify buying the material yourself or get together with a few of your hunting buddies and do a group repair.  If you live close to me, let me know how many you have to repair and we can do them together.


I hope you have learned something here and now have the confidence to do your own repairs.  If you have any questions, please feel free to email me at  mucks_ducks@yahoo.com and I will get back to you as quickly as possible.

Thanks for looking!!!!